WorldWideScience

Sample records for chromatography-electrospray ionization-tandem mass

  1. Specific determination of 20 primary aromatic amines in aqueous food simulants by liquid chromatography-electrospray ionization-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Mortensen, Sarah Kelly; Trier, Xenia Thorsager; Foverskov, Annie;

    2005-01-01

    A multi-analyte method without any pre-treatment steps using reversed-phase liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) was developed and applied for the determination of 20 primary aromatic amines (PAA) associated with polyurethane (PUR) products or azo...

  2. Identification of forced degradation products of tamsulosin using liquid chromatography/electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Namdev, Deepak; Borkar, Roshan M; Raju, B; Kalariya, Pradipbhai D; Rahangdale, Vinodkumar T; Gananadhamu, S; Srinivas, R

    2014-01-01

    A rapid and gradient high-performance liquid chromatography combined with quadrupole time-of-flight electrospray ionization tandem mass spectrometry (LC/Q-TOF-ESI-MS/MS) method has been developed for the identification and structural characterization of stressed degradation products of tamsulosin. Tamsulosin, a selective α1-adrenoceptor antagonist, was subjected to forced degradation studies under hydrolytic (acid, base and neutral), oxidative, photolytic and thermal stress conditions as per ICH guidelines Q1A (R2). The drug degraded significantly under hydrolytic (base and neutral), thermal, oxidative and photolytic conditions, while it was stable to acid hydrolytic stress conditions. A total of twelve degradation products were formed and the chromatographic separation of the drug and its degradation products were achieved on a GRACE C-18 column (250mm×4.6mm, 5μm). All the degradants have been identified and characterized by LC/ESI-MS/MS and accurate mass measurements. To elucidate the structures of degradation products, fragmentation of the [M+H](+) ions of tamsulosin and its degradation products was studied by using LC-MS/MS experiments combined with accurate mass measurements. The product ions of all the protonated degradation products were compared with the product ions of protonated tamsulosin to assign most probable structures for the observed degradation products. PMID:24083958

  3. Chemical Investigation of Saponins in Different Parts of Panax notoginseng by Pressurized Liquid Extraction and Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry

    OpenAIRE

    Si-Jia Hong; Peng Li; Yi-Tao Wang; Shao-Ping Li; Qing-Wen Zhang; Jian-Bo Wan

    2012-01-01

    A pressurized liquid extraction (PLE) and high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) method was developed for the qualitative determination of saponins in different parts of P. notoginseng, including rhizome, root, fibre root, seed, stem, leaf and flower. The samples were extracted using PLE. The analysis was achieved on a Zorbax SB-C18 column with gradient elution of acetonitrile and 8 mM aqueous ammonium acet...

  4. Determination of benzotriazole corrosion inhibitors from aqueous environmental samples by liquid chromatography-electrospray ionization-tandem mass spectrometry.

    Science.gov (United States)

    Weiss, Stefan; Reemtsma, Thorsten

    2005-11-15

    The first method for the determination of commonly used corrosion inhibitors in environmental water samples by liquid chromatography-electrospray ionization-tandem mass spectrometry is presented. Benzotriazole (BTri) and the two isomers of tolyltriazole (5- and 4-TTri) are separated in an isocratic run. By gradient elution, BTri, 4-TTri, 5-TTri, and xylyltriazole can be determined simultaneously with three benzothiazoles, but here TTri isomers coelute. The instrumental detection limit of 2 pg allows the determination of the three most important benzotriazoles from municipal wastewater and most surface waters by direct injection into the HPLC system without previous enrichment. When solid-phase extraction is employed with mean recovery rates of 95-113%, the limit of quantification for benzotriazoles range from 10 ng/L in groundwater to 25 ng/L in untreated wastewater. BTri and TTri were determined in municipal wastewater in microgram per liter concentrations. Elimination in wastewater treatment appears to be poor, and BTri and TTri can be followed through a water cycle from treated municipal wastewater through surface water to bank filtrate used for drinking water production. The TTri isomers show markedly different biodegradation behavior with 4-TTri being more stable. PMID:16285694

  5. Development and comparison of two multiresidue methods for the analysis of 17 mycotoxins in cereals by liquid chromatography electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Desmarchelier, Aurelien; Oberson, Jean-Marie; Tella, Patricia; Gremaud, Eric; Seefelder, Walburga; Mottier, Pascal

    2010-07-14

    Two multiresidue methods based on different extraction procedures have been developed and compared for the liquid chromatography electrospray ionization tandem mass spectrometry analysis of 17 mycotoxins including ochratoxin A, aflatoxins (B(1), B(2), G(1), and G(2)), zearalenone, fumonisins (B(1) and B(2)), T-2 toxin, HT-2 toxin, nivalenol, deoxynivalenol, 3- and 15-acetyldeoxynivalenol, fusarenon-X, diacetoxyscirpenol, and neosolaniol in cereal-based commodities. The extraction procedures considered were a QuEChERS-like method and one using accelerated solvent extraction (ASE). Both extraction procedures gave similar performances in terms of linearity (r(2) > 0.98) and precision (both RSD(r) and RSD(iR) sample throughput as compared to the ASE method. PMID:20527950

  6. Characterization and identification of iridoid glucosides, flavonoids and anthraquinones in Hedyotis diffusa by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Liu, E-Hu; Zhou, Ting; Li, Guo-Bin; Li, Jing; Huang, Xiu-Ning; Pan, Feng; Gao, Ning

    2012-01-01

    The multiple bioactive constituents in Hedyotis diffusa Willd. (H. diffusa) were extracted and characterized by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC-ESI-MS(n)). The optimized separation condition was obtained using an Agilent ZorBax SB-C18 column (4.6×150 mm, 5 μm) and gradient elution with water (containing 0.1% formic acid) and acetonitrile (containing 0.1% formic acid), under which baseline separation for the majority of compounds was achieved. Among the compounds detected, 14 iridoid glucosides, 10 flavonoids, 7 anthraquinones, 1 coumarin and 1 triterpene were unambiguously identified or tentatively characterized based on their retention times and mass spectra in comparison with the data from standards or references. The fragmentation behavior for different types of constituents was also investigated, which could contribute to the elucidation of these constituents in H. diffusa. The present study reveals that even more iridoid glycosides were found in H. diffusa than hitherto assumed. The occurrence of two iridoid glucosides and five flavonoids in particular has not yet been described. This paper marks the first report on the structural characterization of chemical compounds in H. diffusa by a developed HPLC-ESI-MS(n) method. PMID:25940590

  7. Chemical Investigation of Saponins in Different Parts of Panax notoginseng by Pressurized Liquid Extraction and Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Si-Jia Hong

    2012-05-01

    Full Text Available A pressurized liquid extraction (PLE and high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS method was developed for the qualitative determination of saponins in different parts of P. notoginseng, including rhizome, root, fibre root, seed, stem, leaf and flower. The samples were extracted using PLE. The analysis was achieved on a Zorbax SB-C18 column with gradient elution of acetonitrile and 8 mM aqueous ammonium acetate as mobile phase. The mass spectrometer was operated in the negative ion mode using the electrospray ionization, and a collision induced dissociation (CID experiment was also carried out to aid the identification of compounds. Forty one saponins were identified in different parts of P. notoginseng according to the fragmentation patterns and literature reports, among them, 21 saponins were confirmed by comparing the retention time and ESI-MS data with those of standard compounds. The results showed that the chemical characteristics were obviously diverse in different parts of P. notoginseng, which is helpful for pharmacological evaluation and quality control of P. notoginseng.

  8. Investigation of natural phosphatidylcholine sources: separation and identification by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS2) of molecular species.

    Science.gov (United States)

    Le Grandois, Julie; Marchioni, Eric; Zhao, Minjie; Giuffrida, Francesca; Ennahar, Saïd; Bindler, Françoise

    2009-07-22

    This study is a contribution to the exploration of natural phospholipid (PL) sources rich in long-chain polyunsaturated fatty acids (LC-PUFAs) with nutritional interest. Phosphatidylcholines (PCs) were purified from total lipid extracts of different food matrices, and their molecular species were separated and identified by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS(2)). Fragmentation of lithiated adducts allowed for the identification of fatty acids linked to the glycerol backbone. Soy PC was particularly rich in species containing essential fatty acids, such as (18:2-18:2)PC (34.0%), (16:0-18:2)PC (20.8%), and (18:1-18:2)PC (16.3%). PC from animal sources (ox liver and egg yolk) contained major molecular species, such as (16:0-18:2)PC, (16:0-18:1)PC, (18:0-18:2)PC, or (18:0-18:1)PC. Finally, marine source (krill oil), which was particularly rich in (16:0-20:5)PC and (16:0-22:6)PC, appeared to be an interesting potential source for food supplementation with LC-PUFA-PLs, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). PMID:19545117

  9. Determination of selected antibiotics in the Victoria Harbour and the Pearl River, South China using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Xu Weihai [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, Guangzhou 510640 (China); School of Chemistry and Chemical Engineering, Zhongshan University, Guangzhou 510250 (China); Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Post-graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Zhang Gan [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, Guangzhou 510640 (China)]. E-mail: zhanggan@gig.ac.cn; Zou Shichun [School of Chemistry and Chemical Engineering, Zhongshan University, Guangzhou 510250 (China); Li Xiangdong [Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Liu Yuchun [School of Chemistry and Chemical Engineering, Zhongshan University, Guangzhou 510250 (China)

    2007-02-15

    Nine selected antibiotics in the Victoria Harbour of Hong Kong and the Pearl River at Guangzhou, South China, were analyzed using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry. The results showed that the concentrations of antibiotics were mainly below the limit of quantification (LOQ) in the marine water of Victoria Harbour. However, except for amoxicillin, all of the antibiotics were detected in the Pearl River during high and low water seasons with the median concentrations ranging from 11 to 67 ng/L, and from 66 to 460 ng/L, respectively; and the concentrations in early spring were about 2-15 times higher than that in summer with clearer diurnal variations. It was suggested that the concentrations of antibiotics in the high water season were more affected by wastewater production cycles due to quick refreshing rate, while those in the low water season may be more sensitive to the water column dynamics controlled by tidal processes in the river. - Antibiotics were found at high concentrations in an urban reach of Pearl River in southern China with contrast diurnal variations between the high and low water seasons.

  10. Determination of selected antibiotics in the Victoria Harbour and the Pearl River, South China using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry

    International Nuclear Information System (INIS)

    Nine selected antibiotics in the Victoria Harbour of Hong Kong and the Pearl River at Guangzhou, South China, were analyzed using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry. The results showed that the concentrations of antibiotics were mainly below the limit of quantification (LOQ) in the marine water of Victoria Harbour. However, except for amoxicillin, all of the antibiotics were detected in the Pearl River during high and low water seasons with the median concentrations ranging from 11 to 67 ng/L, and from 66 to 460 ng/L, respectively; and the concentrations in early spring were about 2-15 times higher than that in summer with clearer diurnal variations. It was suggested that the concentrations of antibiotics in the high water season were more affected by wastewater production cycles due to quick refreshing rate, while those in the low water season may be more sensitive to the water column dynamics controlled by tidal processes in the river. - Antibiotics were found at high concentrations in an urban reach of Pearl River in southern China with contrast diurnal variations between the high and low water seasons

  11. Analysis by liquid chromatography-electrospray ionization tandem mass spectrometry and acute toxicity evaluation for beta-blockers and lipid-regulating agents in wastewater samples.

    Science.gov (United States)

    Hernando, M D; Petrovic, M; Fernández-Alba, A R; Barceló, D

    2004-08-13

    This paper describes a multiresidue method for the extraction and determination of two therapeutic groups of pharmaceuticals, lipid-regulating agents (clofibric acid, bezafibrate, gemfibrocil, fenofibrate) and beta-blockers (atenolol, sotalol, metoprolol, betaxolol) in waters by solid-phase extraction followed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS). Recoveries obtained from spiked HPLC water, as well as, from spiked real samples (sewage treatment plants influent and effluents, river and tap water) were all above 60%, with the exception of betaxolol with a 52% recovery. The quantitative MS analysis was performed using a multiple reaction monitoring. The LC-MS-MS method gave detection limits ranging from 0.017 to 1.25 microg/l in spiked effluent. Precision of the method, calculated as relative standard deviation, ranged from 3.7 to 18.5%. Individual and combined effects on Daphnia magna were evaluated for both therapeutic groups. Individual effects in culture medium showed these compounds as not harmful and not toxic, an exception is fenofibrate that was found to be harmful, but at high, in the environment unrealistic concentrations (EC50 of 50 mg/l). Combined effect in wastewater showed synergistic toxic effects at low concentration level (2 microg/l). PMID:15387181

  12. Liquid Chromatography-electrospray Ionization Tandem Mass Spectrometry for Simultaneous Determination of Metformin and Glimepiride in Beagle Dog Plasma and Bioequivalence Study

    Institute of Scientific and Technical Information of China (English)

    BAI Jing; SHI Xiao-wei; DU Ying-feng; XIANG Bai; WANG Shuai; CAO De-ying

    2012-01-01

    A sensitive and selective liquid chromatography-electrospray ionization tandem mass spectrometry(LC-ESI-MS/MS) was used for the simultaneous determination of metformin and glimepiride in beagle dog plasma with glipizide as internal standard(IS).After simplified protein precipitation with methanol,both the analytes and IS were chromatographed on a Zorbax CN column via gradient elution with methanol(containing 5 mmol/L ammonium acetate) and 5 mmol/L aqueous ammonium acetate as the mobile phase.Detection was performed by multiple reaction monitoring(MRM) scanning via ESI source operated in positive ionization mode.Specificity,linearity,accuracy,precision,recovery,matrix effect and stability were validated for metformin and glimepiride in beagle dog plasma.The calibration curves were linear in a concentration range of 10--10000 ng/mL for metformin and 4--4000 ng/mL for glimepiride with both correlation coefficients higher than 0.99.The recoveries obtained for the analytes and IS were all between 82.7% and 101.2%.The method exhibited excellent performance in terms of selectivity,robustness,short analytical time and simplicity of sample preparation.Finally,the proposed method was applied to a bioequivalence study of self-made bilayer tablet and commercial formulation containing 500 mg of metformin and 1 mg of glimepiride in beagle dogs.

  13. Simultaneous determination of 13 quinolones in eggs using column high-performance liquid chromatography/electrospray ionization-tandem mass spectrometry and depletion of pefloxacin methanesulfonate in eggs.

    Science.gov (United States)

    Shen, Jianzhong; Li, Haiyan; Jiang, Haiyang; Zhou, Degang; Xu, Fei; Li, Jiancheng; Ding, Shuangyang

    2008-01-01

    An efficient method was developed for simultaneous determination of 13 quinolones--namely, enoaxacin (ENO), marbofloxacin (MAR), ciprofloxacin (CIP), norfloxacin (NOR), ofloxacin (OFL), pefloxacin methanesulfonate (PEF), danofloxacin (DAN), enrofloxacin (ENR), lomefloxacin (LOM), difloxacin (DIF), sarafloxacin (SAR), oxolinic acid (OXO), and flumequine (FLU)--in eggs by column liquid chromatography/electrospray ionization-tandem mass spectrometry. Samples were extracted with a phosphoric acid-phosphate buffer followed by purification with a solid-phase extraction cartridge. Recoveries for the 13 quinolones were 67-93% with intraday and interday coefficients of variation ranging from 4 to 9% and 2 to 18%, respectively. The limit of determination was 0.05 microg/kg for OXO and FLU; 0.1 microg/kg for MAR, OFL, CIP, LOM, DAN, SAR, DIF, NOR, and ENR; and 0.2 microg/kg for ENO and PEF. The method was also applied to study the depletion of PEF in eggs. The concentration of PEF increased and reached a maximum value on the third day, and then decreased rapidly until it could not be detected on day 32; its metabolite NOR was detectable on the second day, and then reached a maximum on the sixth day, after which it could not be detected until day 15. PMID:19202815

  14. Simultaneous Determination of Eight Ginsenosides in Rat Plasma by Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry: Application to Their Pharmacokinetics.

    Science.gov (United States)

    Ma, Li-Yuan; Zhang, You-Bo; Zhou, Qi-Le; Yang, Yan-Fang; Yang, Xiu-Wei

    2015-01-01

    A high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method was successfully developed and validated for the identification and determination of eight ginsenosides: ginsenoside Rg₁ (1); 20(S)-ginsenoside Rh₁ (2); 20(S)-ginsenoside Rg₂ (3); 20(R)-ginsenoside Rh₁ (4); 20(R)-ginsenoside Rg₂ (5); ginsenoside Rd (6); 20(S)-ginsenoside Rg₃ (7); and 20(R)-ginsenoside Rg₃ (8) in rat plasma. The established rapid method had high linearity, selectivity, sensitivity, accuracy, and precision. The method has been used successfully to study the pharmacokinetics of abovementioned eight ginsenosides for the first time. After an oral administration of total saponins in the stems-leaves of Panax ginseng C. A. Meyer (GTSSL) at a dose of 400 mg/kg, the ginsenosides 6, 7, and 8, belonging to protopanaxadiol-type saponins, exhibited relatively long tmax values, suggesting that they were slowly absorbed, while the ginsenosides 1-5, belonging to protopanaxatriol-type saponins, had different tmax values, which should be due to their differences in the substituted groups. Compounds 2 and 4, 3 and 5, 7 and 8 were three pairs of R/S epimerics at C-20, which was interesting that the t1/2 of 20(S)-epimers were always longer than those of 20(R)-epimers. This pharmacokinetic identification of multiple ginsenosides of GTSSL in rat plasma provides a significant basis for better understanding the clinical application of GTSSL. PMID:26633350

  15. Identification of glycerophospholipid molecular species of mussel (Mytilus edulis) lipids by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry.

    Science.gov (United States)

    Yin, Fa-Wen; Zhou, Da-Yong; Zhao, Qi; Liu, Zhong-Yuan; Hu, Xiao-Pei; Liu, Yan-Fei; Song, Liang; Zhou, Xin; Qin, Lei; Zhu, Bei-Wei; Shahidi, Fereidoon

    2016-12-15

    This study was carried out to identify the glycerophosphocholine (GPCho), glycerophosphoethanolamine (GPEtn) and glycerophosphoserine (GPSer) compositions in lipids extracted from mussels using Folch, Bligh-Dyer and methyl-tert-butyl ether (MTBE) methods by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS). The molecular species of GPCho, GPEtn and GPSer were characterized according to the MS and MS/MS information. A semi-quantitative method using internal standard was established to compare the difference in glycerophospholipids (GP) between samples recovered with different methods. At least 212, 230 and 206 GP species were identified, respectively, from lipids recovered by Folch, Bligh-Dyer and MTBE methods. Most of the abundant GP species in mussels contained EPA and DHA. Some GP species with low content were not present in lipids recovered by the Folch and MTBE methods when compared with that recovered by the Bligh-Dyer method. However, for most GP species in lipids recovered by different methods, no quantitative differences existed. PMID:27451190

  16. Diclofenac in municipal wastewater treatment plant: quantification using laser diode thermal desorption--atmospheric pressure chemical ionization--tandem mass spectrometry approach in comparison with an established liquid chromatography-electrospray ionization-tandem mass spectrometry method.

    Science.gov (United States)

    Lonappan, Linson; Pulicharla, Rama; Rouissi, Tarek; Brar, Satinder K; Verma, Mausam; Surampalli, Rao Y; Valero, José R

    2016-02-12

    Diclofenac (DCF), a prevalent non-steroidal anti-inflammatory drug (NSAID) is often detected in wastewater and surface water. Analysis of the pharmaceuticals in complex matrices is often laden with challenges. In this study a reliable, rapid and sensitive method based on laser diode thermal desorption/atmospheric pressure chemical ionization (LDTD/APCI) coupled with tandem mass spectrometry (MS/MS) has been developed for the quantification of DCF in wastewater and wastewater sludge. An established conventional LC-ESI-MS/MS (liquid chromatography-electrospray ionization-tandem mass spectrometry) method was compared with LDTD-APCI-MS/MS approach. The newly developed LDTD-APCI-MS/MS method reduced the analysis time to 12s in lieu of 12 min for LC-ESI-MS/MS method. The method detection limits for LDTD-APCI-MS/MS method were found to be 270 ng L(-1) (LOD) and 1000 ng L(-1) (LOQ). Furthermore, two extraction procedures, ultrasonic assisted extraction (USE) and accelerated solvent extraction (ASE) for the extraction of DCF from wastewater sludge were compared and ASE with 95.6 ± 7% recovery was effective over USE with 86 ± 4% recovery. The fate and partitioning of DCF in wastewater (WW) and wastewater sludge (WWS) in wastewater treatment plant was also monitored at various stages of treatment in Quebec Urban community wastewater treatment plant. DCF exhibited affinity towards WW than WWS with a presence about 60% of DCF in WW in contrary with theoretical prediction (LogKow=4.51). PMID:26805597

  17. Liquid chromatography-electrospray ionization-tandem mass spectrometry for simultaneous analysis of chlorogenic acids and their metabolites in human plasma.

    Science.gov (United States)

    Matsui, Yuji; Nakamura, Shun; Kondou, Naoki; Takasu, Yoshio; Ochiai, Ryuji; Masukawa, Yoshinori

    2007-10-15

    A method using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) was developed for the simultaneous analysis of nine chlorogenic acids (CGAs), three isomers each of caffeoylquinic acids (CQAs), feruloylquinic acids (FQAs) and dicaffeoylquinic acids (dCQAs), and their two metabolites, caffeic acid (CA) and ferulic acid (FA), in human plasma. In simultaneous multiple reaction monitoring (MRM) measurements using ESI-MS/MS with a negative ion mode, a deprotonated molecular ion derived from each of the 11 molecules was used as a precursor ion while three diagnostic product ions characteristic for each were selected for the qualitative analysis. To obtain maximal intensities for all diagnostic product ions, the collision energy was optimized for each one. LC separation was achieved under conditions of a reversed-phase Inertsil ODS-2 column combined with a gradient elution system using 50mM acetic acid with 3% acetonitrile aqueous solution and 50 mM acetic acid with 100% acetonitrile. In the quantitative analysis, one of the three diagnostic product ions for each of the 11 molecules was selected. Application of simultaneous LC-ESI-MS/MS MRM measurements to analyze the 11 standards spiked into blank human plasma indicated that all diagnostic product ions were detected without any interference, and that the sensitivity, linearity and recovery of this method were acceptable. When using this method to analyze those 11 molecules in the plasma after oral ingestion of 250 ml of a drink containing a green coffee bean extract (300 mg CGAs), all 11 molecules were identified and CQAs, FQAs and FA were quantified. CQAs, FQAs and dCQAs in human plasma were detected for the first time. This method should be useful to understand the biological and pharmacological effects of CGAs, such as improvement of human hypertension. PMID:17766198

  18. Study on oligosaccharide composition of wort and beer samples by liquid chromatography/electrospray ionization tandem mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Čmelík, Richard; Berkecz, R.; Janáky, T.; Bobálová, Janette

    Olomouc : Faculty of Science, Palacký University Olomouc, 2010 - (Maier, V.), s. 56-57 ISBN 978-80-244-2470-5. - (CHEMICA 47S). [Advances in Chromatography and Electrophoresis & Chiranal 2010. Olomouc (CZ), 08.02.2010-11.02.2010] R&D Projects: GA MŠk 2B06037; GA MŠk MEB040807 Institutional research plan: CEZ:AV0Z40310501 Keywords : HPLC * mass spectrometry * brewing Subject RIV: CB - Analytical Chemistry, Separation

  19. Differential Isotope Labeling of 38 Dietary Polyphenols and Their Quantification in Urine by Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometry.

    Science.gov (United States)

    Achaintre, David; Buleté, Audrey; Cren-Olivé, Cécile; Li, Liang; Rinaldi, Sabina; Scalbert, Augustin

    2016-03-01

    A large number of polyphenols are consumed with the diet and may contribute to the prevention of chronic diseases such as cardiovascular diseases, diabetes, cancers, and neurodegenerative diseases. More comprehensive methods are needed to measure exposure to this complex family of bioactive plant compounds in epidemiological studies. We report here a novel method enabling the simultaneous measurement in urine of 38 polyphenols representative of the main classes and subclasses found in the diet. This method is based on differential (12)C-/(13)C-isotope labeling of polyphenols through derivatization with isotopic dansyl chloride reagents and on the analysis of the labeled polyphenols by tandem mass spectrometry. This derivatization approach overcomes the need for costly labeled standards. Different conditions for enzyme hydrolysis of polyphenol glucuronides and sulfate esters, extraction, and dansylation of unconjugated aglycones were tested and optimized. Limits of quantification varied from 0.01 to 1.1 μM depending on polyphenols. Intrabatch coefficients of variation varied between 3.9% and 9.6%. Interbatch variations were lower than 15% for 31 compounds and lower than 29% for 6 additional polyphenols out of the 38 tested. Thirty seven polyphenols were validated and then analyzed in 475, 24 h urine samples from the European Prospective Investigation on Cancer and Nutrition (EPIC) study. Thirty four polyphenols could be detected and successfully estimated and showed large interindividual variations of concentrations (2-3 orders of magnitude depending on the compound), with median concentrations spanning from 0.01 to over 1000 μM for all 34 compounds. PMID:26814424

  20. Identification of glyceollin metabolites derived from conjugation with glutathione and glucuronic acid in rats by on-line liquid chromatography-electrospray ionization tandem mass spectrometry

    Science.gov (United States)

    Glyceollin-related metabolites produced in rats following oral glyceollin administration were screened and identified by precursor and product ion scanning using liquid chromatography, coupled on-line with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS), to identify all glyceollin me...

  1. Determination of phosphatidylethanolamine molecular species in various food matrices by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS2).

    Science.gov (United States)

    Zhou, Li; Zhao, Minjie; Ennahar, Saïd; Bindler, Françoise; Marchioni, Eric

    2012-04-01

    A liquid chromatographic-electrospray ionization-tandem mass spectrometric (LC-ESI-MS(2)) method has been developed for determination of the molecular species of phosphatidylethanolamine (PE) in four food matrices (soy, egg yolk, ox liver, and krill oil). The extraction and purification method consisted of a pressurized liquid extraction procedure for total lipid (TL) extraction, purification of phospholipids (PLs) by adsorption on a silica gel column, and separation of PL classes by semi-preparative normal-phase HPLC. Separation and identification of PE molecular species were performed by reversed-phase HPLC coupled with electrospray ionization tandem mass spectrometry (ESI-MS(2)). Methanol containing 5 mmol L(-1) ammonium formate was used as the mobile phase. A variety of PE molecular species were detected in the four food matrices. (C16:0-C18:2)PE, (C18:2-C18:2)PE, and (C16:0-C18:1)PE were the major PE molecular species in soy. Egg yolk PE contained (C16:0-C18:1)PE, (C18:0-C18:1)PE, (C18:0-C18:2)PE, and (C16:0-C18:2)PE as the major molecular species. Ox liver PE was rich in the species (C18:0-C18:1)PE, (C18:0-C20:4)PE, and (C18:0-C18:2)PE. Finally, krill oil which was particularly rich in (C16:0(alkyl)-C22:6(acyl))plasmanylethanolamine (PakE), (C16:0-C22:6)PE, and (C16:0-C20:5)PE, seemed to be an interesting potential source for supplementation of food with eicosapentaenoic acid and docosahexaenoic acid. PMID:22349329

  2. A simple and selective method for determination of phthalate biomarkers in vegetable samples by high pressure liquid chromatography-electrospray ionization-tandem mass spectrometry.

    Science.gov (United States)

    Zhou, Xi; Cui, Kunyan; Zeng, Feng; Li, Shoucong; Zeng, Zunxiang

    2016-06-01

    In the present study, solid-phase extraction cartridges including silica reversed-phase Isolute C18, polymeric reversed-phase Oasis HLB and mixed-mode anion-exchange Oasis MAX, and liquid-liquid extractions with ethyl acetate, n-hexane, dichloromethane and its mixtures were compared for clean-up of phthalate monoesters from vegetable samples. Best recoveries and minimised matrix effects were achieved using ethyl acetate/n-hexane liquid-liquid extraction for these target compounds. A simple and selective method, based on sample preparation by ultrasonic extraction and liquid-liquid extraction clean-up, for the determination of phthalate monoesters in vegetable samples by liquid chromatography/electrospray ionisation-tandem mass spectrometry was developed. The method detection limits for phthalate monoesters ranged from 0.013 to 0.120ngg(-1). Good linearity (r(2)>0.991) between MQLs and 1000× MQLs was achieved. The intra- and inter-day relative standard deviation values were less than 11.8%. The method was successfully used to determine phthalate monoester metabolites in the vegetable samples. PMID:26830597

  3. Precolumn derivatization reagents for high-speed analysis of amines and amino acids in biological fluid using liquid chromatography/electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Shimbo, Kazutaka; Oonuki, Takashi; Yahashi, Akihisa; Hirayama, Kazuo; Miyano, Hiroshi

    2009-05-01

    A rapid analytical method for amines and amino acids was developed, involving derivatization with the novel reagent 3-aminopyridyl-N-hydroxysuccinimidyl carbamate (APDS), followed by reversed-phase high-performance liquid chromatography and electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS). More than 100 different analytes with amino groups, including amino acids in biological fluids such as mammalian plasma, could be measured within 10 min. The analytes were easily derivatized with APDS under the mild conditions. Selective reaction monitoring of ESI-MS/MS in positive mode was carried out to include the transitions of all of the protonated molecular ions of analytes derivatized with APDS to the common fragment at m/z 121, which was derived from the amino pyridyl moiety of the reagent. We evaluated the retention time precision, the quantification limits, the linearity, the intra- and inter-day precisions and the accuracy of 22 typical amino acids found in biological fluids, by analyzing a standard amino acid mixture and rat plasma. The intra-day relative standard deviations (RSDs) of the retention times of the 22 amino acids and their internal standards were within 0.9% and the inter-day RSDs were less than 1.1%, except for asparagines, with an RSD of 1.9%. The intra-day and inter-day RSDs of amino acid analyses in rat plasma were within 8.0% and 4.5%, respectively. The method, which facilitates the amino acid analysis of more than 100 samples in a day, represents an alternative to traditional amino acid analysis techniques, such as chromatography using postcolumn derivatization by ninhydrin. PMID:19350529

  4. Can Edman degradation be used for quantification? Isotope-dilution liquid chromatography-electrospray ionization tandem mass spectrometry and the long-term stability of 20 phenylthiohydantoin-amino acids.

    Science.gov (United States)

    Satoh, Ryo; Goto, Takaaki; Lee, Seon Hwa; Oe, Tomoyuki

    2013-10-01

    Edman degradation is a well-known method for obtaining amino acid (AA) sequences from a peptide by means of sequential reactions that release the N-terminal AAs from the peptide as a phenylthiohydantoin (PTH) derivative. Because of unexpected loss during the reaction and handling, there are few reports of use of this reaction for quantification. This manuscript describes the development of isotope-dilution liquid chromatography-electrospray ionization tandem mass spectrometry for 20 PTH-AA derivatives, and long-term stability testing of PTH-AAs to ensure quantitative quality in the reaction. The 20 corresponding [(13)C6]-PTH-AAs were prepared by use of a one-pot reaction involving a mixture of [(13)C6]-Edman reagent and 20 AAs. Good linearity was observed for standard curves for the PTH-AAs, using the corresponding [(13)C6]-PTH-AAs as internal standards (1-100 pmol per injection, r(2) = 0.989-1.000). Serum albumin (human), pepsin (porcine stomach mucosa), α-casein (bovine milk), ribonuclease A (bovine), lysozyme (chicken egg white), and insulin (bovine) subjected to Edman degradation were examined as model proteins and peptides for N-terminal AA analysis. The results of the impurity test were satisfactory. Yield from the entire reaction with human serum albumin was estimated to be at least 75%, indicating great potential for absolute quantification of proteins without protein standards. PMID:23545858

  5. Determination of gardenia yellow colorants in soft drink, pastry, instant noodles with ultrasound-assisted extraction by high performance liquid chromatography-electrospray ionization tandem mass spectrum.

    Science.gov (United States)

    Zhou, Wei-E; Zhang, Yuan; Li, Yang; Ling, Yun; Li, Hong-Na; Li, Shao-Hui; Jiang, Shou-Jun; Ren, Zhi-Qin; Huang, Zhi-Qiang; Zhang, Feng

    2016-05-13

    A novel, rapid and simple analytical method was developed for the quantitative determination of crocin, crocetin and geniposide in soft drink, pastry and instant noodles. The solid samples were relatively homogenized into powders and fragments. The gardenia yellow colorants were successively extracted with methanol using ultrasound-assisted extraction. The analytes were quantitatively measured in the extracts by liquid chromatography coupled with electrospray ionization tandem mass spectrometry. High correlation coefficients (r(2)>0.995) of crocin, crocetin and geniposide were obtained within their linear ranges respectively (50-1000ng/mL, 50-1000ng/mL, 15-240ng/mL) by external standard method. The limits of detection (LODs) were 0.02μg/g for crocin, 0.01μg/g for crocetin and 0.002μg/g for geniposide. And the limits of quantitation (LOQs) were in the ranges of 0.05-0.45μg/g for crocin, and in the ranges of 0.042-0.32μg/g for crocetin, and in the ranges of 0.02-0.15μg/g for geniposide in soft drink, pastry and instant noodles samples. The average recoveries of crocin, crocetin and geniposide ranged from 81.3% to 117.6% in soft drink, pastry and instant noodles. The intra- and inter-day precisions were respectively in the range of 1.3-4.8% and 1.7-11.8% in soft drink, pastry and instant noodle. The developed methods were successfully validated and applied to the soft drink, pastry, and instant noodles collected from the located market in Beijing from China. Crocin, crocetin and geniposide were detected in the collected samples. The average concentrations ranged from 0.84 to 4.20mg/g for crocin, and from 0.62 to 3.11mg/g for crocetin, and from 0.18 to 0.79mg/g for gardenia in various food samples. The method can provide evidences for government to determine gardenia yellow pigments and geniposide in food. PMID:27086566

  6. Liquid chromatography-electrospray ionization tandem mass spectrometry for on-line characterization, monitoring and isotopic profiling of the main selenium-metabolite in human urine after consumption of Se-rich and Se-enriched food

    International Nuclear Information System (INIS)

    The metabolism of selenium (Se) in the human body has yet not completely been unravelled and hence, an efficient method for characterization and on-line monitoring of the main Se-compound in human urine after consumption of Se-rich food was developed. Total Se-concentration in human urine after consumption of several Se-rich products was measured with inductively coupled plasma mass spectrometry (ICP-MS). The highest Se concentration in urine was observed after 4-10 h. The urine samples were brought onto a reversed phase column and the Se was detected by ICP-MS. Parameters for liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS) measurements were optimized by using commercially available sugars, because it is known that some of the urinary metabolites contain a sugar moiety. In order to characterize the predominant Se-metabolite, it was necessary to extensively clean-up the sample and preconcentrate the species. The main metabolite was measured on its precursor ion on three different m/z according to three isotopes of Se. Relative peak surfaces matched the relative abundances of the isotopes. The product ions could be measured in a human urine sample in accordance to the product ions of the commercially available sugars. Moreover, the evidence of a selenosugar was demonstrated by the use of the Se-isotopes when measuring the product ions. LC-ESI-MS-MS was proven to be very efficient for the characterization of the main urinary Se-metabolite and can be used for on-line monitoring of the compound in urine samples. The method can be extended for clinical screening after consumption of Se-(en)rich(ed) food by use of the Se-isotopic profile and/or of the typical product ions of (methyl)-N-acetyl-hexosamines

  7. Quantification of new antiepileptic drugs by liquid chromatography/electrospray ionization tandem mass spectrometry and its application to cellular uptake experiment using human placental choriocarcinoma BeWo cells.

    Science.gov (United States)

    Furugen, Ayako; Kobayashi, Masaki; Nishimura, Ayako; Takamura, Shigeo; Narumi, Katsuya; Yamada, Takehiro; Iseki, Ken

    2015-10-01

    A method for quantification of new antiepileptic drugs, including lamotrigine (LTG), levetiracetam (LEV), gabapentin (GBP), and topiramate (TPM), in cellular samples, using liquid chromatography/electrospray ionization tandem mass spectrometry was developed to better understand the membrane transport mechanisms of these drugs. Cell lysate was deproteinized by methanol containing LEV-d3 as an internal standard (IS). Chromatographic separation was performed on a C18 column using gradient elution with methanol-water-formic acid (10:90:0.1, v/v/v) and methanol-formic acid (100:0.1, v/v). Analytes were detected in positive ion electrospray mode with selected reaction monitoring (SRM). This method was applicable for a linear range of 5 to 500pmol for LTG; 5 to 1000pmol for LEV; 10 to 10,000pmol for GBP; and 5 to 5000pmol for TPM. The intra-day precision, inter-day precision, and accuracy data were assessed and found to be acceptable. This developed and validated method was then successfully applied to the investigation of uptake of the new antiepileptic drugs in placental choriocarcinoma BeWo cells. The intracellular concentration of these drugs in BeWo cells, accumulating over 30min at 37°C was in the order of GBP>LTG>LEV≈TPM. Furthermore, the uptake of GBP at 4°C was much lower than that at 37°C. The uptake of GBP was saturated at high concentrations. The kinetic parameters calculated for GBP uptake in BeWo cells were determined as Km of 105.4±6.4μM and Vmax at 8153±348pmol/mg protein/min. The novel method described here should enable investigators to elucidate the transport mechanisms of these antiepileptic drugs in BeWo cells. PMID:26343016

  8. Rapid and simultaneous analysis of ten aromatic amines in mainstream cigarette smoke by liquid chromatography/electrospray ionization tandem mass spectrometry under ISO and "Health Canada intensive" machine smoking regimens.

    Science.gov (United States)

    Xie, Fuwei; Yu, Jingjing; Wang, Sheng; Zhao, Ge; Xia, Qiaoling; Zhang, Xiaobing; Zhang, Shusheng

    2013-10-15

    Ten primary aromatic amines (AAs) in mainstream cigarette smoke under both ISO and "Health Canada intensive" machine smoking regimens were determined in this work, which were suspected to be carcinogenic compounds. The measured AAs included aniline, ortho-toluidine, meta-toluidine, para-toluidine, 1-naphthylamine, 2-naphthylamine, 3-aminobiphenyl, 4-aminobiphenyl, meta-phenylenediamine and meta-anisidine. For rapidly and sensitively analyzing these AAs, a liquid chromatography-electrospray ionization tandem mass spectrometric (LC-MS/MS) method coupled with solid phase extraction (SPE) was developed. The particulate phase of mainstream cigarette smoke was collected on a Cambridge filter pads, while the gas phase was trapped by 25 mL 5% HCl solution. Then, the pad was extracted in an ultrasonic bath with the impinger HCl solution. After being neutralized with NaOH, the extract was purified with a HLB solid phase extraction column, and then was analyzed with LC-MS/MS using isotope-labeled internal standard. The overall sample pretreatment and analysis time was less than 1.5h. The limits of detection for all targets ranged from 0.05 ng cig(-1) to 0.96 ng cig(-1) with the recoveries in the range of 75.0-131.8%. And the intra-day and inter-day precisions were less than 10% and 16%, respectively. Under HCI machine smoking regimen, the AAs yields in mainstream cigarette smoke were much higher and the average increases were greater than 100% compared with those under ISO smoking condition. PMID:24054615

  9. Phospholipidomic identification of potential serum biomarkers in dengue fever, hepatitis B and hepatitis C using liquid chromatography-electrospray ionization-tandem mass spectrometry.

    Science.gov (United States)

    Khedr, Alaa; Hegazy, Maha A; Kammoun, Ahmed K; Shehata, Mostafa A

    2016-01-15

    The serum phospholipid (PL) profiles of healthy volunteers (HE) and patients with recently diagnosed dengue fever (DF), hepatitis B (HBV), and hepatitis C (HCV) were investigated using liquid chromatography-ion trap-mass spectrometry (LC-IT-MS) and liquid chromatography-triple quad-mass spectrometry (LC-TQ-MS). Major PLs, including lyso-phosphatidylcholins (LPCs), phosphatidylcholins (PCs), phosphatidylinositols (PIs), phosphatidylethanolamines (PEs) and phosphatidylserines (PSs), were characterized in human serum using LC-IT-MS. Thirty-five PLs were quantified using seven non-endogenous odd-carbon PL standards. An MS search protocol for the identification of PLs is described. The analytical method was optimized to achieve maximum recovery and detection. PLs were detected with minimal ionization suppression. The PLs species were characterized on the basis of (i) MS(2) peaks due to polar head, (ii) precursor ion or neutral loss scans, (iii) identification of fatty acid, (iv) identification of sn-1 and sn-2 fatty acid. The quantitation data were subjected to principal component analysis (PCA), and a significant difference was observed between the PL profiles of the investigated diseases and those of HE subjects. The significance of the changes in each lipid among the four groups was statistically assessed using one-way analysis of variance (ANOVA) followed by Bonferroni post hoc multiple comparison. The serum profiles of 28 PLs were determined to be significantly different and enabled the discrimination between HE individuals and the studied patients. Potentially dysregulated PLs were considered as differentiating biomarkers to diagnose DF, HBV, and HCV. PMID:26708624

  10. 液相色谱-串联质谱法测定保健食品中维生素B12%Determination of vitamin B12 in function foods by liquid chromatography electrospray ionization tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    林宏琳; 华永有; 黄宏南

    2011-01-01

    目的 建立测定保健食品中维生素B12的液相色谱-串联质谱法.方法 样品添加内标人参皂苷Re溶液,固相萃取法( SPE)对试样进行富集、净化,以甲醇(A)和纯水(B)为流动相经Bio Basic-18 PIONEER柱(150 mm×2.1 mm,5μm)梯度洗脱分离,串联离子阱质谱在电喷雾电离正离子(ESI+)-全扫描(full)-二级质谱(MS/MS)模式下按内标法测定.结果 维生素B12在50~500 ng/ml范围内具有良好的线性,相关系数r=0.992,回收率75.2% ~ 89.5%,精密度3.6%~5.9%,检出限为5 ng/g,定量限为16 ng/g.结论本法可应用于保健食品的检测或产品质量控制.%Objective To establish a method of determining vitamin B12 in health food products by liquid chromatography electrospray ionization tandem mass spectrometry (LC-MS/MS). Methods After mixing samples with internal standard solution of ginsenoside Re, the mixtures of samples were extracted by solid phase extraction, and separated on a Bio Basic-18 PIONEER column (ISO mm ×2. 1 mm, 5 u.m) by a mobile phase of methanol ( A) + water ( B) with the gradient elution program. Detection was carried out by a liquid chromatography coupled electrospray ionization and ion trap mass spectrometry with ESI + , MS/MS and full scan mode. Results Calibration curve was linear within the range of 50-SOOng/ml with a correlation coefficient of more than 0. 99; the limit of detection ( LOD) was 5 ng/g and the limit of quantification ( LOQ) was 16 ng/g. The extraction recoveries were 75.2%-88.5%, RSDs were 3.6% -5.9%. Conclusion This method could meet the requirements of domestic and international laws and regulations, and could be used in the determination of VBI2 in health food products or for the quality control of the products.

  11. Validation of a liquid chromatography-electrospray ionization tandem mass spectrometric method to determine six polyether ionophores in raw, UHT, pasteurized and powdered milk.

    Science.gov (United States)

    Pereira, Mararlene Ulberg; Spisso, Bernardete Ferraz; Jacob, Silvana do Couto; Monteiro, Mychelle Alves; Ferreira, Rosana Gomes; Carlos, Betânia de Souza; da Nóbrega, Armi Wanderley

    2016-04-01

    This study aimed to validate a method developed for the determination of six antibiotics from the polyether ionophore class (lasalocid, maduramicin, monensin, narasin, salinomycin and semduramicin) at residue levels in raw, UHT, pasteurized and powdered milk using QuEChERS extraction and high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). The validation was conducted under an in-house laboratory protocol that is primarily based on 2002/657/EC Decision, but takes in account the variability of matrix sources. Overall recoveries between 93% and 113% with relative standard deviations up to 16% were obtained under intermediate precision conditions. CCα calculated values did not exceed 20% the Maximum Residue Limit for monensin and 25% the Maximum Levels for all other substances. The method showed to be simple, fast and suitable for verifying the compliance of raw and processed milk samples regarding the limits recommended by Codex Alimentarius and those adopted in European Community for polyether ionophores. PMID:26593474

  12. Comparison of rapid liquid chromatography-electrospray ionization-tandem mass spectrometry methods for determination of glycoalkaloids in transgenic field-grown potatoes.

    Science.gov (United States)

    Zywicki, Britta; Catchpole, Gareth; Draper, John; Fiehn, Oliver

    2005-01-15

    Two rapid methods for highly selective detection and quantification of the two major glycoalkaloids in potatoes, alpha-chaconine and alpha-solanine, were compared for robustness in high-throughput operations for over 1000 analytical runs using potato tuber samples from field trials. Glycoalkaloids were analyzed using liquid chromatography coupled to tandem mass spectrometry in multiple reaction monitoring mode. An electrospray interface was used in the detection of glycoalkaloids in positive ion mode. Classical reversed phase (RP) and hydrophilic interaction (HILIC) columns were investigated for chromatographic separation, ruggedness, recovery, precision, and accuracy. During the validation procedure both methods proved to be precise and accurate enough in relation to the high degree of endogenous biological variability found for field-grown potato tubers. However, the RP method was found to be more precise, more accurate, and, more importantly, more rugged than the HILIC method for maintaining the analytes' peak shape symmetry in high-throughput operation. When applied to the comparison of six classically bred potato cultivars to six genetically modified (GM) lines engineered to synthesize health beneficial inulins, the glycoalkaloid content in potato peels of all GM lines was found within the range of the six cultivars. We suggest complementing current unbiased metabolomic strategies by validating quantitative analytical methods for important target analytes such as the toxic glycoalkaloids in potato plants. PMID:15620882

  13. Identification and quantification of glucosamine in rabbit cartilage and correlation with plasma levels by high performance liquid chromatography-electrospray ionization-tandem mass spectrometry

    International Nuclear Information System (INIS)

    Graphical abstract: Highlights: → Optimization of an HPLC-ESI-MS/MS method for glucosamine in rabbit cartilage. → Application of the method to an in-vivo study. → Glucosamine presence in cartilage in physiological condition. → Significant increase of cartilage glucosamine concentration after dosing. → Good correlation between cartilage glucosamine levels and plasma concentrations. - Abstract: A new HPLC-ESI-MS/MS method for the determination of glucosamine (2-amino-2-deoxy-D-glucose) in rabbit cartilage was developed and optimized. Glucosamine was extracted from cartilage by cryogenic grinding followed by protein precipitation with trichloroacetic acid. The HPLC separation was achieved with a polymer-based amino column using a mobile phase composed of 10 mM ammonium acetate (pH 7.5)-acetonitrile (20:80%, v/v) at 0.3 mL min-1 flow rate. D-[1-13C]Glucosamine was used as internal standard. Selective detection was performed by tandem mass spectrometry with electrospray source, operating in positive ionization mode and in multiple reaction monitoring acquisition (m/z 180 → 72 and 181 → 73 for glucosamine and internal standard, respectively). Limit of quantification was 0.045 ng injected, corresponding to 0.25 μg g-1 in cartilage. Linearity was obtained up to 20 μg g-1 (R2 > 0.991). Precision values (%R.S.D.) were -1 (n = 6). Glucosamine was present in cartilage in physiological condition before the treatment. After dosing, mean concentration of cartilage glucosamine significantly increased from 461 to 1040 ng g-1. Cartilage glucosamine levels resulted to be well correlated with plasma concentrations, which therefore are useful to predict the target cartilage concentration and its pharmacological activity.

  14. Identification and quantification of glucosamine in rabbit cartilage and correlation with plasma levels by high performance liquid chromatography-electrospray ionization-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Pastorini, Elisabetta; Vecchiotti, Stefania; Colliva, Carolina [Department of Pharmaceutical Sciences, University of Bologna, Via Belmeloro 6, I-40126 Bologna (Italy); Persiani, Stefano [Rottapharm-Madaus, Via Valosa di Sopra 9, 20900 Monza Brianza (Italy); Rotini, Roberto; Roatti, Giulia; Zaccarelli, Lorenzo [Division of Orthopedic Surgery (Section B), Rizzoli Orthopaedic Institute, Via Pupilli 1, 40136 Bologna (Italy); Rovati, Lucio Claudio [Rottapharm-Madaus, Via Valosa di Sopra 9, 20900 Monza Brianza (Italy); Roda, Aldo, E-mail: aldo.roda@unibo.it [Department of Pharmaceutical Sciences, University of Bologna, Via Belmeloro 6, I-40126 Bologna (Italy)

    2011-06-10

    Graphical abstract: Highlights: > Optimization of an HPLC-ESI-MS/MS method for glucosamine in rabbit cartilage. > Application of the method to an in-vivo study. > Glucosamine presence in cartilage in physiological condition. > Significant increase of cartilage glucosamine concentration after dosing. > Good correlation between cartilage glucosamine levels and plasma concentrations. - Abstract: A new HPLC-ESI-MS/MS method for the determination of glucosamine (2-amino-2-deoxy-D-glucose) in rabbit cartilage was developed and optimized. Glucosamine was extracted from cartilage by cryogenic grinding followed by protein precipitation with trichloroacetic acid. The HPLC separation was achieved with a polymer-based amino column using a mobile phase composed of 10 mM ammonium acetate (pH 7.5)-acetonitrile (20:80%, v/v) at 0.3 mL min{sup -1} flow rate. D-[1-{sup 13}C]Glucosamine was used as internal standard. Selective detection was performed by tandem mass spectrometry with electrospray source, operating in positive ionization mode and in multiple reaction monitoring acquisition (m/z 180 {yields} 72 and 181 {yields} 73 for glucosamine and internal standard, respectively). Limit of quantification was 0.045 ng injected, corresponding to 0.25 {mu}g g{sup -1} in cartilage. Linearity was obtained up to 20 {mu}g g{sup -1} (R{sup 2} > 0.991). Precision values (%R.S.D.) were <10%. Accuracy (% bias) ranged from -6.0% to 12%. Mean recoveries obtained at 3 concentration levels were higher than 81% (%R.S.D. {<=} 8%). The method was applied to measure glucosamine levels in rabbit cartilage and plasma after single oral administration of glucosamine sulfate at a dose of 98 mg kg{sup -1} (n = 6). Glucosamine was present in cartilage in physiological condition before the treatment. After dosing, mean concentration of cartilage glucosamine significantly increased from 461 to 1040 ng g{sup -1}. Cartilage glucosamine levels resulted to be well correlated with plasma concentrations, which

  15. Determination of nine sensitizing disperse dyes in activated sludge by ultrasound-assisted liquid-liquid extraction-ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry.

    Science.gov (United States)

    Zhou, Linjun; Shi, Lili; Liu, Jining; Lv, Fenglan; Xu, Yanhua

    2016-01-01

    A method was developed on the basis of ultrasound-assisted liquid-liquid extraction ultra-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (ULLE-UPLC-ESI-MS/MS) to determine nine sensitizing disperse dyes in activated sludge. The samples were extracted using ULLE and separated through UPLC on an ACQUITY UPLCTM BEH C18 column with a gradient elution program of acetonitrile and acidified water (containing 2% acetonitrile, 0.2% formic acid, and 0.005 mol/L ammonium; pH 2.7) as the mobile phase. The samples were then identified and quantified through UPLC-ESI-MS/MS in a positive mode and multiple reaction monitoring. Results showed good linearity (10-1000 μg/L, 0.9934-0.9998), detection limit (0.08-2.17 μg/L), and quantification limit (0.27-7.38 μg/L) for the nine sensitizing disperse dyes, with recoveries ranging from 65.0 to 111.3%. The proposed method was applied to detect and determine the concentration of sensitizing disperse dyes in sludge samples obtained from various sewage treatment plants (six dyeing enterprises and one dye manufacturer). Three sensitizing disperse dyes were identified, and the lowest concentration detected was 10 μg/kg. PMID:26521175

  16. Improving detection sensitivity of amino acids in thyroid tissues by using phthalic acid as a mobile phase additive in hydrophilic interaction chromatography-electrospray ionization-tandem mass spectrometry

    International Nuclear Information System (INIS)

    Highlights: • HILIC–ESI-MS/MS method was used to quantify 24 free AAs in human thyroid tissues. • Addition of 0.08 mM of phthalic acid to the eluent enhanced the sensitivity of AAs. • Narrowed peak shapes of AAs were achieved with phthalic acid in the mobile phase. • The mechanism for the signal intensity enhancement by phthalic acid was investigated. - Abstract: In this work, 0.08 mmol L−1 of phthalic acid was introduced as a mobile phase additive to quantify free amino acids (AAs) by hydrophilic interaction liquid chromatography (HILIC) coupled with electrospray ionization tandem mass spectrometry (ESI-MS/MS). The addition of phthalic acid significantly increased the signal intensity of protonated AA ions, resulting from the decrease of the relative abundance of AA sodium adducts. Meanwhile, the chromatographic peak shapes of AAs were optimized. As a consequence, there was a noticeable increase in the sensitivity of detection for AAs. The limits of detection (LOD) and quantification (LOQ) of the AAs ranged from 0.0500 to 20.0 ng mL−1 and from 0.100 to 50.0 ng mL−1, respectively, which were 4–50 times lower compared to the values measured without the addition of phthalic acid. The enhanced detection and separation of AAs were obtained by merely adding phthalic acid to the mobile phase without changing other conditions. Eventually, this simple method was validated and successfully applied to the analysis of twenty-four kinds of free AAs in human thyroid carcinoma and para-carcinoma tissues, demonstrating a significant increase of most AAs in thyroid carcinoma tissues (p < 0.05)

  17. Improving detection sensitivity of amino acids in thyroid tissues by using phthalic acid as a mobile phase additive in hydrophilic interaction chromatography-electrospray ionization-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Wanshu [National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032 (China); Guan, Qing [Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center (FUSCC), Shanghai 200032 (China); Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Sun, Tuanqi, E-mail: tuanqisun@163.com [Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center (FUSCC), Shanghai 200032 (China); Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Cao, Yanjing [National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032 (China); Zhang, Li, E-mail: zhangli7488@sioc.ac.cn [National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032 (China); Guo, Yinlong, E-mail: ylguo@sioc.ac.cn [National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032 (China)

    2015-04-22

    Highlights: • HILIC–ESI-MS/MS method was used to quantify 24 free AAs in human thyroid tissues. • Addition of 0.08 mM of phthalic acid to the eluent enhanced the sensitivity of AAs. • Narrowed peak shapes of AAs were achieved with phthalic acid in the mobile phase. • The mechanism for the signal intensity enhancement by phthalic acid was investigated. - Abstract: In this work, 0.08 mmol L{sup −1} of phthalic acid was introduced as a mobile phase additive to quantify free amino acids (AAs) by hydrophilic interaction liquid chromatography (HILIC) coupled with electrospray ionization tandem mass spectrometry (ESI-MS/MS). The addition of phthalic acid significantly increased the signal intensity of protonated AA ions, resulting from the decrease of the relative abundance of AA sodium adducts. Meanwhile, the chromatographic peak shapes of AAs were optimized. As a consequence, there was a noticeable increase in the sensitivity of detection for AAs. The limits of detection (LOD) and quantification (LOQ) of the AAs ranged from 0.0500 to 20.0 ng mL{sup −1} and from 0.100 to 50.0 ng mL{sup −1}, respectively, which were 4–50 times lower compared to the values measured without the addition of phthalic acid. The enhanced detection and separation of AAs were obtained by merely adding phthalic acid to the mobile phase without changing other conditions. Eventually, this simple method was validated and successfully applied to the analysis of twenty-four kinds of free AAs in human thyroid carcinoma and para-carcinoma tissues, demonstrating a significant increase of most AAs in thyroid carcinoma tissues (p < 0.05)

  18. Highly sensitive isotope-dilution liquid-chromatography-electrospray ionization-tandem-mass spectrometry approach to study the drug-mediated modulation of dopamine and serotonin levels in Caenorhabditis elegans.

    Science.gov (United States)

    Schumacher, Fabian; Chakraborty, Sudipta; Kleuser, Burkhard; Gulbins, Erich; Schwerdtle, Tanja; Aschner, Michael; Bornhorst, Julia

    2015-11-01

    Dopamine (DA) and serotonin (SRT) are monoamine neurotransmitters that play a key role in regulating the central and peripheral nervous system. Their impaired metabolism has been implicated in several neurological disorders, such as Parkinson's disease and depression. Consequently, it is imperative to monitor changes in levels of these low-abundant neurotransmitters and their role in mediating disease. For the first time, a rapid, specific and sensitive isotope-dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of DA and SRT in the nematode Caenorhabditis elegans (C. elegans). This model organism offers a unique approach for studying the effect of various drugs and environmental conditions on neurotransmitter levels, given by the conserved DA and SRT biology, including synaptic release, trafficking and formation. We introduce a novel sample preparation protocol incorporating the usage of sodium thiosulfate in perchloric acid as extraction medium that assures high recovery of the relatively unstable neurotransmitters monitored. Moreover, the use of both deuterated internal standards and the multiple reaction monitoring (MRM) technique allows for unequivocal quantification. Thereby, to the best of our knowledge, we achieve a detection sensitivity that clearly exceeds those of published DA and SRT quantification methods in various matrices. We are the first to show that exposure of C. elegans to the monoamine oxidase B (MAO-B) inhibitor selegiline or the catechol-O-methyltransferase (COMT) inhibitor tolcapone, in order to block DA and SRT degradation, resulted in accumulation of the respective neurotransmitter. Assessment of a behavioral output of the dopaminergic system (basal slowing response) corroborated the analytical LC-MS/MS data. Thus, utilization of the C. elegans model system in conjunction with our analytical method is well-suited to investigate drug-mediated modulation of the DA and

  19. Validation of a Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry Method for Determination of All-Trans Retinoic Acid in Human Plasma and Its Application to a Bioequivalence Study

    Directory of Open Access Journals (Sweden)

    Jing-Bo Peng

    2014-01-01

    Full Text Available A sensitive, reliable and specific LC-MS-MS method was developed and validated for the identification and quantitation of all-trans retinoic acid (ATRA in human plasma. Acitretin was used as the internal standard (IS. After liquid-liquid extraction of 500 μL plasma with methyl tert-butyl ether (MTBE, ATRA and the IS were chromatographed on a HyPURITY C18 column (150 mm × 2.1 mm, 5 μm with the column temperature set at 40 °C. The mobile phase was consisted of 40% phase A (MTBE–methanol–acetic acid, 50:50:0.5, v/v and 60% phase B (water–methanol–acetic acid, 50:50:0.5, v/v with a flow rate of 0.3 mL/min. The API 4000 triple quadrupole mass spectrometer was operated in multiple reaction monitoring (MRM mode via the positive electrospray ionization interface using the transition m/z 301.4 → 123.1 for ATRA and m/z 326.9 → 177.1 for IS, respectively. The calibration curve was linear over the range of 0.45–217.00 ng/mL (r ≥ 0.999 with a lower limit of quantitation (LLOQ of 0.45 ng/mL. The intra- and inter-day precisions values were below 8% relative standard deviation and the accuracy was from 98.98% to 106.19% in terms of relative error. The validated method was successfully applied in a bioequivalence study of ATRA in Chinese healthy volunteers.

  20. 超高效液相色谱-电喷雾串联质谱法测定塑料成品中的三甲基氯化锡%Determination of trimethyltin in plastic product by using ultra high performance liquid chromatography electrospray ionization tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    陈慧玲; 许欣欣; 毛丽莎; 刘红河; 陆少游

    2016-01-01

    目的:建立塑料成品中三甲基氯化锡(TMT)的超高效液相色谱-串联质谱联用测定法(UPLC-MS/MS)。方法塑料样品用乙酸乙酯提取,洗脱液在40℃水浴下氮气吹干;残渣用流动相溶解,旋涡混匀60s,过0.22μm微孔滤膜,经C18色谱柱完成分离,串联质谱仪上采用多反应监测正离子模式测定三甲基氯化锡,外标法定量。结果三甲基氯化锡在1.0~100.0μg/L 范围内线性关系良好(相关系数 r=0.9997),检出限0.2μg/L。在2.0、10.0和50.0μg/L 3个添加水平范围的RSD小于8.0%,样品加标回收率为88.5%~93.4%。结论建立的超高效液相色谱-串联质谱联用法测定塑料成品中三甲基氯化锡的方法快速简单、准确有效。%Objective An ultra-high performance liquid chromatography eclectrospray ionization tandem mass spectrometry (UPLC-MS/MS) method was developed to determine trimethyltin (TMT) in plastic product. Methods TMT was extracted from plastic product by ethyl acetate, the elute was evaporated to dryness with nitrogen in 40℃ water bath, redissolved with 1ml of moble phase solution, vortexed for 60 s and filtered with 0.22 μm membrane. The filtrate was detected by UPLC-MS/MS in positive ion electrospray and MRM mode with a UPLC C18 column as separation column, and quantified with external standard substances. Results TMT was linear in the range of 1.0~100.0 μg/L with correlation coefficient of 0.9997. The relative standard derivations (RSD) at three levels (2.0 μg/L、10.0 μg/L and 50.0 μg/L) were lower than 8.0%, and the recovery rate was from 88.5% to 93.4%. Conclusion The method of liquid chromatography-electrospray tandem mass spectrometry is simple, reliable and accurate, that adapts to determinate TMT in plastic product.

  1. Characterisation of cholera toxin by liquid chromatography - Electrospray mass spectrometry

    NARCIS (Netherlands)

    Baar, B.L.M. van; Hulst, A.G.; Wils, E.R.J.

    1999-01-01

    Cholera toxin, one of the toxins that may be generated by various strains of the bacterium Vibrio cholerae, can be considered as a substance possibly used in biological warfare. The possibilities of characterising the toxin by liquid chromatography electrospray mass spectrometry (LC-ES-MS) were inve

  2. Glycerophospholipid analysis of Eastern red bat (Lasiurus borealis) hair by electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Pannkuk, Evan L; McGuire, Liam P; Gilmore, David F; Savary, Brett J; Risch, Thomas S

    2014-03-01

    Pilosebaceous units found in the mammalian integument are composed of a hair follicle, the proximal portion of the hair shaft, a sebaceous gland, and the erector pili muscle. Pilosebaceous units release protective oils, or sebum, by holocrine secretion onto skin and hair through rupturing of sebocytes. Sebum is composed largely of polar and neutral lipids including glycerolipids, free fatty acids, sterols, wax esters, sterol esters, and squalene. In addition to these lipid classes, there is a small proportion of ionic/anionic glycerophospholipids (GPs). Composition of GPs on hair is rarely addressed despite their broad biological activities as signaling molecules and membrane stability. Furthermore, knowledge on GP composition in bats is lacking. Bat GP composition is important to document due to GP roles ranging from decreasing drag during migration to interaction with the integumentary microbiome. In this study, we analyzed GP molecular composition with liquid chromatography electrospray ionization tandem mass spectrometry and compared GP content to previous literature. A total of 152 GPs were detected. Broad GP classes identified include lysophosphatidylcholine, phosphatidylcholine (PC), lysophosphatidylethanolamine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, phosphatidic acid, and phosphatidylglycerol, with PC being the most abundant class. The acyl components were consistent with fatty acid methyl esters and triacylglyceride moieties found in Eastern red bat sebum. Glycerophospholipid proportions of the hair surface were different from a previous study on bat lung surfactants. This study determined the broad class and molecular species of bat sebum GPs that may be used in future ecological studies in vespertilionid bats. PMID:24532214

  3. Liquid Chromatography-Electrospray Tandem Mass Spectrometry of Terpenoid Lactones in Ginkgo biloba

    OpenAIRE

    Sun, Yongkai; Li, Wenkui; Fitzloff, John F.; van Breemen, Richard B

    2005-01-01

    Ginkgo biloba (ginkgo) is one of most frequently used botanical dietary supplements. The bioactive constituents include the terpenoid lactones consisting of bilobalide and the ginkgolides A, B, C, and J. A new assay based on high performance liquid chromatography-electrospray tandem mass spectrometry (LC-MS-MS) was developed for the measurement of the terpenoid lactones in ginkgo products such as leaf powder and extracts. Initially, the MS-MS fragmentation pathways of ginkgolides were investi...

  4. Analysis of oak tannins by liquid chromatography-electrospray ionisation mass spectrometry.

    Science.gov (United States)

    Mämmelä, P; Savolainen, H; Lindroos, L; Kangas, J; Vartiainen, T

    2000-09-01

    Extractable tannins were analysed by liquid chromatography-electrospray ionisation mass spectrometry in two oak species, North American white oak (Quercus alba) and European red oak (Quercus robur). They mainly included various glucose gallic and ellagic acid esters. The structures were partially determined, and they included grandinin/roburin E, castalagin/vescalagin, gallic acid, valoneic acid bilactone, monogalloyl glucose, digalloyl glucose, trigalloyl glucose, ellagic acid rhamnose, quercitrin and ellagic acid. PMID:10999626

  5. Determination of macrolide antibiotics in chicken tissues by liquid chromatography-electrospray mass spectrometry

    Science.gov (United States)

    Salikin, Jamilah; Abdullah, Aminah

    2013-11-01

    A methodusingliquid chromatography-electrospray mass spectrometry (LC-(ESI)MS) for the simultaneous determination of three macrolides (tylosin, spiramycin and tilmicosin) in poultry muscle has been developed. The drugs were extracted with EDTA McIlvaine buffer, filter through celite 545 and the extracts were cleaned up by SPE Oasis HLB cartridge. Separation was carried out in end-capped silica-based C18 column and mobile phases containing trifluoroacetic acid-acetonitrile with a binary gradient system at a flow rate 0.5 ml/min. Detection was performed by single mass spectrometry with electrospray ionization in the positive mode. Several parameters affecting the mass spectra were studied. Chicken samples from the market were analyzed to check the residue of macrolide antibiotics.

  6. Quantitative determination of medroxyprogesterone acetate in plasma by liquid chromatography/electrospray ion trap mass spectrometry.

    Science.gov (United States)

    Kim, S M; Kim, D H

    2001-01-01

    A sensitive and rapid liquid chromatography/electrospray ion trap mass spectrometry (LC/MS/MS) method has been developed for the quantitative determination of medroxyprogesterone acetate (MPA) in human plasma. Plasma samples (1.0 mL) were simply extracted with pentane and the extracts were analyzed by HPLC with the detection of the analyte in the selective reaction monitoring (SRM) mode. The determination of MPA was accurate and reproducible, with a limit of quantitation of 0.05 ng/mL in plasma. The standard calibration curve for MPA was linear (r = 0.998) over the concentration range 0.05-6.0 ng/mL in human plasma. Analysis precision over the concentration range of MPA was lower than 18.8% (relative standard deviation, RSD) and accuracy was between 96.2 and 108.7%. PMID:11675672

  7. The analysis of aqueous mixtures using liquid chromatography-electrospray mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, S.

    1999-02-12

    The focus of this dissertation is the use of chromatographic methods coupled with electrospray mass spectrometry (ES-MS) for the determination of both organic and inorganic compounds in aqueous solutions. The combination of liquid chromatography (LC) methods and ES-MS offers one of the foremost methods for determining compounds in complex aqueous solutions. In this work, LC-ES-MS methods are devised using ion exclusion chromatography, reversed phase chromatography, and ion exchange chromatography, as well as capillary electrophoresis (CE). For an aqueous sample, these LC-ES-MS and CE-ES-MS techniques require no sample preparation or analyte derivatization, which makes it possible to observe a wide variety of analytes as they exist in solution. The majority of this work focuses on the use of LC-ES-MS for the determination of unknown products and intermediates formed during electrochemical incineration (ECI), an experimental waste remediation process. This report contains a general introduction to the project and the general conclusions. Four chapters have been removed for separate processing. Titles are: Chapter 2: Determination of small carboxylic acids by ion exclusion chromatography with electrospray mass spectrometry; Chapter 3: Electrochemical incineration of benzoquinone in aqueous media using a quaternary metal oxide electrode in the absence of a soluble supporting electrolyte; Chapter 4: The determination of electrochemical incineration products of 4-chlorophenol by liquid chromatography-electrospray mass spectrometry; and Chapter 5: Determination of small carboxylic acids by capillary electrophoresis with electrospray mass spectrometry.

  8. Determination of palonosetron in human plasma by liquid chromatography-electrospray ionization-mass spectrometry.

    Science.gov (United States)

    Ding, Li; Chen, Yan; Yang, Lin; Wen, Aidong

    2007-06-28

    A high performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) method for the determination of palonosetron (PALO) in human plasma using naloxone as the internal standard (IS) was established. After adjustment to a weakly basic pH with saturated sodium bicarbonate, plasma samples were extracted with ethyl acetate and separated on a Hanbon Lichrospher 5-C18 column with a mobile phase of 40 mM ammonium acetate buffer solution containing 0.04% formic acid-methanol (46:54, v/v). PALO was determined with electrospray ionization-mass spectrometry (ESI-MS). HPLC-ESI-MS was performed in the selected-ion monitoring (SIM) mode using target ions at [M+H]+ m/z 297.2 for PALO and [M+H]+ m/z 328.2 for the IS. Calibration curve was linear over the range of 0.02124-10.62 ng/ml. The lower limit of quantification (LLOQ) was 0.02124 ng/ml. The intra- and inter-run variability values were all less than 10.4%. The method has been successfully applied to determine the plasma concentration of PALO in healthy Chinese volunteers. PMID:17127028

  9. A Nanoparticle-based Solid Phase Extraction Method for Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometric Analysis

    OpenAIRE

    Song, Yaru; Zhao, Shulin; Tchounwou, Paul; Liu, Yi-Ming

    2007-01-01

    A solid-phase extraction (SPE) procedure with the use of superparamagnetic Fe3O4 nanoparticles as extracting agent was developed for HPLC-ESI-MS/MS analysis. Four most heavily used triazine pesticides (herbicides) were taken as the test compounds. The NPs showed an excellent capability to retain the compounds tested, and a quantitative extraction was achieved within 10 min under the testing conditions, i.e. 100 μL NP solution was added to 400 mL sample in a beaker with stirring. After extract...

  10. Analysis of iridoid glucosides in Hedyotis diffusa by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Li, Cunman; Xue, Xingya; Zhou, Dayong; Zhang, Feifang; Xu, Qing; Ren, Lingling; Liang, Xinmiao

    2008-09-10

    An HPLC-DAD-ESI-MS/MS method was developed for analysis of iridoid glucosides (IGs) from Hedyotis diffusa Willd. The optimized separation condition was achieved with the Complex Sample Analysis Software System (CSASS) software, under which the whole analytes were achieved complete resolution especially for some isomeric IGs. Based on the UV and fragmentations, eleven IGs were detected. According to the fragmentation patterns of the three standard IGs, especially those of the isomeric standards, seven IGs including three pairs of isomers were unambiguous/tentatively identified. For the isomeric IGs with methyl ester or carboxyl group at C-4, the extents of the losses of CH3OH and/or H2O from their molecular and/or the aglycone adducts are useful for the differentiation of the stereoisomers in positive ion (PI) mode, which depends on the stereochemistry of the hydroxyl group on the cyclopentanoid unit. PMID:18579330

  11. Study of matrix effects for liquid chromatography-electrospray ionization tandem mass spectrometric analysis of 4 aminoglycosides residues in milk.

    Science.gov (United States)

    Wang, Yuan; Li, Shaohui; Zhang, Feifang; Lu, Yifeng; Yang, Bingcheng; Zhang, Feng; Liang, Xinmiao

    2016-03-11

    Matrix effect (ME) is always a major issue for the development of LC-MS/MS method. ME resulting from co-eluting residual matrix components can affect the ionization efficiency of target analytes, leading to quantification errors of the analytes of interest. The present work evaluates MEs of milk samples on simultaneous analysis of four aminoglycosides residues via LC-ESI/MS/MS including streptomycin, dihydrostreptomycin, spectinomycin and kanamycin. Approaches to reduce MEs were examined: optimization of the sample preparation, sample dilution and lower flow rate used. Three commercial sorbents were tested including Oasis MCX, Oasis HLB and Oasis WCX. WCX behaved better for all analytes, but high MEs (80.8-134.9%) were obtained. Therefore, a consecutive SPE of tC18-WCX was found to effectively reduce ME. Milk samples from different manufacturers were analyzed and low MEs (85.6-112.9%) were obtained. PMID:26875117

  12. Determination of flavone, flavonol, and flavanone aglycones by negative ion liquid chromatography electrospray ion trap mass spectrometry

    OpenAIRE

    Fabre, Nicolas; Rustan, Isabelle; de Hoffmann, Edmond; Quetin-Leclercq, Joëlle

    2001-01-01

    Eleven naturally occurring flavonoid aglycones, belonging to the representative flavone, flavonol, and flavanone types were separated by high performance liquid chromatography and analyzed on-line with negative ion electrospray ionization tandem mass spectrometry (ESI-MS/MS). In order to resolve the MS/MS spectra obtained, each compound was reinvestigated by direct loop injections using an ion trap mass spectrometer. The MSn spectra obtained allowed us to propose plausible schemes for their f...

  13. Quantitative selenium speciation in human urine by using liquid chromatography-electrospray tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lu Ying [University of Crete, Department of Chemistry, Environmental Chemical Processes Laboratory, Voutes Campus, Heraklion 71003, Crete (Greece); Rumpler, Alice; Francesconi, Kevin A. [Institute of Chemistry-Analytical Chemistry, Karl-Franzens University Graz, Graz (Austria); Pergantis, Spiros A., E-mail: spergantis@chemistry.uoc.gr [University of Crete, Department of Chemistry, Environmental Chemical Processes Laboratory, Voutes Campus, Heraklion 71003, Crete (Greece)

    2012-06-20

    Highlights: Black-Right-Pointing-Pointer Development of a selected reaction monitoring mass spectrometric method for the identification of Se species in human urine. Black-Right-Pointing-Pointer A selenosugar was detected as the major human urinary metabolite of selenium in the samples analysed. Black-Right-Pointing-Pointer The trimethylselenonium ion was detected in the urine of one volunteer before and after receiving a selenium supplement. Black-Right-Pointing-Pointer Strict quality control measures were applied to validate identification. Black-Right-Pointing-Pointer Quantitation was conducted using an isotopically labelled internal standard and the standard additions methodology. - Abstract: A liquid chromatography-electrospray-tandem mass spectrometry (ES-MS/MS) method was developed for the speciation analysis of four organic selenium species of relevance to human urinary metabolism, namely trimethylselenomium ion (TMSe{sup +}), selenomethionine (SeMet) and the two selenosugars, methyl 2-acetamido-2-deoxy-1-seleno-{beta}-D-galactos/-glucos-amine (SeGalNAc and SeGluNAc, respectively). Their chromatographic separation was achieved by using a cation exchange pre-column coupled in-series with a reversed-phase high-performance liquid chromatography column, along with an isocratic mobile phase. Online detection was performed using ES-MS/MS in selective reaction monitoring mode. SeGalNAc was detected as the major human urinary metabolite of selenium in the samples analysed, whereas TMSe{sup +} was detected in the urine of one volunteer before and after receiving a selenium supplement. SeMet was not detected as a urine excretory metabolite in this study. Spiking experiments performed with the urine samples revealed significant signal suppression caused by coeluting matrix constituents. To overcome such interferences, isotopically labelled {sup 13}CD{sub 3}{sup 82}SeGalNAc was used as an internal standard, whereas in the absence of an isotopically labelled internal

  14. Conversion of 3-nitrotyrosine to 3-aminotyrosine residues facilitates mapping of tyrosine nitration in proteins by electrospray ionization-tandem mass spectrometry using electron capture dissociation.

    Science.gov (United States)

    Guo, Jia; Prokai, Laszlo

    2012-12-01

    Protein tyrosine nitration is associated with oxidative stress and various human diseases. Tandem mass spectrometry has been the method of choice for the identification and localization of this posttranslational modification to understand the underlying mechanisms and functional consequences. Due to the electron predator effect of the nitro group limiting fragmentation of the peptide backbone, electron-based dissociation has not been applicable, however, to nitrotyrosine-containing peptides. A straightforward conversion of the nitrotyrosine to the aminotyrosine residues is introduced to address this limitation. When tested with nitrated ubiquitin and human serum albumin as model proteins in top-down and bottom-up approaches, respectively, this chemical derivatization enhanced backbone fragmentation of the corresponding nitroproteins and nitropeptides by electron capture dissociation (ECD). Increased sequence coverage has been obtained by combining in the bottom-up strategy the conversion of nitrotyrosine to aminotyrosine and introducing, in addition to trypsin, a further digesting enzyme of complementary specificity, when protein nitration was mapped by liquid chromatography-electrospray ionization tandem mass spectrometry using both collision-induced dissociation (CID) and ECD. PMID:23280749

  15. Liquid Chromatography-Electrospray Ionization Mass Spectrometry Method for the Rapid Identification of Citrus Limonoid Glucosides in Citrus Juices and Extracts

    Science.gov (United States)

    A rapid and selective liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method to screen citrus samples for limonoid glucosides and estimate their relative concentrations has been developed. This method utilizes a phenyl stationary phase, whereas previous methods have reli...

  16. Identification of Phenylethanoid Glycosides in Plant Extract of Plantago asiatica L. by Liquid Chromatography-Electrospray Ionization Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    LI,Li; LIU,Chunming; LIU,Zhiqiang; TSAO,Rong; LIU,Shuying

    2009-01-01

    The present work describes a liquid chromatography-electrospray ionization mass spectrometry(LC-ESI-MS)method for rapid identification of phenylethanoid glycosides in plant extract from Plnmgo asiatica L.By using a binary mobile phase system consisting of 0.2% acetic acid and acetonitrile under gradient conditions,a good sepa-ration was achieved on a reversed-phase C18 column.The[M-H] ions,the molecular weights,and the fragmentions of phenvlethanoid glycosides were obtained in the negative ion mode using LC-ESI-MS.The identification of the phenylethanoid glycosides(peaks 1-3) in the extract of P. asiatica L.was based on matching their retention time.the detection of molecular ions.and the fragment ions obtained by collision-induced dissociation(CID)ex-periments with those of the authentic standards and data reported in the literature.

  17. Analysis of alcohols, as dimethylglycine esters, by electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Johnson, D W

    2001-03-01

    Dimethylglycine (DMG) esters are new derivatives for the rapid, sensitive and selective analysis of primary and secondary alcohols, in complex mixtures, by electrospray ionization tandem mass spectrometry (ESI-MS/MS). Their development was inspired by the use of the complementary dimethylaminoethyl esters for the trace, rapid analysis of fatty acids. DMG esters are simply prepared by heating a dichloromethane solution of the imidazolide of dimethylglycine, containing triethylamine, and an alcohol. DMG esters of long-chain fatty alcohols, isoprenoidal alcohols and hydroxy-acids are analysed by electrospray ionization tandem mass spectrometry with a precursor ion of m/z 104 scan. Diols, glyceryl esters, glyceryl ethers and some sterols are analysed by a neutral loss of 103 Da scan. Trimethylglycine (TMG) ester iodides, prepared by alkylation of DMG esters with methyl iodide, are more sensitive derivatives for molecules containing secondary alcohol groups, such as cholesterol and gibberellic acid. They are analysed by a precursor ion of m/z 118 scan. DMG or TMG derivatives were shown to be at least comparable and sometimes an order of magnitude more sensitive than N-methylpyridyl ether derivatives for ESI-MS/MS analysis of the different classes of alcohols. Applications of these derivatives for the diagnosis of inherited disorders and the analysis of natural products are presented. PMID:11312519

  18. Metabolic profile of naringenin in the stomach and colon using liquid chromatography/electrospray ionization linear ion trap quadrupole-Orbitrap-mass spectrometry (LC-ESI-LTQ-Orbitrap-MS) and LC-ESI-MS/MS.

    Science.gov (United States)

    Orrego-Lagarón, Naiara; Vallverdú-Queralt, Anna; Martínez-Huélamo, Miriam; Lamuela-Raventos, Rosa M; Escribano-Ferrer, Elvira

    2016-02-20

    Several biological activities (antioxidant, anti-inflammatory, anticarcinogenic) are attributed to naringenin (NAR)-a predominant flavonoid of citrus fruit and tomato-despite its low bioavailability after ingestion. NAR undergoes extensive metabolism when crossing the gastrointestinal tract, resulting in enteric, hepatic and microbial metabolites, some of them with recognized beneficial effects on human health. This study sought to provide new insights into the metabolism of NAR in regions of the gastrointestinal tract where it has been less studied: the stomach and colon. With this purpose, liquid chromatography coupled with an electrospray ionization hybrid linear ion trap quadrupole Orbitrap mass spectrometry technique (LC-ESI-LTQ-Orbitrap-MS) was used for an accurate identification of NAR metabolites, and liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) on a triple quadrupole was used for their identification and quantification. The combination of both analytical techniques provided a broader metabolic profile of NAR. As far as we know, this is the first in-depth metabolic profiling study of NAR in the stomach of mice. Three of the metabolites determined using the LC-LTQ-Orbitrap could not be identified by LC-ESI-MS/MS in stomach perfusion samples: apigenin, 3-(4-hydroxyphenyl) propionic acid and phloroglucinol. The number of colonic metabolites determined using the LTQ-Orbitrap-MS was more than twice the number identified by LC-ESI-MS/MS. PMID:26698229

  19. Chemical ionization tandem mass spectrometer for the in situ measurement of methyl hydrogen peroxide

    International Nuclear Information System (INIS)

    A new approach for measuring gas-phase methyl hydrogen peroxide [(MHP) CH3OOH] utilizing chemical ionization mass spectrometry is presented. Tandem mass spectrometry is used to avoid mass interferences that hindered previous attempts to measure atmospheric CH3OOH with CF3O- clustering chemistry. CH3OOH has been successfully measured in situ using this technique during both airborne and ground-based campaigns. The accuracy and precision for the MHP measurement are a function of water vapor mixing ratio. Typical precision at 500 pptv MHP and 100 ppmv H2O is ±80 pptv (2 sigma) for a 1 s integration period. The accuracy at 100 ppmv H2O is estimated to be better than ±40%. Chemical ionization tandem mass spectrometry shows considerable promise for the determination of in situ atmospheric trace gas mixing ratios where isobaric compounds or mass interferences impede accurate measurements.

  20. Optimized combination of dilution and refined QuEChERS to overcome matrix effects of six types of tea for determination eight neonicotinoid insecticides by ultra performance liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Jiao, Weiting; Xiao, Yu; Qian, Xiaosan; Tong, Mengmeng; Hu, Yizheng; Hou, Ruyan; Hua, Rimao

    2016-11-01

    Liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) is a primary tool for analysis of low volatility compounds in complex matrices. However, complex matrices, such as different types of tea, complicate analysis through ionization suppression or enhancement. In this study, sample preparation by a refined QuEChERS method combined with a dilution strategy removed almost all matrix effects caused by six types of tea. Tea samples were soaked with water and extracted with acetonitrile, cleaned up with a combination of PVPP (160mg) and GCB (20mg), and dried. Dried extracts were diluted with 20mL acetonitrile/water (15:85, v/v) before analysis by UPLC-MS/MS. The average recoveries of eight neonicotinoid insecticides (dinotefuran, nitenpyram, thiamethoxam, imidacloprid, clothianidin, imidaclothiz, acetamiprid, and thiacloprid) ranged from 66.3 to 108.0% from tea samples spiked at 0.01-0.5mgkg(-1). Relative standard deviations were below 16% for all recovery tests. The limit of quantification ranged from 0.01 to 0.05mgkg(-1). PMID:27211616

  1. Characterisation of a proposed internet synthesis of N,N-dimethyltryptamine using liquid chromatography/electrospray ionisation tandem mass spectrometry.

    Science.gov (United States)

    Martins, Cláudia P B; Freeman, Sally; Alder, John F; Brandt, Simon D

    2009-08-14

    The psychoactive properties of N,N-dimethyltryptamine (DMT) are known to induce altered states of consciousness in humans. These properties attract great interest from clinical, neuroscientific, clandestine and forensic communities. The Breath of Hope Synthesis was reported on an internet website as a convenient two-step methodology for the preparation of DMT. The analytical characterisation of the first stage was the subject of previous publications by the authors and involved the thermal decarboxylation of tryptophan and the formation of tryptamine. The present study reports on the characterisation of the second step of this procedure which was based on the methylation of tryptamine. This employed methyl iodide and benzyltriethylammonium chloride/sodium hydroxide as a phase transfer catalyst. The reaction product was characterised by liquid chromatography/electrospray ionisation tandem mass spectrometry and orthogonal acceleration time-of-flight mass spectrometry. Quantitative evaluation was carried out in positive multiple reaction monitoring mode (MRM), which included synthesis of the identified reaction products. MRM screening of the product did not lead to the detection of DMT. Instead, 11.1% tryptamine starting material, 21.0% N,N,N-trimethyltryptammonium iodide (TMT) and 47.4% 1-N-methyl-TMT were detected. A 0.5% trace of the monomethylated N-methyltryptamine was also detected. This study demonstrated the impact on product purity of doubtful synthetic methodologies discussed on the internet. PMID:19592003

  2. Trace analysis of quinolone and fluoroquinolone antibiotics from wastewaters by liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Xiao, Yang; Chang, Hong; Jia, Ai; Hu, Jianying

    2008-12-19

    A sensitive liquid chromatography-electrospray tandem mass spectrometry method, combined with solid-phase extraction and a weak cation exchange cartridge cleanup, was established for twenty quinolone and fluoroquinolone antibiotics (pipemidic acid, flerofloxacin, ofloxacin, pefloxacin, enoxacin, norfloxacin, ciprofloxacin, danofloxacin, enrofloxacin, lomefloxacin, difloxacin, sarafloxacin, gatifloxacin, sparfloxacin, moxifloxacin, cinoxacin, oxolinic acid, nalidixic acid, flumequine, and piromidic acid) in influent, effluent, and river waters. For the various water matrices considered, the overall recoveries were from 64% to 127% except for piromidic acid (27-33%), and no obvious matrix effect was observed. The method detection limits for the twenty target antibiotics in the influent, effluent, and surface water samples were 1.6-50 ng/L, 0.6-50 ng/L, and 0.8-50 ng/L, respectively. This method was applied to analyze residual quinolone and fluoroquinolone antibiotics in wastewater and surface water samples from Beijing, China. Eight antibiotics (12 (pipemidic acid)-1208 ng/L (ofloxacin)) were detected in wastewater, and seven (1.3 (lomefloxacin)-535 ng/L (ofloxacin)) were detected in surface water samples. Gatifloxacin, a 4th generation fluoroquinolone antibiotic, was detected for the first time in influent (111 ng/L), effluent (56 ng/L), and river water (16-42 ng/L). PMID:19007934

  3. Gas Chromatography/Atmospheric Pressure Chemical Ionization Tandem Mass Spectrometry for Fingerprinting the Macondo Oil Spill.

    Science.gov (United States)

    Lobodin, Vladislav V; Maksimova, Ekaterina V; Rodgers, Ryan P

    2016-07-01

    We report the first application of a new mass spectrometry technique (gas chromatography combined to atmospheric pressure chemical ionization tandem mass spectrometry, GC/APCI-MS/MS) for fingerprinting a crude oil and environmental samples from the largest accidental marine oil spill in history (the Macondo oil spill, the Gulf of Mexico, 2010). The fingerprinting of the oil spill is based on a trace analysis of petroleum biomarkers (steranes, diasteranes, and pentacyclic triterpanes) naturally occurring in crude oil. GC/APCI enables soft ionization of petroleum compounds that form abundant molecular ions without (or little) fragmentation. The ability to operate the instrument simultaneously in several tandem mass spectrometry (MS/MS) modes (e.g., full scan, product ion scan, reaction monitoring) significantly improves structural information content and sensitivity of analysis. For fingerprinting the oil spill, we constructed diagrams and conducted correlation studies that measure the similarity between environmental samples and enable us to differentiate the Macondo oil spill from other sources. PMID:27281271

  4. Identification of the Related Substances in Ampicillin Capsule by Rapid Resolution Liquid Chromatography Coupled with Electrospray Ionization Tandem Mass Spectrometry

    OpenAIRE

    Lei Zhang; Xian Long Cheng; Yang Liu; Miao Liang; Honghuan Dong; Beiran Lv; Wenning Yang; Zhiqiang Luo; Mingmin Tang

    2014-01-01

    Rapid Resolution Liquid Chromatography coupled with Electrospray Ionization Tandem Mass Spectrometry (RRLC-ESI-MSn) was used to separate and identify related substances in ampicillin capsule. The fragmentation behaviors of related substances were used to identify their chemical structures. Finally, a total of 13 related substances in ampicillin capsule were identified, including four identified components for the first time and three groups of isomers on the basis of the exact mass, fragmenta...

  5. Ultra-high performance liquid chromatography-electrospray tandem mass spectrometry for the analysis of antibiotic residues in environmental waters.

    Science.gov (United States)

    Xue, Qiang; Qi, Yanjie; Liu, Fei

    2015-11-01

    An optimized solid-phase extraction (SPE) and ultra-high performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-MS/MS) method was developed for the effective analysis of 35 antibiotics including sulfonamides (SAs), quinolones (QLs), tetracyclines (TCs), macrolides (MALs), lincomycin (LIN), and chloramphenicol (CAP). The addition of 0.1% formic acid to the mobile phase was favorable for the formation of [M + H](+) and the enhancement in the detection signals, but using ammonium formate decreased [M + H](+) with a corresponding reduction in the response of CAP. The optimal pH range for the SPE was 4.5 ∼ 5.0 with 6 mL aqueous ammonia/methanol (5/95, v/v) as the optimized eluent. An internal standard (IS) was selected for each type of analytes based on similarities in classification and retention time. The detection was completed in less than 10 min and was excellent with method detection limits (MDL) of 0.29 ∼ 4.03 ng/L. The recoveries of the antibiotics in samples from ultrapure water and groundwater were 67.13 ∼ 93.00% and 68.91 ∼ 92.67%, respectively. The antibiotics in samples collected from wastewater, surface water, and groundwater were also effectively detected. This newly developed method has the advantages of short detection times, small sample consumption, excellent reproducibility, and high sensitivity. This provides a reliable and promising technique for the simultaneous detection and monitoring of various residual antibiotics in aqueous environmental samples. PMID:26104902

  6. Enantiomeric quantification of (S)-(+)-methamphetamine in urine by an immunoaffinity column and liquid chromatography-electrospray-mass spectrometry

    International Nuclear Information System (INIS)

    A method using an immunoaffinity column (IAC) and liquid chromatography-electrospray ionization mass spectrometry (LC/MS) for on-line detecting the presence of MA in the effluent was developed for the quantitative and enantiomeric determination of (S)-(+)-methamphetamine (D-MA) in urine. The IAC was made in our laboratory and utilized in the LC/MS to simultaneously extract and separate enantiomers of MA from urine samples. An aqueous ammonium acetate buffer was used as the mobile phase. Urine samples were spiked with racemic deuterated methamphetamine (MA-d14) as internal standard (IS), filtered through a membrane, and injected into the LC/MS without any further pre-treatment. Protonated molecular ion of MA and MA-d14 (m/z 150 and 164) were isolated and further fragmented, the respective product ions, m/z 119 and 130, were collected for quantitative determination. This is an improvement of our previous method (A.C. Lua, Tsong-Yung Chou, J. Chromatogr. A 967 (2002) 191). In the previous method, MA was separated with HPLC, the efflux was fractionated and each fraction was either determined with an immunoassay or GC/MS. Monitoring of MA in the efflux is tedious and time consuming. Urine samples spiked with different concentrations of D-MA were measured by this method. A linear relationship exists in the 150-1050 ng/mL range, and the detection limit (defined as signal-to-noise ratio 3) of D-MA was determined to be 18 ng/mL. The linearity of the method for D-MA can be described by the equation (Y = 1.415 x 10-3 X + 0.034, correlation coefficient: r 2 = 0.999). Within run, accuracy and precision (n = 6, relative error: -7.2 to +4.0% and relative standard deviation: 3.8-9.3%) of the method are fairly good

  7. Quantification of γ-Aminobutyric Acid in Cerebrospinal Fluid Using Liquid Chromatography-Electrospray Tandem Mass Spectrometry.

    Science.gov (United States)

    Arning, Erland; Bottiglieri, Teodoro

    2016-01-01

    We describe a simple stable isotope dilution method for accurate and precise measurement of γ-aminobutyric acid (GABA), a major inhibitory neurotransmitter in human cerebrospinal fluid (CSF) as a clinical diagnostic test. Determination of GABA in CSF (50 μL) was performed utilizing high performance liquid chromatography coupled with electrospray positive ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Analysis of free and total GABA requires two individual sample preparations and mass spectrometry analyses. Free GABA in CSF is determined by a 1:2 dilution with internal standard (GABA-D2) and injected directly onto the HPLC-ESI-MS/MS system. Determination of total GABA in CSF requires additional sample preparation in order to hydrolyze all the bound GABA in the sample to the free form. This requires hydrolyzing the sample by boiling in acidic conditions (hydrochloric acid) for 4 h. The sample is then further diluted 1:10 with a 90 % acetonitrile/0.1 % formic acid solution and injected into the HPLC-ESI-MS/MS system. Each assay is quantified using a five-point standard curve and is linear from 6 nM to 1000 nM and 0.63 μM to 80 μM for free and total GABA, respectively. PMID:26602123

  8. A method for profiling gangliosides in animal tissues using electrospray ionization-tandem mass spectrometry.

    Science.gov (United States)

    Tsui, Zhao-Chun; Chen, Qi-Rui; Thomas, Michael J; Samuel, Michael; Cui, Zheng

    2005-06-15

    Gangliosides are critical in many functions of mammalian cells but present as a minor lipid component with many molecular species of subtle differences. Conventional strategies for profiling gangliosides suffer from poor reproducibility, low sensitivity, and low-throughput capacity. Prior separation of gangliosides by thin-layer chromatography and/or high-performance liquid chromatography not only was laborious and tedious but also could introduce uneven losses of molecular species. We developed a new strategy of using electrospray ionization-tandem mass spectrometry (ESI-MS/MS) to profile gangliosides with high-throughput potential. This strategy involves three new findings: (i) collision-induced fragmentation of gangliosides gave rise to a common ion of m/z 290, a derivative of N-acetylneuraminic acid; (ii) phospholipids exert a profound suppression of ganglioside detection in ESI-MS/MS to prevent a direct detection in total cellular lipid extracts; and (iii) enrichment of gangliosides in the aqueous phase from total cellular lipid extracts eliminates the damping effect of phospholipids and permits direct precursor scan. PMID:15907870

  9. Tools to discover anionic and nonionic polyfluorinated alkyl surfactants by liquid chromatography electrospray ionisation mass spectrometry

    DEFF Research Database (Denmark)

    Trier, Xenia; Granby, Kit; Christensen, Jan H.

    2011-01-01

    A tiered approach is proposed for the discovery of unknown anionic and nonionic polyfluorinated alkyl surfactants (PFASs) by reversed phase ultra high performance liquid chromatography (UHPLC) – negative electrospray ionisation – quadrupole time of flight mass spectrometry (UHPLC–ESI−–QTOF–MS). T.......g., structural PFAS isomers. The method has been used to discover PFASs in industrial blends and in extracts from food contact materials....

  10. Quantitative determination of capsaicinoids by liquid chromatography-electrospray mass spectrometry.

    Science.gov (United States)

    Thompson, Robert Q; Phinney, Karen W; Welch, Michael J; White, Edward

    2005-04-01

    Eight naturally occurring capsaicinoids have been determined in Capsicum by use of high-purity standards, with norcapsaicin as an internal standard. The solid standards were rigorously checked for purity. The sensitivity of electrospray ionization (ESI), atmospheric-pressure chemical ionization (APCI), and coordination ion-spray (CIS; with silver) toward the capsaicinoids were measured and compared. The highest sensitivity was found for positive-ion ESI. Method validation of the liquid chromatography-ESI-mass spectrometry (LC-ESI-MS) determination is reported, including tests for repeatability (4%), detection limit (5 pg injected), linear range (20-6 ng injected), quantitation (excellent linearity; pepper fruits were quantified. PMID:15803309

  11. Determination of synthetic ferric chelates used as fertilizers by liquid chromatography-electrospray/mass spectrometry in agricultural matrices.

    Science.gov (United States)

    Alvarez-Fernández, Ana; Orera, Irene; Abadía, Javier; Abadía, Anunciación

    2007-01-01

    A high-performance liquid chromatography-electrospray ionization/mass spectrometry (time of flight) method has been developed for the simultaneous determination of synthetic Fe(III)-chelates used as fertilizers. Analytes included the seven major Fe(III)-chelates used in agriculture, Fe(III)-EDTA, Fe(III)-DTPA, Fe(III)-HEDTA, Fe(III)-CDTA, Fe(III)-o,oEDDHA, Fe(III)-o,pEDDHA, and Fe(III)-EDDHMA, and the method was validated using isotope labeled (57)Fe(III)-chelates as internal standards. Calibration curves had R values in the range 0.9962-0.9997. Limits of detection and quantification were in the ranges 3-164 and 14-945 pmol, respectively. Analyte concentrations could be determined between the limits of quantification and 25 muM (racemic and meso Fe(III)-o,oEDDHA and Fe(III)-EDDHMA) or 50 muM (Fe(III)-EDTA, Fe(III)-HEDTA, Fe(III)-DTPA, Fe(III)-CDTA and Fe(III)-o,pEDDHA). The average intraday repeatability values were approximately 0.5 and 5% for retention time and peak area, respectively, whereas the interday repeatability values were approximately 0.7 and 8% for retention time and peak area, respectively. The method was validated using four different agricultural matrices, including nutrient solution, irrigation water, soil solution, and plant xylem exudates, spiked with Fe(III)-chelate standards and their stable isotope-labeled corresponding chelates. Analyte recoveries found were in the ranges 92-101% (nutrient solution), 89-102% (irrigation water), 82-100% (soil solution), and 70-111% (plant xylem exudates). Recoveries depended on the analyte, with Fe(III)-EDTA and Fe(III)-DTPA showing the lowest recoveries (average values of 87 and 88%, respectively, for all agricultural matrices used), whereas for other analytes recoveries were between 91 and 101%. The method was also used to determine the real concentrations of Fe(III)-chelates in commercial fertilizers. Furthermore, the method is also capable of resolving two more synthetic Fe(III)-chelates, Fe

  12. Quantitation of S-Adenosylmethionine and S-Adenosylhomocysteine in Plasma Using Liquid Chromatography-Electrospray Tandem Mass Spectrometry.

    Science.gov (United States)

    Arning, Erland; Bottiglieri, Teodoro

    2016-01-01

    We describe a simple stable isotope dilution method for accurate determination of S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) in plasma as a diagnostic test. SAM and SAH are key metabolic intermediates of methionine metabolism and the methylation cycle. Determination of SAM and SAH in plasma was performed by high performance liquid chromatography coupled with electrospray positive ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Calibrators (SAM and SAH) and internal standards ((2)H3-SAM and (2)H4-SAH) were included in each analytical run for calibration. Sample preparation involved combining 20 μL sample with 180 μL of internal standard solution consisting of heavy isotope labeled internal standards in mobile phase A and filtering by ultracentrifugation through a 10 kd MW cutoff membrane. Sample filtrate (3 μL) was injected by a Shimadzu Nexera LC System interfaced with a 5500 QTRAP(®) (AB Sciex). Chromatographic separation was achieved on a 250 mm × 2.0 mm EA:faast column from Phenomenex. Samples were eluted at a flow rate of 0.20 mL/min with a binary gradient with a total run time of 10 min. The source operated in positive ion mode at an ion spray voltage of +5000 V. SAM and SAH resolved by a gradient to 100 % methanol with retention times of 6.0 and 5.7 min, respectively. The observed m/z values of the fragment ions were m/z 399 → 250 for SAM, m/z 385 → 136 for SAH, m/z 402 → 250 for (2)H3-SAM, m/z 203 → 46. The calibration curve was linear over the ranges of 12.5-5000 nmol/L for SAM and SAH. PMID:26602137

  13. Identification of 3',4'-Dimethoxy Flavonol-3-β-d-Glucopyranoside Metabolites in Rats by Liquid Chromatography-Electrospray Ionization Ion Trap Mass Spectrometry.

    Science.gov (United States)

    Zhu, Yuan; Wen, Jun; Cao, Yuqing; Jiang, Yuanying; Huang, Jinghua; Fan, Guorong; Lou, Yuefen

    2016-01-01

    A method using liquid chromatography-electrospray ionization ion trap mass spectrometry was established for the identification of metabolites in feces, urine and bile in rats after oral administration of 3',4'-dimethoxy flavonol-3-β-d-glucopyranoside (abbreviated DF3G). Seven metabolites in rat feces, urine and bile were firstly identified on the basis of their MS fragmentation behaviors. Three metabolites were identified in the feces, 6 in the urine and 2 in the bile, which suggested that demethylation, deglycosylation and deglycosylation followed by glucuronide conjugation were the major metabolic pathways for DF3G in vivo. Hydrolyzation might be the first step in the absorption and metabolism of DF3G. The possible metabolic pathway was proposed for the first time. The established method was simple, reliable and sensitive, revealing that it could be used to rapidly screen and identify the structures of metabolites of DF3G to better understand its metabolism in vivo. PMID:27070571

  14. Identification of the Related Substances in Ampicillin Capsule by Rapid Resolution Liquid Chromatography Coupled with Electrospray Ionization Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2014-01-01

    Full Text Available Rapid Resolution Liquid Chromatography coupled with Electrospray Ionization Tandem Mass Spectrometry (RRLC-ESI-MSn was used to separate and identify related substances in ampicillin capsule. The fragmentation behaviors of related substances were used to identify their chemical structures. Finally, a total of 13 related substances in ampicillin capsule were identified, including four identified components for the first time and three groups of isomers on the basis of the exact mass, fragmentation behaviors, retention time, and chemical structures in the literature. This study avoided time-consuming and complex chemosynthesis of related substances of ampicillin and the results could be useful for the quality control of ampicillin capsule to guarantee its safety in clinic. In the meantime, it provided a good example for the rapid identification of chemical structures of related substances of drugs.

  15. Identification of the related substances in ampicillin capsule by rapid resolution liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Zhang, Lei; Cheng, Xian Long; Liu, Yang; Liang, Miao; Dong, Honghuan; Lv, Beiran; Yang, Wenning; Luo, Zhiqiang; Tang, Mingmin

    2014-01-01

    Rapid Resolution Liquid Chromatography coupled with Electrospray Ionization Tandem Mass Spectrometry (RRLC-ESI-MS(n)) was used to separate and identify related substances in ampicillin capsule. The fragmentation behaviors of related substances were used to identify their chemical structures. Finally, a total of 13 related substances in ampicillin capsule were identified, including four identified components for the first time and three groups of isomers on the basis of the exact mass, fragmentation behaviors, retention time, and chemical structures in the literature. This study avoided time-consuming and complex chemosynthesis of related substances of ampicillin and the results could be useful for the quality control of ampicillin capsule to guarantee its safety in clinic. In the meantime, it provided a good example for the rapid identification of chemical structures of related substances of drugs. PMID:25530907

  16. Liquid chromatographic-mass spectrometric analysis of glucuronide-conjugated anabolic steroid metabolites: method validation and interlaboratory comparison

    NARCIS (Netherlands)

    Hintikka, L.; Kuuranne, T.; Leinonen, A.; Thevis, M.; Schanzer, W.; Halket, J.; Cowan, D.; Grosse, J.; Hemmersbach, P.; Nielen, M.W.F.; Kostiainen, R.

    2008-01-01

    Liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method for simultaneous and direct detection of 12 glucuronide-conjugated anabolic androgenic steroid (AAS) metabolites in human urine is described. The compounds selected were the main metabolites detected in huma

  17. Separation of small molecular peptides with the same amino acid composition but different sequences by high performance liquid chromatography-electrospray ionization-mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Peptidomics has emerged as a new discipline in recent years. Mass spectrometry (MS) is the most universal and efficient tool for structure identification of proteins and peptides. However,there is a limitation for the identification of peptides with the same amino acid composition but different se-quences because these peptides have identical mass spectra of molecular ions. This paper presents a high performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) method for the separation of small molecular peptides with the same amino acid composition but dif-ferent sequences. Two tripeptides of Gly-Ser-Phe and Gly-Phe-Ser were used as a model sample. The separation behavior has been investigated and the separation conditions have been optimized. Under the optimum conditions,good repeatability was achieved. The developed method could provide a helpful reference for the separation of other peptides with the same amino acid composition but different sequences in the study of proteomics and peptidomics.

  18. Quantification of voriconazole in human plasma by high-performance liquid chromatography-electrospray ionization mass spectrometry: application to a bioequivalence study.

    Science.gov (United States)

    Cheng, Ying; Zhang, Zun-Jian; Tian, Yuan; Li, Wen-Jing; Wei, Wei

    2011-01-01

    A sensitive and specific liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method was developed and validated for the identification and quantification of voriconazole (VRC, CAS 137234-62-9) in human plasma. Following liquid-liquid extraction, VRC and loratadine (internal standard, CAS 79794-75-5) were separated using a mobile phase comprised of methanol: water (0.1% formic acid) = 75:25 v/v on a Shimadzu Shim-pack VP-ODS C18 (150 x 2.0 mm ID, 5 microm) column and analyzed by electrospray ionization mass spectrometry. The chromatographic separation was achieved in less than 6 min. The standard curves were linear (r = 0.9994) over the concentration range of 2-2000 ng/mL for VRC and had good accuracy and precision. Both intra- and inter-batch standard deviations were less than 15%. The method was successfully applied to study the comparative bioavailability of VRC tablets test vs. reference in healthy Chinese volunteers through the statistical comparison of pharmacokinetic parameters obtained with the two formulations. PMID:21428249

  19. Identification of 3′,4′-Dimethoxy Flavonol-3-β-d-Glucopyranoside Metabolites in Rats by Liquid Chromatography-Electrospray Ionization Ion Trap Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Yuan Zhu

    2016-04-01

    Full Text Available A method using liquid chromatography-electrospray ionization ion trap mass spectrometry was established for the identification of metabolites in feces, urine and bile in rats after oral administration of 3′,4′-dimethoxy flavonol-3-β-d-glucopyranoside (abbreviated DF3G. Seven metabolites in rat feces, urine and bile were firstly identified on the basis of their MS fragmentation behaviors. Three metabolites were identified in the feces, 6 in the urine and 2 in the bile, which suggested that demethylation, deglycosylation and deglycosylation followed by glucuronide conjugation were the major metabolic pathways for DF3G in vivo. Hydrolyzation might be the first step in the absorption and metabolism of DF3G. The possible metabolic pathway was proposed for the first time. The established method was simple, reliable and sensitive, revealing that it could be used to rapidly screen and identify the structures of metabolites of DF3G to better understand its metabolism in vivo.

  20. High-internal-phase-emulsion polymeric monolith coupled with liquid chromatography-electrospray tandem mass spectrometry for enrichment and sensitive detection of trace cytokinins in plant samples.

    Science.gov (United States)

    Du, Fuyou; Sun, Lin; Zhen, Xian; Nie, Honggang; Zheng, Yanjie; Ruan, Guihua; Li, Jianping

    2015-08-01

    High-internal-phase-emulsion polymers (polyHIPEs) show great promise as solid-phase-extraction (SPE) materials because of the tremendous porosity and highly interconnected framework afforded by the high-internal-phase-emulsion (HIPE) technique. In this work, polyHIPE monolithic columns as novel SPE materials were prepared and applied to trace enrichment of cytokinins (CKs) from complex plant samples. The polyHIPE monoliths were synthesized via the in-situ polymerization of the continuous phase of a HIPE containing styrene (STY) and divinylbenzene (DVB) in a stainless column, and revealed highly efficient and selective enrichment ability for aromatic compounds. Under the optimized experimental conditions, a method using a monolithic polyHIPE column combined with liquid chromatography-electrospray tandem mass spectrometry (LC-MS-MS) was developed for the simultaneous extraction and sensitive determination of trans-zeatin (tZ), meta-topolin (mT), kinetin (K), and kinetin riboside (KR). The proposed method had good linearity, with correlation coefficients (R (2)) from 0.9957 to 0.9984, and low detection limits (LODs, S/N = 3) in the range 2.4-47 pg mL(-1) for the four CKs. The method was successfully applied to the determination of CKs in real plant samples, and obtained good recoveries ranging from 68.8 % to 103.0 % and relative standard deviations (RSDs) lower than 16 %. PMID:26025552

  1. Fast gas chromatography and negative-ion chemical ionization tandem mass spectrometry for forensic analysis of cannabinoids in whole blood.

    Science.gov (United States)

    Thomas, Aurélien; Widmer, Christèle; Hopfgartner, Gérard; Staub, Christian

    2007-11-01

    The present work describes a fast gas chromatography/negative-ion chemical ionization tandem mass spectrometric assay (Fast GC/NICI-MS/MS) for analysis of tetrahydrocannabinol (THC), 11-hydroxy-tetrahydrocannabinol (THC-OH) and 11-nor-9-carboxy-tetrahydrocannabinol (THC-COOH) in whole blood. The cannabinoids were extracted from 500 microL of whole blood by a simple liquid-liquid extraction (LLE) and then derivatized by using trifluoroacetic anhydride (TFAA) and hexafluoro-2-propanol (HFIP) as fluorinated agents. Mass spectrometric detection of the analytes was performed in the selected reaction-monitoring mode on a triple quadrupole instrument after negative-ion chemical ionization. The assay was found to be linear in the concentration range of 0.5-20 ng/mL for THC and THC-OH, and of 2.5-100 ng/mL for THC-COOH. Repeatability and intermediate precision were found less than 12% for all concentrations tested. Under standard chromatographic conditions, the run cycle time would have been 15 min. By using fast conditions of separation, the assay analysis time has been reduced to 5 min, without compromising the chromatographic resolution. Finally, a simple approach for estimating the uncertainty measurement is presented. PMID:17913432

  2. Characterization of Proanthocyanidins from Parkia biglobosa (Jacq. G. Don. (Fabaceae by Flow Injection Analysis — Electrospray Ionization Ion Trap Tandem Mass Spectrometry and Liquid Chromatography/Electrospray Ionization Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Wagner Vilegas

    2013-03-01

    Full Text Available The present study investigates the chemical composition of the African plant Parkia biglobosa (Fabaceae roots and barks by Liquid Chromatography - Electrospray Ionization and Direct Injection Tandem Mass Spectrometry analysis. Mass spectral data indicated that B-type oligomers are present, namely procyanidins and prodelphinidins, with their gallate and glucuronide derivatives, some of them in different isomeric forms. The analysis evidenced the presence of up to 40 proanthocyanidins, some of which are reported for the first time. In this study, the antiradical activity of extracts of roots and barks from Parkia biglobosa was evaluated using DPPH method and they showed satisfactory activities.

  3. Analysis of caged xanthones from the resin of Garcinia hanburyi using ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Yan [Hong Kong Jockey Club Institute of Chinese Medicine, Shatin, Hong Kong (China); Liu Xin [Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, Sichuan Province (China); Yang Jing [School of Chemistry and Chemical Technology, Shanghai Jiao Tong University, Shanghai 200240 (China); Han Quanbin; Song Jingzheng; Li Songlin; Qiao Chunfeng [Hong Kong Jockey Club Institute of Chinese Medicine, Shatin, Hong Kong (China); Ding Lisheng [Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, Sichuan Province (China)], E-mail: lsding@cib.ac.cn; Xu Hongxi [Hong Kong Jockey Club Institute of Chinese Medicine, Shatin, Hong Kong (China)], E-mail: xuhongxi@hkjcicm.org

    2008-11-23

    On-line ultra high-performance liquid chromatography (UHPLC) coupled with electrospray quadrupole time-of-flight tandem mass spectrometry (ESI-QTOF-MS/MS/MS) has been developed for the analysis of a series of caged xanthones in the resin of Garcinia hanburyi. The fragmentation of protonated molecular ions for 12 known cadged xanthones was carried out using low-energy collision-induced electrospray ionization tandem mass spectrometry. It was found that Retro-Diels-Alder rearrangement occurred in the CID processes and produced the characteristic fragment ions, which are especially valuable for the identification of this class of xanthones. The fragmentation differential between some cis-, trans-isomers was uncovered. Computation methods were utilized to rationalize the observed MS behaviors. On-line UHPLC-ESI-MS/MS/MS method has proved to be rapid and efficient in that within 6 min, 15 caged scaffold xanthones, including three pairs of epimers and four pairs of isomers in gamboges, were effectively separated and identified. Among them, two known, namely isogambogenin (13) and isomorellinol (14) and one likely new caged Garcinia xanthones from the Garcinia hanburyi were tentatively characterized based on the tandem mass spectra of known ones.

  4. Analysis of caged xanthones from the resin of Garcinia hanburyi using ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry

    International Nuclear Information System (INIS)

    On-line ultra high-performance liquid chromatography (UHPLC) coupled with electrospray quadrupole time-of-flight tandem mass spectrometry (ESI-QTOF-MS/MS/MS) has been developed for the analysis of a series of caged xanthones in the resin of Garcinia hanburyi. The fragmentation of protonated molecular ions for 12 known cadged xanthones was carried out using low-energy collision-induced electrospray ionization tandem mass spectrometry. It was found that Retro-Diels-Alder rearrangement occurred in the CID processes and produced the characteristic fragment ions, which are especially valuable for the identification of this class of xanthones. The fragmentation differential between some cis-, trans-isomers was uncovered. Computation methods were utilized to rationalize the observed MS behaviors. On-line UHPLC-ESI-MS/MS/MS method has proved to be rapid and efficient in that within 6 min, 15 caged scaffold xanthones, including three pairs of epimers and four pairs of isomers in gamboges, were effectively separated and identified. Among them, two known, namely isogambogenin (13) and isomorellinol (14) and one likely new caged Garcinia xanthones from the Garcinia hanburyi were tentatively characterized based on the tandem mass spectra of known ones

  5. Development of a method for comprehensive and quantitative analysis of plant hormones by highly sensitive nanoflow liquid chromatography-electrospray ionization-ion trap mass spectrometry

    International Nuclear Information System (INIS)

    In recent plant hormone research, there is an increased demand for a highly sensitive and comprehensive analytical approach to elucidate the hormonal signaling networks, functions, and dynamics. We have demonstrated the high sensitivity of a comprehensive and quantitative analytical method developed with nanoflow liquid chromatography-electrospray ionization-ion trap mass spectrometry (LC-ESI-IT-MS/MS) under multiple-reaction monitoring (MRM) in plant hormone profiling. Unlabeled and deuterium-labeled isotopomers of four classes of plant hormones and their derivatives, auxins, cytokinins (CK), abscisic acid (ABA), and gibberellins (GA), were analyzed by this method. The optimized nanoflow-LC-ESI-IT-MS/MS method showed ca. 5-10-fold greater sensitivity than capillary-LC-ESI-IT-MS/MS, and the detection limits (S/N = 3) of several plant hormones were in the sub-fmol range. The results showed excellent linearity (R2 values of 0.9937-1.0000) and reproducibility of elution times (relative standard deviations, RSDs, <1.1%) and peak areas (RSDs, <10.7%) for all target compounds. Further, sample purification using Oasis HLB and Oasis MCX cartridges significantly decreased the ion-suppressing effects of biological matrix as compared to the purification using only Oasis HLB cartridge. The optimized nanoflow-LC-ESI-IT-MS/MS method was successfully used to analyze endogenous plant hormones in Arabidopsis and tobacco samples. The samples used in this analysis were extracted from only 17 tobacco dry seeds (1 mg DW), indicating that the efficiency of analysis of endogenous plant hormones strongly depends on the detection sensitivity of the method. Our analytical approach will be useful for in-depth studies on complex plant hormonal metabolism.

  6. Development of a method for comprehensive and quantitative analysis of plant hormones by highly sensitive nanoflow liquid chromatography-electrospray ionization-ion trap mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Izumi, Yoshihiro; Okazawa, Atsushi; Bamba, Takeshi; Kobayashi, Akio [Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Fukusaki, Eiichiro, E-mail: fukusaki@bio.eng.osaka-u.ac.jp [Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2009-08-26

    In recent plant hormone research, there is an increased demand for a highly sensitive and comprehensive analytical approach to elucidate the hormonal signaling networks, functions, and dynamics. We have demonstrated the high sensitivity of a comprehensive and quantitative analytical method developed with nanoflow liquid chromatography-electrospray ionization-ion trap mass spectrometry (LC-ESI-IT-MS/MS) under multiple-reaction monitoring (MRM) in plant hormone profiling. Unlabeled and deuterium-labeled isotopomers of four classes of plant hormones and their derivatives, auxins, cytokinins (CK), abscisic acid (ABA), and gibberellins (GA), were analyzed by this method. The optimized nanoflow-LC-ESI-IT-MS/MS method showed ca. 5-10-fold greater sensitivity than capillary-LC-ESI-IT-MS/MS, and the detection limits (S/N = 3) of several plant hormones were in the sub-fmol range. The results showed excellent linearity (R{sup 2} values of 0.9937-1.0000) and reproducibility of elution times (relative standard deviations, RSDs, <1.1%) and peak areas (RSDs, <10.7%) for all target compounds. Further, sample purification using Oasis HLB and Oasis MCX cartridges significantly decreased the ion-suppressing effects of biological matrix as compared to the purification using only Oasis HLB cartridge. The optimized nanoflow-LC-ESI-IT-MS/MS method was successfully used to analyze endogenous plant hormones in Arabidopsis and tobacco samples. The samples used in this analysis were extracted from only 17 tobacco dry seeds (1 mg DW), indicating that the efficiency of analysis of endogenous plant hormones strongly depends on the detection sensitivity of the method. Our analytical approach will be useful for in-depth studies on complex plant hormonal metabolism.

  7. Fully automated analysis of beta-lactams in bovine milk by online solid phase extraction-liquid chromatography-electrospray-tandem mass spectrometry.

    Science.gov (United States)

    Kantiani, Lina; Farré, Marinella; Sibum, Martin; Postigo, Cristina; López de Alda, Miren; Barceló, Damiá

    2009-06-01

    A fully automated method for the detection of beta-lactam antibiotics, including six penicillins (amoxicillin, ampicillin, cloxacillin, dicloxacillin, oxacillin, and penicillin G) and four cephalosporins (cefazolin, ceftiofur, cefoperazone, and cefalexin) in bovine milk samples has been developed. The outlined method is based on online solid-phase extraction-liquid chromatography/electrospray-tandem mass spectrometry (SPE-LC/ESI-MS-MS). Target compounds were concentrated from 500 microL of centrifuged milk samples using an online SPE procedure with C18 HD cartridges. Target analytes were eluted with a gradient mobile phase (water + 0.1% formic acid/methanol + 0.1% formic acid) at a flow rate of 0.7 mL/min. Chromatographic separation was achieved within 10 min using a C-12 reversed phase analytical column. For unequivocal identification and confirmation, two multiple reaction monitoring (MRM) transitions were acquired for each analyte in the positive electrospray ionization mode (ESI(+)). Method limits of detection (LODs) in milk were well below the maximum residue limits (MRLs) set by the European Union for all compounds. Limits of quantification in milk were between 0.09 ng/mL and 1.44 ng/mL. The developed method was validated according to EU's requirements, and accuracy results ranged from 80 to 116%. Finally, the method was applied to the analysis of twenty real samples previously screened by the inhibition of microbial growth test Eclipse 100. This new developed method offers high sensitivity and accuracy of results, minimum sample pre-treatment, and uses for the first time an automated online SPE offering a high throughput analysis. Because of all these characteristics, the proposed method is applicable and could be deemed necessary within the field of food control and safety. PMID:19402673

  8. Analysis of Norditerpenoid Alkaloids Extracted from Aconitum sinomantanum Nakai by Electrospray Ionization Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Electrospray ionization mass spectrometry(ESI-MS) was applied simultaneously in determining norditerpenoid alkaloids from the roots of Aconitum sinomantanum Nakai (RAS) based on molecular mass information. The tandem mass spectra(ESI-MSn) provided the alkaloidal structural information, through which the existence of these alkaloids was further confirmed. Accordingly, six known norditerpenoid alkaloids were simultaneously determined on the basis of their ESI-MSn spectra. Furthermore, based on the diagnostic fragmentation pathways of alkaloidal MSn, a rapid method for direct detection and characterization of alkaloids from an ethanolic extract of RAS was described.

  9. Characteristic Fragmentation Behavior of Steroidal Phosphoramidate Conjugates in Electrospray Ionization Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    JI, San-Hao; JU, Yong; XIAO, Qiang; ZHAO, Yu-Fen

    2006-01-01

    Novel steroidal phosphoramidate conjugates of 3'-azido-2',3'-dideoxythymidine (AZT) and amino acid esters were synthesized and determined by positive and negative ion electrospray ionization mass spectrometry. The MS fragmentation behaviors of the steroidal phosphoramidate conjugates have been investigated in conjunction with tandem mass spectrometry of ESI-MS/MS. There were three characteristic fragment ions in the positive ion ESI mass spectra, which were the Na adduct ions with loss of steroidal moiety, amino acid ester moiety from pseudo molecular ion (M+Na)+, and the phosphoamino acid methyl ester Na adduct ion by a-cleavage of the phosphoramidate respectively. The main fragment ions in negative ion ESI mass spectra were the ion (M-HN3)-, the ion (M - AZT - H)- , and the ion (M-steroidal moiety-H)- besides the pseudo molecular ion (M-H)-. The fragmentation patterns did not depend on the attached amino acid ester moiety.

  10. High explosives vapor detection by atmospheric sampling glow discharge ionization/tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    McLuckey, S.A.; Goeringer, D.E.; Asano, K.G. [Oak Ridge National Lab., TN (United States). Chemical and Analytical Sciences Div.

    1996-02-01

    The combination of atmospheric sampling glow discharge ionization with tandem mass spectrometry for the detection of traces of high explosives is described. Particular emphasis is placed on use of the quadrupole ion trap as the type of tandem mass spectrometer. Atmospheric sampling glow discharge provides a simple, rugged, and efficient means for anion formation while the quadrupole ion trap provides for efficient tandem mass spectrometry. Mass selective ion accumulation and non-specific ion activation methods can be used to overcome deleterious effects arising from ion/ion interactions. Such interactions constitute the major potential technical barrier to the use of the ion trap for real-time monitoring of targeted compounds in uncontrolled and highly variable matrices. Tailored waveforms can be used to effect both mass selective ion accumulation and ion activation. Concatenated tailored waveforms allow for both functions in a single experiment thereby providing the capability for monitoring several targeted species simultaneously. The combination of atmospheric sampling glow discharge ionization with a state-of-the-art analytical quadrupole ion trap is a highly sensitive and specific detector for traces of high explosives. The combination is also small and inexpensive relative to virtually any other form of tandem mass spectrometry. The science and technology underlying the glow discharge/ion trap combination is sufficiently mature to form the basis for an engineering effort to make the detector portable. 85 refs.

  11. Study of electrospray ionization tandem mass spectrometry of the benzofuranone compounds

    Institute of Scientific and Technical Information of China (English)

    Zhan Qi Niu; Yu Min Sun; Feng Niu; Jian Han; Da Wei Chen

    2008-01-01

    A detailed analysis of benzofuranone compounds under multiple tandem mass spectrometry (ESI-MS(n)) conditions is reported. Element composition data of the fragment ions were obtained with the aid of comparison of the multiple tandem mass spectra of four compounds, and the structures of which are identical except for some substituted groups or epimers or ra-r/ww-isomers. Attempts have been made to provide rational pathways for the formation of the fragment ions from these protonated compounds. And the structure-fragmentation relationships will facilitate the characterization of the structures of other analogs.

  12. A novel automated hydrophilic interaction liquid chromatography method using diode-array detector/electrospray ionization tandem mass spectrometry for analysis of sodium risedronate and related degradation products in pharmaceuticals.

    Science.gov (United States)

    Bertolini, Tiziana; Vicentini, Lorenza; Boschetti, Silvia; Andreatta, Paolo; Gatti, Rita

    2014-10-24

    A simple, sensitive and fast hydrophilic interaction liquid chromatography (HILIC) method using ultraviolet diode-array detector (UV-DAD)/electrospray ionization tandem mass spectrometry was developed for the automated high performance liquid chromatography (HPLC) determination of sodium risedronate (SR) and its degradation products in new pharmaceuticals. The chromatographic separations were performed on Ascentis Express HILIC 2.7μm (150mm×2.1mm, i.d.) stainless steel column (fused core). The mobile phase consisted of formate buffer solution (pH 3.4; 0.03M)/acetonitrile 42:58 and 45:55 (v/v) for granules for oral solution and effervescent tablet analysis, respectively, at a flow-rate of 0.2mL/min, setting the wavelength at 262nm. Stability characteristics of SR were evaluated by performing stress test studies. The main degradation product formed under oxidation conditions corresponding to sodium hydrogen (1-hydroxy-2-(1-oxidopyridin-3-yl)-1-phosphonoethyl)phosphonate was characterized by high performance liquid chromatography-electrospray ionization-mass tandem mass spectrometry (HPLC-ESI-MS/MS). The validation parameters such as linearity, sensitivity, accuracy, precision and selectivity were found to be highly satisfactory. Linear responses were observed in standard and in fortified placebo solutions. Intra-day precision (relative standard deviation, RSD) was ≤1.1% for peak area and ≤0.2% for retention times (tR) without significant differences between intra- and inter-day data. Recovery studies showed good results for all the examined compounds (from 98.7 to 101.0%) with RSD ranging from 0.6 to 0.7%. The limits of detection (LOD) and quantitation (LOQ) were 1 and 3ng/mL, respectively. The high stability of standard and sample solutions at room temperature means an undoubted advantage of the method allowing the simultaneous preparation of many samples and consecutive chromatographic analyses by using an autosampler. The developed stability indicating

  13. Analysis of acylcarnitine profiles in umbilical cord blood and during the early neonatal period by electrospray ionization tandem mass spectrometry

    International Nuclear Information System (INIS)

    Acylcarnitine profiling by electrospray ionization tandem mass spectrometry (ESI-MS/MS) is a potent tool for the diagnosis and screening of fatty acid oxidation and organic acid disorders. Few studies have analyzed free carnitine and acylcarnitines in dried blood spots (DBS) of umbilical cord blood (CB) and the postnatal changes in the concentrations of these analytes. We have investigated these metabolites in healthy exclusively breastfed neonates and examined possible effects of birth weight and gestational age. DBS of CB were collected from 162 adequate for gestational age neonates. Paired DBS of heel-prick blood were collected 4-8 days after birth from 106 of these neonates, the majority exclusively breastfed. Methanol extracts of DBS with deuterium-labeled internal standards were derivatized before analysis by ESI-MS/MS. Most of the analytes were measured using a full-scan method. The levels of the major long-chain acylcarnitines, palmitoylcarnitine, stearoylcarnitine, and oleoylcarnitine, increased by 27, 12, and 109%, respectively, in the first week of life. Free carnitine and acetylcarnitine had a modest increase: 8 and 11%, respectively. Propionylcarnitine presented a different behavior, decreasing 9% during the period. The correlations between birth weight or gestational age and the concentrations of the analytes in DBS were weak (r ≤ 0.20) or nonsignificant. Adaptation to breast milk as the sole source of nutrients can explain the increase of these metabolites along the early neonatal period. Acylcarnitine profiling in CB should have a role in the early detection of metabolic disorders in high-risk neonates

  14. Analysis of acylcarnitine profiles in umbilical cord blood and during the early neonatal period by electrospray ionization tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    E. Vieira Neto

    2012-06-01

    Full Text Available Acylcarnitine profiling by electrospray ionization tandem mass spectrometry (ESI-MS/MS is a potent tool for the diagnosis and screening of fatty acid oxidation and organic acid disorders. Few studies have analyzed free carnitine and acylcarnitines in dried blood spots (DBS of umbilical cord blood (CB and the postnatal changes in the concentrations of these analytes. We have investigated these metabolites in healthy exclusively breastfed neonates and examined possible effects of birth weight and gestational age. DBS of CB were collected from 162 adequate for gestational age neonates. Paired DBS of heel-prick blood were collected 4-8 days after birth from 106 of these neonates, the majority exclusively breastfed. Methanol extracts of DBS with deuterium-labeled internal standards were derivatized before analysis by ESI-MS/MS. Most of the analytes were measured using a full-scan method. The levels of the major long-chain acylcarnitines, palmitoylcarnitine, stearoylcarnitine, and oleoylcarnitine, increased by 27, 12, and 109%, respectively, in the first week of life. Free carnitine and acetylcarnitine had a modest increase: 8 and 11%, respectively. Propionylcarnitine presented a different behavior, decreasing 9% during the period. The correlations between birth weight or gestational age and the concentrations of the analytes in DBS were weak (r £ 0.20 or nonsignificant. Adaptation to breast milk as the sole source of nutrients can explain the increase of these metabolites along the early neonatal period. Acylcarnitine profiling in CB should have a role in the early detection of metabolic disorders in high-risk neonates.

  15. Analysis of acylcarnitine profiles in umbilical cord blood and during the early neonatal period by electrospray ionization tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Vieira Neto, E. [Serviço de Genética Médica, Instituto de Puericultura e Pediatria Martagão Gesteira, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Laboratório Diagnósticos Laboratoriais Especializados, Rio de Janeiro, RJ (Brazil); Fonseca, A.A.; Almeida, R.F. [Laboratório Diagnósticos Laboratoriais Especializados, Rio de Janeiro, RJ (Brazil); Figueiredo, M.P.; Porto, M.A.S. [Maternidade Escola, Rio de Janeiro, RJ (Brazil); Ribeiro, M.G. [Serviço de Genética Médica, Instituto de Puericultura e Pediatria Martagão Gesteira, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil)

    2012-04-13

    Acylcarnitine profiling by electrospray ionization tandem mass spectrometry (ESI-MS/MS) is a potent tool for the diagnosis and screening of fatty acid oxidation and organic acid disorders. Few studies have analyzed free carnitine and acylcarnitines in dried blood spots (DBS) of umbilical cord blood (CB) and the postnatal changes in the concentrations of these analytes. We have investigated these metabolites in healthy exclusively breastfed neonates and examined possible effects of birth weight and gestational age. DBS of CB were collected from 162 adequate for gestational age neonates. Paired DBS of heel-prick blood were collected 4-8 days after birth from 106 of these neonates, the majority exclusively breastfed. Methanol extracts of DBS with deuterium-labeled internal standards were derivatized before analysis by ESI-MS/MS. Most of the analytes were measured using a full-scan method. The levels of the major long-chain acylcarnitines, palmitoylcarnitine, stearoylcarnitine, and oleoylcarnitine, increased by 27, 12, and 109%, respectively, in the first week of life. Free carnitine and acetylcarnitine had a modest increase: 8 and 11%, respectively. Propionylcarnitine presented a different behavior, decreasing 9% during the period. The correlations between birth weight or gestational age and the concentrations of the analytes in DBS were weak (r ≤ 0.20) or nonsignificant. Adaptation to breast milk as the sole source of nutrients can explain the increase of these metabolites along the early neonatal period. Acylcarnitine profiling in CB should have a role in the early detection of metabolic disorders in high-risk neonates.

  16. Direct analysis by electrospray ionization tandem mass spectrometry of mixtures of phosphatidyldiacylglycerols from Lactobacillus.

    Science.gov (United States)

    Cabrera, G M; Murga, M L; de Valdez, G F; Seldes, A M

    2000-12-01

    Electrospray ionization followed by collision-induced dissociation in a quadrupole ion trap mass spectrometer of mixtures of deprotonated phosphatidyldiacylglycerols afforded a group of three diagnostic ions of convenient abundance for each phosphatidyldiacylglycerol (PG) present in the mixture. Thus, it was possible to determine unmistakably the identity and substitution positions (sn-1 or sn-2) for both acyl groups of each PG present in the mixture. The method also allows the study of isomeric mixtures of PG and mixtures containing minor amounts of some PG from crude extracts of Lactobacillus acidophillus. The present results improve those of previous studies using fast atom bombardment and electrospray ionization tanden mass spectrometry, in which it was reported that it was possible to differentiate the identity and position of the sn-2 acyl substituent only by the presence of one ion, with variable abundance. PMID:11180636

  17. Quantitative analysis of positional isomers of triacylglycerols via electrospray ionization tandem mass spectrometry of sodiated adducts.

    Science.gov (United States)

    Herrera, Lisandra Cubero; Potvin, Michael A; Melanson, Jeremy E

    2010-09-01

    Herein we report a reversed-phase high-performance liquid chromatography tandem mass spectrometry (RP-HPLC/MS/MS) method for the analysis of positional isomers of triacylglycerols (TAGs) in vegetable oils. The fragmentation behavior of [M + X](+) ions (X = NH(4), Li, Na or Ag) was studied on a quadrupole-time-of-flight (Q-TOF) mass spectrometer under low-energy collision-induced dissociation (CID) conditions. Mass spectra that were dependent on the X(+) ion and the nature and position of the acyl substituents were observed for four pairs of 'AAB/ABA'-type TAGs, namely PPO/POP, OOP/OPO, LLO/LOL and OOL/OLO (where P is 16:0, palmitic acid; O is 18:1, oleic acid; and L is 18:2, linoleic acid). For the majority of [M + X](+) adducts, the loss of the fatty acid in the outer positions (sn-1 or sn-3) was favored over the loss in the central position (sn-2), which enabled the determination of the fractional abundance of the isomers. Ratios of the intensity of fragment ions at various AAB/ABA compositions produced linear calibration curves with positive slopes, comparable to those obtained traditionally by ESI-MS/MS of [M + NH(4)](+) adducts. The only exceptions were the [M + Ag](+) adducts of the PPO/POP system, which produced calibration curves with negative slopes. Sodium adducts provided the most consistent level of isomeric discrimination for the TAGs studied and also offered the most convenience in that they required no additive to the mobile phase. Therefore, calibration curve data derived from [M + Na](+) adducts were applied to the quantification of TAG regioisomers in sunflower and olive oils. The regiospecific analysis showed that palmitic acid was typically located at positions sn-1 or sn-3, whereas unsaturated fatty acids, oleic and linoleic acids were mostly found at the sn-2 position. PMID:20814981

  18. Determination of the brominated flame retardant, hexabroomcyclodocane in sediments and biota by liquid chromatography-electrospray ionization mass spectrometry

    NARCIS (Netherlands)

    Morris, S.; Bersuder, P.; Allchin, C.R.; Zegers, B.; Boon, J.P.; Leonards, P.E.G.; Boer, de J.

    2006-01-01

    A method involving reversed-phase, liquid chromatography coupled to electrospray ionisation mass spectrometry (LC-ESI-MS) was developed for separation, detection and quantitation of the alpha-, beta- and gamma-diastereoisomers of hexabromocyclododecane (HBCD). To address the lack of environmental da

  19. Characterisation of tryptic peptides of phosphorylated tyrosine hydroxylase by high-pressure liquid chromatography electrospray ionisation mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Mark E. [Molecular Structure and Detection Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308 (Australia); Dickson, Phillip W. [School of Biomedical Science, University of Newcastle, Callaghan, NSW 2308 (Australia); Dunkley, Peter R. [School of Biomedical Science, University of Newcastle, Callaghan, NSW 2308 (Australia); Nagy-Felsobuki, Ellak I. von [Molecular Structure and Detection Group, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308 (Australia)]. E-mail: ellak@newcastle.edu.au

    2005-03-01

    Tyrosine hydroxylase (TH) is involved in the biosynthesis of catecholamines and is activated by phosphorylation. Phosphorylated TH was analysed using high-pressure liquid chromatography combined with electrospray mass spectrometry (HPLC ESI-MS). Two mass scanning methods were used to detect tryptic cleavage products of TH. In the positive electrospray ionisation mode (ESI+), the peptides that contain the phosphorylation sites of TH were identified. In the alternative method, a phosphopeptide was detected in the negative electrospray ionisation mode (ESI-) using single ion monitoring in combination with a sequential ESI+ switching experiment. A raised baseline interfered with detection of hydrophilic peptides in ESI-, with the signal-to-noise ratio indicating that the method was operating near the limit of detection for a conventional electrospray source. The switching method improved the certainty of identification of phosphopeptides.

  20. Characterisation of tryptic peptides of phosphorylated tyrosine hydroxylase by high-pressure liquid chromatography electrospray ionisation mass spectrometry

    International Nuclear Information System (INIS)

    Tyrosine hydroxylase (TH) is involved in the biosynthesis of catecholamines and is activated by phosphorylation. Phosphorylated TH was analysed using high-pressure liquid chromatography combined with electrospray mass spectrometry (HPLC ESI-MS). Two mass scanning methods were used to detect tryptic cleavage products of TH. In the positive electrospray ionisation mode (ESI+), the peptides that contain the phosphorylation sites of TH were identified. In the alternative method, a phosphopeptide was detected in the negative electrospray ionisation mode (ESI-) using single ion monitoring in combination with a sequential ESI+ switching experiment. A raised baseline interfered with detection of hydrophilic peptides in ESI-, with the signal-to-noise ratio indicating that the method was operating near the limit of detection for a conventional electrospray source. The switching method improved the certainty of identification of phosphopeptides

  1. Quantitative Analysis of Seven Triazine Herbicides by On-Line Micellar Electrokinetic Chromatography-Electrospray Ionization Mass Spectrometry

    International Nuclear Information System (INIS)

    This paper presents a successful demonstration of the on-line coupling of MEKC (micellar electrokinetic chromatography) to ESIMS (electrospray ionization mass spectrometry) for the quantitative analysis of seven s-triazine herbicides. The on-line MEKC-ESIMS was used to determine the structure of CE-separated peaks of seven triazine herbicides. The mixture of triazine herbicides was separated in a 20 mM sodium borate buffer (pH 8.5) containing 15 mM sodium dodecylsulfate (SDS) by using a bare fused-silica capillary. Electrospray ionization mass spectrometer was operated in the positive-ion mode when the mass spectra of seven triazine herbicides were observed from each peak, and the solution of water-methanol-formic acid (50/49/1 v/v/v) was used as a sheath liquid. The effects of SDS concentration, the run buffer pH, and the electric field on the separation of seven s-triazine herbicides were investigated. The MEKC-ESIMS detection showed 5 to 10 times higher sensitivity compared to the MEKC-UV detection. In addition, it did not need any pretreatment step

  2. Retention behavior of lipids in reversed-phase ultrahigh-performance liquid chromatography-electrospray ionization mass spectrometry.

    Science.gov (United States)

    Ovčačíková, Magdaléna; Lísa, Miroslav; Cífková, Eva; Holčapek, Michal

    2016-06-10

    Reversed-phase ultrahigh-performance liquid chromatography (RP-UHPLC) method using two 15cm sub-2μm particles octadecylsilica gel columns is developed with the goal to separate and unambiguously identify a large number of lipid species in biological samples. The identification is performed by the coupling with high-resolution tandem mass spectrometry (MS/MS) using quadrupole - time-of-flight (QTOF) instrument. Electrospray ionization (ESI) full scan and tandem mass spectra are measured in both polarity modes with the mass accuracy better than 5ppm, which provides a high confidence of lipid identification. Over 400 lipid species covering 14 polar and nonpolar lipid classes from 5 lipid categories are identified in total lipid extracts of human plasma, human urine and porcine brain. The general dependences of relative retention times on relative carbon number or relative double bond number are constructed and fit with the second degree polynomial regression. The regular retention patterns in homologous lipid series provide additional identification point for UHPLC/MS lipidomic analysis, which increases the confidence of lipid identification. The reprocessing of previously published data by our and other groups measured in the RP mode and ultrahigh-performance supercritical fluid chromatography on the silica column shows more generic applicability of the polynomial regression for the description of retention behavior and the prediction of retention times. The novelty of this work is the characterization of general trends in the retention behavior of lipids within logical series with constant fatty acyl length or double bond number, which may be used as an additional criterion to increase the confidence of lipid identification. PMID:27179677

  3. Identification and quantification of salinomycin in intoxicated human plasma by liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Li, Yu; Fang, Junjian; Wu, Shengming; Ma, Kunpeng; Li, Haijing; Yan, Xianzhong; Dong, Fangting

    2010-09-01

    Salinomycin is a polyether ionophore antibiotic that is widely used in poultry and livestock. Exposure of humans to salinomycin via inhalation or ingestion can cause severe toxicity. The aim of the present work was to develop a simple and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the rapid identification and quantification of salinomycin in human plasma. After removing protein using methanol, plasma samples were eluted from a Waters Xterra(®) MS C18 column with an isocratic mobile phase. Detection and quantification of the drug were performed with a triple-quadruple mass spectrometer by monitoring for two specific transitions in the electrospray, positive-ion, multiple-reaction monitoring mode. Assay validation showed good linearity (r(2) = 0.998). The detection and quantification limits of the method were 0.6 and 16 pg/mL, respectively. The inter- and intraday coefficients of variation for the assay were both intoxicated patients were analyzed using this method. Salinomycin was detected in six samples, at concentrations of between 0.6 and 46.5 pg/mL. The described assay method allows the sensitive and rapid identification and quantification of salinomycin in human plasma, and thus provides a valuable tool for the specific diagnosis of salinomycin intoxication in clinical and emergency rescue practice. PMID:20652685

  4. Determination of diallyldimethylammonium chloride in drinking water by reversed-phase ion-pair chromatography-electrospray ionization mass spectrometry.

    Science.gov (United States)

    Jin, Fen; Hu, Jianying; Yang, Min; Jin, Xiaohui; He, Wenjie; Han, Hongda

    2006-01-01

    A method for the direct determination of diallyldimethylammonium chloride (DADMAC) in water samples, using ion-pair liquid chromatography-mass spectrometry system was developed. The chromatographic separation was performed using a C18 column. The type, the concentration of ion-pair reagent and the pH were optimized to give good chromatographic retention and sensitivity for DADMAC. Quantification was achieved in the positive electrospray ionization mode using selected ion monitoring. The cone voltage was also studied to establish the optimal experimental conditions. Finally, the reproducibility of the proposed method was shown by good run-to-run and day-to-day precision values. No sample preparation was required and the detection limit was 0.1 microg/L. The method was used to detect residual DADMAC at drinking water treatment plants in Tianjin, north China. The concentration of DADMAC observed in drinking water ranged from below quantitation limit to 22.0 microg/L. PMID:16243342

  5. Determination of chlorinated acid herbicides in vegetation and soil by liquid chromatography/electrospray-tandem mass spectrometry.

    Science.gov (United States)

    Schaner, Angela; Konecny, Jaclyn; Luckey, Laura; Hickes, Heidi

    2007-01-01

    The method presented uses reversed-phase liquid chromatography with negative electrospray ionization and tandem mass spectrometry to analyze 9 chlorinated acid herbicides in soil and vegetation matrixes: clopyralid, dicamba, MCPP, MCPA, 2,4-DP, 2,4-D, triclopyr, 2,4-DB, and picloram. A 20 g portion is extracted with a basic solution and an aliquot acidified and micropartitioned with 3 mL chloroform. Vegetation samples are subjected to an additional cleanup with a mixed-mode anion exchange solid-phase extraction cartridge. Two precursor product ion transitions per analyte are measured and evaluated to provide the maximum degree of confidence in results. Average recoveries for 3 different soil types tested ranged from 72 to 107% for all compounds with the exception of 2,4-DB at 56-99%. Average recoveries for the 3 different vegetation types studied were lower and ranged from 53 to 80% for all compounds. PMID:17955986

  6. Analysis of ribo- and deoxyribonucleic acids using ionpair-reversed-phase liquid-chromatography electrospray-mass spectrometry

    International Nuclear Information System (INIS)

    The fast progress in natural sciences like biology, biochemistry, medicine or genetics make high demands on the analytical chemistry. The on-line coupling of ionpair-reversed phase-liquid chromatography (IP-RP-HPLC) to mass spectrometry (MS) becomes more and more the method of choice for the analysis of biomolecules. The success is based on the introduction of soft ionization methods, like electrospray ionization (ESI), which allows the transfer of intact biopolymers into the gasphase. This combination enables the on-line separation of complex biological mixtures with additional identification of the compounds by their molecular mass. The first part describes the development of a new ionsource, which combines the advantages of a micro-ESI- and a nanospray-source. In combination with additional optimization of the chromatographic conditions the new ionsource showed an improvement of the quality of the spectra by a factor of 5 and a stability of the ionspray by a factor of 2, which resulted in an overall improvement of sensitivity by a factor of 10 for the HPLC-MS system. The second part describes the quality control of synthetic RNA molecules. Using IP-RP-HPLC-ESI-MS it was possible to separate failure sequences and derivatives in raw products of short synthetic RNAs. The derivatives were formed of protecting groups, which were not removed during the deprotection step. The analysis of coupling products of the synthesis of aminoacylated transfer RNAs showed a derivative, which was formed by the addition of the used coupling reagent N-(3-dimethylaminopropyl)N'-ethylcarbodiimide (EDC). The identification of the derivatives led to the optimization of the reaction conditions which resulted in the synthesis of the wanted transfer RNA without any additional derivatives. Another experiment involved the fragmentation of RNA molecules. Tandem mass spectrometry provides the opportunity to determine the sequence of nucleic acids. Fragmentation experiments showed different

  7. Simultaneous quantitation of atorvastatin and its two active metabolites in human plasma by liquid chromatography/(-) electrospray tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    Pankaj Partani; S. Manaswita Verma; Sanjay Gurule; Arshad Khuroo; Tausif Monif

    2014-01-01

    A sensitive, accurate and selective liquid chromatography-tandem mass spectrometry method (LC-MS/MS) was developed and validated for the simultaneous quantitation of atorvastatin (AT) and its equipotent hydroxyl metabolites, 2-hydroxy atorvastatin (2-AT) and 4-hydroxy atorvastatin (4-AT), in human plasma. Electrospray ionization (ESI) interface in negative ion mode was selected to improve the selectivity and the sensitivity required for this application. Additionally, a solid phase extraction (SPE) step was performed to reduce any ion-suppression and/or enhancement effects. The separation of all compounds was achieved in less than 6 min using a C18 reverse-phase fused-cores column and a mobile phase, composed of a mixture of 0.005%formic acid in water:acetonitrile:methanol (35:25:40, v/v/v), in isocratic mode at a flow rate of 0.6 mL/min. The method has lower limit of quantitation (LLOQ) of 0.050 ng/mL for all analytes. The method has shown tremendous reproducibility, with intra-and inter-day precision less than 6.6%, and intra- and inter-day accuracy within 74.3% of nominal values, for all analytes, and has proved to be highly reliable for the analysis of clinical samples.

  8. Improvement of sugar analysis sensitivity using anion-exchange chromatography-electrospray ionization mass spectrometry with sheath liquid interface.

    Science.gov (United States)

    Xu, Xian-Bing; Liu, Ding-Bo; Guo, Xiao Ming; Yu, Shu-Juan; Yu, Pei

    2014-10-31

    A novel interface that enables high-performance anion-exchange chromatography (HPAEC) to be coupled with electrospray ionization (ESI) mass spectrometry (MS) is reported. A sheath liquid consisting of 50mM NH4Ac in isopropanol with 0.05% acetic acid, infused at a flow rate of 3μL/min at the tip of the electrospray probe, requires less ESI source cleaning and promotes efficient ionization of mono- and di-carbohydrates. The results suggest that use of a sheath liquid interface rather than a T-joint allows volatile ammonium salts to replace non-volatile metal salts as modifiers for improving sugar ESI signals. The efficient ionization of mono- and di-carbohydrates in the ESI source is affected by the sheath liquid properties such as buffer concentration and type of organic solvent. HPAEC-ESI-MS was used for the analysis of monocarbohydrates in pectins, particularly co-eluted sugars, and the performance was evaluated. Addition of a make-up solution through the sheath liquid interface proved to be an efficient tool for enhancing the intensities of sugars analyzed using HPAEC-ESI-MS. PMID:25246101

  9. Determination of 16 insect growth regulators in edible Chinese traditional herbs by liquid chromatography electrospray tandem mass spectrometry.

    Science.gov (United States)

    Qian, Mingrong; Wu, Liqin; Zhang, Hu; Xu, Mingfei; Li, Rui; Wang, Xiangyun; Sun, Caixia

    2012-03-01

    A new sensitive multiresidue liquid chromatography-tandem mass spectrometry (LC-MS/MS) analytical method for the determination of 16 insect growth regulator (IGR) residues-RH-5849 (1,2-dibenzoyl-1-tert-butylhydrazine), halofenozide, methoxyfenozide, chromafenozide, fufenozide, tebufenozide, diflubenzuron, chlorbenzuron, triflumuron, hexaflumuron, novaluron, lufenuron, teflubenzuron, flucycloxuron, flufenoxuron, and chlorfluazuron-in herbs (Perilla frutescens, flos chrysanthemi, lily bulbs, and ginger) has been developed. After the herbs had been extracted with acetonitrile, a combined graphitized nonporous carbon/aminopropyl (ENVI-Carb/LC-NH(2)) cartridge and a Florisil cartridge were used to clean up the extracts. LC-MS/MS was performed in multiple reaction monitoring mode with two specific precursor ion-product ion transitions per IGR to confirm and quantitate the residues in herbs. Quantitation was performed on the basis of matrix-matched calibrations. The method showed excellent linearity (r(2) > 0.99) and precision (relative standard deviations of 13.6 or lower) for all the target insecticides. The limits of quantitation were 0.6-10 μg kg(-1) for the 16 insecticides in the four herbs. The average recoveries, measured at three concentrations (0.01, 0.1, 1 mg kg(-1)), were in the range 74.8-105.3%. The method was satisfactorily applied for the analysis of 60 herb samples (Perilla frutescens, flos chrysanthemi, lily bulbs, and ginger). Hexaflumuron was detected at concentrations of 0.029 and 0.051 mg kg(-1) in Perilla frutescens. PMID:22271101

  10. Analysis of organophosphate flame retardant diester metabolites in human urine by liquid chromatography electrospray ionisation tandem mass spectrometry.

    Science.gov (United States)

    Van den Eede, Nele; Neels, Hugo; Jorens, Philippe G; Covaci, Adrian

    2013-08-16

    A new analytical method was developed for the determination of dialkyl and diaryl phosphates (DAPs), which are metabolites of organophosphate triesters (PFRs), in human urine. Target DAPs included dibutyl phosphate (DBP), diphenyl phosphate (DPHP), bis(2-butoxyethyl) phosphate (BBOEP), bis(2-chloroethyl) phosphate (BCEP), bis(1-chloro-2-propyl) phosphate (BCPP), and bis(1,3-dichloro-2-propyl) phosphate (BDCIPP). Sample preparation was based on solid phase extraction using a weak anion exchange sorbent (Oasis WAX). Although several instrumental techniques have been tested, best results were obtained with reversed phase liquid chromatography-negative electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS) taking the total analysis time into account. Method accuracy at 3ng/mL in pooled urine ranged between 69 and 119% (recovery), while inter-day imprecision (as relative standard deviation) was sensitivity for BCEP, BCIPP, and BDCIPP, their respective mLOQs being 0.1, 0.06, 0.02ng/mL, compared to 1.2, 3.7, and 0.5ng/mL by LC-MS/MS. A set of urine samples from volunteers was analysed, in which DPHP was the major DAP metabolite. A significant increase of DPHP levels was observed in the group of smokers (geometric mean of 1.55ng/mL) compared to the non-smokers (geometric mean of 0.88ng/mL). Metabolic transformation of triphenyl phosphate to DPHP by metabolic enzymes induced in smokers could be an explanation for this observation. PMID:23849782

  11. Simultaneous Determination of Eight Ginsenosides in Rat Plasma by Liquid Chromatography–Electrospray Ionization Tandem Mass Spectrometry: Application to Their Pharmacokinetics

    OpenAIRE

    Li-Yuan Ma; You-Bo Zhang; Qi-Le Zhou; Yan-Fang Yang; Xiu-Wei Yang

    2015-01-01

    A high-performance liquid chromatography–electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method was successfully developed and validated for the identification and determination of eight ginsenosides: ginsenoside Rg1 (1); 20(S)-ginsenoside Rh1 (2); 20(S)-ginsenoside Rg2 (3); 20(R)-ginsenoside Rh1 (4); 20(R)-ginsenoside Rg2 (5); ginsenoside Rd (6); 20(S)-ginsenoside Rg3 (7); and 20(R)-ginsenoside Rg3 (8) in rat plasma. The established rapid method had high linearity, selectivit...

  12. Characterization of heat-labile toxin-subunit B from Escherichia coli by liquid chromatography-electrospray ionization-mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Sospedra, I; De Simone, C; Soriano, J M; Mañes, J; Ferranti, P; Ritieni, A

    2012-11-01

    The possibilities of characterizing the heat-labile enterotoxin (LT) of enterotoxigenic Escherichia coli (ETEC) by liquid chromatography electrospray mass spectrometry (LC/ESI-MS) and matrix-assisted laser desorption with time-of-flight mass spectrometry (MALDI-TOF-MS) were investigated. The B subunit from recombinant E. coli (expression in Pichia pastoris) can be detected by LC/ESI-MS expressed in P. pastoris and the charge envelope signals can be observed; LC/ESI-MS and MALDI-TOF-MS analysis allowed the acquisition of labile toxin subunit B (LTB) molecular weight and preliminary structural characterization of LTB toxin. MALDI-TOF analysis after reduction and alkylation of the protein evidenced the presence of one disulfide bond in the structure of the protein. Confirmatory analysis was carried out by detection of most of the tryptic fragments of the B subunit by MALDI-TOF-MS, obtaining total coverage of the protein sequence. Possible biovariations in the toxin can mostly be determined by sequencing, where an increase of molecular mass in the N-terminal side of the protein was identified. This modification may be due to an O-GlcNAc-1-phosphorylation. PMID:22921353

  13. Letter: characterisation and identification of spermine and spermidine derivatives in Microdesmis keayana and Microdesmis puberula roots by electrospray ionisation tandem mass spectrometry and high-performance liquid chromatography/electrospray ionisation tandem mass spectrometry.

    Science.gov (United States)

    Roumy, Vincent; Hennebelle, Thierry; Zamblé, Alexis; Zamblé Yao, Jacques; Sahpaz, Sevser; Bailleul, François

    2008-01-01

    Three new N(1),N(5),N(14)-tris(4- hydroxycinnamoyl)spermines were identified in hydromethanolic root extracts of Microdesmis keayana J. Léonard and Microdesmis puberula Hook f. The electrospray ionisation tandem mass spectrometry (ESI-MS/MS) technique with specific nuclear magnetic resonance analysis of hydrolysed products made it possible to identify N(1),N(5),N(14)-tris(p-coumaroyl)spermine, N(1)-feruloyl,N(5),N(14)-di(p-coumaroyl)spermine and N(1),N(5),N(14)-tris(feruloyl)spermine, named keayanines B, C and D, respectively. ESI-MS/MS analysis most effectively provided structural data although high-performance liquid chromatography/electrospray ionisation tandem mass spectrometry was also used to characterise four other compounds from Microdesmis puberula-keayanidines A, B, C and keayanine A-which had already been identified in M. keayana. This chemical data is the first to be published for M. puberula which is a commonly used plant in Central African traditional medicine. PMID:18493101

  14. Rapid and sensitive hormonal profiling of complex plant samples by liquid chromatography coupled to electrospray ionization tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Müller Maren

    2011-11-01

    Full Text Available Abstract Background Plant hormones play a pivotal role in several physiological processes during a plant's life cycle, from germination to senescence, and the determination of endogenous concentrations of hormones is essential to elucidate the role of a particular hormone in any physiological process. Availability of a sensitive and rapid method to quantify multiple classes of hormones simultaneously will greatly facilitate the investigation of signaling networks in controlling specific developmental pathways and physiological responses. Due to the presence of hormones at very low concentrations in plant tissues (10-9 M to 10-6 M and their different chemistries, the development of a high-throughput and comprehensive method for the determination of hormones is challenging. Results The present work reports a rapid, specific and sensitive method using ultrahigh-performance liquid chromatography coupled to electrospray ionization tandem spectrometry (UPLC/ESI-MS/MS to analyze quantitatively the major hormones found in plant tissues within six minutes, including auxins, cytokinins, gibberellins, abscisic acid, 1-amino-cyclopropane-1-carboxyic acid (the ethylene precursor, jasmonic acid and salicylic acid. Sample preparation, extraction procedures and UPLC-MS/MS conditions were optimized for the determination of all plant hormones and are summarized in a schematic extraction diagram for the analysis of small amounts of plant material without time-consuming additional steps such as purification, sample drying or re-suspension. Conclusions This new method is applicable to the analysis of dynamic changes in endogenous concentrations of hormones to study plant developmental processes or plant responses to biotic and abiotic stresses in complex tissues. An example is shown in which a hormone profiling is obtained from leaves of plants exposed to salt stress in the aromatic plant, Rosmarinus officinalis.

  15. Determination of Phenolic Content in Different Barley Varieties and Corresponding Malts by Liquid Chromatography-diode Array Detection-Electrospray Ionization Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Daniel O. Carvalho

    2015-08-01

    Full Text Available A simple and reliable method for the simultaneous determination of nine phenolic compounds in barley and malted barley was established, using liquid chromatography-diode array detection-electrospray ionization tandem mass spectrometry (HPLC-DAD-ESI-MS/MS. The phenolic compounds can be easily detected with both systems, despite significant differences in sensitivity. Concentrations approximately 180-fold lower could be achieved by mass spectrometry analysis compared to diode array detection, especially for the flavan-3-ols (+-catechin and (−-epicatechin, which have poor absorptivity in the UV region. Malt samples were characterized by higher phenolic content comparing to corresponding barley varieties, revealing a significant increase of the levels of (+-catechin and (−-epicatechin during the malting process. Moreover, the industrial malting is responsible for modification on the phenolic profile from barley to malt, namely on the synthesis or release of sinapinic acid and epicatechin. Accordingly, the selection of the malting parameters, as well as the barley variety plays an important role when considering the quality and antioxidant stability of beer.

  16. Determination of betamethasone and betamethasone 17-monopropionate in human plasma by liquid chromatography-positive/negative electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Zou, Jian-Jun; Dai, Li; Ding, Li; Xiao, Da-Wei; Bin, Zhu-Yu; Fan, Hong-Wei; Liu, Li; Wang, Guang-Ji

    2008-10-01

    This study presents a high-performance liquid chromatography-positive/negative electrospray ionization tandem mass spectrometric (LC-ESI(+/-)-MS-MS) method for the determination of betamethasone (BOH) and betamethasone 17-monopropionate (B17P) in human plasma using beclomethasone dipropionate as the internal standard (I.S.). Both compounds were extracted from human plasma with ether-cyclohexane (4:1, v/v) and were separated by HPLC on a Hanbon Lichrospher C(18) column with a mobile phase of methanol-water (85:15, v/v) at a flow rate of 0.7ml/min. Calibration curves were linear over the range of 0.10-50ng/ml for BOH and 0.050-50ng/ml for B17P. The inter-run relative standard deviations were less than 14.4% for BOH and 12.3% for B17P. The intra-run relative standard deviations were less than 9.3% for BOH and 7.9% for B17P. The mean plasma extraction recovery for BOH and B17P were in the ranges of 82.7-85.9% and 83.6-85.3%, respectively. The method was successfully applied to study the pharmacokinetics of a new formulation of betamethasone phosphate/betamethasone dipropionate injection in healthy Chinese volunteers. PMID:18757252

  17. Direct identification of phenolic constituents in Boldo Folium (Peumus boldus Mol.) infusions by high-performance liquid chromatography with diode array detection and electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Simirgiotis, M J; Schmeda-Hirschmann, G

    2010-01-22

    A very simple and direct method was developed for the qualitative analysis of polyphenols in boldo (Peumus boldus Mol., Monimiaceae) leaves infusions by high-performance liquid chromatography with diode array detection (HPLC-DAD) and electrospray ionization tandem mass spectrometry (HPLC-MS(n)). The phenolic constituents identified in infusions of the crude drug Boldo Folium were mainly proanthocyanidins and flavonol glycosides. In the infusions, 41 compounds were detected in male and 43 compounds in female leaf samples, respectively. Nine quercetin glycosides, eight kaempferol derivatives, nine isorhamnetin glycosides, three phenolic acids, one caffeoylquinic acid glycoside and twenty one proanthocyanidins were identified by HPLC-DAD and ESI-MS for the first time in the crude drug. Isorhamnetin glucosyl-di-rhamnoside was the most abundant flavonol glycoside in the male boldo sample, whereas isorhamnetin di-glucosyl-di-rhamnoside was the main phenolic compound in female boldo leaves infusion. The results suggest that the medicinal properties reported for this popular infusion should be attributed not only to the presence of catechin and boldine but also to several phenolic compounds with known antioxidant activity. The HPLC fingerprint obtained can be useful in the authentication of the crude drug Boldo Folium as well as for qualitative analysis and differentiation of plant populations in the tree distribution range. PMID:20022332

  18. Determination of torasemide in human plasma and its bioequivalence study by high-performance liquid chromatography with electrospray ionization tandem mass spectrometry$

    Institute of Scientific and Technical Information of China (English)

    Lin Zhang; Rulin Wang; Yuan Tian; Zunjian Zhang

    2016-01-01

    A sensitive and selective method using high-performance liquid chromatography coupled with elec-trospray ionization tandem mass spectrometry (HPLC–ESI–MS) to determine the concentration of tor-asemide in human plasma samples was developed and validated. Tolbutamide was chosen as the internal standard (IS). The chromatography was performed on a Gl Sciences Inertsil ODS-3 column (100 mm ? 2.1 mm i.d., 5.0 mm) within 5 min, using methanol with 10 mM ammonium formate (60:40, v/v) as mobile phase at a flow rate of 0.2 mL/min. The targeted compound was detected in negative io-nization at m/z 347.00 for torasemide and 269.00 for IS. The linearity range of this method was found to be within the concentration range of 1–2500 ng/mL (r¼0.9984) for torasemide in human plasma. The accuracy of this measurement was between 94.05%and 103.86%. The extracted recovery efficiency was from 84.20% to 86.47% at three concentration levels. This method was also successfully applied in pharmacokinetics and bioequivalence studies in Chinese volunteers.

  19. Determination of torasemide in human plasma and its bioequivalence study by high-performance liquid chromatography with electrospray ionization tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Lin Zhang

    2016-04-01

    Full Text Available A sensitive and selective method using high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC–ESI–MS to determine the concentration of torasemide in human plasma samples was developed and validated. Tolbutamide was chosen as the internal standard (IS. The chromatography was performed on a Gl Sciences Inertsil ODS-3 column (100 mm×2.1 mm i.d., 5.0 µm within 5 min, using methanol with 10 mM ammonium formate (60:40, v/v as mobile phase at a flow rate of 0.2 mL/min. The targeted compound was detected in negative ionization at m/z 347.00 for torasemide and 269.00 for IS. The linearity range of this method was found to be within the concentration range of 1–2500 ng/mL (r=0.9984 for torasemide in human plasma. The accuracy of this measurement was between 94.05% and 103.86%. The extracted recovery efficiency was from 84.20% to 86.47% at three concentration levels. This method was also successfully applied in pharmacokinetics and bioequivalence studies in Chinese volunteers.

  20. Targeted analysis and determination of β-agonists, hormones, glucocorticoid and psychiatric drugs in feed by liquid chromatography with electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Zhu, Yufei; Xie, Shuyu; Chen, Dongmei; Pan, Yuanhu; Qu, Wei; Wang, Xu; Liu, Zhenli; Peng, Dapeng; Huang, Lingli; Tao, Yanfei; Yuan, Zonghui

    2016-07-01

    A comprehensive strategy combining a quantitative method was developed for 30 banned drugs including β-agonists, hormones, glucocorticoid and psychiatric drugs in swine and chicken feeds. This rapid, simple and effective extraction method was based on matrix solid-phase dispersion and electrospray ionization tandem mass spectrometry. The quantitative method was validated after previous statistical optimization of the main parameters of matrix solid-phase dispersion. The limit of quantification of dopamine hydrochloride, chlormadinone acetate, melengestrol acetate, testosterone propionate, nandrolone and midazolam was 2 μg/kg and that of the other 24 drugs was 1 μg/kg. The recoveries of β-agonists, hormones, glucocorticoid and psychiatric drugs spiked in swine and chicken feeds at a concentration range of 1-8 μg/kg were above 70.1% with inter-day relative standard deviations less than 15.8%. The analytical strategy was applied to 100 feed samples collected from a local market in Wuhan (China). Clenbuterol, ractopamine and melengestrol acetate were identified and quantified at the level 0.2∼3.5 μg/kg. The rapid and reliable method can be used to efficiently separate, characterize and quantify the residues of 30 banned drugs in swine and chicken feeds with advantages of simple pretreatment and environmental friendly nature. PMID:27145483

  1. Simultaneous determination of urinary parabens, bisphenol A, triclosan, and 8-hydroxy-2'-deoxyguanosine by liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Ren, Lu; Fang, Jianzhang; Liu, Guihua; Zhang, Jianqing; Zhu, Zhou; Liu, Honghe; Lin, Kai; Zhang, Huimin; Lu, Shaoyou

    2016-04-01

    A simple and fast method was developed for the simultaneous determination of five parabens, bisphenol A (BPA), triclosan (TCS), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in human urine using liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The solid-phase extraction (SPE) procedure, chromatographic conditions, and MS/MS parameters were optimized to achieve maximum sensitivity and accuracy for the analytes. The validation results showed that the correlation coefficients (R (2)) and recoveries ranged from 0.999 to 1 and 83.9 to 109.9 %, respectively, and the intra-day and inter-day precisions (relative standard deviation, RSD) were within the range of 1.3-8.5 % and 1.3-9.0 %, respectively. The limits of detection for the analytes ranged from 0.001 to 0.05 μg/L. The method was successfully employed to determine parabens, BPA, TCS, and 8-OHdG in urine samples from school students in Guangzhou, China. The results showed that methyl, ethyl, n-propyl parabens, BPA, TCS, and 8-OHdG were frequently detected in urine samples. n-Butyl and benzyl parabens were only detected in a part of the samples due to their low concentrations in urine. PMID:26873198

  2. Ultra high performance liquid chromatography with electrospray ionization tandem mass spectrometry coupled with hierarchical cluster analysis to evaluate Wikstroemia indica (L.) C. A. Mey. from different geographical regions.

    Science.gov (United States)

    Wei, Lan; Wang, Xiaobo; Mu, Shanxue; Sun, Lixin; Yu, Zhiguo

    2015-06-01

    A sensitive, rapid and simple ultra high performance liquid chromatography with electrospray ionization tandem mass spectrometry method was developed to determine seven constituents (umbelliferone, apigenin, triumbelletin, daphnoretin, arctigenin, genkwanin and emodin) in Wikstroemia indica (L.) C. A. Mey. The chromatographic analysis was performed on an ACQUITY UPLC® BEH C18 column (2.1 × 50 mm, 1.7 μm) by gradient elution with the mobile phase of 0.05% formic acid aqueous solution (A) and acetonitrile (B). Multiple reaction monitoring mode with positive and negative electrospray ionization interface was carried out to detect the components. This method was validated in terms of specificity, linearity, accuracy, precision and stability. Excellent linear behavior was observed over the certain concentration ranges with the correlation coefficient values higher than 0.999. The intraday and innerday precisions were within 2.0%. The recoveries of seven analytes were 99.4-101.1% with relative standard deviation less than 1.2%. The 18 Wikstroemia indica samples from different origins were classified by hierarchical clustering analysis according to the contents of seven components. The results demonstrated that the developed method could successfully be used to quantify simultaneously of seven components in Wikstroemia indica and could be a helpful tool for the detection and confirmation of the quality of traditional Chinese medicines. PMID:25866087

  3. Study on Flavonoids From Meconopsis Maxim by Electrospray Ionization Tandem Mass Spectrometry%绿绒蒿属植物中黄酮类化合物的电喷雾电离串联质谱研究

    Institute of Scientific and Technical Information of China (English)

    阿布拉江·克依木; 尚小雅; 贺玖明; 再帕尔·阿不力孜; 石建功

    2004-01-01

    The fragmentation behavior of six known flavonoids from Meconopsis Maxim were studied by electrospray ionization tandem mass spectrometry (ESI-MSn). Besides the structure of aglycones and hydroxyl group on it, the position of the sugar substitution also affected the fragmentation of the flavonoids. The diagnostic fragmentations of flavonoids and aglycones were obtained in the positive and negative ion ESI-MSn experiments, and the fragmentation pathways were discussed.

  4. Comparison of microbial communities in Lake Tahoe surface sample with Tonga Trench water column samples using High Pressure Liquid Chromatography - Electrospray Ionization - Mass Spectroscopy (HPLC - ESI - MS) and Global Natural Products Social Molecular Network (GNPS)

    Science.gov (United States)

    Belmonte, M. A.

    2015-12-01

    Intact polar lipids (IPLs) are lipids composed of a head group, a glycerol, and a fatty acid chain that make up the lipid bilayer of cell membranes in living cells; and the varying head groups can be indicative of the type of microbes present in the environment (Van Mooy 2010). So by distinguishing and identifying the IPL distribution in an environment one can make inferences about the microbial communities in the said environment. In this study, we used High Pressure Liquid Chromatography-Electrospray Ionization- Mass Spectroscopy (HPLC-ESI-MS) and Global Natural Products Social Molecular Networking (GNPS) to compare the IPL distributions of two oligotrophic environments: surface waters of Lake Tahoe in the Sierra Nevada Mountains, and the water column of the Tonga Trench in the South Pacific. We hypothesized that the similar nutrient dynamics of the two oligotrophic environments would result in similar eukaryotic and prokaryotic communities, which would be reflected in the IPL composition of suspended particulate organic matter (POM). For simplicity we focused on the classes of IPLs most commonly observed in the marine environment: phosphotidylglycerol (PG), phosphotidylethanolamine (PE), diacylglyceryl-trimethyl-homoserine (DGTS), diacylglyceryl-hydroxymethyl-trimethylalanine (DGTA), sulfoquinovosyldiacylglycerol (SQDG), monoglycosyldiacylglycerol (MGDG) and diglycosyldiacylglycerol (DGDG). Our results showed that all of the marine IPLs of interest were present in Lake Tahoe which confirms that there are many of the same microbial communities in the fresh waters of Lake Tahoe and the salt waters Tonga Trench.

  5. Elucidation of O-Phosphoryl and N-Phosphoryl Amino Acids by Electrospray Ionization Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Jian-Chen(张建臣); CAO,Shu-Xiaa(曹书霞); XU,Juna(徐军); LIAO,Xin-Cheng(廖新成); ZHAO,Yu-Fen(赵玉芬)

    2004-01-01

    Mass spectroscopic characteristics of phosphoryl amino acids were studied in detail by positive and negative electrospray ionization mass spectrometry (ESI-MS) in conjunction with tandem mass spectrometry (MS/MS). Besides N-diisopropyloxyphosphoryl amino acids (N-DIPP-AA), O-phospho- and O-diisopropyloxyphosphoryl amino acids (O-DIPP-AA) were studied and compared to N-DIPP-AA. The fragmentation pathways of [M+H]+, [M+Na]+ and [M-H]- ions of phosphoryl amino acids were summarized. In addition to several similar patterns,each of them showed its characteristic fragmention.

  6. Spatially resolved protein hydrogen exchange measured by subzero-cooled chip-based nanoelectrospray ionization tandem mass spectrometry

    DEFF Research Database (Denmark)

    Amon, Sabine; Trelle, Morten B; Jensen, Ole N; Jørgensen, Thomas J D

    2012-01-01

    Mass spectrometry has become a valuable method for studying structural dynamics of proteins in solution by measuring their backbone amide hydrogen/deuterium exchange (HDX) kinetics. In a typical exchange experiment one or more proteins are incubated in deuterated buffer at physiological conditions...... optimized mass spectrometric conditions where gas-phase hydrogen scrambling is negligible. Our results show that the known dynamic behavior of ubiquitin in solution is accurately reflected in the deuterium contents of the fragment ions....

  7. A high-performance liquid chromatographic-atmospheric pressure chemical ionization-tandem mass spectrometric method for determination of risperidone and 9-hydroxyrisperidone in human plasma.

    Science.gov (United States)

    Moody, David E; Laycock, John D; Huang, Wei; Foltz, Rodger L

    2004-09-01

    Risperidone, a benzisoxazole derivative, is an antipsychotic agent used for the treatment of schizophrenia. We developed a liquid chromatographic-atmospheric pressure chemical ionization-tandem mass spectrometric (LC-APCI-MS-MS) method with improved sensitivity, selectivity, and dynamic range for determination of risperidone and 9-hydroxyrisperidone in human plasma. A structural analogue of risperidone, RO68808 (5 ng/mL), is added as the internal standard to 1 mL of human plasma. Plasma is made basic, extracted with pentane/methylene chloride (3:1), the organic phase evaporated to dryness, and the residue is reconstituted in water with 0.1% formic acid/acetonitrile (20:1). For LC-MS-MS analysis, a Metachem Inertsel HPLC column (2.1 x 150 mm, 5-microm particle size) is connected to a Finnigan TSQ7000 tandem MS via the Finnigan API interface. Both electrospray (ESI) and APCI produced predominantly MH(+) ions for the two analytes and the internal standard. Ions detected by selected reaction monitoring correspond to the following transitions: m/z 411 to 191 for risperidone, m/z 427 to 207 for 9-hydroxyrisperidone, and m/z 421 to 201 for the internal standard. APCI provided a larger dynamic range (0.1 to 25 ng/mL) and better precision and accuracy than ESI. Intrarun accuracy and precision determined at 0.1, 0.25, 2.5, and 15 ng/mL were within 12% of target with %CVs not exceeding 10.9%. Interrun accuracy and precision determined at the same concentrations were within 9.6% of target with %CVs not exceeding 6.7%. Analytes were stable in plasma after 24 h at room temperature, 2 freeze-thaw cycles, and 490 days at -20 degrees C. PMID:15516302

  8. N-alkylpyridinium quaternization combined with liquid chromatography–electrospray ionization-tandem mass spectrometry: A highly sensitive method to quantify fatty alcohols in thyroid tissues

    International Nuclear Information System (INIS)

    Highlights: • N-alkylpyridinium quaternization was combined with LC–ESI-MS/MS analysis to quantify fatty alcohols. • This method lowered the detection limits of fatty alcohols to 0.25 pg mL−1. • Ten kinds of even carbon-numbered fatty alcohols (C8–C24) were detected in human thyroid tissues. • Concentrations of fatty alcohols (free and esterified) in thyroid carcinoma tissues were lower than those in paired para-carcinoma tissues (p < 0.05). - Abstract: A highly sensitive method was developed for the identification and quantification of fatty alcohols in biological tissues. In the presence of pyridine-d0 and triflic anhydride (Tf2O), fatty alcohols were converted into permanently charged N-alkylpyridinium ions. Stable isotope-labeled derivatives were generated by pyridine-d5 and added as internal standard (IS). The mixture was analyzed by liquid chromatography coupled to positive electrospray ionization tandem mass spectrometry (LC–ESI-MS/MS). This method was optimized and validated in terms of reaction time, derivatization efficiency, stability, desalting, and ion suppression effect. Besides, fatty alcohols exhibited good linear relationship (r2 > 0.993) over the concentration range of 10 ng mL−1–1 μg mL−1. The limits of detection (LODs) were lowered from previously reported 0.1 ng mL−1 to 0.25 pg mL−1. Precision (RSD% < 15.6%), accuracy (93.0–107.2%), matrix effect, and recovery (in thyroid tissues) were validated as well. Finally, this method was applied for the analysis of ten even carbon-numbered fatty alcohols (C8–C24) in human thyroid carcinoma and para-carcinoma tissues, revealing a significant decrease of fatty alcohols (free and esterified) in thyroid carcinoma tissues (p < 0.05)

  9. Simultaneous Determination of Eight Ginsenosides in Rat Plasma by Liquid Chromatography–Electrospray Ionization Tandem Mass Spectrometry: Application to Their Pharmacokinetics

    Directory of Open Access Journals (Sweden)

    Li-Yuan Ma

    2015-12-01

    Full Text Available A high-performance liquid chromatography–electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS method was successfully developed and validated for the identification and determination of eight ginsenosides: ginsenoside Rg1 (1; 20(S-ginsenoside Rh1 (2; 20(S-ginsenoside Rg2 (3; 20(R-ginsenoside Rh1 (4; 20(R-ginsenoside Rg2 (5; ginsenoside Rd (6; 20(S-ginsenoside Rg3 (7; and 20(R-ginsenoside Rg3 (8 in rat plasma. The established rapid method had high linearity, selectivity, sensitivity, accuracy, and precision. The method has been used successfully to study the pharmacokinetics of abovementioned eight ginsenosides for the first time. After an oral administration of total saponins in the stems-leaves of Panax ginseng C. A. Meyer (GTSSL at a dose of 400 mg/kg, the ginsenosides 6, 7, and 8, belonging to protopanaxadiol-type saponins, exhibited relatively long tmax values, suggesting that they were slowly absorbed, while the ginsenosides 1–5, belonging to protopanaxatriol-type saponins, had different tmax values, which should be due to their differences in the substituted groups. Compounds 2 and 4, 3 and 5, 7 and 8 were three pairs of R/S epimerics at C-20, which was interesting that the t1/2 of 20(S-epimers were always longer than those of 20(R-epimers. This pharmacokinetic identification of multiple ginsenosides of GTSSL in rat plasma provides a significant basis for better understanding the clinical application of GTSSL.

  10. Multi-residue analysis of eight anticoagulant rodenticides in animal plasma and liver using liquid chromatography combined with heated electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Vandenbroucke, Virginie; Desmet, Noël; De Backer, Patrick; Croubels, Siska

    2008-06-15

    A sensitive method for the simultaneous quantification of eight anticoagulant rodenticides (brodifacoum, bromadiolone, chlorophacinone, coumatetralyl, difenacoum, difethialone, flocoumafen and warfarin) in animal plasma and liver using liquid chromatography combined with heated electrospray ionization tandem mass spectrometry (LC-HESI-MS/MS) is described. The sample preparation includes a liquid-liquid extraction with acetone. The compound 7-acetoxy-6-(2,3-dibromopropyl)-4,8-dimethylcoumarin is used as an internal standard. Chromatographic separation was achieved using a Nucleodur C18 gravity column. Good linearity was observed up to 750 ng mL(-1) for chlorophacinone and up to 500 ng mL(-1) for the other compounds in plasma. In liver, good linearity was seen up to 500 ng g(-1) for brodifacoum, chlorophacinone, difenacoum and difethialone and up to 750 ng g(-1) for the other compounds. Depending on the compound, a level of 1 or 5 ng mL(-1) could be quantified fulfilling the criteria for accuracy and precision and was therefore set as limit of quantification of the method in plasma. In liver, the limit of quantification was set at 250 ng g(-1) for coumatetralyl and warfarin and at 100 ng g(-1) for the other compounds. In plasma, the limit of detection varied from 0.07 ng mL(-1) for flocoumafen to 3.21 ng mL(-1) for brodifacoum. In liver, the limit of detection varied from 0.37 ng g(-1) for warfarin to 4.64 ng g(-1) for chlorophacinone. The method was shown to be of use in a pharmacokinetic study after single oral administration to mice and in the confirmation of suspected poisoning cases in domestic animals. PMID:18502701

  11. Screening and identification of glyceollins and their metabolites by electrospray ionization tandem mass spectrometry with precursor ion scanning

    Science.gov (United States)

    A method has been developed for screening glyceollins and their metabolites based upon precursor ion scanning. Under higher-energy collision conditions, employing a triple quadrupole mass spectrometer in the negative ion mode, deprotonated glyceollin precursors yield a diagnostic radical product ion...

  12. Quantitative analysis of adenosine using Liquid Chromatography/Atmospheric Pressure Chemical Ionization - tandem Mass Spectrometry (LC/APCI-MS/MS)

    OpenAIRE

    Van Dycke, Annelies; Verstraete, Alain; Pil, Kristof; Raedt, Robrecht; Vonck, Kristl; Boison, Detlev; Boon, Paul

    2010-01-01

    Adenosine-secreting cellular brain implants constitute a promising therapeutic approach for the treatment of epilepsy. To engineer neural stem cells for therapeutic adenosine delivery, a reliable and fast analytical method is necessary to quantify cell-based adenosine release. Here we describe the development, optimization and validation of adenosine measurement using liquid chromatography – atmospheric pressure chemical ionization – tandem mass spectrometry (LC-APCI-MS/MS). LC-MS/MS in posit...

  13. Identification of Perfluorooctanoic Acid Release from Commercial Coated Cooking Pans by Liquid Chromatography Coupled to Electrospray Ionization Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Monica Bononi

    2007-01-01

    Full Text Available Salts of perfluorooctanoic acid (PFOA can be used in the manufacture of fluoropolymers employed for coating pans; moreover, PFOA can be formed as a byproduct of thermolysis of the aforesaid fluoropolymers. This study was carried out to evaluate PFOA migration into food cooked in fluoropolymer-coated pans. The pans were purchased from a local retailer and subjected to cooking conditions. Used oil was extracted with a methanol/water solution and analyzed by liquid chromatography tandem mass spectrometry (LC/MS/MS. We found that PFOA can enter cooked food during a container's first phases of use, not only in containers already abused by kitchen tools or otherwise scratched.

  14. Analysis of triptophenolide and its related compounds from Tripterygium wilfordii Hook.f by electrospray ionization tandem mass spectrometry

    Science.gov (United States)

    Li, Rui; Peng, Aihua; He, Chunmei; Wang, Xianhuo; Shi, Jianyou; Chen, Lijuan; Wei, Yuquan

    2008-11-01

    Triptophenolide and its related compounds from Tripterygium wilfordii Hook.f is a kind of diterpenoids which shows anti-inflammatory activity. To study the metabolites of triptophenolide related compounds, the fragmentation mechanisms of them were investigated by using negative electrospray tandem mass spectrometry. With the aid of high resolution of ESI-QTOF-MS/MS, the fragmentation mechanisms of six diterpenoid compounds were systematically investigated. The fragmentation behavior mainly depends on what substituent groups the benzyl C ring bears. If there is a hydroxyl group on the position of C14, loss of CH4 is dominating. However, the successive loss of two CH3 radicals is predominant when the hydroxyl group of O14 is methylated. The lactone ring is prone to be dissociated to loss of CO, CO2 and C2H2O2 molecules. The pericyclic reaction can occur on A ring if there is an active hydrogen resides on C ring. Furthermore, one metabolite of compound A1 was confirmed by cytochrome P450 in vitro and the structure was proposed by tandem mass experiment together with the fragmentation mechanisms of this type of compounds.

  15. Studies on Fragmentation Pathways of N-Ethoxy(phenyl) phosphoryl Amino Acids by Electrospray Ionization Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The positive and negative ESI-MS/MS spectra of N-ethoxy(phenyl) phosphoryl amino acids(EPP-AA) were investigated by electrospray ionization(ESI) ion trap mass spectrometry. The fragmentation pathways of [M + Na]+ and [M-H]- ions areproposed and rationalized. The observation may have some potential applications in the interpretation of the MS/MS spectra of novel N-phosphoryl compounds. The complexity of MS/MS spectra of EPP-AA [M + Na] + ions is decreased compared with that of N-dialkyloxyphosphoryl amino acid. Therefore, the new phosphonamidate method may be considered one of the superior methods that can be used in sequencing peptides and proteins extensively.

  16. Detection and Characterization of Non-covalent Complex between Lappaconitine and β-Cyclodextrin by Electrospray Ionization Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    Qing Xuan XU; Li LI; Hao YUE; Zhi Qiang LIU; Ming Quan GUO; Shu Ying LIU

    2006-01-01

    The non-covalent complexes between lappaconitine (LA) and β-cyclodextrin (β-CD) have been detected and characterized by electrospray ionization combined with ion trap tandem mass spectrometry (ESI-MSn). The experimental results showed that only 1:1 non-covalent complex can be formed in different starting molar ratios of LA to β-CD. Furthermore, the diagnostic fragmentation of the β-CD-LA complex, with a significant contribution of covalent fragmentation of LA leaving the N-acetyl anthranoyl (AN) moiety inserted to β-CD, provided the convincing evidence for the formation of non-covalent complex between LA and β-CD and the cite of LA molecule included to cavity of β-CD assigned to AN residue.

  17. Characterization of isoquinoline alkaloids, diterpenoids and steroids in the Chinese herb Jin-Guo-Lan (Tinospora sagittata and Tinospora capillipes) by high-performance liquid chromatography/electrospray ionization with multistage mass spectrometry.

    Science.gov (United States)

    Zhang, Yufeng; Shi, Qirong; Shi, Peiying; Zhang, Weidong; Cheng, Yiyu

    2006-01-01

    This study sought to determine the primary components (isoquinoline alkaloids, diterpenoids and steroids) in crude extracts of the Chinese herb Jin-Guo-Lan, prepared from the roots of Tinospora sagittata and T. capillipes, by liquid chromatography/electrospray ionization multistage mass spectrometry coupled with diode-array detection (LC-DAD/ESI-MS(n)). After separation on a reversed-phase C(18) column using gradient elution, positive and negative ESI-MS experiments were performed. In positive ion mode, the three types of compounds showed very different characteristic ions: strong [M](+) or [M+H](+) ions were observed for isoquinoline alkaloids; [M+NH(4)](+) and/or [M+H-CO(2)](+) for diterpenoids; [M+H-nH(2)O](+) (n=1-3) for steroids. These adduct ions and/or fragments were used to deduce the mass and categories of known and unknown components in crude extracts, and their structures were further confirmed by ESI-MS(n) in positive ion mode. Moreover, UV absorption peaks obtained from DAD provided useful functional group information to aid the MS(n)-based identification. As a result, 11 compounds were unambiguously identified by comparing with standard compounds and 13 compounds were tentatively identified or deduced according to their MS(n) data. Two of these compounds (13-hydroxycolumbamine and 13-hydroxyjatrorrhizine) were found to be new compounds and another one (13-hydroxypalmatine) was detected for the first time as a natural product. In addition, a [M-*CH(3)-H(2)O](*+) ion in MS(2) of [M](+) after in-source collision-induced dissociation was used to differentiate positional isomers of protoberberine alkaloids, columbamine and jatrorrhizine. Although the roots of T. sagittata and T. capillipes contain almost identical compounds, the content of the compounds in them is dramatically different, suggesting the necessity for further comparison of the bioactivities of the two species. PMID:16817243

  18. A capillary electrophoresis system with dual capacitively coupled contactless conductivity detection and electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Francisco, Kelliton José Mendonça; do Lago, Claudimir Lucio

    2016-07-01

    A commercial system that is comprised of a CE coupled to an ESI triple quadrupole mass spectrometer was equipped with two capacitively coupled contactless conductivity detectors (C(4) Ds). The first C(4) D was positioned inside the original cartridge, and the second C(4) D was positioned as close as possible to the ESI probe entrance by using a 3D-printed support. The C(4) Ds electropherograms were matched to the ESI-MS electropherogram by correcting their timescales by the factor LT /LD , where LT and LD are the total capillary length and the length until the C(4) D, respectively. A general approach for method development supporting the simultaneous conductivity and MS detection is discussed, while application examples are introduced. These examples include the use of C(4) D as a simple device that dismiss the use of an EOF marker, a low-selectivity detector that continuously provide information about unexpected features of the sample, and even a detector that can be more sensitive than ESI-MS. The C(4) D used in this setup proved to have a smaller contribution to the peak broadening than ESI-MS, which allowed that a C(4) D, positioned at 12 cm from the inlet of an 80-cm-long capillary, could be used to foresee position and shape of the peaks being formed 6.8 times slower at the ESI-MS electropherogram. PMID:27027468

  19. Potential of gas chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry for screening and quantification of hexabromocyclododecane.

    Science.gov (United States)

    Sales, Carlos; Portolés, Tania; Sancho, Juan Vicente; Abad, Esteban; Ábalos, Manuela; Sauló, Jordi; Fiedler, Heidelore; Gómara, Belén; Beltrán, Joaquim

    2016-01-01

    A fast method for the screening and quantification of hexabromocyclododecane (sum of all isomers) by gas chromatography using a triple quadrupole mass spectrometer with atmospheric pressure chemical ionization (GC-APCI-QqQ) is proposed. This novel procedure makes use of the soft atmospheric pressure chemical ionization source, which results in less fragmentation of the analyte than by conventional electron impact (EI) and chemical ionization (CI) sources, favoring the formation of the [M - Br](+) ion and, thus, enhancing sensitivity and selectivity. Detection was based on the consecutive loses of HBr from the [M - Br](+) ion to form the specific [M - H5Br6](+) and [M - H4Br5](+) ions, which were selected as quantitation (Q) and qualification (q) transitions, respectively. Parameters affecting ionization and MS/MS detection were studied. Method performance was also evaluated; calibration curves were found linear from 1 pg/μL to 100 pg/μL for the total HBCD concentration; instrumental detection limit was estimated to be 0.10 pg/μL; repeatability and reproducibility, expressed as relative standard deviation, were better than 7% in both cases. The application to different real samples [polyurethane foam disks (PUFs), food, and marine samples] pointed out a rapid way to identify and allow quantification of this compound together with a number of polybrominated diphenyl ethers (BDE congeners 28, 47, 66, 85, 99, 100, 153, 154, 183, 184, 191, 196, 197, and 209) and two other novel brominated flame retardants [i.e., decabromodiphenyl ethane (DBDPE) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE)] because of their presence in the same fraction when performing the usual sample treatment. PMID:26554601

  20. Quantitative determination of dexamethasone in bovine milk by liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry.

    Science.gov (United States)

    Cherlet, Marc; De Baere, Siegrid; De Backer, Patrick

    2004-06-01

    Dexamethasone (DXM) is a synthetic glucocorticoid that is authorized for therapeutic use in veterinary medicine. The European Community (EC) fixed a maximum residue limit (MRL) at 2ng/g for liver, 0.75ng/g for muscle and kidney tissues, and 0.3ng/ml for milk, while its use as growth-promoter is completely banned. The purpose of this study was to develop and validate a simple and reliable method to determine DXM residues in bovine milk. Milk proteins were removed by the addition of concentrated trichloroacetic acid and paper filtration. Solid-phase extraction clean-up on a C18 reversed phase column was performed to obtain an extract suitable for liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Chromatographic separation of DXM and the internal standard desoximetasone, was achieved on a PLRP-S polymeric reversed phase column, using a mixture of 0.1% (v/v) acetic acid in water (mobile phase A) and acetonitrile (mobile phase B) as the mobile phases. They were identified using the MS/MS detection technique, and were subsequently quantified. The method has been validated according to the requirements of the EC at 0.15, 0.30 and 0.60ng/ml (being half the MRL, the MRL and double the MRL levels fixed by the EC). Calibration graphs were prepared in the 0.15-5ng/ml range and good linearity was achieved (r>or=0.99 and goodness of fit

  1. Identification of Intact High Molecular Weight Glutenin Subunits from the Wheat Proteome Using Combined Liquid Chromatography-Electrospray Ionization Mass Spectrometry

    OpenAIRE

    Lagrain, Bert; Brunnbauer, Markus; Rombouts, Ine; Koehler, Peter

    2013-01-01

    The present paper describes a method for the identification of intact high molecular weight glutenin subunits (HMW-GS), the quality determining proteins from the wheat storage proteome. The method includes isolation of HMW-GS from wheat flour, further separation of HMW-GS by reversed-phase high-performance liquid chromatography (RP-HPLC), and their subsequent molecular identification with electrospray ionization mass spectrometry using a quadrupole-time-of-flight mass analyzer. For HMW-GS iso...

  2. Ion-pairing reversed-phase liquid chromatography/electrospray ionization mass spectrometric analysis of 76 underivatized amino acids of biological interest: a new tool for the diagnosis of inherited disorders of amino acid metabolism.

    Science.gov (United States)

    Piraud, Monique; Vianey-Saban, Christine; Petritis, Konstantinos; Elfakir, Claire; Steghens, Jean-Paul; Bouchu, Denis

    2005-01-01

    Seventy-six molecules of biological interest for the diagnosis of inherited disorders of amino acids (AA) metabolism have previously been demonstrated to be detectable in electrospray ionization tandem mass spectrometry (ESI-MS/MS) positive mode without derivatization. Reversed-phase liquid chromatography (RPLC) separation on different C18 columns using various perfluorinated carboxylic acids as ion-pairing agents has been found suitable for coupling with MS/MS, and for the separation of AA. A new procedure was optimized in order to replace the usual ion-exchange chromatographic, post-column ninhydrin derivatization, time-consuming routine method. This procedure allowed an adequate separation of all the molecules from other known interfering compounds, and a throughput of two samples per hour. Quantification limits for each molecule were found to be compatible with their measurement in plasma and urine. We validated the qualitative part of the method by analyzing plasma and urine samples from patients affected with several inherited disorders of AA metabolism. We validated the quantification of 16 AA using their stable isotopes as internal standard. The calibration curves were linear over the range 0-3 mM. The quantitative results obtained with the new method on 105 plasma and 99 urine samples were in good agreement with those obtained by the established routine method. Spiking experiments and precision results were also satisfactory. PMID:15915446

  3. Regiospecific analysis of neutral ether lipids by liquid chromatography/electrospray ionization/single quadrupole mass spectrometry: validation with synthetic compounds

    DEFF Research Database (Denmark)

    Hartvigsen, Karsten; Ravandi, A.; Bukhave, Klaus;

    2001-01-01

    A reversed-phase high-performance liquid chromatography (HPLC) method with on-line electrospray ionization/collision-induced dissociation/mass spectrometry (ESI/CID/MS) is presented for the regiospecific analysis of synthetic reference compounds of neutral ether lipids. The reference compounds were...... are suggested for each neutral ether lipid class. The present study demonstrates that reversed-phase HPLC and positive ion ESI/CID/MS provide direct and unambiguous information about the configuration and identity of molecular species in neutral 1-O-alkyl-sn-glycerol classes....... characterized by chromatographic retention times, full mass spectra, and fragmentation patterns as an aid to clarify the regiospecificity of ether lipids from natural sources. The results clearly show that single quadrupole mass spectroscopic analysis may elucidate the regiospecific structure of neutral ether...

  4. Characterisation by liquid chromatography-electrospray tandem mass spectrometry of anthocyanins in extracts of Myrtus communis L. berries used for the preparation of myrtle liqueur.

    Science.gov (United States)

    Montoro, Paola; Tuberoso, Carlo I G; Perrone, Angela; Piacente, Sonia; Cabras, Paolo; Pizza, Cosimo

    2006-04-21

    Anthocyanins in extracts of berries of Myrtus communis, prepared following a typical Sardinia myrtle liqueur recipe, were identified and quantified by HPLC coupled with electrospray/tandem mass spectrometry using, respectively, an ion trap and a triple quadrupole mass analyser. The fragmentation patterns of the anthocyanidins were dependent on the MS technique employed, and differed considerably from those previously reported. The anthocyanin profile of five anthocyanin glucosides and four anthocyanin arabinosides, the latter not previously identified in this specie, was specific for myrtle berry extracts. The quantitative compositions of extracts of myrtle berries derived from different geographical areas in Italy were compared. PMID:16376912

  5. Classification of cultivation locations of panax quinquefolius L samples using high performance liquid chromatography-electrospray ionization mass spectrometry and chemometric analysis

    Science.gov (United States)

    Panax quinquefolius L (P. quinquefolius L) samples grown in the United States and China were analyzed with high performance liquid chromatography-mass spectrometry (HPLC—MS). Prior to classification, the two-way datasets were subjected to pretreatment including baseline correction and retention ti...

  6. Identification of intact high molecular weight glutenin subunits from the wheat proteome using combined liquid chromatography-electrospray ionization mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Bert Lagrain

    Full Text Available The present paper describes a method for the identification of intact high molecular weight glutenin subunits (HMW-GS, the quality determining proteins from the wheat storage proteome. The method includes isolation of HMW-GS from wheat flour, further separation of HMW-GS by reversed-phase high-performance liquid chromatography (RP-HPLC, and their subsequent molecular identification with electrospray ionization mass spectrometry using a quadrupole-time-of-flight mass analyzer. For HMW-GS isolation, wheat proteins were reduced and extracted from flour with 50% 1-propanol containing 1% dithiothreitol. HMW-GS were then selectively precipitated from the protein mixture by adjusting the 1-propanol concentration to 60%. The composition of the precipitated proteins was first evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis with Coomassie staining and RP-HPLC with ultraviolet detection. Besides HMW-GS (≥65%, the isolated proteins mainly contained ω5-gliadins. Secondly, the isolated protein fraction was analyzed by liquid chromatography-mass spectrometry. Optimal chromatographic separation of HMW-GS from the other proteins in the isolated fraction was obtained when the mobile phase contained 0.1% trifluoroacetic acid as ion-pairing agent. Individual HMW-GS were then identified by determining their molecular masses from the high-resolution mass spectra and comparing these with theoretical masses calculated from amino acid sequences. Using formic acid instead of trifluoroacetic acid in the mobile phase increased protein peak intensities in the base peak mass chromatogram. This allowed the detection of even traces of other wheat proteins than HMW-GS in the isolated fraction, but the chromatographic separation was inferior with a major overlap between the elution ranges of HMW-GS and ω-gliadins. Overall, the described method allows a rapid assessment of wheat quality through the direct determination of the HMW-GS composition and

  7. Liquid chromatography-electrospray ionization mass spectrometry of the diarrhetic shellfish-poisoning toxins okadaic acid, dinophysistoxin-1 and pectenotoxin-6 in bivalves.

    Science.gov (United States)

    Suzuki, T; Yasumoto, T

    2000-04-01

    Determination of diarrhetic shellfish-poisoning (DSP) toxins, okadaic acid (OA), dinophysistoxin-1 (DTX1) and pectenotoxin-6 (PTX6) was carried out by liquid chromatography (LC) followed by on-line atmospheric pressure electrospray ionization-mass spectrometric (ESI-MS) detection with a heated capillary interface. Mass spectra of authentic OA, DTXI and PTX6 standards exhibited abundant [M-H] at m/z 803, 817 and 887, respectively. Linearity of peak area obtained by selected-ion monitoring (SIM) for [M-H]- of each toxin was confirmed over a wide range of concentrations from 10 pg to 30 ng. LC-ESI-MS analysis of OA, DTX1 and PTX6 in scallops and mussels, collected at the same site (Mutsu Bay, Japan), was carried out. Scallops and mussels collected at the same site showed different toxin profiles. Although PTX6 was detected from scallops, it was not detected from mussels. PMID:10817358

  8. Screening of polycyclic polyprenylated acylphloroglucinols from Garcinia species using precursor ion discovery (PID) scan and ultra performance liquid chromatography electrospray ionization Q-TOF tandem mass spectrometry.

    Science.gov (United States)

    Zhou, Yan; Huang, Sheng-Xiong; Song, Jing-Zheng; Qiao, Chun-Feng; Li, Song-Lin; Han, Quan-Bin; Xu, Hong-Xi

    2009-10-01

    A strategy was newly developed to rapidly screen polycyclic polyprenylated acyl-phloroglucinols (PPAPs) from the plant matrices of nine Garcinia species using ultra-performance liquid chromatography (UPLC) coupled with comprehensive mass spectrometric approaches including precursor ion discovery (PID) and tandem mass (MS/MS) scans. The PPAPs share the same diagnostic product ion at m/z 177.02 in positive MS/MS scan, which may be increased as the base peak by ramping the cone voltage from 45 to 100 V. With this ramping cone voltage PID scan, it is feasible to selectively screen the PPAPs from 29 samples of nine Garcinia species. This approach has proven to be a powerful, highly selective, and sensitive tool for rapid screening and detection of nontargeted components in natural products before the purification and structural elucidation process. PMID:19643632

  9. Determination of carnitine and acylcarnitines in urine by high-performance liquid chromatography-electrospray ionization ion trap tandem mass spectrometry.

    Science.gov (United States)

    Vernez, Laurence; Hopfgartner, Gérard; Wenk, Markus; Krähenbühl, Stephan

    2003-01-17

    A high-performance liquid chromatography-mass spectrometry method has been developed for the simultaneous determination of native carnitine and eight acylcarnitines in urine. The procedure uses a solid-phase extraction on a cation-exchange column and the separation is performed without derivatization within 17 min on a reversed-phase C8 column in the presence of a volatile ion-pairing reagent. The detector was an ion trap mass spectrometer and quantification was carried out in the MS-MS mode. Validation was done for aqueous standards at ranges between 0.75 and 200 micromol/l, depending on the compound. Carnitine was quantified in urine and comparison with a radioenzymatic assay gave a satisfactory correlation (R2 = 0.981). The assay could be successfully applied to the diagnostic of pathological acylcarnitines profile of metabolic disorders in urines of patients suffering from different organic acidurias. PMID:12564691

  10. Selenium metabolomics in yeast using complementary reversed-phase/hydrophilic ion interaction (HILIC) liquid chromatography-electrospray hybrid quadrupole trap/Orbitrap mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Arnaudguilhem, C.; Bierla, K.; Ouerdane, L.; Preud' homme, H. [CNRS/UPPA, Laboratoire de Chimie Analytique Bio-inorganique et Environnement, UMR 5254, Helioparc, 2, Av. Pr. Angot, 64053 Pau (France); Yiannikouris, A. [Alltech Inc., 3031 Catnip Hill Pike, Nicholasville, KY (United States); Lobinski, R., E-mail: ryszard.lobinski@univ-pau.fr [CNRS/UPPA, Laboratoire de Chimie Analytique Bio-inorganique et Environnement, UMR 5254, Helioparc, 2, Av. Pr. Angot, 64053 Pau (France); Chair of Analytical Chemistry, Warsaw University of Technology, 00-664 Warszawa (Poland)

    2012-12-13

    Highlights: Black-Right-Pointing-Pointer The use of bimodal chromatographic separation enlarged amount of compounds identified. Black-Right-Pointing-Pointer The method allowed the largest scale ever (>60 compounds) speciation analysis of selenium metabolites in Se-rich yeast. Black-Right-Pointing-Pointer The estimated concentration of compounds was given. - Abstract: A high efficiency chromatographic separation on a porous graphitic carbon stationary phase was developed for a large-scale separation of selenium metabolites in Se-rich yeast prior to their identification by electrospray hybrid quadrupole trap/Orbitrap mass spectrometry (Orbitrap MS{sup n}). The reversed-phase (RP) separation mode offered distinctly higher separation efficiency than the hydrophilic ion interaction (HILIC) mode. The latter was nevertheless complementary and useful to validate the detection of several compounds. The method allowed the detection of 64 metabolites including 30 Se-Se or Se-S conjugates (3 triple S/Se/S ones) and 14 selenoethers. 21 previously unreported metabolites were detected on the basis of the selenium isotopic pattern usually matched with the sub-ppm mass accuracy. 9 of these metabolites were subsequently identified using the multi-stage high mass accuracy (<5 ppm) mass spectrometry. The identified metabolites (and their groups) were quantified on-line by ICP-MS fitted with a frequency-matching generator allowing a quasi-uniform response over the large (20-90%) acetonitrile mobile phase concentration range. The morphology of HPLC-ICP-MS chromatograms was remarkably similar to that of HPLC multi-ion extracted ESI-MS chromatograms. The detection limits obtained by ICP MS and ESI MS were 1 and 2 ppb, respectively.

  11. Analysis of [3′,3′-d2]-nicotine and [3′,3′-d2]-cotinine by capillary liquid chromatography-electrospray tandem mass spectrometry

    OpenAIRE

    Murphy, Sharon E.; Villalta, Peter; Ho, Sing-Wei; von Weymarn, Linda B.

    2007-01-01

    A selective and sensitive LC/MS/MS assay was developed for the quantification of d2-nicotine and d2-cotinine in plasma of current and past smokers administered d2-nicotine. After solid phase extraction and liquid liquid extraction, HPLC separation was achieved on a capillary hydrophilic interaction chromatography phase column. The analytes were monitored by tandem mass spectrometry with electrospray positive ionization. Linear calibration curves were generated for d2-nicotine (0.03 to 6.0 ng/...

  12. Determination of the metabolic profile of gentianine after oral administration to rats by high performance liquid chromatography/electrospray ionization-trap mass spectrometry.

    Science.gov (United States)

    Wu, Xiuhong; Tang, Shuhan; Jin, Yan; Wang, Shanshan; Wang, Xijun; Hattori, Masao; Zhang, Hailong; Wang, Zhigang

    2015-05-01

    We investigated the metabolic fate of gentianine after oral administration to Wistar rats for the first time. Liquid chromatography/ion trap mass spectrometry detected four metabolites secogentianoxide, gentiandiol, gentianepoxide and gentianoxide in rat plasma together with the original compound gentianine. The structures of the metabolites were identified by comparing the retention times, as well as MS (mass) and MS/MS (tandem mass) spectra with those of authentic compounds, which were synthesized from gentianine or isolated from the urine. Three of the metabolites, secogentianoxide, gentianepoxide and gentianoxide, are novel compounds. The major in vivo metabolic processes associated with gentianine include N-oxide, epoxidation, dihydroxylation of double bond and hydrolysis of lactone. Gentianine together with the metabolites in plasma were quantified using gentianone as the internal standard. The mean C(max) of G0, G1, G2 and G3 are 425.76, 287.56, 188.45 and 85.05 ng/mL, respectively. The mean T(max) of G0, G1, G2 and G3 are 1.16, 3.87, 6.23 and 4.28 h, respectively. The mean T(1/2) of G0, G1, G2 and G3 are 5.23, 12.34, 7.78 and 5.64 h, respectively. A comprehensive metabolic pathway was proposed. The new metabolites may shed light on clinical efficacy of gentianine. PMID:25813903

  13. Efficient mining of myxobacterial metabolite profiles enabled by liquid chromatography-electrospray ionisation-time-of-flight mass spectrometry and compound-based principal component analysis

    International Nuclear Information System (INIS)

    Bacteria producing secondary metabolites are an important source of natural products with highly diverse structures and biological activities. Developing methods to efficiently mine procaryotic secondary metabolomes for the presence of potentially novel natural products is therefore of considerable interest. Modern mass spectrometry-coupled liquid chromatography can effectively capture microbial metabolic diversity with ever improving sensitivity and accuracy. In addition, computational and statistical tools increasingly enable the targeted analysis and exploration of information-rich LC-MS datasets. In this article, we describe the use of such techniques for the characterization of myxobacterial secondary metabolomes. Using accurate mass data from high-resolution ESI-TOF measurements, target screening has facilitated the rapid identification of known myxobacterial metabolites in extracts from nine Myxococcus species. Furthermore, principal component analysis (PCA), implementing an advanced compound-based bucketing approach, readily revealed the presence of further compounds which contribute to variation among the metabolite profiles under investigation. The generation of molecular formulae for putative novel compounds with high confidence due to evaluation of both exact mass position and isotopic pattern, is exemplified as an important key for de-replication and prioritization of candidates for further characterization

  14. Regiospecific analysis of neutral ether lipids by liquid chromatography/electrospray ionization/single quadrupole mass spectrometry: validation with synthetic compounds

    DEFF Research Database (Denmark)

    Hartvigsen, Karsten; Ravandi, A.; Bukhave, Klaus; Hølmer, Gunhild Kofoed; Kuksis, A.

    2001-01-01

    + H - H2O](+), whereas the reverse situation characterized the sn-3 species. Furthermore, corresponding sn-2 and sn-3 species were separated by the chromatographic system. However, loss of water was promoted as fatty acid unsaturation was raised, which may complicate interpretation of the mass spectra...... are suggested for each neutral ether lipid class. The present study demonstrates that reversed-phase HPLC and positive ion ESI/CID/MS provide direct and unambiguous information about the configuration and identity of molecular species in neutral 1-O-alkyl-sn-glycerol classes....

  15. Method development for the determination of selected pesticides on tobacco by high-performance liquid chromatography-electrospray ionisation-tandem mass spectrometry.

    Science.gov (United States)

    Mayer-Helm, Bernhard; Hofbauer, Ludwig; Müller, Jutta

    2008-02-15

    A method was developed for the quantitative determination of alachlor, benalaxyl, clomazone, diflubenzuron, dimethomorph, diphenamid, ethofumesate, metalaxyl, methoprene, metobromuron and piperonyl butoxide on tobacco. The pesticides were extracted with water and methanol from five different types of tobacco. The extracts were purified by partition on an extraction cartridge containing diatomaceous earth. The purified extracts were analysed by reversed-phase high-performance liquid chromatography connected to an atmospheric pressure ionisation-electrospray-triple quadrupole mass spectrometer operating in the positive ion mode. Two different transitions and their relative intensities were monitored for unambiguous identification. All pesticides presented overall recovery rates between 35% and 110%. The trueness is near 100% and the interday precision is below 15%. The limits of quantifications are equal or below the guidance residue levels proposed by the Agrochemical Advisory Committee of CORESTA, an association of organisations having scientific research relative to tobacco. PMID:18371768

  16. Ion chromatography electrospray ionization mass spectrometry method development and investigation of lithium hexafluorophosphate-based organic electrolytes and their thermal decomposition products.

    Science.gov (United States)

    Kraft, Vadim; Grützke, Martin; Weber, Waldemar; Winter, Martin; Nowak, Sascha

    2014-08-01

    A method based on the coupling of ion chromatography (IC) and electrospray ionization mass spectrometry (ESI-MS) for the separation and determination of thermal decomposition products of LiPF6-based organic electrolytes is presented. The utilized electrolytes, LP30 and LP50, are commercially available and consist of 1mol/l LiPF6 dissolved in ethylene carbonate/dimethyl carbonate and ethylene carbonate/ethyl methyl carbonate, respectively. For the separation method development three ion chromatographic columns with different capacity and stationary phase were used and compared. Besides the known hydrolysis products of lithium hexafluorophosphate, several new organophosphates were separated and identified with the developed IC-ESI-MS method during aging investigations of the electrolytes. The chemical structures were elucidated with IC-ESI-MS/MS. PMID:24939088

  17. Antioxidant activity and identification of bioactive compounds from leaves of Anthocephalus cadamba by ultra-performance liquid chromatography/electrospray ionization quadrupole time of flight mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    Madhu Chandel; Upendra Sharma; Neeraj Kumar; Bikram Singh; Satwinderjeet Kaur

    2012-01-01

    Objective: To evaluate the antioxidant potential of different extract/fractions of Anthocephalus cadamba (A. cadamba) (Roxb.) Miq. (Rubiaceae) and study the tentative identification of their active constituents. Methods: The extract/fractions were screened for antioxidant activity using various in vitro assays viz. DPPH assay, ABTS assay, superoxide anion radical scavenging assay, reducing power assay and plasmid DNA nicking assay. Total phenolic content of extract/fractions was determined by colorimetric method. An ultra-performance LC-electrospray-quadrupole-time of flight mass spectrometry method was used to analyse the active constituents of extract/fractions of A. cadamba. Results: The ethyl acetate fraction was found to be most active fraction in all the assays as compared to other extract/fractions. The IC50 value of ethyl acetate fraction (ETAC fraction) was 21.24 μg/mL, 1.12 μg/mL, 9.68 μg/mL and 57.81 μg/mL in DPPH assay, ABTS assay, reducing power assay and superoxide scavenging assay respectively. All the extract/fractions also showed the potential to protect the plasmid DNA (pBR322) against the attack of hydroxyl radicals generated by Fenton’s reagent. The bioactive compounds were identified by UPLC-ESI-QTOF-MS, by comparing the mass and λmax with literature values. Conclusions: The potential of the extract/fractions to scavenge different free radicals in different systems indicated that they may be useful therapeutic agents for treating radical-related pathologic damage.

  18. Column-switching high-performance liquid chromatography-electrospray ionization mass spectrometry for identification of heroin metabolites in human urine.

    Science.gov (United States)

    Katagi, M; Nishikawa, M; Tatsuno, M; Miki, A; Tsuchihashi, H

    2001-02-10

    In order to prove heroin (DAM) use, a simple, rapid and sensitive analytical method has been established by combining semi-microcolumn HPLC, a column switching technique and electrospray ionization mass spectrometry (ESI-MS). Urine samples were directly introduced to the system, and endogenous urinary constituents were removed by using on-line column switching solid-phase extraction with a strong cation-exchange (SCX) cartridge column (2.0 mm I.D. x 10 mm). Heroin and its metabolites enriched on the top of the column were then successfully analyzed with excellent separation by use of a SCX semi-microcolumn (1.5 mm I.D. x 150 mm), accompanied by ESI mass spectral detection. The proposed conditions are as follows: mobile phase, 10 mM ammonium acetate (pH 6.0)-acetonitrile (30:70, v/v) (for main separation) and 30 mM ammonium acetate (for trapping); flow-rates, 120 microl/min (for main separation) and 200 microl/min (for trapping); capillary voltage, +4.5 kV; cone voltage, 50 V. Linear calibration curves were obtained in the selected ion monitoring (SIM) mode using protonated molecular ions (m/z 370 for DAM, m/z 328 for MAM and m/z 286 for MOR) over the concentration ranges from 10 to 1000 ng/ml for morphine (MOR) and 1-100 ng/ml for DAM and 6-acetylmorphine (MAM). The detection limits were 0.1-3 ng/ml. Upon applying the scan mode, 2-30 ng/ml were the detection limits. The present HPLC-ESI-MS method was successfully applied to the determination of opiates in users' urine samples. PMID:11232848

  19. Metabolomics Analysis of Health Functions of Physalis Pubescens L. using by Ultra-performance Liquid Chromatography/Electrospray Ionization Quadruple Time-of-Flight Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    Hang Chu; Hui Sun; Guang-Li Yan; Ai-Hua Zhang; Chang Liu; Hui Dong; Xiang-Cai Meng; Xi-Jun Wang

    2015-01-01

    Herbal medicines may benefit from metabolomics studies, and applying metabolomics may provide answers about which herbal interventions may be effective for individuals, which metabolic processes are triggered, and the subsequent chemical pathways of activity. Physalis pubescens L (PPL) is an herbal fruit for one year living plant and has been developed into healthy function’s food. However, the mechanisms of health functions are still unclear. To comprehensively and holistically assess its anti-fatigue and antioxidant effects, a novel integrative metabolomics approach was applied. In this study, we present metabolomics analysis applying ultra performance liquid chromatography coupled to quadrupole with time-of-flight mass spectrometry (UPLC-Q/TOF-MS) to determine metabolite alterations after oral administration PPL to rats. Fifteen metabolites in urine were identified as potential biomarkers. Pattern analysis of the UPLC-Q/TOF-MS data disclosed that PPL could relieve fatigue rats by ameliorating the disturbance in amino acids metabolism and energy metabolism, alleviating the oxidative stress from reactive oxygen species and the inflammatory damage, and recovering the destructed regulation. Based on these results, we demonstrated that PPL is a promising source of natural anti-fatigue and antioxidants material for use in functional foods and medicines.

  20. Metabolomics Analysis of Health Functions of Physalis Pubescens L. using by Ultra-performance Liquid Chromatography/Electrospray Ionization Quadruple Time-of-Flight Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Hang Chu

    2015-07-01

    Full Text Available Herbal medicines may benefit from metabolomics studies, and applying metabolomics may provide answers about which herbal interventions may be effective for individuals, which metabolic processes are triggered, and the subsequent chemical pathways of activity. Physalis pubescens L (PPL is an herbal fruit for one year living plant and has been developed into healthy function's food. However, the mechanisms of health functions are still unclear. To comprehensively and holistically assess its anti-fatigue and antioxidant effects, a novel integrative metabolomics approach was applied. In this study, we present metabolomics analysis applying ultra performance liquid chromatography coupled to quadrupole with time-of-flight mass spectrometry (UPLC-Q/TOF-MS to determine metabolite alterations after oral administration PPL to rats. Fifteen metabolites in urine were identified as potential biomarkers. Pattern analysis of the UPLC-Q/TOF-MS data disclosed that PPL could relieve fatigue rats by ameliorating the disturbance in amino acids metabolism and energy metabolism, alleviating the oxidative stress from reactive oxygen species and the inflammatory damage, and recovering the destructed regulation. Based on these results, we demonstrated that PPL is a promising source of natural anti-fatigue and antioxidants material for use in functional foods and medicines.

  1. Ultra-performance liquid chromatography electrospray ionization–tandem mass spectrometry method for the simultaneous determination of itraconazole and hydroxy itraconazole in human plasma

    Directory of Open Access Journals (Sweden)

    Ashish Dwivedi

    2014-10-01

    Full Text Available A highly sensitive, selective, and precise ultra-performance liquid chromatography tandem mass spectrometry method was developed and validated for simultaneous quantification of itraconazole and hydroxy itraconazole in human plasma by a single liquid–liquid extraction step. The precursor to product ion transitions of m/z 705.3/392.3, m/z 721.2/408.3 and m/z 708.2/435.4 were used to detect and quantify itraconazole, hydroxy itraconazole and itraconazole-d3 respectively. The lower limit of quantitation was found to be 0.500 ng/mL for itraconazole and 1.00 ng/mL for hydroxy itraconazole. The mean recoveries for itraconazole and hydroxy itraconazole were found to be 100.045% and 100.021%, respectively. This developed method with a chromatographic run time of 2.0 min was successfully applied to a bioequivalence study of 100 mg itraconazole capsule.

  2. Detection and confirmation of milk adulteration with cheese whey using proteomic-like sample preparation and liquid chromatography-electrospray-tandem mass spectrometry analysis.

    Science.gov (United States)

    Campos Motta, T M; Hoff, R B; Barreto, F; Andrade, R B S; Lorenzini, D M; Meneghini, L Z; Pizzolato, T M

    2014-03-01

    Caseinomacropeptide (CMP) is a peptide released by chymosin in cheese production, remaining in whey. Thus, CMP can be used as a biomarker to fluid milk adulteration through whey addition. Commonly, CMP is analyzed by reversed phase (RP-HPLC) or size-exclusion chromatography (SEC). However, some psychrotropic microorganisms - specially Pseudomonas fluorescens - when present in storaged milk, can produce, by enzymatic pathway, a CMP-like peptide generally called pseudo-CMP. These two peptides differ from each other only by one amino acid. RP-HPLC and SEC methods are unable to distinguish these two peptides, which demand development of a confirmatory method with high selectivity. Considering the several degrees of glycosilation and phosphorylation sites in CMP, allied with possible genetic variation (CMP A and CMP B), analytical methods able to differentiate these peptides are extremely complex. In the present work, we developed a proteomic-like technique for separation and characterization of these peptides, using liquid chromatography coupled to mass spectrometry with electrospray ionization able to differentiate and subsequently quantify CMP and pseudo-CMP in milk samples in order to identify adulteration or contamination of these products. The method shows satisfactory precision (<11%) with a detection limit of 1.0 µg mL(-1) and quantification limit of 5.0 µg mL(-1). Specificity, matrix effects and applicability to real samples analysis were also performed and discussed. PMID:24468402

  3. Use of a partial filling technique and reverse migrating micelles in the study of N-methylcarbamate pesticides by micellar electrokinetic chromatography-electrospray ionization mass spectrometry.

    Science.gov (United States)

    Molina, M; Wiedmer, S K; Jussila, M; Silva, M; Riekkola, M L

    2001-08-24

    This study describes three ways to couple micellar electrokinetic chromatography (MEKC) on-line with electrospray ionization mass spectrometry (ESI-MS) for the analysis of N-methylcarbamate pesticides. The methods involved the use of a partial filling (PF) technique under basic conditions and the use of reverse migrating micelles (RMMs) under acidic and basic conditions. The use of RMMs in basic electrolyte solutions required coated capillaries with low electroosmotic flows, and capillaries coated with anionic poly(sodium 2-acrylamide-2-methylpropanesulfonate) were selected for the purpose. Before the on-line MEKC-ESI-MS coupling, the MEKC and MS conditions were separately optimized under off-line conditions. The methods were compared in terms of detection limits and the stability of the electrospray process. The PF method offered good separation but poorer stability of the electrospray relative to the other methods. A more stable electrospray performance was obtained with use of RMMs in acidic electrolyte solutions, but some of the analytes were protonated and could not be detected due to the increase in their retention factors. However, with the use of anionic polymer-coated capillaries and RMMs at pH 8.5, all analytes were successfully separated. The high-salt stacking method was applied to improve the sensitivity of MEKC-ESI-MS and the detection limits were in the range of 0.04-2.0 microg/ml. PMID:11572389

  4. Trace analysis of trimethoprim and sulfonamide, macrolide, quinolone, and tetracycline antibiotics in chlorinated drinking water using liquid chromatography electrospray tandem mass spectrometry

    Science.gov (United States)

    Ye, Z.; Weinberg, H.S.; Meyer, M.T.

    2007-01-01

    A multirun analytical method has been developed and validated for trace determination of 24 antibiotics including 7 sulfonamides, 3 macrolides, 7 quinolones, 6 tetracyclines, and trimethoprim in chlorine-disinfected drinking water using a single solid-phase extraction method coupled to liquid chromatography with positive electrospray tandem mass spectrometry detection. The analytes were extracted by a hydrophilic-lipophilic balanced resin and eluted with acidified methanol (0.1% formic acid), resulting in analyte recoveries generally above 90%. The limits of quantitation were mostly below 10 ng/L in drinking water. Since the concentrated sample matrix typically caused ion suppression during electrospray ionization, the method of standard addition was used for quantitation. Chlorine residuals in drinking water can react with some antibiotics, but ascorbic acid was found to be an effective chlorine quenching agent without affecting the analysis and stability of the antibiotics in water. A preliminary occurrence study using this method revealed the presence of some antibiotics in drinking waters, including sulfamethoxazole (3.0-3.4 ng/L), macrolides (1.4-4.9 ng/L), and quinolones (1.2-4.0 ng/L). ?? 2007 American Chemical Society.

  5. Analysis of phospholipid molecular species in brains from patients with infantile and juvenile neuronal-ceroid lipofuscinosis using liquid chromatography-electrospray ionization mass spectrometry.

    Science.gov (United States)

    Käkelä, Reijo; Somerharju, Pentti; Tyynelä, Jaana

    2003-03-01

    Phospholipids (PL) in cerebral cortex from patients with infantile (INCL or CLN1) and juvenile (JNCL or CLN3) forms of neuronal ceroid-lipofuscinosis (NCL) and controls were analysed by normal phase HPLC and on-line electrospray ionization ion-trap mass spectrometric detection (LC-ESI-MS). The method provided quantitative data on numerous molecular species of different PL classes, which are not achieved by using the conventional chromatographic methods. Compared with the controls, the INCL brains contained proportionally more phosphatidylcholine (PC), and less phosphatidylethanolamine (PE) and phosphatidylserine (PS). Different molecular species of PC, PE, PS, phosphatidylinositol and sphingomyelin were quantified using multiple internal PL standards that differed in fatty acyl chain length and thus allowed correction for chain length dependency of instrument response. In INCL cortex, which had lost 65% of the normal PL content, the proportions of polyunsaturated molecular species, especially the PS and PE that contained docosahexaenoic acid (22:6n-3), were dramatically decreased. The membranes may have adapted to this alteration by increasing the proportions of PL molecules substituted with monounsaturated and short-chain fatty acids. Lysobisphosphatidic acid was highly elevated in the INCL brain and consisted mostly of polyunsaturated species. It is possible that changes in the composition of PL membranes accelerate progression of INCL by altering signalling and membrane trafficking in neurons. PMID:12603829

  6. Determination of energy metabolites in cancer cells by porous graphitic carbon liquid chromatography electrospray ionization mass spectrometry for the assessment of energy metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Szoboszlai, Norbert, E-mail: szobosz@chem.elte.hu [Laboratory of Environmental Chemistry and Bioanalytics, Department of Analytical Chemistry, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter stny 1/A, H-1117 Budapest (Hungary); Guo, Xinghua [Institute of Analytical Chemistry and Food Chemistry, Graz University of Technology, Stremayrgasse 9, 8010 Graz (Austria); Ozohanics, Olivér [Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Pusztaszeri u. 59-67, H-1025 Budapest (Hungary); Oláh, Júlia [1st Institute of Pathology and Experimental Cancer Research, Semmelweis University, H-1085 Budapest (Hungary); Gömöry, Ágnes [Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Pusztaszeri u. 59-67, H-1025 Budapest (Hungary); Mihucz, Victor G. [Laboratory of Environmental Chemistry and Bioanalytics, Department of Analytical Chemistry, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter stny 1/A, H-1117 Budapest (Hungary); Jeney, András [1st Institute of Pathology and Experimental Cancer Research, Semmelweis University, H-1085 Budapest (Hungary); Vékey, Károly [Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Pusztaszeri u. 59-67, H-1025 Budapest (Hungary)

    2014-03-01

    Graphical abstract: - Highlights: • All types of sugar metabolites can be investigated in one run on graphitic stationary phase. • Method development for acidic metabolites of energy metabolism using a single LC–MS run. • Study of 15 acidic energy metabolites on a PGC column using common eluents. • Lactate, acidic amino acid, organic acid and sugar phosphate determination in a single run. • Metabolism of U-{sup 13}C glucose and 1-{sup 13}C acetate in ZR-75-1 cells studied. - Abstract: A high performance liquid chromatography (HPLC) tandem mass spectrometric (MS/MS) method has been developed for the simultaneous determination of fifteen glucose, or acetate derived metabolites isolated from tumor cells. Glycolytic and tricarboxylic acid (TCA) cycle metabolites as well as acidic amino acids were separated on a HPLC porous graphitic carbon (PGC) column and simultaneously determined by means of triple quadrupole MS/MS using multiple reaction monitoring (MRM). Target compounds were eluted within 10 min with 8% v/v formic acid as an electronic modifier added to a 4:1 v/v methanol water mobile phase. The calibration is linear in the 1–100 μM concentration range for each analyte. The limit of detection ranges between 0.39 and 2.78 μM for the analytes concerned. To test the PGC–HPLC–MS/MS method in metabolomic studies, ZR-75.1 human mammary adenocarcinoma cells were labeled with U-{sup 13}C glucose or 1-{sup 13}C acetate. Applying the MRM mode, the incorporation of {sup 13}C into metabolites, isolated from the tumor cells, and derived from glucose or acetate, could be properly identified.

  7. Determination of pharmaceutical compounds in surface- and ground-water samples by solid-phase extraction and high-performance liquid chromatography-electrospray ionization mass spectrometry

    Science.gov (United States)

    Cahill, J.D.; Furlong, E.T.; Burkhardt, M.R.; Kolpin, D.; Anderson, L.G.

    2004-01-01

    Commonly used prescription and over-the-counter pharmaceuticals are possibly present in surface- and ground-water samples at ambient concentrations less than 1 μg/L. In this report, the performance characteristics of a combined solid-phase extraction isolation and high-performance liquid chromatography–electrospray ionization mass spectrometry (HPLC–ESI-MS) analytical procedure for routine determination of the presence and concentration of human-health pharmaceuticals are described. This method was developed and used in a recent national reconnaissance of pharmaceuticals in USA surface waters. The selection of pharmaceuticals evaluated for this method was based on usage estimates, resulting in a method that contains compounds from diverse chemical classes, which presents challenges and compromises when applied as a single routine analysis. The method performed well for the majority of the 22 pharmaceuticals evaluated, with recoveries greater than 60% for 12 pharmaceuticals. The recoveries of angiotensin-converting enzyme inhibitors, a histamine (H2) receptor antagonist, and antihypoglycemic compound classes were less than 50%, but were retained in the method to provide information describing the potential presence of these compounds in environmental samples and to indicate evidence of possible matrix enhancing effects. Long-term recoveries, evaluated from reagent-water fortifications processed over 2 years, were similar to initial method performance. Method detection limits averaged 0.022 μg/L, sufficient for expected ambient concentrations. Compound-dependent matrix effects on HPLC/ESI-MS analysis, including enhancement and suppression of ionization, were observed as a 20–30% increase in measured concentrations for three compounds and greater than 50% increase for two compounds. Changing internal standard and more frequent ESI source maintenance minimized matrix effects. Application of the method in the national survey demonstrates that several

  8. Determination of energy metabolites in cancer cells by porous graphitic carbon liquid chromatography electrospray ionization mass spectrometry for the assessment of energy metabolism

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • All types of sugar metabolites can be investigated in one run on graphitic stationary phase. • Method development for acidic metabolites of energy metabolism using a single LC–MS run. • Study of 15 acidic energy metabolites on a PGC column using common eluents. • Lactate, acidic amino acid, organic acid and sugar phosphate determination in a single run. • Metabolism of U-13C glucose and 1-13C acetate in ZR-75-1 cells studied. - Abstract: A high performance liquid chromatography (HPLC) tandem mass spectrometric (MS/MS) method has been developed for the simultaneous determination of fifteen glucose, or acetate derived metabolites isolated from tumor cells. Glycolytic and tricarboxylic acid (TCA) cycle metabolites as well as acidic amino acids were separated on a HPLC porous graphitic carbon (PGC) column and simultaneously determined by means of triple quadrupole MS/MS using multiple reaction monitoring (MRM). Target compounds were eluted within 10 min with 8% v/v formic acid as an electronic modifier added to a 4:1 v/v methanol water mobile phase. The calibration is linear in the 1–100 μM concentration range for each analyte. The limit of detection ranges between 0.39 and 2.78 μM for the analytes concerned. To test the PGC–HPLC–MS/MS method in metabolomic studies, ZR-75.1 human mammary adenocarcinoma cells were labeled with U-13C glucose or 1-13C acetate. Applying the MRM mode, the incorporation of 13C into metabolites, isolated from the tumor cells, and derived from glucose or acetate, could be properly identified

  9. Quantitative analysis of phenolic compounds in Chinese hawthorn (Crataegus spp.) fruits by high performance liquid chromatography-electrospray ionisation mass spectrometry.

    Science.gov (United States)

    Liu, Pengzhan; Kallio, Heikki; Lü, Deguo; Zhou, Chuansheng; Yang, Baoru

    2011-08-01

    Eleven major phenolic compounds (hyperoside, isoquercitrin, chlorogenic acid, ideain, epicatechin, two procyanidin (PA) dimers, three PA trimers and a PA dimer-hexoside) were quantified in the fruits of 22 cultivars/origins of three species of the Chinese hawthorn (Crataegus spp.) by HPLC-ESI-MS-SIR. Hyperoside (0.1-0.8mg/g dry mass [DM]), isoquercitrin (0.1-0.3mg/g DM), chlorogenic acid (0.2-1.6mg/g DM), epicatechin (0.9-11.7mg/g DM), PA B2 (0.7-12.4mg/g DM), PA dimer II (0.1-1.5mg/g DM), PA trimer I (0.1-2.7mg/g DM), PA trimer II (0.7-6.9mg/g DM), PA trimer III (0.01-1.2mg/g DM) and a PA dimer-hexoside (trace-1.1mg/g DM) were detected in all the samples. Ideain (0.0-0.7mg/g DM) was found in all the samples except Crataegus scabrifolia. Significant correlations between the contents of individual PA aglycons were observed (r>0.9, P<0.01). A strong correlation between flavonols was also shown (r=0.71, P<0.01). Fruits of Crataegus pinnatifida var. major had higher contents of PAs but lower contents of flavonols compared with Crataegus brettschneideri. The fruits of C. scabrifolia contained the highest level of PA dimer-hexoside, which was present in trace amounts in the fruits of C. pinnatifida. PMID:25214140

  10. Determination of synthetic phenolic antioxidants and relative metabolites in sewage treatment plant and recipient river by high performance liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Liu, Runzeng; Ruan, Ting; Song, Shanjun; Lin, Yongfeng; Jiang, Guibin

    2015-02-13

    Robust analytical methods were developed for the determination of eight emerging synthetic phenolic antioxidants (SPAs) and three metabolites in sewage sludge, effluent and river water matrices. Accelerated solvent extraction was employed for the extraction of the target analytes from sludge, dichloromethane/hexane=3:1 (extraction solvent) and 90°C (extraction temperature) were used after optimization. Silica gel packed column was chosen for the subsequent clean-up procedure for sludge extract. For the water sample analysis, liquid-liquid extraction combined with silica gel clean-up was used. The targets were determined by optimized high performance liquid chromatography-tandem mass spectrometry method in negative electrospray ionization mode. The method quantification limits of the 11 analytes ranged from 0.1 to 23 ng/L, 0.1 to 20 ng/L and 0.1 to 15 ng/g for sewage effluent, river water and sludge matrices, respectively. The total recoveries of the pretreatment varied from 63 to 106%, with relative standard deviations less than 17% for the three matrices at different spiking levels. Nine targets including 2,6-di-tert-butyl-4-methylphenol (BHT), 3,5-di-tert-butyl-4-hydroxybenzaldehyde (BHT-CHO), 2,6-di-tert-butyl-1,4-benzoquinone (BHT-Q), 2,6-di-tert-butyl-4-hydroxy-4-methyl-2,5-cyclohexadienone (BHT-quinol), 3-tert-butyl-4-hydroxyanisole (BHA), 4-tert-octylphenol (4-tOP), 2,2'-methylenebis(6-tert-butyl-4-methylphenol) (AO 2246), 4,4'-butylidenebis(2-(1,1-dimethylethyl)-5-methyl-phenol) (AO 44B25) and 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (AO 330) were identified in the collected samples, with concentrations ranging 1.1-2325 ng/g and 0.4-2510 ng/L for sludge and water matrices, respectively. Sewage effluent was considered as a possible contamination source of certain SPA homologues and relative metabolites to the recipient aquatic systems. PMID:25614188

  11. Quantitative analysis of N-glycans from human alfa-acid-glycoprotein using stable isotope labeling and zwitterionic hydrophilic interaction capillary liquid chromatography electrospray mass spectrometry as tool for pancreatic disease diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Giménez, Estela, E-mail: estelagimenez@ub.edu [Department of Analytical Chemistry, University of Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Balmaña, Meritxell [Biochemistry and Molecular Biology Unit, Department of Biology, University of Girona, Campus Montilivi s/n, 17071 Girona (Spain); Figueras, Joan [Department of Surgery, Dr. Josep Trueta University Hospital, IdlBGi, 17007 Girona (Spain); Fort, Esther [Digestive Unit, Dr. Josep Trueta University Hospital, 17007 Girona (Spain); Bolós, Carme de [Gastroesophagic Cancer Research Group, Research Programme in Cancer, Hospital del Mar Medical Research Institute (IMIM), Dr. Aiguader, 88, 08003 Barcelona (Spain); Sanz-Nebot, Victòria [Department of Analytical Chemistry, University of Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Peracaula, Rosa [Biochemistry and Molecular Biology Unit, Department of Biology, University of Girona, Campus Montilivi s/n, 17071 Girona (Spain); Rizzi, Andreas [Institute of Analytical Chemistry, University of Vienna, Währinger Straße 38, A-1090 Vienna (Austria)

    2015-03-25

    Highlights: • The method enables relative quantitation of hAGP glycans from pathological samples • Pancreatic cancer samples clearly showed an increase of hAGP fucosylated glycans. • Fucosylated glycans could be potential biomarkers for diagnosing pancreatic cancer. • The established method could be extremely useful to find novel glycoprotein biomarkers - Abstract: In this work we demonstrate the potential of glycan reductive isotope labeling (GRIL) using [{sup 12}C]- and [{sup 13}C]-coded aniline and zwitterionic hydrophilic interaction capillary liquid chromatography electrospray mass spectrometry (μZIC-HILIC-ESI-MS) for relative quantitation of glycosylation variants in selected glycoproteins present in samples from cancer patients. Human α{sub 1}-acid-glycoprotein (hAGP) is an acute phase serum glycoprotein whose glycosylation has been described to be altered in cancer and chronic inflammation. However, it is not clear yet whether some particular glycans in hAGP can be used as biomarker for differentiating between these two pathologies. In this work, hAGP was isolated by immunoaffinity chromatography (IAC) from serum samples of healthy individuals and from those suffering chronic pancreatitis and different stages of pancreatic cancer, respectively. After de-N-glycosylation, relative quantitation of the hAGP glycans was carried out using stable isotope labeling and μZIC-HILIC-ESI-MS analysis. First, protein denaturing conditions prior to PNGase F digestion were optimized to achieve quantitative digestion yields, and the reproducibility of the established methodology was evaluated with standard hAGP. Then, the proposed method was applied to the analysis of the clinical samples (control vs. pathological). Pancreatic cancer samples clearly showed an increase in the abundance of fucosylated glycans as the stage of the disease increases and this was unlike to samples from chronic pancreatitis. The results gained here indicate the mentioned glycan in h

  12. Quantitative analysis of N-glycans from human alfa-acid-glycoprotein using stable isotope labeling and zwitterionic hydrophilic interaction capillary liquid chromatography electrospray mass spectrometry as tool for pancreatic disease diagnosis

    International Nuclear Information System (INIS)

    Highlights: • The method enables relative quantitation of hAGP glycans from pathological samples • Pancreatic cancer samples clearly showed an increase of hAGP fucosylated glycans. • Fucosylated glycans could be potential biomarkers for diagnosing pancreatic cancer. • The established method could be extremely useful to find novel glycoprotein biomarkers - Abstract: In this work we demonstrate the potential of glycan reductive isotope labeling (GRIL) using [12C]- and [13C]-coded aniline and zwitterionic hydrophilic interaction capillary liquid chromatography electrospray mass spectrometry (μZIC-HILIC-ESI-MS) for relative quantitation of glycosylation variants in selected glycoproteins present in samples from cancer patients. Human α1-acid-glycoprotein (hAGP) is an acute phase serum glycoprotein whose glycosylation has been described to be altered in cancer and chronic inflammation. However, it is not clear yet whether some particular glycans in hAGP can be used as biomarker for differentiating between these two pathologies. In this work, hAGP was isolated by immunoaffinity chromatography (IAC) from serum samples of healthy individuals and from those suffering chronic pancreatitis and different stages of pancreatic cancer, respectively. After de-N-glycosylation, relative quantitation of the hAGP glycans was carried out using stable isotope labeling and μZIC-HILIC-ESI-MS analysis. First, protein denaturing conditions prior to PNGase F digestion were optimized to achieve quantitative digestion yields, and the reproducibility of the established methodology was evaluated with standard hAGP. Then, the proposed method was applied to the analysis of the clinical samples (control vs. pathological). Pancreatic cancer samples clearly showed an increase in the abundance of fucosylated glycans as the stage of the disease increases and this was unlike to samples from chronic pancreatitis. The results gained here indicate the mentioned glycan in hAGP as a candidate

  13. Detection of 20 carbamate pesticides in asparagus by ultra performance liquid chromatography-electrospray ionization-mass spectrometry-mass spectrometry%超高效液相色谱-电喷雾串联四极杆质谱法检测芦笋中20种氨基甲酸酯类农药残留

    Institute of Scientific and Technical Information of China (English)

    赵晓琳; 霍乃蕊; 花锦; 宋欢

    2015-01-01

    目的:建立芦笋及其罐头制品中20种氨基甲酸酯类农药残留的定性定量分析方法。方法采用改进的 QuEchERS 法提取和净化,利用超高效液相色谱-电喷雾串联四极杆质谱仪,在多反应监测正离子扫描模式下对样品进行添加回收率试验。结果分别对绿芦笋、白芦笋、绿芦笋罐头、白芦笋罐头4种空白基质添加0.005~0.050 mg/kg农药样品进行回收率试验,回收率为62.44%~85.99%,定量限均为0.005 mg/kg, RSD均小于9%。结论该方法简单快速,灵敏度高,能够同时满足芦笋及其罐头制品中20种氨基甲酸酯类农药残留的检测要求。%Objective To establish an ultra performance liquid chromatography-electrospray ionization-mass spectrometry-mass spectrometry method for detecting of 20 kinds of carbamate pesticides in asparagus and asparagus products. Methods Samples were extracted by modified QuEchERS method, and the mode of multi-reaction monitoring positive ion scanning was applied for analysis by ultra high performance liquid chromatography-electrospray tandem quadrupole mass spectrometer. Results The blank matrixes (green asparagus, white asparagus, canned white asparagus, canned white asparagus) were added 0.005~0.050 mg/kg carbamate pesticides separately and recovery tests were performed. Results demonstrated that the recovery rates were in the range of 62.44%~85.99% and the limits of quantification were 0.005 mg/kg for all the 20 carbamate pesticides tested with the relative standard deviations (RSDs) below 9%. Conclusion The method, not only simple and fast but also high sensitive, can satisfy the international detection requirement for 20 carbamate pesticides residue in asparagus product simultaneously.

  14. Quantification of 3α-hydroxytibolone in human plasma by high performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS: Application in a bioequivalence study in healthy postmenopausal volunteers

    Directory of Open Access Journals (Sweden)

    Lucas Azevedo Portela

    2016-06-01

    Full Text Available A sensitive, specific and fast method to quantify 3α-hydroxytibolone in human plasma using deuterated 3α-hydroxytibolone (d5 as internal standard is described. The analyte and the internal standard were extracted from plasma (900 μL by liquid-liquid extraction using ethyl ether/hexane (50/50, v/v and ammonium hydroxide (50%. The extracts were analyzed by high performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry without derivatization. Chromatography was performed isocratically on a Gemini-NX™ C18 5 μm (150 × 4.6 mm i. d. column. The method had a chromatographic run time of 3.75 min and a linear calibration curve over the range 1–100 ng/mL. The limit of quantification validated was 1 ng/mL. This method was used to assess the bioequivalence between two different tibolone oral formulations: Livolon (1.25 mg tablet provided by Biolab Sanus Farmacêutica (Brazil, as the test formulation, and Libiam™ (1.25 mg tablet produced by Libbs Farmacêutica (Brazil, as the reference formulation. A single 3.75 mg dose of each formulation was administered to 46 postmenopausal female healthy volunteers. The study was conducted in an open, randomized, two-period crossover balanced design with a 2 week washout interval between the doses. The 90% confidence interval for Cmax, AUC(0-last and AUC(0-inf individual test/reference ratios were 97.48–111.51, 95.35–103.20 and 96.42–103.86, respectively. It is concluded that Livolon (1.25 mg tablet is bioequivalent to Libiam™ (1.25 mg tablet, with regards to both rate and extent of absorption.

  15. Identification and Quantification of the Major Constituents in Egyptian Carob Extract by Liquid Chromatography–Electrospray Ionization-Tandem Mass Spectrometry

    OpenAIRE

    Asmaa Ibrahim Owis; El-Motaz Bellah El-Naggar

    2016-01-01

    Background: Carob - Ceratonia siliqua L., commonly known as St John's-bread or locust bean, family Fabaceae - is one of the most useful native Mediterranean trees. There is no data about the chromatography methods performed by high performance liquid chromatography (HPLC) for determining polyphenols in Egyptian carob pods. Objective: To establish a sensitive and specific liquid chromatography–electrospray ionization (ESI)-tandem mass spectrometry (MSn) methodology for the identification of th...

  16. Natural products in Glycyrrhiza glabra (licorice) rhizome imaged at the cellular level by atmospheric pressure matrix-assisted laser desorption/ionization tandem mass spectrometry imaging

    DEFF Research Database (Denmark)

    Li, Bin; Bhandari, Dhaka Ram; Janfelt, Christian;

    2014-01-01

    .02 Da. With a mass resolving power of 140 000 and a bin width of 5 ppm in the image processing, the two compounds were well resolved in full-scan mode, and appeared with different distributions in the tissue sections. The identities of the compounds and their distributions were validated in a subsequent...... saponins in legume species, combing the spatially resolved chemical information with morphological details at the microscopic level. Furthermore, the technique offers a scheme capable of high-throughput profiling of metabolites in plant tissues....

  17. Identification of bradykinin: related peptides from Phyllomedusa nordestina skin secretion using electrospray ionization tandem mass spectrometry after a single-step liquid chromatography

    Directory of Open Access Journals (Sweden)

    K Conceição

    2009-01-01

    Full Text Available Amphibian skin secretions are a source of potential new drugs with medical and biotechnological applications. Rich in peptides produced by holocrine-type serous glands in the integument, these secretions play different roles, either in the regulation of physiological skin functions or in the defense against predators or microorganisms. The aim of the present work was to identify novel peptides with bradykinin-like structure and/or activity present in the skin of Phyllomedusa nordestina. In order to achieve this goal, the crude skin secretion of this frog was pre-fractionated by solid phase extraction and separated by reversed-phase chromatography. The fractions were screened for low-molecular-mass peptides and sequenced by mass spectrometry. It was possible to identify three novel bradykinin-related peptides, namely: KPLWRL-NH2 (Pnor 3, RPLSWLPK (Pnor 5 and VPPKGVSM (Pnor 7 presenting vascular activities as assessed by intravital microscopy. Pnor 3 and Pnor 7 were able to induce vasodilation. On the other hand, Pnor 5 was a potent vasoconstrictor. These effects were reproduced by their synthetic analogues.

  18. Optimization of the Extraction of Anthocyanins from the Fruit Skin of Rhodomyrtus tomentosa (Ait. Hassk and Identification of Anthocyanins in the Extract Using High-Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (HPLC-ESI-MS

    Directory of Open Access Journals (Sweden)

    Yuan-Ming Sun

    2012-05-01

    Full Text Available Anthocyanins are naturally occurring polyphenols that impart bright color to fruits, vegetables and plants. In this study, the extraction of anthocyanins from freeze-dried fruit skin of downy rose-myrtle (Rhodomyrtus tomentosa (Ait. Hassk var. Gangren was optimized using response surface methodology (RSM. Using 60% ethanol containing 0.1% (v/v hydrochloric acid as extraction solvent, the optimal conditions for maximum yields of anthocyanin (4.358 ± 0.045 mg/g were 15.7:1 (v/w liquid to solid ratio, 64.38 °C with a 116.88 min extraction time. The results showed good fits with the proposed model for the anthocyanin extraction (R2 = 0.9944. Furthermore, the results of high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS analysis of the anthocyanins extracted from the fruit skin of downy rose-myrtle revealed the presence of five anthocyanin components, which were tentatively identified as delphinidin-3-glucoside, cyanidin-3-glucoside, peonidin-3-glucoside, petunidin-3-glucoside and malvidin-3-glucoside.

  19. Evaluation of matrix solid-phase dispersion extraction for 11 β-agonists in swine feed by liquid chromatography with electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Tao, Yanfei; Zhu, Fangwei; Chen, Dongmei; Xie, Shuyu; Yuanhu, Pan; Wang, Xu; Liu, Zhenli; Peng, Dapeng; Yuan, Zonghui

    2014-09-01

    A sensitive liquid chromatography with tandem mass spectrometry method was developed for the determination of 11 β-agonists (clenbuterol, salbutamol, ractopamine, terbutaline, fenoterol, cimaterol, isoxsuprine, mabuterol, mapenterol, clenproperol, and tulobuterol) in swine feed. This rapid, simple, and effective extraction method was based on matrix solid-phase dispersion. The limit of quantification of clenbuterol, cimaterol, mabuterol, salbutamol, terbutaline, mapenterol, clenproperol, and tulobuterol was 1 μg/kg and that of ractopamine, fenoterol, and isoxsuprine was 2 μg/kg. The recoveries of β-agonists spiked in swine feeds at a concentration range of 1-8 μg/kg were >83.1% with relative standard deviations <9.3%. This rapid and reliable method can be used to efficiently separate, characterize, and quantify the residues of 11 β-agonists in swine feeds with advantages of simple pretreatment and environmental friendliness. PMID:24981594

  20. Quantification of levoglucosan and its isomers by High Performance Liquid Chromatography – Electrospray Ionization tandem Mass Spectrometry and its applications to atmospheric and soil samples

    Directory of Open Access Journals (Sweden)

    C. Piot

    2011-07-01

    Full Text Available The determination of atmospheric concentrations of levoglucosan and its two isomers, unambiguous tracers of biomass burning emissions, became even more important with the development of wood as renewable energy for domestic heating. Many researches demonstrated the increase during recent years of atmospheric particulate matter load due to domestic biomass combustion in developed countries. Analysis of biomass burning tracers is traditionally performed with Gas Chromatography-Mass Spectrometry (GC-MS technique after derivatization and requires an organic solvent extraction. A simpler and faster technique using Liquid Chromatography – Electrospray Ionisation – tandem Mass Spectrometry (LC-ESI-MS/MS was optimized for the analysis of levoglucosan, mannosan and galactosan isomers after an aqueous extraction. This technique allows a good separation between the three compounds in a very reduced time (runtime ~5 min. LOD and LOQ of this method are 30 μg l−1 and 100 μg l−1 respectively, allowing the use of filters from low-volume sampler (as commonly used in routine campaigns. A comparison of simultaneous levoglucosan measurements by GC-MS and LC-ESI-MS/MS for about 50 samples coming from different types of sampling sites and seasons was realized and shows very good agreement between the two methods. Therefore LC-ESI-MS/MS method can be used as an alternative to GC-MS particularly for measurement campaigns in routine where analysis time is important and detection limit is reduced. This paper shows that this method is also applicable to other environmental sample types like soil.

  1. Quantification of levoglucosan and its isomers by High Performance Liquid Chromatography – Electrospray Ionization tandem Mass Spectrometry and its applications to atmospheric and soil samples

    Directory of Open Access Journals (Sweden)

    N. Marchand

    2012-01-01

    Full Text Available The determination of atmospheric concentrations of levoglucosan and its two isomers, unambiguous tracers of biomass burning emissions, became even more important with the development of wood as renewable energy for domestic heating. Many researches demonstrated the increase during recent years of atmospheric particulate matter load due to domestic biomass combustion in developed countries. Analysis of biomass burning tracers is traditionally performed with Gas Chromatography-Mass Spectrometry (GC-MS technique after derivatization and requires an organic solvent extraction. A simpler and faster technique using Liquid Chromatography – Electrospray Ionisation – tandem Mass Spectrometry (LC-ESI-MS/MS was optimized for the analysis of levoglucosan, mannosan and galactosan isomers after an aqueous extraction. This technique allows a good separation between the three compounds in a very reduced time (runtime ~5 min. LOD and LOQ of this method are 30 μg l−1 and 100 μg l−1 respectively, allowing the use of filters from low-volume sampler (as commonly used in routine campaigns. A comparison of simultaneous levoglucosan measurements by GC-MS and LC-ESI-MS/MS for about 50 samples coming from different types of sampling sites and seasons was realized and shows very good agreement between the two methods. Therefore LC-ESI-MS/MS method can be used as an alternative to GC-MS particularly for measurement campaigns in routine where analysis time is important and detection limit is reduced. This paper shows that this method is also applicable to other environmental sample types like soil.

  2. Determination of talinolol in human plasma using automated on-line solid phase extraction combined with atmospheric pressure chemical ionization tandem mass spectrometry.

    Science.gov (United States)

    Bourgogne, Emmanuel; Grivet, Chantal; Hopfgartner, Gérard

    2005-06-01

    A specific LC-MS/MS assay was developed for the automated determination of talinolol in human plasma, using on-line solid phase extraction system (prospekt 2) combined with atmospheric pressure chemical ionization (APCI) tandem mass spectrometry. The method involved simple precipitation of plasma proteins with perchloric acid (contained propranolol) as the internal standard (IS) and injection of the supernatant onto a C8 End Capped (10 mmx2 mm) cartridge without any evaporation step. Using the back-flush mode, the analytes were transferred onto an analytical column (XTerra C18, 50 mmx4.6 mm) for chromatographic separation and mass spectrometry detection. One of the particularities of the assay is that the SPE cartridge is used as a column switching device and not as an SPE cartridge. Therefore, the same SPE cartridge could be used more than 28 times, significantly reducing the analysis cost. APCI ionization was selected to overcome any potential matrix suppression effects because the analyte and IS co-eluted. The mean precision and accuracy in the concentration range 2.5-200 ng/mL was found to be 103% and 7.4%, respectively. The data was assessed from QC samples during the validation phase of the assay. The lower limit of quantification was 2.5 ng/mL, using a 250 microL plasma aliquot. The LC-MS/MS method provided the requisite selectivity, sensitivity, robustness accuracy and precision to assess pharmacokinetics of the compound in several hundred human plasma samples. PMID:15866498

  3. Identification and quantification of the major constituents in Egyptian carob extract by liquid chromatography–electrospray ionization-tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Asmaa Ibrahim Owis

    2016-01-01

    Full Text Available Background: Carob - Ceratonia siliqua L., commonly known as St John's-bread or locust bean, family Fabaceae - is one of the most useful native Mediterranean trees. There is no data about the chromatography methods performed by high performance liquid chromatography (HPLC for determining polyphenols in Egyptian carob pods. Objective: To establish a sensitive and specific liquid chromatography–electrospray ionization (ESI-tandem mass spectrometry (MSn methodology for the identification of the major constituents in Egyptian carob extract. Materials and Methods: HPLC with diode array detector and ESI-mass spectrometry (MS was developed for the identification and quantification of phenolic acids, flavonoid glycosides, and aglycones in the methanolic extract of Egyptian C. siliqua. The MS and MSn data together with HPLC retention time of phenolic components allowed structural characterization of these compounds. Peak integration of ions in the MS scans had been used in the quantification technique. Results: A total of 36 compounds were tentatively identified. Twenty-six compounds were identified in the negative mode corresponding to 85.4% of plant dry weight, while ten compounds were identified in the positive mode representing 16.1% of plant dry weight, with the prevalence of flavonoids (75.4% of plant dry weight predominantly represented by two methylapigenin-O-pentoside isomers (20.9 and 13.7% of plant dry weight. Conclusion: The identification of various compounds present in carob pods opens a new door to an increased understanding of the different health benefits brought about by the consumption of carob and its products.

  4. Determination of eight nitrosamines in water at the ng L{sup -1} levels by liquid chromatography coupled to atmospheric pressure chemical ionization tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ripolles, Cristina; Pitarch, Elena; Sancho, Juan V.; Lopez, Francisco J. [Research Institute for Pesticides and Water, University Jaume I, Avda. Sos Baynat, E-12071 Castellon (Spain); Hernandez, Felix, E-mail: felix.hernandez@qfa.uji.es [Research Institute for Pesticides and Water, University Jaume I, Avda. Sos Baynat, E-12071 Castellon (Spain)

    2011-09-19

    Highlights: {center_dot} Eight N-nitrosamines in water by LC(APCI)MS/MS QqQ analysis. {center_dot} Validation at two levels: 10 ng L{sup -1} (LOQ) and 100 ng L{sup -1} in drinking water. {center_dot} Developed method applied to different types of water samples. {center_dot} NDMA was the analyte more frequently detected and at the highest concentration levels. - Abstract: In this work, we have developed a sensitive method for detection and quantification of eight N-nitrosamines, N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMor), N-nitrosomethylethylamine (NMEA), N-nitrosopirrolidine (NPyr), N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPip), N-nitroso-n-dipropylamine (NDPA) and N-nitrosodi-n-butylamine (NDBA) in drinking water. The method is based on liquid chromatography coupled to tandem mass spectrometry, using atmospheric pressure chemical ionization (APCI) in positive mode with a triple quadrupole analyzer (QqQ). The simultaneous acquisition of two MS/MS transitions in selected reaction monitoring mode (SRM) for each compound, together with the evaluation of their relative intensity, allowed the simultaneous quantification and reliable identification in water at ppt levels. Empirical formula of the product ions selected was confirmed by UHPLC-(Q)TOF MS accurate mass measurements from reference standards. Prior to LC-MS/MS QqQ analysis, a preconcentration step by off-line SPE using coconut charcoal EPA 521 cartridges (by passing 500 mL of water sample) was necessary to improve the sensitivity and to meet regulation requirements. For accurate quantification, two isotope labelled nitrosamines (NDMA-d{sub 6} and NDPA-d{sub 14}) were added as surrogate internal standards to the samples. The optimized method was validated at two concentration levels (10 and 100 ng L{sup -1}) in drinking water samples, obtaining satisfactory recoveries (between 90 and 120%) and precision (RSD < 20%). Limits of detection were found to be in the range of 1-8 ng L{sup -1

  5. Protocol for an electrospray ionization tandem mass spectral product ion library: development and application for identification of 240 pesticides in foods.

    Science.gov (United States)

    Zhang, Kai; Wong, Jon W; Yang, Paul; Hayward, Douglas G; Sakuma, Takeo; Zou, Yunyun; Schreiber, André; Borton, Christopher; Nguyen, Tung-Vi; Kaushik, Banerjee; Oulkar, Dasharath

    2012-07-01

    Modern determination techniques for pesticides must yield identification quickly with high confidence for timely enforcement of tolerances. A protocol for the collection of liquid chromatography (LC) electrospray ionization (ESI)-quadruple linear ion trap (Q-LIT) mass spectrometry (MS) library spectra was developed. Following the protocol, an enhanced product ion (EPI) library of 240 pesticides was developed by use of spectra collected from two laboratories. A LC-Q-LIT-MS workflow using scheduled multiple reaction monitoring (sMRM) survey scan, information-dependent acquisition (IDA) triggered collection of EPI spectra, and library search was developed and tested to identify the 240 target pesticides in one single LC-Q-LIT MS analysis. By use of LC retention time, one sMRM survey scan transition, and a library search, 75-87% of the 240 pesticides were identified in a single LC/MS analysis at fortified concentrations of 10 ng/g in 18 different foods. A conventional approach with LC-MS/MS using two MRM transitions produced the same identifications and comparable quantitative results with the same incurred foods as the LC-Q-LIT using EPI library search, finding 1.2-49 ng/g of either carbaryl, carbendazim, fenbuconazole, propiconazole, or pyridaben in peaches; carbendazim, imazalil, terbutryn, and thiabendazole in oranges; terbutryn in salmon; and azoxystrobin in ginseng. Incurred broccoli, cabbage, and kale were screened with the same EPI library using three LC-Q-LIT and a LC-quadruple time-of-flight (Q-TOF) instruments. The library search identified azoxystrobin, cyprodinil, fludioxinil, imidacloprid, metalaxyl, spinosyn A, D, and J, amd spirotetramat with each instrument. The approach has a broad application in LC-MS/MS type targeted screening in food analysis. PMID:22686274

  6. Determination of Tetracyclin, Oxytetracycline and Roxithromycin in Water Samples by Solid Phase Extraction-Ultra Performance Liquid Chromatography Electrospray Tandem Mass Spectrometry%固相萃取-超高效液相色谱三重四级杆质谱联用法测定水中四环素、土霉素及罗红霉素

    Institute of Scientific and Technical Information of China (English)

    尹燕敏

    2013-01-01

    A rapid analytical method for simultaneous determination of tetracyclin, oxytetracycline and roxithromycin in water sample was developed. Water samples were purified and concentrated by solid phase extraction(SPE), then analyzed by ultra performance liquid chromatography electrospray tandem mass spectrometry(UPLC-MS/MS). Using formic acid and acetonitrile as the mobile phase, the three antibiotics were separated within 5 min. The limit of determination for anlytes were 0.08-0.35 ng/L with the relative standard deviation of 1.4%-5.6%. The recoveries of the antibiotics were in the range of 82.5%-114%for blank and 71.5%-126%for real samples.%建立了固相萃取-超高效液相色谱三重四级杆质谱联用法同时测定水中的罗红霉素、四环素和土霉素残留。水样经过固相萃取纯化、富集,液质联用分析,采用甲酸溶液和乙腈作为流动相,在5 min内完成对3种目标化合物的分析,3种目标化合物的方法检出限介于0.08~0.35 ng/L之间,测定结果的相对标准偏差为1.4%~5.6%,空白样品和实际样品的加标回收率分别为82.5%~114%,71.5%~126%。

  7. 直接进样电喷雾串联质谱法测定草鱼肌肉组织中磷脂%Determination of Phospholipids from Ctenopharyngodon Idellus Muscle by Direct-injection Electrospray Ionization Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    王友谊; 张虹; 戴志远

    2012-01-01

    A method was developed for the determination of phospholipids from Ctenopharyngodon idellus muscle by direct-injection electrospray ionization tandem mass spectrometry (ESI-MS/MS). The samples were extracted with modified Bligh Dyer method and the crude extracts were taken directly into the electrospray ionization source by syringe pump. Under the precursor ion scan and neutral loss scan) intrasource separation and identification of six classes of phospholipids including phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl inositoU phosphatidyl serine, phos-phatidyl glycerol and phosphatidic acid were achieved. The intensity of quasi-molecular ion of the phospholipids and concentration showed good linear relation in a certain range. The recoveries (67.1% -96.6%) and precision meet the requirements for analyzing biological samples. This method has been applied to analyze the molecular species and content of four class phospholipids from Cteno-pharyngodon idellus muscle. The method is simple, fast accurate, and reproducibility with excellent stability, and suitable to analyze phospholipids from various biological samples for lipidomics research.%建立了直接进样电喷雾串联质谱测定草鱼肌肉组织中磷脂的方法.以Bligh Dyer法提取总脂质,采用流动注射泵直接进样的方式将样品导人电喷雾离子源,利用串联三重四级杆质谱的母离子扫描和中性丢失扫描功能,通过扫描磷脂的特征性子离子或中性质量丢失实现对磷脂酰胆碱、磷脂酰乙醇胺、磷脂酰肌醇、磷脂酰丝氨酸、磷脂酰甘油和磷脂酸六类磷脂的源内分离和鉴定.结果显示,在-定的浓度范围内,磷脂的浓度与磷脂直接进样电喷雾电离后形成准分子离子的响应值呈现良好的线性关系,回收率(67.1%~96.6%)和精密度可以满足生物样品分析的要求.采用本方法测定了草鱼肌肉组织中磷脂酰胆碱、磷脂酰乙醇胺、磷脂

  8. Peptide profiling of Internet-obtained Cerebrolysin using high performance liquid chromatography - electrospray ionization ion trap and ultra high performance liquid chromatography - ion mobility - quadrupole time of flight mass spectrometry.

    Science.gov (United States)

    Gevaert, Bert; D'Hondt, Matthias; Bracke, Nathalie; Yao, Han; Wynendaele, Evelien; Vissers, Johannes Petrus Cornelis; De Cecco, Martin; Claereboudt, Jan; De Spiegeleer, Bart

    2015-09-01

    Cerebrolysin, a parenteral peptide preparation produced by controlled digestion of porcine brain proteins, is an approved nootropic medicine in some countries. However, it is also easily and globally available on the Internet. Nevertheless, until now, its exact chemical composition was unknown. Using high performance liquid chromatography (HPLC) coupled to ion trap and ultra high performance liquid chromatography (UHPLC) coupled to quadrupole-ion mobility-time-of-flight mass spectrometry (Q-IM-TOF MS), combined with UniProt pig protein database search and PEAKS de novo sequencing, we identified 638 unique peptides in an Internet-obtained Cerebrolysin sample. The main components in this sample originate from tubulin alpha- and beta-chain, actin, and myelin basic protein. No fragments of known neurotrophic factors like glial cell-derived neurotrophic factor (GDNF), neurotrophin nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and ciliary neurotrophic factor (CNTF) were found, suggesting that the activities reported in the literature are likely the result of new, hitherto unknown cryptic peptides with nootropic properties. PMID:26017115

  9. Expediting the method development and quality control of reversed-phase liquid chromatography electrospray ionization mass spectrometry for pharmaceutical analysis by using an LC/MS performance test mix.

    Science.gov (United States)

    Tang, L; Fitch, W L; Alexander, M S; Dolan, J W

    2000-11-01

    Mass spectrometry combined with liquid chromatography (LC/MS) has become an important analytical methodology in both pharmaceutical and biomolecule analyses. LC/MS, especially with reversed-phase HPLC (RP-LC), is extensively used in the separation and structural identification of pharmaceutical samples. However, many parameters have to be considered when a new LC/MS method is developed for either separation and structural analysis of unknown mixtures or quantitative analysis of a set of known compounds in an assay. The optimization of a new LC/MS method can be a time-consuming process. A novel kit-LC/MS performance test mix-composed of aspartame, cortisone, reserpine, and dioctyl phthalate has been developed to accelerate the process of establishing a new RP-LC/MS method. The LC/MS mix makes the evaluation and validation of an LC/MS method more efficient and easier. It also simplifies the quality control procedure for an LC/MS method in use. PMID:11080866

  10. A simplified procedure for the analysis of formoterol in human urine by liquid chromatography-electrospray tandem mass spectrometry: application to the characterization of the metabolic profile and stability of formoterol in urine.

    Science.gov (United States)

    Mazzarino, Monica; de la Torre, Xavier; Fiacco, Ilaria; Pompei, Chiara; Calabrese, Fabiana; Botrè, Francesco

    2013-07-15

    Since 1992, formoterol is included in the prohibited list of doping substances and methods, presently reviewed and updated by the World Anti-Doping Agency. Recently a threshold value of 40ng/mL has been established to differentiate between the prohibited (oral) and the permitted (inhalatory) administration of formoterol to athletes. This paper considers the urinary excretion profile of formoterol and its main metabolites after inhalation of different doses of two of the most used medicaments, available in Italy, containing formoterol fumarate bihydrate (12 and 36μg twice a day of Foradil(®) or 9 and 27μg twice a day of Symbicort(®)), focusing also on the effects, on the measured levels of formoterol, of potential alteration processes (thermal and/or microbiological) that may take place after the collection of the urine samples. Urine sample preparation included an enzymatic hydrolysis and a dilution step. Detection of analytes was performed by a newly developed and validated direct LC-ESI-MS/MS procedure, using a triple quadrupole mass spectrometer under positive ion electro-spray ionization conditions and selected reaction monitoring acquisition mode. The results showed the capability and suitability of the direct LC-ESI-MS/MS analysis for the quantitative confirmation analysis of formoterol in urine samples. The data from the analysis of the urine samples obtained in the excretion studies showed that formoterol is excreted mainly as unmodified drug and to a lesser degree as O-demethylated metabolite. The urinary levels of formoterol (40-60%) and its metabolites (O-demethylated metabolite 5-25%; glucuronide metabolites 25-40%) vary significantly depending both on the administered drug formulation and the subject tested. The maximum urinary concentration reached in this study was 15ng/mL (free+glucuronide), that is significantly lower than the threshold value fixed to report an adverse analytical finding. Finally, our results also showed that formoterol is

  11. Evaluation of Offline Tandem and Online Solid-Phase Extraction with Liquid Chromatography/Electrospray Ionization-Mass Spectrometry for Analysis of Antibiotics in Ambient Water and Comparison to an Independent Method

    Science.gov (United States)

    Meyer, M.T.; Lee, E.A.; Ferrell, G.M.; Bumgarner, J.E.; Varns, Jerry

    2007-01-01

    This report describes the performance of an offline tandem solid-phase extraction (SPE) method and an online SPE method that use liquid chromatography/mass spectrometry for the analysis of 23 and 35 antibiotics, respectively, as used in several water-quality surveys conducted since 1999. In the offline tandem SPE method, normalized concentrations for the quinolone, macrolide, and sulfonamide antibiotics in spiked environmental samples averaged from 81 to 139 percent of the expected spiked concentrations. A modified standard-addition technique was developed to improve the quantitation of the tetracycline antibiotics, which had 'apparent' concentrations that ranged from 185 to 1,200 percent of their expected spiked concentrations in matrix-spiked samples. In the online SPE method, normalized concentrations for the quinolone, macrolide, sulfonamide, and tetracycline antibiotics in matrix-spiked samples averaged from 51 to 142 percent of their expected spiked concentrations, and the beta-lactam antibiotics in matrix-spiked samples averaged from 22 to 76 percent of their expected spiked concentration. Comparison of 44 samples analyzed by both the offline tandem SPE and online SPE methods showed 50 to 100 percent agreement in sample detection for overlapping analytes and 68 to 100 percent agreement in a presence-absence comparison for all analytes. The offline tandem and online SPE methods were compared to an independent method that contains two overlapping antibiotic compounds, sulfamethoxazole and trimethoprim, for 96 and 44 environmental samples, respectively. The offline tandem SPE showed 86 and 92 percent agreement in sample detection and 96 and 98 percent agreement in a presence-absence comparison for sulfamethoxazole and trimethoprim, respectively. The online SPE method showed 57 and 56 percent agreement in sample detection and 72 and 91 percent agreement in presence-absence comparison for sulfamethoxazole and trimethoprim, respectively. A linear regression with

  12. 固相萃取-超高效液相色谱-电喷雾串联质谱法检测梨树叶中熊果苷%Quantitative and qualitative determination of arbutin in pear leaves by ultra performance liquid chromatography-electrospray tandem mass spectrometry coupled with solid phase extraction

    Institute of Scientific and Technical Information of China (English)

    赵洁; 何强; 孔祥虹; 李建华; 乐爱山; 姚秉华

    2011-01-01

    建立了固相萃取净化、超高效液相色谱-串联质谱检测梨树叶中熊果苷含量的方法.将粉碎的梨树叶样品用甲醇提取,ENVITM-18固相萃取柱净化,超高效液相-电喷雾串联四级杆质谱检测,外标法定量.测定时用 Acquity UPLC HSS T3 色谱柱(50 mm×2.1 mm,1.8μm)分离,甲醇-水(V/V,7+93)洗脱,多重反应监测 (MRM) 模式检测,定量离子对为m/z 271.2>107.8,定性离子对为 m/z 271.2>160.9.熊果苷的最低检出限为 0.05μg/mL,在0.1~10.0μg/mL 的范围内标准溶液的峰面积与浓度呈良好的线性关系,回收率为93.2%~106.5%,相对标准偏差低于5.9%.%An ultra performance liquid chromatography-electrospray tandem mass spectrometries (UPLC-ESI-MS/MS) method was developed for the quantitative and qualitative determination of arbutin in pear leaves. The full powdered pear leaves were extracted with methanol and purified by ENVITM-18 SPE columns. Analysis was performed on UPLC-ESI-MS/MS and quantitation was carried out using an external standard method. Separation of the samples was performed on an acquity UPLC HSS T3 column (50 mm × 2. 1 mm, 1.8 μm) using methanolwater(V/V, 7 + 93 ) as mobile phase. MS/MS was performed with multiple reaction monitoring (MRM) mode using m/z 271.2 > 107. 8 as quantitative ion pair and m/z 271.2 > 160. 9 as qualitative ion pair. The detection limit of arbutin was 0. 05 μg/mL. The method showed good linear relationship in the range of 0. 1 ~ 10. 0 μg/mL.

  13. 液相色谱-串联质谱法测定河豚鱼和鳗鱼中9种青霉素类抗生素%Determination of 9 penicillins in Fugu and eel by high pressure liquid chromatography-electrospray tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    李学民; 曹彦忠; 张进杰; 母健; 王蕾; 王贺琴

    2013-01-01

      目的建立高压液相色谱-电喷雾串联质谱(HPLC-MS-MS)同时测定河豚鱼和鳗鱼中9种青霉素残留量的检测方法。方法样品经乙腈-氨水溶液提取后,用C18色谱柱分离,乙腈-乙酸为流动相梯度洗脱,最后采用液相色谱-电喷雾串联质谱在正离子多反应监测模式下测定。结果在1.0~20μg/kg(LOQ~10LOQ)范围时,方法线性关系良好,相关系数大于0.999。在LOQ、2 LOQ、4 LOQ、10 LOQ四个添加水平下青霉素的回收率在81.4%~109.7%之间,相对标准偏差在2.81%~7.12%之间,方法检出限是:萘夫西林、青霉素 G、哌拉西林、青霉素 V、苯唑西林为1.0μg/kg;阿莫西林、氨苄西林、氯唑西林、双氯西林为2.0μg/kg。结论此方法灵敏度高,准确性好,适用于水产品中青霉素的定量检测。%Objective A sensitive method was developed for the determination of 9 penicillins in Fugu and eel by high pressure liquid chromatography-electrospray tandem mass spectrometry (HPLC-MS/MS). Methods Samples were extracted with acetonitrile-ammonia water, separated on a C18 column by gradient elution with acetonitrile and 0.3%acetic acid solution as mobile phase. Identification was achieved by electro-spray ionization(ESI) in positive mode. Results The method showed a good linearity over the range of 1.0~20μg/kg for 9 compounds of penicillins with r≥0.999. Recoveries of 9 penicillins were between 81.4% and 109.7% (n=6) at spiked levels of LOQ, 2LOQ, 4LOQ and 10LOQ with relative standard deviations (RSD of 2.81%∼7.12%). The limit of quantitation(LOQ) for nafcillin, penicillin G, piperacillin, penicillin V and oxacil-lin were 1.0 μg/kg and the LOQ for amoxicillin, ampicillin, cloxacillin and dicloxacillin were 2.0 μg/kg. Conclusion This method is sensitive and accurate, and it is suitable for the analysis of 9 penicillins in aquatic products.

  14. A strategy for identification and structural characterization of compounds from Gardenia jasminoides by integrating macroporous resin column chromatography and liquid chromatography-tandem mass spectrometry combined with ion-mobility spectrometry.

    Science.gov (United States)

    Wang, Lu; Liu, Shu; Zhang, Xueju; Xing, Junpeng; Liu, Zhiqiang; Song, Fengrui

    2016-06-24

    In this paper, an analysis strategy integrating macroporous resin (AB-8) column chromatography and high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) combined with ion mobility spectrometry (IMS) was proposed and applied for identification and structural characterization of compounds from the fruits of Gardenia jasminoides. The extracts of G. jasminoides were separated by AB-8 resin column chromatography combined with reversed phase liquid chromatography (C18 column) and detected by electrospray ionization tandem mass spectrometry. Additionally, ion mobility spectrometry (IMS) was employed as a supplementary separation technique to discover previously undetected isomers from the fruits of G. jasminoides. A total of 71 compounds, including iridoids, flavonoids, triterpenes, monoterpenoids, carotenoids and phenolic acids were identified by the characteristic high resolution mass spectrometry and the ESI-MS/MS fragmentations. In conclusion, the IMS-MS technique achieved the separation of isomers in crocin-3 and crocin-4 according to their acquired mobility drift times differing from classical analysis by mass spectrometry. The proposed strategy can be used as a highly sensitive and efficient procedure for identification and separation isomeric components in extracts of herbal medicines. PMID:27208986

  15. 牛膝中三萜皂甙类化合物的电喷雾质谱研究%Studies on Triterpene Saponin From Achyranthes bientata BI by Electrospray Ionization Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    梁勇; 方昆阳; 郭宝江; 梁冠洪; 宋艳平

    2004-01-01

    AchyranthosideI and Achyranthoside Ⅱ which were considered to be effective constituents from Achyranthes bientata BI were identified by electrospray tandem ionization mass spectrometric (ESI-MSn) methods after macro-porous adsorbent chromatographic separation. Their characteristic mass spectra can be use as fingerprint for the identification of AchyranthosideI and Achyranthoside Ⅱ . This method is simple .,rapid and highly sensitive.

  16. Bacteriophage cell lysis of Shiga toxin-producing Escherichia coli for top-down proteomic identification of Shiga toxin 1 & 2 using matrix-assisted laser desorption/ionization tandem time-of-light mass spectrometry

    Science.gov (United States)

    RATIONALE: Analysis of bacteria by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) often relies upon sample preparation methods that result in cell lysis, e.g. bead-beating. However, Shiga toxin-producing Escherichia coli (STEC) can undergo bacteriophage...

  17. Top-down proteomic identification of Shiga toxin 2 subtypes from Shiga toxin-producing Escherichia coli by Matrix-Assisted Laser Desorption Ionization-Tandem Time of Flight mass spectrometry

    Science.gov (United States)

    We have analyzed 26 Shiga toxin-producing Escherichia coli (STEC) strains for Shiga toxin 2 (Stx2) production using matrix-assisted laser desorption/ionization time-of-flight-time-of-flight tandem mass spectrometry (MALDI-TOF-TOF-MS/MS) and top-down proteomic analysis. STEC strains were induced to ...

  18. Development of a new multi-residue laser diode thermal desorption atmospheric pressure chemical ionization tandem mass spectrometry method for the detection and quantification of pesticides and pharmaceuticals in wastewater samples.

    Science.gov (United States)

    Boisvert, Michel; Fayad, Paul B; Sauvé, Sébastien

    2012-11-19

    A new solid phase extraction (SPE) method coupled to a high throughput sample analysis technique was developed for the simultaneous determination of nine selected emerging contaminants in wastewater (atrazine, desethylatrazine, 17β-estradiol, ethynylestradiol, norethindrone, caffeine, carbamazepine, diclofenac and sulfamethoxazole). We specifically included pharmaceutical compounds from multiple therapeutic classes, as well as pesticides. Sample pre-concentration and clean-up was performed using a mixed-mode SPE cartridge (Strata ABW) having both cation and anion exchange properties, followed by analysis by laser diode thermal desorption atmospheric pressure chemical ionization coupled to tandem mass spectrometry (LDTD-APCI-MS/MS). The LDTD interface is a new high-throughput sample introduction method, which reduces total analysis time to less than 15s per sample as compared to minutes with traditional liquid-chromatography coupled to tandem mass spectrometry (LC-MS/MS). Several SPE parameters were evaluated in order to optimize recovery efficiencies when extracting analytes from wastewater, such as the nature of the stationary phase, the loading flow rate, the extraction pH, the volume and composition of the washing solution and the initial sample volume. The method was successfully applied to real wastewater samples from the primary sedimentation tank of a municipal wastewater treatment plant. Recoveries of target compounds from wastewater ranged from 78% to 106%, the limit of detection ranged from 30 to 122ng L(-1) while the limit of quantification ranged from 90 to 370ng L(-1). Calibration curves in the wastewater matrix showed good linearity (R(2)≥0.991) for all target analytes and the intraday and interday coefficient of variation was below 15%, reflecting a good precision. PMID:23140957

  19. Novel analytical approach for brominated flame retardants based on the use of gas chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry with emphasis in highly brominated congeners.

    Science.gov (United States)

    Portolés, Tania; Sales, Carlos; Gómara, Belén; Sancho, Juan Vicente; Beltrán, Joaquim; Herrero, Laura; González, María José; Hernández, Félix

    2015-10-01

    The analysis of brominated flame retardants (BFRs) commonly relies on the use of gas chromatography coupled to mass spectrometry (GC-MS) operating in electron ionization (EI) and electron capture negative ionization (ECNI) modes using quadrupole, triple quadrupole, ion trap, and magnetic sector analyzers. However, these brominated contaminants are examples of compounds for which a soft and robust ionization technique might be favorable since they show high fragmentation in EI and low specificity in ECNI. In addition, the low limits of quantification (0.01 ng/g) required by European Commission Recommendation 2014/118/EU on the monitoring of traces of BFRs in food put stress on the use of highly sensitive techniques/methods. In this work, a new approach for the extremely sensitive determination of BFRs taking profit of the potential of atmospheric pressure chemical ionization (APCI) combined with GC and triple quadrupole (QqQ) mass analyzer is proposed. The objective was to explore the potential of this approach for the BFRs determination in samples at pg/g levels, taking marine samples and a cream sample as a model. Ionization and fragmentation behavior of 14 PBDEs (congeners 28, 47, 66, 85, 99, 100, 153, 154, 183, 184, 191, 196, 197, and 209) and two novel BFRs, decabromodiphenyl ethane (DBDPE) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), in the GC-APCI-MS system has been investigated. The formation of highly abundant (quasi) molecular ion was the main advantage observed in relation to EI. Thus, a notable improvement in sensitivity and specificity was observed when using it as precursor ion in tandem MS. The improved detectability (LODs < 10 fg) achieved when using APCI compared to EI has been demonstrated, which is especially relevant for highly brominated congeners. Analysis of samples from an intercomparison exercise and samples from the marine field showed the potential of this approach for the reliable identification and quantification at very low

  20. Liquid Chromatography with Post-Column Reagent Addition of Ammonia in Methanol Coupled to Negative Ion Electrospray Ionization Tandem Mass Spectrometry for Determination of Phenoxyacid Herbicides and their Degradation Products in Surface Water

    Directory of Open Access Journals (Sweden)

    Michele L. Etter

    2010-02-01

    Full Text Available A new liquid chromatography (LC-negative ion electrospray ionization (ESI–tandem mass spectrometry (MS/MS method with post-column addition of ammonia in methanol has been developed for the analysis of acid herbicides: 2,4-dichlorophenoxy ace- tic acid, 4-chloro-o-tolyloxyacetic acid, 2-(2-methyl-4-chlorophenoxybutyric acid, mecoprop, dichlorprop, 4-(2,4-dichlorophenoxy butyric acid, 2,4,5-trichlorophenoxy propionic acid, dicamba and bromoxynil, along with their degradation products: 4-chloro-2- methylphenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol and 3,5-dibromo-4-hydroxybenzoic acid. The samples were extracted from the surface water matrix using solid-phase extraction (SPE with a polymeric sorbent and analyzed with LC ESI- with selected reaction monitoring (SRM using a three-point confirmation approach. Chromatography was performed on a Zorbax Eclipse XDB-C18 (50 × 4.6 mm i.d., 1.8 µm with a gradient elution using water-methanol with 2 mM ammonium acetate mobile phase at a flow rate of 0.15 mL/min. Ammonia in methanol (0.8 M was added post-column at a flow rate of 0.05 mL/min to enhance ionization of the deg- radation products in the MS source. One SRM transition was used for quantitative analysis while the second SRM along with the ratio of SRM1/SRM2 within the relative standard deviation determined by standards for each individual pesticide and retention time match were used for confirmation. The standard deviation of ratio of SRM1/SRM2 obtained from standards run on the day of analysis for different phenoxyacid herbicides ranged from 3.9 to 18.5%. Limits of detection (LOD were between 1 and 15 ng L-1 and method detection limits (MDL with strict criteria requiring

  1. Simultaneous extraction of acetylsalicylic acid and salicylic acid from human plasma and simultaneous estimation by liquid chromatography and atmospheric pressure chemical ionization/tandem mass spectrometry detection. Application to a pharmacokinetic study.

    Science.gov (United States)

    Nirogi, Ramakrishna; Kandikere, Vishwottam; Mudigonda, Koteshwara; Ajjala, Devender; Suraneni, Ramakrishna; Thoddi, Parthasarathi

    2011-01-01

    A simple analytical method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in atmospheric chemical ionization mode (APCI) for the simultaneous estimation of acetylsalicylic acid (ASA, CAS 50-78-2) and its active metabolite salicylic acid (SA, CAS 69-72-7) in human plasma has been developed and validated. ASA and SA were analyzed simultaneously despite differences in plasma concentration ranges of ASA and SA after oral administration of ASA. In spite of having different chemical, ionization and chromatographic properties, ASA and SA were extracted simultaneously from the plasma sample using acetonitrile protein precipitation followed by liquid-liquid extraction. The analytes were separated on a reversed phase column with rapid gradient program using mobile phase consisting of ammonium acetate buffer and methanol. The structural analogue diclofenac was used as an internal standard. The multiple reaction monitoring (MRM) transitions m/z 179 --> 137 for ASA, m/z 137 --> 65 for SA and m/z 294 --> 250 for IS were used. The assay exhibited a linear dynamic range of 0.02-10 microg/mL for ASA and 0.1-50 microg/mL for SA. The between-batch precision (%CV) ranged from 2.1 to 7.9% for ASA and from 0.2 to 5.2% for SA. The between-batch accuracy ranged from 95.4 to 96.7% for ASA and from 94.6 to 111.3% for SA. The validated method was successfully applied for the evaluation of pharmacokinetics of ASA after single oral administration of 650 mg test formulation versus two 325 mg reference formulations of ASA in human subjects. PMID:21755814

  2. An integrated strategy for rapid and accurate determination of free and cell-bound microcystins and related peptides in natural blooms by liquid chromatography-electrospray-high resolution mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry using both positive and negative ionization modes.

    Science.gov (United States)

    Flores, Cintia; Caixach, Josep

    2015-08-14

    An integrated high resolution mass spectrometry (HRMS) strategy has been developed for rapid and accurate determination of free and cell-bound microcystins (MCs) and related peptides in water blooms. The natural samples (water and algae) were filtered for independent analysis of aqueous and sestonic fractions. These fractions were analyzed by MALDI-TOF/TOF-MS and ESI-Orbitrap-HCD-MS. MALDI, ESI and the study of fragmentation sequences have been provided crucial structural information. The potential of combined positive and negative ionization modes, full scan and fragmentation acquisition modes (TOF/TOF and HCD) by HRMS and high resolution and accurate mass was investigated in order to allow unequivocal determination of MCs. Besides, a reliable quantitation has been possible by HRMS. This composition helped to decrease the probability of false positives and negatives, as alternative to commonly used LC-ESI-MS/MS methods. The analysis was non-target, therefore covered the possibility to analyze all MC analogs concurrently without any pre-selection of target MC. Furthermore, archived data was subjected to retrospective "post-targeted" analysis and a screening of other potential toxins and related peptides as anabaenopeptins in the samples was done. Finally, the MS protocol and identification tools suggested were applied to the analysis of characteristic water blooms from Spanish reservoirs. PMID:26141269

  3. Identification of phenolic compounds in strawberries by liquid chromatography electrospray ionization mass spectroscopy

    OpenAIRE

    Seeram, Navindra P.; Lee, R; Scheuller, H S; Heber, D

    2006-01-01

    Strawberry (Fragaria x ananassa Duch.) fruits contain phenolic compounds that have antioxidant, anticancer, antiatherosclerotic and anti-neurodegenerative properties. Identification of food phenolics is necessary since their nature, size, solubility, degree and position of glycosylation and conjugation influence their absorption, distribution, metabolism and excretion in humans. Freeze-dried whole strawberry fruit powder and strawberry fruit extracts were analyzed by liquid chromatography ele...

  4. Multiresidue Analysis of Seven Anticoagulant Rodenticides by high-performance liquid chromatography/electrospray/mass spectrometry

    Science.gov (United States)

    Mice and rat populations are commonly controlled by two classes of rodenticide anticoagulants, coumarins and indandiones. However, poisoning of nontarget animals also often occurs. For cases such as these, a rapid, multi-residue method, which provides positive confirmation for both classes of antico...

  5. Determination of neonicotinoids in Estonian honey by liquid chromatography-electrospray mass spectrometry.

    Science.gov (United States)

    Laaniste, Asko; Leito, Ivo; Rebane, Riin; Lõhmus, Rünno; Lõhmus, Ants; Punga, Fredrik; Kruve, Anneli

    2016-07-01

    The aim of the study was to provide a comprehensive overview of neonicotinoid pesticide residues in honey samples for a single country and compare the results with the import data for neonicotinoid pesticides. The levels of four neonicotinoid pesticides, namely thiamethoxam, imidacloprid, acetamiprid, and thiacloprid, were determined in 294 honey samples harvested from 2005 to 2013 from more than 200 locations in Estonia. For the analyzed honey samples, 27% contained thiacloprid, and its levels in all cases were below the maximum residue level set by the European Union. The other neonicotinoids were not detected. The proportion of thiacloprid-positive samples for different years correlates well with the data on thiacloprid imports into Estonia, indicating that honey contamination with neonicotinoids can be estimated based on the import data. PMID:27050772

  6. Analysis of meat samples for anabolic steroids residues by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Blasco, Cristina; Van Poucke, Christof; Van Peteghem, Carlos

    2007-06-22

    A rapid, specific and highly sensitive multi-residue method for the determination of anabolic steroid residues in bovine, pork and poultry muscle tissues was developed. The sample preparation involves enzymatic digestion followed by extraction with methanol. The crude extract was cleaned up by solid-phase extraction (SPE) combining C18 and NH2 columns. The detection was carried out by a highly sensitive liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method using both positive and negative ionization modes. Natural and synthetic steroids covering different polarities could be extracted, concentrated and purified using one single method. Mobile phase composition and additives were optimized to achieve the highest sensitivity. The linearity was not good enough for quantitative analysis but the method was well-suited for qualitative confirmation. The method was validated according to the European Commission Decision 2002/657/EC. Decision limits (CCalpha) and detection capabilities (CCbeta) were below 0.5 ng g(-1) for all the compounds in the three types of meat studied. The developed method is suitable for routine analysis in our laboratories. PMID:17459396

  7. [Determination of five synthetic sweeteners in wines using high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Ji, Chao; Feng, Feng; Chen, Zhengxing; Sun, Li; Chu, Xiaogang

    2010-08-01

    A high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI MS/MS) method for the determination of five synthetic sweeteners (acesulfame, sodium saccharin, sodium cyclamate, aspartame and neotame) in wines has been developed. The HPLC separation was carried out on an Ultimate C18 column (100 mm x 2.1 mm, 3 microm). Several parameters, including the composition and pH of the mobile phase, column temperature and the monitor ions, were optimized for improving the chromatographic performance and the sensitivity of determination. The results demonstrated that the separation can be completed in less than 5 min by gradient elution with 20 mmol/L ammonium formate and 0.1% (v/v) formic acid (pH 3.8) and methanol as the mobile phase. The column temperature was kept at 45 degrees C. When the analytes were detected by ESI -MS/MS under multiple reaction monitoring mode, the detection limits were 0.6, 5, 1, 0.8 and 0.2 microg/L for acesulfame, sodium saccharin, sodium cyclamate, aspartame and neotame, respectively. The average recoveries ranged from 87.2% to 103%. The relative standard deviations were not more than 1.2%. This method is rapid, accurate, highly sensitive and suitable for the quality control of low concentration of the synthetic sweeteners, which are illegally added to wines and other foods with complex matrices. PMID:21261041

  8. Simultaneous Determination and Pharmacokinetic Study of Protocatechuic Aldehyde and Its Major Active Metabolite Protocatechuic Acid in Rat Plasma by Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Wang, Xiangyang; Yan, Kaijing; Ma, Xiaohui; Li, Wei; Chu, Yang; Guo, Jiahua; Li, Shuming; Zhou, Shuiping; Zhu, Yonghong; Liu, Changxiao

    2016-05-01

    A very simple and selective high-performance liquid chromatography electrospray ionization tandem mass spectrometry (LC-MS-MS) method was developed for simultaneous determination and pharmacokinetic study of protocatechuic aldehyde (PAL) and its active metabolite protocatechuic acid (PCA). The method involves a simple liquid-liquid extraction with ethyl acetate. The separation was performed on a Hypersil GOLD C18column (2.1 × 150 mm, 3.0 µm; particle, Thermo, USA) with isocratic elution using a mobile phase consisted of methanol and water (containing 0.1% formic acid) at a flow rate of 0.2 mL/min. The detection of target compounds was done by using low-energy collision dissociation tandem mass spectrometry (CID-MS-MS) using the selective reaction monitoring scan mode. The method was linear for all analytes over the investigated range for all correlation coefficients greater than 0.9950. The lower limits of quantification were 2.0 ng/mL for PAL and PCA. The intra- and interday precisions (relative standard deviation, RSD %) were <6.84 and 5.54%, and the accuracy (relative error, RE %) was between -2.85 and 0.74% (n= 6). The developed method was applied to study the pharmacokinetics of PAL and its major active metabolite PCA in rat plasma after oral and intravenous administration of PAL. PMID:26969682

  9. Determination of chloramphenicol, thiamphenicol, florfenicol and florfenicol amine in poultry, swine, bovine and fish by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Barreto, Fabiano; Ribeiro, Cristina; Barcellos Hoff, Rodrigo; Dalla Costa, Teresa

    2016-06-01

    A simple, rapid and sensitive method for confirmatory and quantitative purposes using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) was developed and validated for determination of chloramphenicol, thiamphenicol, florfenicol and its metabolite, florfenicol amine, in poultry, swine, bovine and fish muscle. Sample preparation was based on extraction with organic solvent (ethyl acetate: ammonium hydroxide, 98:2) followed by evaporation and fat removal using hexane. The chromatographic separation was carried out with an XTerra C18 column with a gradient elution using water and acetonitrile both with 2mM of ammonium acetate. Mass spectrometry with electrospray ionization was operated in positive or negative polarity using selected-reaction monitoring (SRM) analysis mode, achieving the requirements of four identification points for each compound. Chloramphenicol-D5 was added as internal standard. Method validation was performed according to the criteria of Commission Decision 2002/657/EC. Parameters as precision, reproducibility, trueness, CCα and CCβ were determined. Trueness values were within the range 82-108% and 84-111% for bovine and fish, respectively. Precision ranged from 1.1% to 10.1% and within-laboratory reproducibility ranged from 4.3 to 18.1%, depending on matrix. The CCα and CCβ for bovine muscle, for instance, were established as 0.06 and 0.11μgkg(-1), respectively. The method was successfully applied for several interlaboratory proficiency testing programs, achieving 100% of satisfactory results. PMID:27133862

  10. Chiral liquid chromatography-mass spectrometry (LC-MS/MS) method development for the detection of salbutamol in urine samples.

    Science.gov (United States)

    Chan, Sue Hay; Lee, Warren; Asmawi, Mohd Zaini; Tan, Soo Choon

    2016-07-01

    A sequential solid-phase extraction (SPE) method was developed and validated using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for the detection and quantification of salbutamol enantiomers in porcine urine. Porcine urine samples were hydrolysed with β-glucuronidase/arylsulfatase from Helix pomatia and then subjected to a double solid-phase extraction (SPE) first using the Abs-Elut Nexus SPE and then followed by the Bond Elut Phenylboronic Acid (PBA) SPE. The salbutamol enantiomers were separated using the Astec CHIROBIOTIC™ T HPLC column (3.0mm×100mm; 5μm) maintained at 15°C with a 15min isocratic run at a flow rate of 0.4mL/min. The mobile phase constituted of 5mM ammonium formate in methanol. Salbutamol and salbutamol-tert-butyl-d9 (internal standard, IS) was monitored and quantified with the multiple reaction monitoring (MRM) mode. The method showed good linearity for the range of 0.1-10ng/mL with limit of quantification at 0.3ng/mL. Analysis of the QC samples showed intra- and inter-assay precisions to be less than 5.04%, and recovery ranging from 83.82 to 102.33%. PMID:27232053

  11. [Determination of three sweeteners in vinegars by solid phase extraction-high performance liquid chromatography/tandem mass spectrometry].

    Science.gov (United States)

    Yin, Feng; Ding, Zhaowei; Cao, Xue; Gao, Jie; Jiang, Deming; Kuang, Denghui; Gu, Yanping; He, Guoliang

    2011-06-01

    A solid phase extraction-high performance liquid chromatography/electrospray ionization-tandem mass spectrometry (SPE-HPLC/ESI-MS/MS) method for the determination of 3 sweeteners (acesulfame (AK), sodium saccharin (SA), sodium cyclamate (SC)) in vinegars has been developed. The sample was diluted with acidic water, then purified and enriched with a weak anion exchange SPE column. The HPLC separation was performed on a Pursuit C18 column (150 mm x 2.0 mm, 3 microm) by gradient elution with 10 mmol/L ammonium acetate containing 0.1% (v/v) ammonia water and acetonitrile as the mobile phases. The analytes were detected by ESI--MS/MS in multiple reaction monitoring (MRM) mode to satisfy qualitative and quantitative detections. Good linearities (r2 > 0.99) were obtained over the range of 0.01 - 0.50 mg/L. The limits of quantification (LOQs) for SA, AK and SC were 10, 5 and 5 microg/kg, respectively. The average recoveries ranged from 72.1% to 96.8% at the spiked levels of 0.01 and 0.1 mg/L with the relative standard deviations (RSDs) less than 15%. This method is accurate, highly sensitive for qualitative and quantitative analysis of the 3 sweeteners in vinegars. PMID:22032168

  12. Identification of Glioblastoma Phosphotyrosine-Containing Proteins with Two-Dimensional Western Blotting and Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Tianyao Guo

    2015-01-01

    Full Text Available To investigate the presence of, and the potential biological roles of, protein tyrosine phosphorylation in the glioblastoma pathogenesis, two-dimensional gel electrophoresis- (2DGE- based Western blotting coupled with liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS analysis was used to detect and identify the phosphotyrosine immunoreaction-positive proteins in a glioblastoma tissue. MS/MS and Mascot analyses were used to determine the phosphotyrosine sites of each phosphopeptide. Protein domain and motif analysis and systems pathway analysis were used to determine the protein domains/motifs that contained phosphotyrosine residue and signal pathway networks to clarify the potential biological functions of protein tyrosine phosphorylation. A total of 24 phosphotyrosine-containing proteins were identified. Each phosphotyrosine-containing protein contained at least one tyrosine kinase phosphorylation motif and a certain structural and functional domains. Those phosphotyrosine-containing proteins were involved in the multiple signal pathway systems such as oxidative stress, stress response, and cell migration. Those data show 2DGE-based Western blotting, MS/MS, and bioinformatics are a set of effective approaches to detect and identify glioblastoma tyrosine-phosphorylated proteome and to effectively rationalize the biological roles of tyrosine phosphorylation in the glioblastoma biological systems. It provides novel insights regarding tyrosine phosphorylation and its potential role in the molecular mechanism of a glioblastoma.

  13. Rapid determination of phenoxy acid residues in rice by modified QuEChERS extraction and liquid chromatography-tandem mass spectrometry

    International Nuclear Information System (INIS)

    A new method for the analysis of phenoxy acid herbicide residues in rice, based on the use of liquid extraction/partition and dispersive solid phase extraction (dispersive-SPE) followed by ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS), is reported. 5% (v/v) formic acid in acetonitrile as the extraction solvent and inclusion of citrate buffer helped partitioning of all the analytes into the acetonitrile phase. The extract was then cleaned up by dispersive-SPE using C18 and alumina neutral as selective sorbents. Further optimization of sample preparation and determination allowed recoveries of between 45 and 104% for all 13 phenoxy acid herbicides with RSD values lower than 13.3% at 5.0 μg kg-1 concentration level. Limit of detections (LODs) of 0.5 μg kg-1 or below were attained for all 13 phenoxy acids. Quantitative analysis was done in the multiple-reaction monitoring (MRM) mode using two combinations of selected precursor ion and product ion transition for each compound. This developed method produced relatively higher recoveries of the acid herbicides with a smaller range of variation and less susceptibility to matrix effects, than the original QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method

  14. Comparative study of different fabric phase sorptive extraction sorbents to determine emerging contaminants from environmental water using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Lakade, Sameer S; Borrull, Francesc; Furton, Kenneth G; Kabir, Abuzar; Fontanals, Núria; Marcé, Rosa Maria

    2015-11-01

    A new sorptive extraction technique, fabric phase sorptive extraction (FPSE), using different coating chemistries: non-polar sol-gel poly(dimethyldiphenylsiloxane) (PDMDPS), medium polar sol-gel poly(tetrahydrofuran) (PTHF), and polar sol-gel poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEG-PPG-PEG triblock) and sol-gel Carbowax 20 M were evaluated to extract a group of pharmaceuticals and personal care products (PPCPs) with wide range of polarity from environmental aqueous samples. Different parameters affecting FPSE such as sample pH, stirring speed, addition of salt, extraction time, sample volume, elution solvent and desorption time were optimized for each sorbent coated FPSE media. Under optimum conditions, FPSE media coated with sol-gel Carbowax 20 M provided the highest absolute recoveries (77-85%) for majority of the analytes with the exception of the most polar ones. Nevertheless, all four sorbents offered better recovery compared to the commercially available coating for stir-bar sorptive extraction based on Ethylene Glycol/Silicone (EG/Silicone). The method based on FPSE with sol-gel Carbowax 20 M media and liquid chromatography-(electrospray ionization) tandem mass spectrometry (LC-(ESI) MS/MS) was developed and validated for environmental water samples. Good apparent recoveries (41-80%), detection limits (1-50 ng L(-1)), repeatability (%RSD<15%, n=5) and reproducibility (%RSD<18%, n=5) were achieved. PMID:26452968

  15. Detection of triclocarban and two co-contaminating chlorocarbanilides in US aquatic environments using isotope dilution liquid chromatography tandem mass spectrometry

    International Nuclear Information System (INIS)

    The antimicrobial compound triclocarban (TCC; 3,4,4'-trichlorocarbanilide; CAS-bar 101-20-2) is a high-production-volume chemical, recently suggested to cause widespread contamination of US water resources. To test this hypothesis, we developed an isotope dilution liquid chromatography electrospray ionization tandem mass spectrometry method for ultratrace analysis of TCC (0.9ng/L detection limit) and analyzed low-volume water samples (200mL) along with primary sludge samples from across the United States. All river water samples (100%) collected downstream of wastewater treatment plants had detectable levels of TCC, as compared to 56% of those taken upstream. Concentrations of TCC (mean+/-standard deviation) downstream of sewage treatment plants (84+/-110ng/L) were significantly higher (Pw/w each) in technical grade TCC (99%). Application of the new method for chlorocarbanilide analysis yielded TCC occurrence data for 13 US states, confirmed the role of sewage treatment plants as environmental inputs of TCC, and identified DCC and TetraCC as previously unrecognized pollutants released into the environment alongside TCC

  16. Cloud-point extraction is compatible with liquid chromatography coupled to electrospray ionization mass spectrometry for the determination of antazoline in human plasma.

    Science.gov (United States)

    Giebułtowicz, Joanna; Kojro, Grzegorz; Piotrowski, Roman; Kułakowski, Piotr; Wroczyński, Piotr

    2016-09-01

    Cloud-point extraction (CPE) is attracting increasing interest in a number of analytical fields, including bioanalysis, as it provides a simple, safe and environmentally-friendly sample preparation technique. However, there are only few reports on the application of this extraction technique in liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) analysis. In this study, CPE was used for the isolation of antazoline from human plasma. To date, only one method of antazoline isolation from plasma exists-liquid-liquid extraction (LLE). The aim of this study was to prove the compatibility of CPE and LC-ESI-MS/MS and the applicability of CPE to the determination of antazoline in spiked human plasma and clinical samples. Antazoline was isolated from human plasma using Triton X-114 as a surfactant. Xylometazoline was used as an internal standard. NaOH concentration, temperature and Triton X-114 concentration were optimized. The absolute matrix effect was carefully investigated. All validation experiments met international acceptance criteria and no significant relative matrix effect was observed. The compatibility of CPE and LC-ESI-MS/MS was confirmed using clinical plasma samples. The determination of antazoline concentration in human plasma in the range 10-2500ngmL(-1) by the CPE method led to results which are equivalent to those obtained by the widely used liquid-liquid extraction method. PMID:27289300

  17. Multiplex liquid chromatography-tandem mass spectrometry for the detection of wheat, oat, barley and rye prolamins towards the assessment of gluten-free product safety.

    Science.gov (United States)

    Manfredi, Anita; Mattarozzi, Monica; Giannetto, Marco; Careri, Maria

    2015-10-01

    Celiac patients should feel confident in the safety of foods labelled or expected to be gluten-free. In this context, a targeted proteomic approach based on liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) technique was proposed to assess the presence of celiotoxic cereals, namely wheat, oats, barley and rye, in raw and processed food products. To this aim, unique marker peptides were properly selected in order to distinguish between the different cereal types. A revised cocktail solution based on reducing and denaturing agents was exploited for prolamin extraction from raw and processed food; in addition, defatting with hexane was carried out for sample clean-up, allowing to largely reduce problems related to matrix effect. Method validation on fortified rice flour showed good analytical performance in terms of sensitivity (limits of detection in the 2-18 mg kg(-1) range). However, poor trueness was calculated for self-made incurred bread (between 3 and 30% depending on the peptide), probably due to baking processes, which reduce gluten extractability. Thus, it is evident that in the case of processed foods further insights into sample treatment efficiency and reference materials for protein calibration are required to obtain accurate gluten determination. Finally, the developed method was applied for the analysis of market food products, offering the possibility to discriminate among cereals, with good agreement with labelled ingredients for gluten-containing foodstuffs. PMID:26454460

  18. Quantitative determination of multi markers in five varieties of Withania somnifera using ultra-high performance liquid chromatography with hybrid triple quadrupole linear ion trap mass spectrometer combined with multivariate analysis: Application to pharmaceutical dosage forms.

    Science.gov (United States)

    Chandra, Preeti; Kannujia, Rekha; Saxena, Ankita; Srivastava, Mukesh; Bahadur, Lal; Pal, Mahesh; Singh, Bhim Pratap; Kumar Ojha, Sanjeev; Kumar, Brijesh

    2016-09-10

    An ultra-high performance liquid chromatography electrospray ionization tandem mass spectrometry method has been developed and validated for simultaneous quantification of six major bioactive compounds in five varieties of Withania somnifera in various plant parts (leaf, stem and root). The analysis was accomplished on Waters ACQUITY UPLC BEH C18 column with linear gradient elution of water/formic acid (0.1%) and acetonitrile at a flow rate of 0.3mLmin(-1). The proposed method was validated with acceptable linearity (r(2), 0.9989-0.9998), precision (RSD, 0.16-2.01%), stability (RSD, 1.04-1.62%) and recovery (RSD ≤2.45%), under optimum conditions. The method was also successfully applied for the simultaneous determination of six marker compounds in twenty-six marketed formulations. Hierarchical cluster analysis and principal component analysis were applied to discriminate these twenty-six batches based on characteristics of the bioactive compounds. The results indicated that this method is advance, rapid, sensitive and suitable to reveal the quality of Withania somnifera and also capable of performing quality evaluation of polyherbal formulations having similar markers/raw herbs. PMID:27475405

  19. Analysis of major antioxidants from extracts of Myrmecodia pendans by UV/visible spectrophotometer, liquid chromatography/tandem mass spectrometry, and high-performance liquid chromatography/UV techniques

    Directory of Open Access Journals (Sweden)

    Adam Mekonnen Engida

    2015-06-01

    Full Text Available In the present work, heat reflux extraction with ethanol/water (80:20; v/v as the solvent was used to extract antioxidants from Myrmecodia pendans. The crude extract (CE was fractionated using hexane and ethyl acetate. Ethyl acetate fraction (EAF and aqueous fraction were collected. Antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl-radical radical and ferric reducing power of the CE, EAF, and aqueous fraction were evaluated. EAF showed comparable antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl-radical radical and ferric reducing power to those of the CE. UV/visible, liquid chromatography/electrospray ionization/tandem mass spectrometry, and high-performance liquid chromatography were employed for identifying the major antioxidant compounds in the EAF. Three major phenolic compounds (rosmarinic acid, procyanidin B1, and polymer of procyanidin B1 were identified. The first two compounds were confirmed and quantified by high-performance liquid chromatography using authentic standards, but confirmation of the third compound was hampered by a lack of commercial standard. Concentrations of rosmarinic acid and procyanidin B1 in the EAF were found to be 20.688 ± 1.573 mg/g dry sample and 3.236 ± 0.280 mg/g dry sample, respectively. All these three compounds are reported for the first time in sarang semut.

  20. Are liquid chromatography/electrospray tandem quadrupole fragmentation ratios unequivocal confirmation criteria?

    Science.gov (United States)

    Kaufmann, Anton; Butcher, Patrick; Maden, Kathryn; Widmer, Mirjam; Giles, Kevin; Uría, Diana

    2009-04-01

    Multiple reaction monitoring (MRM) ratios as provided by tandem mass spectrometers are used to confirm positive residue findings (e.g. veterinary drugs or pesticides). The Commission Decision 2002/657/EEC defines tolerance levels for MRM ratios, which are intended to prevent the reporting of false positives. This paper reports findings where blank sample extracts have been spiked by a drug (difloxacin) and the corresponding measured MRM ratios significantly deviated from MRM ratios observed in matrix-free solution. The observation was explained by the formation of two different [M+H](+) analyte ions within the electrospray ionization (ESI) interface. These two ions vary only by the site of analyte protonation. Since they are isobaric, they are equally transmitted through the first quadrupole, but are differently fragmented in the collision chamber. The existence of two isobaric ions was deduced by statistical data and the observation of a doubly charged analyte ion. It was hypothesized that the combined presence of [M+H](+) and [M+2H](2+) implies the existence of two different singly charged ion species differing only by the site of protonation. Low- and high-energy interface-induced fragmentation was performed on the samples. The surviving precursor ion population was mass selected and again fragmented in the collision chamber. Equal product ion spectra would be expected. However, very different product ion spectra were observed for the two interface regimes. This is consistent with the assumption that the two postulated isobaric precursor ions show different stability in the interface. Hence the abundance ratio among the two types of surviving precursor ions will shift and change the resulting product ion spectra. The existence of the postulated singly charged ions with multiple chargeable sites was finally confirmed by successful ion mobility separation. PMID:19241450

  1. 40 CFR Appendix A to Subpart C of... - Alternative Testing Methods Approved for Analyses Under the Safe Drinking Water Act

    Science.gov (United States)

    2010-07-01

    ... Selective Electrode 4500-CN− F Gas Chromatography/MassSpectrometry Headspace ME355.01 7 Fluoride Ion... in Drinking Water by Ion Chromatography Electrospray Ionization Tandem Mass Spectrometry (IC-ESI-MS... for Analyses Under the Safe Drinking Water Act A Appendix A to Subpart C of Part 141 Protection...

  2. Determination of DNA and RNA Methylation in Circulating Tumor Cells by Mass Spectrometry.

    Science.gov (United States)

    Huang, Wei; Qi, Chu-Bo; Lv, Song-Wei; Xie, Min; Feng, Yu-Qi; Huang, Wei-Hua; Yuan, Bi-Feng

    2016-01-19

    DNA methylation (5-methylcytosine, 5-mC) is the best characterized epigenetic mark that has regulatory roles in diverse biological processes. Recent investigation of RNA modifications also raises the possible functions of RNA adenine and cytosine methylations on gene regulation in the form of "RNA epigenetics." Previous studies demonstrated global DNA hypomethylation in tumor tissues compared to healthy controls. However, DNA and RNA methylation in circulating tumor cells (CTCs) that are derived from tumors are still a mystery due to the lack of proper analytical methods. In this respect, here we established an effective CTCs capture system conjugated with a combined strategy of sample preparation for the captured CTCs lysis, nucleic acids digestion, and nucleosides extraction in one tube. The resulting nucleosides were then further analyzed by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). With the developed method, we are able to detect DNA and RNA methylation (5-methyl-2'-deoxycytidine, 5-methylcytidine, and N(6)-methyladenosine) in a single cell. We then further successfully determined DNA and RNA methylation in CTCs from lung cancer patients. Our results demonstrated, for the first time, a significant decrease of DNA methylation (5-methyl-2'-deoxycytidine) and increase of RNA adenine and cytosine methylations (N(6)-methyladenosine and 5-methylcytidine) in CTCs compared with whole blood cells. The discovery of DNA hypomethylation and RNA hypermethylation in CTCs in the current study together with previous reports of global DNA hypomethylation in tumor tissues suggest that nucleic acid modifications play important roles in the formation and development of cancer cells. This work constitutes the first step for the investigation of DNA and RNA methylation in CTCs, which may facilitate uncovering the metastasis mechanism of cancers in the future. PMID:26707930

  3. 玉米中9种磺酰脲类除草剂的超高效液相色谱-串联质谱法同时测定%Simultaneous Determination of 9 Sulfonylurea Herbicides in Corn Using Solid-phase Extraction and Ultra Performance Liquid Chromatography with Electrospray Ionization Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    丁菲; 李范珠; 储晓刚; 张峰; 凌云; 孙利; 杨敏莉; 吕泉福; 许成保

    2011-01-01

    采用超高效液相色谱-串联四极杆质谱(UPLC-MS/MS),在多反应监测(MRM )模式下建立了玉米中9种磺酰脲类除草剂残留的定性定量分析方法.样品浸泡后采用甲醇-丙酮(体积比1:1)提取、浓缩,经C18固相萃取柱净化处理.采用UPLC-ESI MS/MS方法测定,外标法定量.9种磺酰脲类除草剂在0.05~2.0 mg·L-1范围内具有较好的线性关系,相关系数均大于0.99,该方法的检出限(LOD,S/N=3)为0.001~0.005 mg·L-1,定量下限(LOQ,S/N=10)为0.062~0.080 mg·kg-1.在1LOQ、2LOQ和5LOQ 3个加标水平下的回收率为60%~85%,相对标准偏差(RSDs)均在10%以内.该方法简便快速,满足玉米中9种磺酰脲类除草剂的快速检测要求.%A new method based on solid phase extraction and ultra performance liquid chromatography -tandem mass spectrometry( UPLC -ESI MS/MS) was developed for the determination of 9 sulfonylurea herbicides(metoxuron, foramsulfuron, cinosulfuron, methabenthiazuron, prosulfuron, linuron, ethoxysulfuron, chloroxuron and cyclosulfamuron) in corn. The corn sample was soared in water, and then extracted with methanol - acetone ( 1: 1, by volume). The extract was cleaned up by C18 solid phase extraction cartridge. The eluent was evaporated to near dryness under a stream of nitregen gas, and redissolved by methanol. The identification and detection of target compounds were achieved under multiple reactions monitoring (MRM) mode with positive electrospray ionization (ESI). 9 sulfonylurea herbcides were quantified by external standard method. The calibration curves of 9 sulfonylurea herbicides were linear in the range of 0. 05 - 2.0 mg · L-1 with correlation coefficients more than O. 99. The limits of detection ( LOD, S/N = 3 ) and the limits of quantitation ( LOQ, S/N= 10) were in the range of 0. 001 -0. 005 mg · L-1 and 0. 062 -0. 080 mg · kg-1, respectively. 1LOQ,2LOQ and 5LOQ were chosen as the three spiked levels of recovery for the method. The recoveries of 9

  4. Studies on Transition Metal-Quercetin Complexes Using Electrospray Ionization Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Yuanzhen Liu

    2015-05-01

    Full Text Available To systematically study the effects of the number of d electrons of the first transition metal ions (Fe, Co, Ni, Cu and Zn on the formation and stability of metal flavonoid complexes, we took the quercetin/M2+ complex as a model system to investigate the structures and properties of these complexes. Based on considerable structural information obtained through ESI-MSn, all of the first transition metal ions (Fe2+, Co2+, Ni2+, Cu2+ and Zn2+ were found to form different complexes with quercetin, while with the number of chelating flavonoids decreasing along with the reduction of the metal ionic radius. Quercetin forms different complexes with the above metal divalent ions through its 5-OH and 4-carbonyl groups; the complex stability is highly dependent on both the metallic ion and the flavonoid chelator itself. As for the central ion (M2+, when chelated with quercetin to form the complex, the stability of the complex decreased in the following order: Cu2+ > Ni2+ > Co2+ > Fe2+ > Zn2+. With flavonoid: metal stoichiometries at 2:1, the complexes formed between quercetin and metal ions (Fe2+, Ni2+, Co2+ and Zn2+ have the similar fragmentation mechanism, while Cu2+ displayed different fragmentation mechanism due to the concurrent oxidation.

  5. GLYCEROPHOSPHOLIPID ANALYSIS OF EASTERN RED BAT (Lasiurus borealis) HAIR BY ELECTROSPRAY IONIZATION TANDEM MASS SPECTROMET

    OpenAIRE

    Pannkuk, Evan L.; Liam P McGuire; Gilmore, David F.; Savary, Brett J.; Risch, Thomas S.

    2014-01-01

    Pilosebaceous units found in the mammalian integument are composed of a hair follicle, the proximal portion of the hair shaft, a sebaceous gland, and the erector pili muscle. Pilosebaceous units release protective oils, or sebum, by holocrine secretion onto skin and hair through rupturing of sebocytes. Sebum is largely composed of polar and neutral lipids including glycerolipids, free fatty acids, sterols, wax esters, sterol esters, and squalene. In addition to these lipid classes, there is a...

  6. Liquid Chromatography-Electrospray Quadrupole Linear Ion Trap Mass Spectrometric Method for Quantitation of Domperidone in Chinese Healthy Volunteers

    Institute of Scientific and Technical Information of China (English)

    WU Yi; CHU Yang; ZHANG Yun-hui; WU Dan; GU Jing-kai

    2007-01-01

    A rapid, sensitive, and accurate method based on LC/MS/MS was developed and validated for the determination of domperidone in human plasma. Domperidone and internal standard, tramadol, were extracted from plasma with diethyl ether-dichloromethane(60: 40, volume ratio) and separated by reversed-phase HPLC with methanol-water-ammonia solution(80: 20: 0.2, volume ratio) as the mobile phase. Detection was carried out via multiple-reaction monitoring(MRM) on a Q-trapTM LC/MS/MS system(Q-trapTM). The assay result was linear over a concentration range of 0.1-30 ng/mL with a limit of quantitation (LOQ) of 0.1 ng/mL. The inter- and intra-day precision levels were within 7.52% and 12. 9%, respectively, whereas the accuracy was within a range of 87. 3%-114%. This method has been successfully applied to evaluate the pharmacokinetics of domperidone in Chinese healthy volunteers given an oral dose of 10 mg.

  7. Multi residue screening of intact testosterone esters and boldenone undecylenate in bovine hair using liquid chromatography electrospray tandem mass spectrometry

    NARCIS (Netherlands)

    Nielen, M.W.F.; Lasaroms, J.J.P.; Mulder, P.P.J.; Hende, van J.; Rhijn, van J.A.; Groot, M.J.

    2006-01-01

    The abuse of esters of natural androgenic steroids in cattle fattening and sports is hard to control via routine urine testing. The esters are rapidly hydrolysed in vivo into substances which are also endogenously present in urine. In veterinary control strange findings of 17ß-testosterone and 17¿-t

  8. Screening for gestagens in kidney fat using accelerated solvent extraction and liquid chromatography electrospray tandem mass spectrometry

    NARCIS (Netherlands)

    Hooijerink, H.; Bennekom, van E.O.; Nielen, M.W.F.

    2003-01-01

    A screening method has been developed for the determination of various anabolic steroids in kidney fat. Fat samples are extracted and steroids are trapped "on-line" during accelerated solvent extraction (ASE). Following this initial extraction samples are further purified with C18 solid-phase extrac

  9. Liquid Chromatography Tandem Mass Spectrometry Method for Quantification of Solifenacin in Human Plasma and its Application to Bioequivalence Study

    Directory of Open Access Journals (Sweden)

    Nishant Paliwal

    2013-06-01

    Full Text Available A hasty, specific and robust assay based on liquid-liquid extraction and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI MS-MS has been developed and validated for the quantitative analysis of Solifenacin ( a drug used for urinary incontinence in human plasma using Solifenacin D5 as internal standard (ISTD. The precursor to product ion transitions of m/z 363.20/110.10 and m/z 368.14/110.20 were used to measure the analyte and the ISTD, respectively. The method was validated in terms of selectivity, matrix effect, sensitivity, linearity, precision and accuracy, various stabilities (standard stock solution stability in refrigerator and at room temperature, stock dilution stability at refrigerator and room temperature, auto sampler stability, freeze thaw stability, long term stability- 65 o C ± 10o C & long term stability- 22 o C ± 5°C, reagent stability, bench top stability, dry extract stability, wet extract stability in refrigerator, effect of potentially interfering drugs, dilution integrity, recovery, lon suppression through infusion, and blood Stability. The mean percentage recovery of Solifenacin and the internal standard was 65.39 ± 3.646% and 66.24 ± 2.209% respectively. The assay exhibited a linear dynamic range of 0.200 to 30.361 ng mL-1. The RSD % of intra-day and inter-day assay was ≤15%. The application of this assay was demonstrated in a bioequivalence study and will be ideal for clinical pharmacokinetic studies in study population with as lower as 0.200 ng mL-1 analytical sensitivity and as little as 300 μL plasma sample.

  10. A workflow for multiclass determination of 256 pesticides in essential oils by liquid chromatography tandem mass spectrometry using evaporation and dilution approaches: Application to lavandin, lemon and cypress essential oils.

    Science.gov (United States)

    Fillatre, Yoann; Rondeau, David; Daguin, Antoine; Communal, Pierre-Yves

    2016-03-01

    This paper describes the determination of 256 multiclass pesticides in cypress and lemon essential oils (EOs) by the way of liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS) analysis using the scheduled selected reaction monitoring mode (sSRM) available on a hybrid quadrupole linear ion trap (QLIT) mass spectrometer. The performance of a sample preparation of lemon and cypress EOs based on dilution or evaporation under nitrogen assisted by a controlled heating were assessed. The best limits of quantification (LOQs) were achieved with the evaporation under nitrogen method giving LOQs≤10µgL(-1) for 91% of the pesticides. In addition the very satisfactory results obtained for recovery, repeatability and linearity showed that for EOs of relatively low evaporation temperature, a sample preparation based on evaporation under nitrogen is well adapted and preferable to dilution. By compiling these results with those previously published by some of us on lavandin EO, we proposed a workflow dedicated to multiresidue determination of pesticides in various EOs by LC-ESI/sSRM. Among the steps involved in this workflow, the protocol related to mass spectrometry proposes an alternative confirmation method to the classical SRM ratio criteria based on a sSRM survey scan followed by an information-dependent acquisition using the sensitive enhanced product ion (EPI) scan to generate MS/MS spectra then compared to a reference. The submitted workflow was applied to the case of lemon EOs samples highlighting for the first time the simultaneous detection of 20 multiclass pesticides in one EO. Some pesticides showed very high concentration levels with amounts greatly exceeding the mgL(-1). PMID:26717829

  11. Validation and use of a fast sample preparation method and liquid chromatography-tandem mass spectrometry in analysis of ultra-trace levels of 98 organophosphorus pesticide and carbamate residues in a total diet study involving diversified food types.

    Science.gov (United States)

    Chung, Stephen W C; Chan, Benny T P

    2010-07-16

    This paper reports a comprehensive sensitive multi-residue liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for detection, identification and quantitation of 73 pesticides and their related products, a total of 98 analytes, belonging to organophosphorus pesticides (OPPs) and carbamates, in foods. The proposed method makes use of a modified QuEChERS (quick, easy, cheap, effective, rigged, and safe) procedure that combines isolation of the pesticides and sample clean-up in a single step. Analysis is performed by liquid chromatography-electrospray ionization-tandem mass spectrometry operated in the multiple reaction monitoring (MRM) mode, acquiring two specific precursor-product ion transitions per target compound. Two main fragment ions for each pesticide were obtained to achieve the identification according to the SANCO guidelines 10684/2009. The method was validated with various food samples, including edible oil, meat, egg, cheese, chocolate, coffee, rice, tree nuts, citric fruits, vegetables, etc. No significant matrix effect was observed for tested pesticides, therefore, matrix-matched calibration was not necessary. Calibration curves were linear and covered from 1 to 20 microg L(-1) for all compounds studied. The average recoveries, measured at 10 microg kg(-1), were in the range 70-120% for all of the compounds tested with relative standard deviations below 20%, while a value of 10 microg kg(-1) has been established as the method limit of quantitation (MLOQ) for all target analytes. Similar trueness and precision results were also obtained for spiking at 200 microg kg(-1). Expanded uncertainty values were in the range 21-27% while the HorRat ratios were below 1. The method has been successfully applied to the analysis of 700 food samples in the course of a baseline monitoring study of OPPs and carbamates. PMID:20557892

  12. Development, validation, and application of a liquid chromatography-tandem mass spectrometry method for the determination of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol in human hair.

    Science.gov (United States)

    Yao, Li; Yang, Jun; Guan, Ya-feng; Liu, Bai-zhan; Zheng, Sai-jing; Wang, Wei-miao; Zhu, Xiao-lan; Zhang, Zhi-dan

    2012-11-01

    The tobacco-specific nitrosamine metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) is a valuable biomarker for human exposure to the carcinogenic nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in tobacco and tobacco smoke. In this work, an efficient and sensitive method for the analysis of NNAL in human hair was developed and validated. The hair sample was extracted by NaOH solution digestion, purified by C(18) solid-phase extraction (SPE) and molecularly imprinted solid-phase extraction, further enriched by reverse-phase ultrasound-assisted dispersive liquid-liquid microextraction (USA-DLLME) into 1.0 % aqueous formic acid, and finally analyzed by liquid chromatography-electrospray ionization tandem mass spectrometry. Good linearity was obtained in the range of 0.24-10.0 pg/mg hair with a correlation coefficient of 0.9982, when 150 mg hair was analyzed. The limit of detection and lower limit of quantification were 0.08 and 0.24 pg/mg hair, respectively. Accuracies determined from hair samples spiked with three different levels of NNAL ranged between 87.3 and 107.7 %. Intra- and inter-day relative standard deviations varied from 4.1 to 8.5 % and from 6.9 to 11.3 %, respectively. Under the optimized conditions, an enrichment factor of 20 was obtained. Finally, the developed method was applied for the analysis of NNAL in smokers' hair. The proposed sample preparation procedure combining selectivity of two-step SPE and enrichment of DLLME significantly improves the purification and enrichment of the analyte and should be useful to analyze NNAL in hair samples for cancer risk evaluation and cancer prevention in relation to exposure to the tobacco-specific carcinogen NNK. PMID:22926132

  13. Hydrophilic interaction liquid chromatography-tandem mass spectrometry quantitative method for the cellular analysis of varying structures of gemini surfactants designed as nanomaterial drug carriers.

    Science.gov (United States)

    Donkuru, McDonald; Michel, Deborah; Awad, Hanan; Katselis, George; El-Aneed, Anas

    2016-05-13

    Diquaternary gemini surfactants have successfully been used to form lipid-based nanoparticles that are able to compact, protect, and deliver genetic materials into cells. However, what happens to the gemini surfactants after they have released their therapeutic cargo is unknown. Such knowledge is critical to assess the quality, safety, and efficacy of gemini surfactant nanoparticles. We have developed a simple and rapid liquid chromatography electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the quantitative determination of various structures of gemini surfactants in cells. Hydrophilic interaction liquid chromatography (HILIC) was employed allowing for a short simple isocratic run of only 4min. The lower limit of detection (LLOD) was 3ng/mL. The method was valid to 18 structures of gemini surfactants belonging to two different structural families. A full method validation was performed for two lead compounds according to USFDA guidelines. The HILIC-MS/MS method was compatible with the physicochemical properties of gemini surfactants that bear a permanent positive charge with both hydrophilic and hydrophobic elements within their molecular structure. In addition, an effective liquid-liquid extraction method (98% recovery) was employed surpassing previously used extraction methods. The analysis of nanoparticle-treated cells showed an initial rise in the analyte intracellular concentration followed by a maximum and a somewhat more gradual decrease of the intracellular concentration. The observed intracellular depletion of the gemini surfactants may be attributable to their bio-transformation into metabolites and exocytosis from the host cells. Obtained cellular data showed a pattern that grants additional investigations, evaluating metabolite formation and assessing the subcellular distribution of tested compounds. PMID:27086283

  14. A combined liquid chromatography-triple-quadrupole mass spectrometry method for the residual detection of veterinary drugs in porcine muscle, milk, and eggs.

    Science.gov (United States)

    Zhang, Dan; Park, Zee-Yong; Park, Jin-A; Kim, Seong-Kwan; Jeong, Daun; Cho, Sang-Hyun; Shim, Jae-Han; Kim, Jin-Suk; Abd El-Aty, A M; Shin, Ho-Chul

    2016-06-01

    A liquid chromatography-electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method was developed for monitoring and detection of four different drugs, namely acetanilide, pentylenetetrazole, phenacetin, and tetramethrin in porcine muscle, pasteurized milk, and table egg samples. For acetanilide and pentylenetetrazole, the samples were extracted with 0.1 % formic acid in acetonitrile, followed by defatting with n-hexane, partitioning at -20 °C for 1 h, centrifugation, and filtration, whereas the quick, easy, cheap, effective, rugged, and safe "QuEChERS" method was used for phenacetin and tetramethrin. The final extracts were combined and analyzed in a single chromatographic run using an XBridge(TM) analytical column and 0.1 % formic acid and 10 mM ammonium formate in ultrapure water (A) and 0.1 % formic acid and 10 mM ammonium formate in methanol (B) as the mobile phase. Owing to the unavailability of internal standards, matrix-matched calibrations were used for analyte quantification with coefficients of determination (R (2)) ≥ 0.9865. The intra- and inter-day accuracies ranged from 60.75 to 90.90 % and from 63.75 to 89.30 %, respectively, while the respective analytical precisions were 1.48-17.44 % (23.3 % for porcine sample spiked with phenacetin) and 1.97-15.78 %. The limits of quantification (LOQ) were between 0.5 and 2.5 ng/g in the matrices tested. Food samples purchased from local markets in Seoul were analyzed using the developed method and none of the tested drugs was detected. PMID:27178050

  15. Simultaneous determination of five phenolic components and paeoniflorin in rat plasma by liquid chromatography-tandem mass spectrometry and pharmacokinetic study after oral administration of Cerebralcare granule(®).

    Science.gov (United States)

    Wang, Xiang-yang; Ma, Xiao-hui; Li, Wei; Chu, Yang; Guo, Jia-hua; Li, Shu-ming; Wang, Jun-mei; Zhang, Hong-chao; Zhou, Shui-ping; Zhu, Yong-hong

    2013-12-01

    A simple, sensitive and selective high-performance liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method was developed for simultaneous determination and pharmacokinetic study of six active components, protocatechuic acid, chlorogenic acid, caffeic acid, ferulic acid rosmarinic acid and paeoniflorin in rat plasma after oral administration of Cerebralcare granule(®) for the first time. The method involves a simple liquid-liquid extraction with ethyl acetate. The separation was performed on a Luna C18 column (2.0×100mm i.d., 3.0μm, particle, Phenomenex, USA) with gradient elution using a mobile phase composed of acetonitrile and water (containing 0.1% formic acid) at a flow rate of 0.2ml/min. Electrospray ionization (ESI) in negative ion mode and selective reaction monitoring (SRM) was used for the quantification of six active components and internal standard (IS, Chloroamphenicol). The method was linear for all analytes over investigated range with all correlation coefficients greater than 0.9914. The lower limits of quantification (LLOQ) were 1.0ng/ml for protocatechuic acid, 1.0ng/ml for chlorogenic acid, 1.0ng/ml for caffeic acid, 5.0ng/ml for ferulic acid, 1.5ng/ml for rosmarinic acid and 6.0ng/ml for paeoniflorin, respectively. The intra- and inter-day precisions (R.S.D.%) were less than 6.60% and 11.68%, and accuracy (RE %) between -3.26% and 1.13% (n=6). The developed method was applied for the first time to the pharmacokinetic study of protocatechuic acid, chlorogenic acid, caffeic acid, ferulic acid, rosmarinic acid and paeoniflorin in rat plasma after oral administration of Cerebralcare granule(®). PMID:23994763

  16. A laser ablation ICP-MS based method for multiplexed immunoblot analysis

    DEFF Research Database (Denmark)

    de Bang, Thomas Christian; Petersen, Jørgen; Pedas, Pai Rosager;

    2015-01-01

    developed a multiplexed antibody-based assay and analysed selected PSII subunits in barley (Hordeum vulgare L.). A selection of antibodies were labelled with specific lanthanides and immunoreacted with thylakoids exposed to Mn deficiency after western blotting. Subsequently, western blot membranes were...... analysed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), which allowed selective and relative quantitative analysis via the different lanthanides. The method was evaluated against established liquid chromatography electrospray ionization tandem mass spectrometry (LC...

  17. Simultaneous determination of seven flavonoids in Epimedium by liquid chromatography-tandem mass spectrometry method

    Institute of Scientific and Technical Information of China (English)

    Cai Sheng Wu; Bao Lin Guo; Yu Xin Sheng; Jin Lan Zhang

    2008-01-01

    In this paper, a sensitive and specific liquid chromatography-electrospray ionisation-mass spectrometry (LC-ESI-MS) method has been developed and validated for the identification and determination of seven flavonoids, namely epimedin A, epimedin B, epimedin C, icariin, sagittatoside B, 2"-0-rhamnosyl icariside II, and baohuoside I in Epimedium from different sources.

  18. A U-HPLC-ESI-MS/MS-based stable isotope dilution method for the detection and quantitation of methotrexate in plasma

    OpenAIRE

    Boer, Ethan; Heil, Sandra; Zelst, Bertrand; Schneider, Petra; Koch, B.C.P.; Winkel, Mariël Lizet; Heuvel-Eibrink, Marry; Luider, Theo; de Jonge, Robert

    2012-01-01

    textabstractINTRODUCTION: High-dose methotrexate (MTX) is used in the treatment of proliferative diseases such as acute lymphoblastic leukemia. Therapeutic drug monitoring of plasma MTX is important to monitor efficacy and adverse events. The authors aimed to develop a liquid chromatography, electrospray ionization, tandem mass spectrometry (LC-ESI-MS/MS)-based method to determine MTX in plasma for therapeutic drug monitoring and pharmacokinetic studies. METHODS: Samples were analyzed using a...

  19. Natural taurine promotes apoptosis of human hepatic stellate cells in proteomics analysis

    OpenAIRE

    Xin Deng, Jian Liang, Zhi-Xiu Lin, Fa-Sheng Wu, Ya-Ping Zhang, Zhi-Wei Zhang

    2010-01-01

    AIM: To study the differential expression of proteins between natural taurine treated hepatic stellate cells and controls, and investigate the underlying regulatory mechanism of natural taurine in inhibiting hepatic fibrosis.METHODS: A proteomic strategy combining two-dimensional gel electrophoresis and ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) was used to study the differential expression of proteins and Western blotting was use...

  20. Metabolites of A Novel Antibiotic Bitespiramycin in Rat Urine and Bile

    Institute of Scientific and Technical Information of China (English)

    Xiang Guo SHI; Da Fang ZHONG; Yu Ming SUN; Yu Feng ZHANG

    2004-01-01

    A sensitive analytical method to identify active metabolites of bitespiramycin in rat urine and bile was developed by liquid chromatography-electrospray ionization tandem mass spectrometry(LC/ESI-MSn).Bitespiramycin and its major active metabolites in rat urine and bile were isolated and identified as M1 serial(spiramycin I,II,III),M2 serial(platenomycin A1,josamycin and leucomycin A1)and M3 serial(deisovalerylplatenomycin A1,deisovaleryl-josamycin,deisovalerylleucomycin A1).

  1. High efficiency and quantitatively reproducible protein digestion by trypsin-immobilized magnetic microspheres

    OpenAIRE

    Sun, Liangliang; Li, Yihan; Yang, Ping; Zhu, Guijie; Dovichi, Norman J.

    2011-01-01

    Aldehyde- and NHS-activated magnetic microspheres were used to immobilize trypsin (CHO-trypsin and NHS-trypsin), and their performance for protein digestion was evaluated by reversed phase liquid chromatography-electrospray ionization-tandem mass spectrometry using an LTQ Orbitrap Velos instrument. NHS-trypsin provided greater sequence coverage and identified more peptides for the digestion of bovine serum albumin. A one-minute digestion at room temperature using the immobilized trypsin also ...

  2. Proteomic analysis in pterygium; upregulated protein expression of ALDH3A1, PDIA3, and PRDX2

    OpenAIRE

    Kim, Sun Woong; Lee, Jonghoon; Lee, Boram; Rhim, TaiYoun

    2014-01-01

    Purpose To identify differentially expressed proteins in the pterygium compared to healthy conjunctiva using a proteomic analysis. Methods Pterygial and healthy conjunctival tissues were obtained from 24 patients undergoing pterygium excision. Total proteins of the pterygia and healthy conjunctiva were analyzed with one-dimensional electrophoresis, and protein bands of interest were excised and subjected to liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-MS/MS) usin...

  3. Preventive doping control analysis: Liquid and gas chromatography time-to-flight mass spectrometry for detection of designer steriods

    NARCIS (Netherlands)

    Georgakopoulos, C.G.; Vonaparti, A.; Stamou, M.; Kiousi, P.; Lyris, E.; Angelis, Y.S.; Tsoupras, G.; Wuest, B.; Nielen, M.W.F.; Panderi, I.; Koupparis, M.

    2007-01-01

    A new combined doping control screening method for the analysis of anabolic steroids in human urine using liquid chromatography/electrospray ionization orthogonal acceleration time-of-flight mass spectrometry (LCoaTOFMS) and gas chromatography/electron ionization orthogonal acceleration time-of-flig

  4. Rapid and sensitive hormonal profiling of complex plant samples by liquid chromatography coupled to electrospray ionization tandem mass spectrometry

    OpenAIRE

    Müller Maren; Munné-Bosch Sergi

    2011-01-01

    Abstract Background Plant hormones play a pivotal role in several physiological processes during a plant's life cycle, from germination to senescence, and the determination of endogenous concentrations of hormones is essential to elucidate the role of a particular hormone in any physiological process. Availability of a sensitive and rapid method to quantify multiple classes of hormones simultaneously will greatly facilitate the investigation of signaling networks in controlling specific devel...

  5. Multiresidue analysis of pesticides in traditional Chinese medicines using gas chromatography - negative chemical ionization tandem mass spectrometry

    Science.gov (United States)

    In this study, a residue analysis method for the simultaneous determination of 107 pesticides in the traditional Chinese medicines (TCMs), Angelica sinensis, Angelica dahurica, Leonurus heterophyllus Sweet, Pogostemon cablin, and Lonicera japonica Thunb, was developed using gas chromatography couple...

  6. Identifying the related compounds using electrospray ionization tandem mass spectrometry: bromotyrosine alkaloids from marine sponge Psammaplysilla purpurea

    Digital Repository Service at National Institute of Oceanography (India)

    Tilvi, S.; DeSouza, L.

    (arbitrary units); ion spray voltage 5700 V; declustering potential (DP) 120 V; focusing potential (FP) 365 V; declustering potential (DP2) 14 V and collision gas (CAD) 3 (arbitrary units). Full-scan data acquisition was performed, scanning from m/z 100...

  7. Identification of Plasmalogen Cardiolipins from Pectinatus by Liquid Chromatography-High Resolution Electrospray Ionization Tandem Mass Spectrometry

    Czech Academy of Sciences Publication Activity Database

    Řezanka, Tomáš; Matoulková, D.; Kyselová, I.; Sigler, Karel

    2013-01-01

    Roč. 48, č. 12 (2013), s. 1237-1251. ISSN 0024-4201 R&D Projects: GA ČR(CZ) GAP503/11/0215 Institutional support: RVO:61388971 Keywords : Pectinatus * Plasmalogens * Cardiolipins Subject RIV: EE - Microbiology, Virology Impact factor: 2.353, year: 2013

  8. Rapid and simple extraction of lipids from blood plasma and urine for liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Bang, Dae Young; Byeon, Seul Kee; Moon, Myeong Hee

    2014-02-28

    A simple and fast lipid extraction method from human blood plasma and urine is introduced in this study. The effective lipid extraction from biological systems with a minimization of the matrix effect is important for the successful qualitative and quantitative analysis of lipids in liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). The method described here is based on the modification of the quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction method, which was originally developed for pesticide residue analysis in food, for the purpose of isolating lipids from biological fluids. Applicability of QuEChERS method for lipids was evaluated by varying organic solvents for the extraction/partitioning of lipids in MgSO4/CH3COONa for the removal of water and by varying sorbents (primary secondary amines, graphitized carbon black, silica, strong anion exchange resins and C18 particles) for the dispersive solid-phase extraction (dSPE) step. This study shows that 2:1 (v/v) CHCl3/CH3OH is effective in the extraction/partitioning step and that 50mg of C18 particles (for 0.1mL plasma and 1mL of urine) are more suitable for sample cleanup for the dSPE step of the QuEChERS method. Matrix effects were calculated by comparing the recovery values of lipid standards spiked to both plasma and urine samples after extraction with those of the same standards in a neat solution using nanoflow LC-ESI-MS/MS, resulting in improved MS signals due to the decrease of the ion suppression compared to the conventional Folch method. The modified QuEChERS method was applied to lipid extracts from both human urine and plasma samples, demonstrating that it can be powerfully utilized for high-speed (<15min) preparation of lipids compared to the Folch method, with equivalent or slightly improved results in lipid identification using nLC-ESI-MS/MS. PMID:24491523

  9. Liquid chromatography-electrospray-tandem mass spectrometry method for determination of organophosphate diesters in biotic samples including Great Lakes herring gull plasma.

    Science.gov (United States)

    Su, Guanyong; Greaves, Alana K; Gauthier, Lewis; Letcher, Robert J

    2014-12-29

    Environmentally relevant organophosphate (OP) triester flame retardants are known to degrade to OP diester phosphoric acids. In this study, a quantitatively sensitive method was developed for OP diesters in biological samples of varying complexity, bovine serum, chicken egg homogenate and pork liver. Fortified with 1ng or 10ng each of the six OP diester and six OP triester standards, samples were extracted by accelerated solvent extraction that completely separated OP diesters and triesters. OP diester fractions were cleaned up using weak anion exchange solid phase extraction and eluted with high ionic strength ammonium acetate buffer. Optimal analysis of chlorinated OP diesters was via decamethonium hydroxide dicationic reagent derivatization and by LC-ESI(+)-MS/MS, and for all non-chlorinated OP diesters by non-derivatized LC-ESI(-)-MS/MS. Except for derivatization LC-ESI(+)-MS/MS analysis of liver, at the 10ng spiking level for the three matrices, recovery efficiencies, matrix effects and method limits of quantification (MLOQs) of OP diesters ranged from 55-116%, 92-119%, and 0.02-0.31ng/g wet weight (ww) respectively. Plasma samples of n=6 herring gulls (2010, Chantry Is., Laurentian Great Lakes) contained triphenyl phosphate and tris(1-3-dichloro-2-propyl) phosphate ranging from 1.3 to 4.0ng/g ww and

  10. Determination of hexamethylphosphoramide and other highly polar phosphoramides in water samples using reversed-phase liquid chromatography/electrospray ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Blotevogel, Jens; Borch, Thomas

    2011-09-16

    The widely used solvent hexamethylphosphoramide (HMPA) and its biological (metabolic) and chemical (abiotic) phosphoramide-based oxidation products may cause adverse health effects through occupational exposure and intake of contaminated groundwater. However, no current methods exist for the separation and the detection of the many polar HMPA oxidation products. Thus, we developed a new RPLC/ESI-TOF-MS method and further investigated the chromatographic performances of two columns (i.e., XTerra Phenyl and XBridge Phenyl). In addition, the impact of (forced) acid hydrolysis for optimized chromatographic performance of the XTerra Phenyl column is investigated. The XTerra Phenyl column showed the best separation of the less polar major metabolic oxidation products pentamethylphosphoramide and hydroxymethyl-pentamethylphosphoramide, however, only after treating the column with formic acid (acid-treated). The XTerra column separated most of the investigated HMPA oxidation products (11 of 16 compounds) in a single chromatographic run. In contrast, the XBridge Phenyl column requires one method for the less polar and another method for the more polar oxidation products. However, this results in an overall better separation performance of the XBridge Phenyl column, especially for the less polar major abiotic oxidation products hydroxymethyl-pentamethylphosphoramide and formyl-pentamethylphosphoramide, as well as for 11 highly polar oxidation products (R(S)>1.5). The RPLC/ESI-TOF-MS method presented and validated in this study is the first analytical method that can be used to separate and detect HMPA (LOD 0.10 μM without preconcentration) and all of its oxidation products. PMID:21835414

  11. Pharmacokinetic study of nobiletin and tangeretin in rat serum by high-performance liquid chromatography-electrospray ionization-mass spectrometry

    Science.gov (United States)

    Nobiletin (NOB) and tangeretin (TAN), two of the main polymethoxylated flavones in citrus, influence a number of key biological pathways in mammalian cells. While the impacts of NOB and TAN on glucose homeostasis and cholesterol regulation have been investigated in human clinical trials, much inform...

  12. Metabolomics Analysis of Health Functions of Physalis Pubescens L. using by Ultra-performance Liquid Chromatography/Electrospray Ionization Quadruple Time-of-Flight Mass Spectrometry

    OpenAIRE

    Hang Chu; Hui Sun; Guang-Li Yan; Ai-Hua Zhang; Chang Liu; Hui Dong; Xiang-Cai Meng; Xi-Jun Wang

    2015-01-01

    Herbal medicines may benefit from metabolomics studies, and applying metabolomics may provide answers about which herbal interventions may be effective for individuals, which metabolic processes are triggered, and the subsequent chemical pathways of activity. Physalis pubescens L (PPL) is an herbal fruit for one year living plant and has been developed into healthy function's food. However, the mechanisms of health functions are still unclear. To comprehensively and holistically assess its an...

  13. Dual biosensor immunoassay-directed identification of fluoroquinolones in chicken muscle by liquid chromatography electrospray time-of-flight mass spectrometry

    NARCIS (Netherlands)

    Marchesini, G.R.; Haasnoot, W.; Delahaut, P.; Gercek, H.; Nielen, M.W.F.

    2007-01-01

    Fluoroquinolones (FQs) are synthetic antibiotics of broad-spectrum antibacterial activity widely used to treat infections in farmed fish, turkeys, pigs, calves and poultry. Monitoring these substances residues is therefore regulated by law. For the detection of FQs, we studied the feasibility of cou

  14. Characterization of steroidal saponins from Dioscorea villosa and D Cayennensis using ultrahigh performance liquid chromatography/electrospray ionization quadruple time-of-flight mass spectrometry

    Science.gov (United States)

    Steroidal saponins were reported to be the major physiologically active constituents in yams. The structural characteristics of steroidal saponins in methanolic extracts from dried rhizomes of two Dioscorea species (D. villosa L. and D. cayenensis Lam.) and dietary supplements have analyzed using U...

  15. Ethyl glucuronide in vitreous humor and blood postmortem specimens: analysis by liquid chromatography-electrospray tandem mass spectrometry and interpreting results of neo-formation of ethanol

    Directory of Open Access Journals (Sweden)

    Sara Vezzoli

    2015-03-01

    Full Text Available Introduction. The determination of ethyl glucuronide (EtG, a stable and sensitive marker that is specific to alcohol intake, finds many applications both in the forensic toxicology and clinical fields. Aim. The aim of the study is to examine the possibility of using a cadaveric biological matrix, vitreous humor (VH, to determine EtG as a marker of recent ethanol use. Methods. The blood, taken from the femoral vein, and the VH were obtained from 63 autopsy cases. Analysis of the EtG was performed using an LC/MS/MS system. Analyses of the ethanol and putrefaction biomarkers, such as acetaldehyde and n-propanol, were performed using the HS-GC/FID technique in both the matrices. Results. In 17 cases, both ethanol and EtG were absent in both matrices.Nineteen cases presented ethanol in blood from 0.05 to 0.30 g/L, EtG-Blood concentration from 0.02 to 3.27 mg/L, and EtG-VH concentration from 0.01 mg/L to 2.88 mg/L. Thirteen cases presented ethanol in blood > 0.05 g/L but EtG concentration in blood and VH lower than 0.01 mg/L, are part of these 8 samples presented acetic aldehyde and n- propanol in blood or VH, means identification of putrefaction indicators. Fourteen cases presented ethanol in blood > 0.46 and EtG concentration in blood and VH higher than 0.01 mg/L. Conclusions. The determination of EtG in biological material is important in those cases where the intake of ethanol appears doubtful, as it allows us to exclude the possibility of any post-mortem formation of ethanol.

  16. Ethyl glucuronide in vitreous humor and blood postmortem specimens: analysis by liquid chromatography-electrospray tandem mass spectrometry and interpreting results of neo-formation of ethanol

    OpenAIRE

    Sara Vezzoli; Marzia Bernini; Francesco De Ferrari

    2015-01-01

    Introduction. The determination of ethyl glucuronide (EtG), a stable and sensitive marker that is specific to alcohol intake, finds many applications both in the forensic toxicology and clinical fields. Aim. The aim of the study is to examine the possibility of using a cadaveric biological matrix, vitreous humor (VH), to determine EtG as a marker of recent ethanol use. Methods. The blood, taken from the femoral vein, and the VH were obtained from 63 autopsy cases. Analysis of the EtG was perf...

  17. Quantification of the Triazole Antifungal Compounds Voriconazole and Posaconazole in Human Serum or Plasma Using Liquid Chromatography Electrospray Tandem Mass Spectrometry (HPLC-ESI-MS/MS).

    Science.gov (United States)

    Molinelli, Alejandro R; Rose, Charles H

    2016-01-01

    Voriconazole and posaconazole are triazole antifungal compounds used in the treatment of fungal infections. Therapeutic drug monitoring of both compounds is recommended in order to guide drug dosing to achieve optimal blood concentrations. In this chapter we describe an HPLC-ESI-MS/MS method for the quantification of both compounds in human plasma or serum following a simple specimen preparation procedure. Specimen preparation consists of protein precipitation using methanol and acetonitrile followed by a cleanup step that involves filtration through a cellulose acetate membrane. The specimen is then injected into an HPLC-ESI-MS/MS equipped with a C18 column and separated over an acetonitrile gradient. Quantification of the drugs in the specimen is achieved by comparing the response of the unknown specimen to that of the calibrators in the standard curve using multiple reaction monitoring. PMID:26660172

  18. UPLC-MRM Mass Spectrometry Method for Measurement of the Coagulation Inhibitors Dabigatran and Rivaroxaban in Human Plasma and Its Comparison with Functional Assays.

    Directory of Open Access Journals (Sweden)

    Joachim Kuhn

    Full Text Available The fast, precise, and accurate measurement of the new generation of oral anticoagulants such as dabigatran and rivaroxaban in patients' plasma my provide important information in different clinical circumstances such as in the case of suspicion of overdose, when patients switch from existing oral anticoagulant, in patients with hepatic or renal impairment, by concomitant use of interaction drugs, or to assess anticoagulant concentration in patients' blood before major surgery.Here, we describe a quick and precise method to measure the coagulation inhibitors dabigatran and rivaroxaban using ultra-performance liquid chromatography electrospray ionization-tandem mass spectrometry in multiple reactions monitoring (MRM mode (UPLC-MRM MS. Internal standards (ISs were added to the sample and after protein precipitation; the sample was separated on a reverse phase column. After ionization of the analytes the ions were detected using electrospray ionization-tandem mass spectrometry. Run time was 2.5 minutes per injection. Ion suppression was characterized by means of post-column infusion.The calibration curves of dabigatran and rivaroxaban were linear over the working range between 0.8 and 800 μg/L (r >0.99. Limits of detection (LOD in the plasma matrix were 0.21 μg/L for dabigatran and 0.34 μg/L for rivaroxaban, and lower limits of quantification (LLOQ in the plasma matrix were 0.46 μg/L for dabigatran and 0.54 μg/L for rivaroxaban. The intraassay coefficients of variation (CVs for dabigatran and rivaroxaban were < 4% and 6%; respectively, the interassay CVs were < 6% for dabigatran and < 9% for rivaroxaban. Inaccuracy was < 5% for both substances. The mean recovery was 104.5% (range 83.8-113.0% for dabigatran and 87.0% (range 73.6-105.4% for rivaroxaban. No significant ion suppressions were detected at the elution times of dabigatran or rivaroxaban. Both coagulation inhibitors were stable in citrate plasma at -20°C, 4°C and even at RT for at

  19. A multi-class bioanalytical methodology for the determination of bisphenol A diglycidyl ethers, p-hydroxybenzoic acid esters, benzophenone-type ultraviolet filters, triclosan, and triclocarban in human urine by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Asimakopoulos, Alexandros G; Wang, Lei; Thomaidis, Nikolaos S; Kannan, Kurunthachalam

    2014-01-10

    A liquid-liquid extraction (LLE; ethyl acetate) protocol, followed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) methodology, was developed for the determination of 19 compounds, including bisphenol A diglycidyl ethers (BADGEs; industrial ethers), benzophenone-type UV filters (BP-UV filters; precursors and metabolites), p-hydroxybenzoic acid esters (parabens; preservatives), triclosan (TCS) and triclocarban (TCC) in human urine. Urine specimens were enzymatically deconjugated with β-glucuronidase (from Helix pomatia) and extracted by a LLE procedure for the measurement of total concentrations (i.e., free+conjugated forms) of target analytes. Absolute recoveries of BADGEs, BP-UV filters, parabens, TCS and TCC ranged 25-135%, 84-125%, 52-126%, 75-118% and 90-124%, respectively. Method precision (absolute values; N=5 replicate analyses at the fortification level of 10 ng, k=5 days) ranged from 5.8 (ethyl paraben) to 24.0% (TCS). The limits of quantification (LOQs) varied depending on the target compound and generally ranged from 0.2 to 2.0 ng/mL. The matrix effects ranged from +11 (2,3,4-trihydroxybenzophenone) to -86% (2,4-dihydroxybenzophenone). A total of 30 urine specimens collected from Athens, Greece, were analyzed for the 19 target compounds to demonstrate the applicability of the developed method. The concentrations of target chemicals in urine were presented on volume-, specific gravity (SG)-, and creatinine-normalization bases. MeP, EtP, PrP, OH-EtP, BADGE·2H2O, BP-1 and TCS were found frequently in urine at concentrations in the range of 2.7-436 ng/mL, <0.5-25.4 ng/mL, <0.5-575 ng/mL, <2-18.4 ng/mL, <0.5-13.8 ng/mL, <1-14.6 ng/mL and <0.5-95.3 ng/mL, respectively. PMID:24315674

  20. Isolation and identification of Phenolic compounds by HPLC and Electrospray Ionization Mass Spectrometry of Svensonia Hyderobadensis ? A Rare Medicinal Plant Taxon

    OpenAIRE

    Linga Rao M; Savithramma N

    2014-01-01

    The impetus for developing analytical methods for phenolic compounds in natural products has proved to be multifaceted. Hence the present study intended to isolate phenolic compounds from leaves of Svensonia hyderobadensis by using 70% acetone and poly vinyl poly pyrrolidone (PVPP); and characterized by U.V. Visible spectrometry, High performance liquid chromatography/ electrospray ionization mass spectrometry. Total 82 phenolic compounds were obtained at both positive and negative ion modes ...

  1. High performance liquid chromatography (HPLC) fingerprints and primary structure identification of corn peptides by HPLC-diode array detection and HPLC-electrospray ionization tandem mass spectrometry

    OpenAIRE

    Chi Wang; Hui He; Jiu-liang Zhang; Xing Li; Zhi-li Ma

    2016-01-01

    Corn peptides (CPs) are reported to have many biological functions, such as facilitating alcohol metabolism, antioxidation, antitumor, antihypertension, and hepatoprotection. To develop a method for quality control, the high-performance liquid chromatography (HPLC) system was applied. Twenty-eight common peaks were found in all the CPs of corn samples from Enshi, China, based on which, a fingerprinting chromatogram was established for use in quality control in future research. Subsequently, t...

  2. A Study on SNP by Electrospray Ionization Tandem Mass Spectrometry%SNP的电喷雾串联质谱研究

    Institute of Scientific and Technical Information of China (English)

    陈华勇; 宋任芳; 马慧敏

    2007-01-01

    采用电喷雾串联质谱技术对两组单核苷酸多态性(SNP)样品进行了研究,初步研究结果显示应用串联质谱可快速鉴定SNP分型以及确定SNP位点.采用16.3 mmol/L三乙胺(TEA)-400 mmol/L六氟异丙醇(HFIP)缓存溶液,电喷雾负离子模式下,长度为20 bp的寡核苷酸的MS扫描谱图显示其母离子呈较宽的多电荷态分布.选择低电荷态[M-4H]4-母离子,碰撞能为54 eV时,MS/MS扫描得到丰富的碎片离子,通过鉴定特征离子碎片(w和a-B离子系列)可确定其序列.

  3. Identification of bradykinin: related peptides from Phyllomedusa nordestina skin secretion using electrospray ionization tandem mass spectrometry after a single-step liquid chromatography

    OpenAIRE

    K Conceição; FM Bruni; JM Sciani; Konno, K; RL Melo; MM Antoniazzi; C Jared; M Lopes-Ferreira; DC Pimenta

    2009-01-01

    Amphibian skin secretions are a source of potential new drugs with medical and biotechnological applications. Rich in peptides produced by holocrine-type serous glands in the integument, these secretions play different roles, either in the regulation of physiological skin functions or in the defense against predators or microorganisms. The aim of the present work was to identify novel peptides with bradykinin-like structure and/or activity present in the skin of Phyllomedusa nordestina. In or...

  4. Structural Characterization and Identification of Major Constituents in Jitai Tablets by High-Performance Liquid Chromatography/Diode-Array Detection Coupled with Electrospray Ionization Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Weidong Zhang

    2012-09-01

    Full Text Available In the present study a universally applicable HPLC-DAD/ESI-MS/MS method was developed for carrying out the comprehensive characterization of Jitai tablets (JTT. Based on the ESI-MSn fragmentation patterns of the reference standards, a total of 101 components were identified or tentatively characterized by comparing their retention times, UV and MS spectra with those of reference standards or through the matching of empirical information with those of published components in the in-house library. The characteristic fragmentation pattern of alkaloids, phenolic acids, tanshinones, flavonoid glycosides, cyanogenic glycosides, ginsenosides, 2-(2-phenylethyl chromones, phthalides and gingerol-related compounds were tentatively elucidated using structurally-relevant product ions. It was observed that neutral losses of C9H10O3 and C9H8O2 were the characteristic product ions of scopola alkaloids. Neutral fragment mandelonitrile was the characteristic ion of cyanogenic glycosides. To our knowledge, tropylium ion and C4H2O unit were the characteristic ions of 2-(2-phenylethyl chromone, which resulted from the Retro-Diels-Alder (RDA cleavage of the C ring. The results indicated that the developed analysis method could be employed as a rapid, effective technique for structural characterization of chemical constituents in TCM. This work is expected to provide comprehensive information for the quality evaluation and pharmacokinetic studies of JTT.

  5. Quantitative analysis of 15N labeled positional isomers of glutamine and citrulline via electrospray ionization tandem mass spectrometry of their dansyl derivatives

    Science.gov (United States)

    The enteral metabolism of glutamine and citrulline are intertwined because, while glutamine is one of the main fuel sources for the enterocyte, citrulline is one of its products. It has been shown that the administration of 15N labeled glutamine results in the incorporation of the 15N label into cit...

  6. Structural Characterization and Identification of Major Constituents in Jitai Tablets by High-Performance Liquid Chromatography/Diode-Array Detection Coupled with Electrospray Ionization Tandem Mass Spectrometry

    OpenAIRE

    Weidong Zhang; Yaohua Hu; Lingling Wang; Lei Liu; Shuping Wang; Runhui Liu

    2012-01-01

    In the present study a universally applicable HPLC-DAD/ESI-MS/MS method was developed for carrying out the comprehensive characterization of Jitai tablets (JTT). Based on the ESI-MSn fragmentation patterns of the reference standards, a total of 101 components were identified or tentatively characterized by comparing their retention times, UV and MS spectra with those of reference standards or through the matching of empirical information with those of published componen...

  7. Structure determination of two conotoxins from Conus textile by a combination of matrix-assisted laser desorption/ionization time-of-flight and electrospray ionization mass spectrometry and biochemical methods

    DEFF Research Database (Denmark)

    Kalume, D E; Stenflo, J; Czerwiec, E;

    2000-01-01

    Two highly modified conotoxins from the mollusc Conus textile, epsilon-TxIX and Gla(1)-TxVI, were characterized by matrix-assisted laser desorption/ionization and electrospray mass spectrometry and also by electrospray ionization tandem and triple mass spectrometry in combination with enzymatic...

  8. Simultaneous quantification of purine and pyrimidine bases, nucleosides and their degradation products in bovine blood plasma by high performance liquid chromatography tandem mass spectrometry

    DEFF Research Database (Denmark)

    Nielsen, Charlotte Stentoft; Vestergaard, Mogens; Løvendahl, Peter;

    2014-01-01

    ), and their degradation products (uric acid, allantoin, β-alanine, β-ureidopropionic acid, β-aminoisobutyric acid) in blood plasma of dairy cows. The high performance liquid chromatography-based technique coupled to electrospray ionization tandem mass spectrometry (LC–MS/MS) was combined with individual...

  9. Subfractions of enamel matrix derivative differentially influence cytokine secretion from human oral fibroblasts.

    Science.gov (United States)

    Villa, Oscar; Brookes, Steven J; Thiede, Bernd; Heijl, Lars; Lyngstadaas, Staale P; Reseland, Janne E

    2015-01-01

    Enamel matrix derivative is used to promote periodontal regeneration during the corrective phase of the treatment of periodontal defects. Our main goal was to analyze the bioactivity of different molecular weight fractions of enamel matrix derivative. Enamel matrix derivative, a complex mixture of proteins, was separated into 13 fractions using size-exclusion chromatography and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and liquid chromatography-electrospray ionization-tandem mass spectrometry. Human periodontal ligament fibroblasts were treated with either enamel matrix derivative or the different fractions. Proliferation and cytokine secretion to the cell culture medium were measured and compared to untreated cells. The liquid chromatography-electrospray ionization-tandem mass spectrometry analyses revealed that the most abundant peptides were amelogenin and leucine-rich amelogenin peptide related. The fractions containing proteins above 20 kDa induced an increase in vascular endothelial growth factor and interleukin-6 secretion, whereas lower molecular weight fractions enhanced proliferation and secretion of interleukin-8 and monocyte chemoattractant protein-1 and reduced interleukin-4 release. The various molecular components in the enamel matrix derivative formulation might contribute to reported effects on tissue regeneration through their influence on vascularization, the immune response, and chemotaxis. PMID:26090085

  10. Oxidation of Intracellular and Extracellular Fatty Acids in Skeletal Muscle: Application of kinetic modeling, stable isotopes and liquid chromatography/electrospray ionization ion-trap tandem mass spectrometry technology

    OpenAIRE

    Xu, J; Zhou, L.; Persson, X-M.; Balagopal, P.; Jensen, M D; Guo, ZK.

    2008-01-01

    Fatty acids are a major fuel for many tissues and abnormal utilization is implicated in diseases. However, tissue fatty acid oxidation has not been determined reliably in vivo. Furthermore, fatty acid oxidation has not been partitioned into intracellular and extracellular components. In this report, a one-pool model is described that enables direct quantitation of fluxes of intracellular and plasma fatty acids to mitochondria in skeletal muscle using dual stable isotopes and liquid chromatogr...

  11. Transcription factor proteomics: identification by a novel gel mobility shift-three-dimensional electrophoresis method coupled with southwestern blot and high-performance liquid chromatography-electrospray-mass spectrometry analysis.

    Science.gov (United States)

    Jiang, Daifeng; Jia, Yinshan; Jarrett, Harry W

    2011-09-28

    Transcription factor (TF) purification and identification is an important step in elucidating gene regulatory mechanisms. In this study, we present two new electrophoretic mobility shift assay (EMSA)-based multi-dimensional electrophoresis approaches to isolate and characterize TFs, using detection with either southwestern or western blotting and HPLC-nanoESI-MS/MS analysis for identification. These new techniques involve several major steps. First, EMSA is performed with agents that diminish non-specific DNA-binding and the DNA-protein complex is separated by native PAGE gel. The gel is then electrotransferred to PVDF membrane and visualized by autoradiography. Next, the DNA-protein complex, which has been transferred onto the blot, is extracted using a detergent-containing elution buffer. Following detergent removal, concentrated extract is separated by SDS-PAGE (EMSA-2DE), followed by in-gel trypsin digestion and HPLC-nanoESI-MS/MS analysis, or the concentrated extract is separated by two-dimensional gel electrophoresis (EMSA-3DE), followed by southwestern or western blot analysis to localize DNA binding proteins on blot which are further identified by on-blot trypsin digestion and HPLC-nanoESI-MS/MS analysis. Finally, the identified DNA binding proteins are further validated by EMSA-immunoblotting or EMSA antibody supershift assay. This approach is used to purify and identify GFP-C/EBP fusion protein from bacterial crude extract, as well as purifying AP1 and CEBP DNA binding proteins from a human embryonic kidney cell line (HEK293) nuclear extract. AP1 components, c-Jun, Jun-D, c-Fos, CREB, ATF1 and ATF2 were successfully identified from 1.5 mg of nuclear extract (equivalent to 3×10(7) HEK293 cells) with AP1 binding activity of 750 fmol. In conclusion, this new strategy of combining EMSA with additional dimensions of electrophoresis and using southwestern blotting for detection proves to be a valuable approach in the identification of transcriptional complexes by proteomic methods. PMID:21880322

  12. Development, validation and application of a stable isotope dilution liquid chromatography electrospray ionization/selected reaction monitoring/mass spectrometry (SID-LC/ESI/SRM/MS) method for quantification of keto-androgens in human serum✩, ✩✩

    OpenAIRE

    Tamae, Daniel; Byrns, Michael; Marck, Brett; Mostaghel, Elahe A.; Peter S Nelson; de Lange, Paul; Lin, Daniel; Taplin, Mary-Ellen; Balk, Steven; Ellis, William; True, Larry; Vessella, Robert; Montgomery, Bruce; Blair, Ian A.; Penning, Trevor M.

    2013-01-01

    Prostate cancer is the most frequently diagnosed form of cancer in males in the United States. The disease is androgen driven and the use of orchiectomy or chemical castration, known as androgen deprivation therapy (ADT) has been employed for the treatment of advanced prostate cancer for over 70 years. Agents such as GnRH agonists and non-steroidal androgen receptor antagonists are routinely used in the clinic, but eventually relapse occurs due to the emergence of castration-resistant prostat...

  13. Identification of two-dimensional electrophoresis-separated proteins in human hepatoma cell by electrospray ion trap mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    As one of the most important analytical methods in proteome research, mass spectrometry was utilized to identify proteins separated by two-dimensional electrophoresis in the human hepatoma cell line BEL-7404. The protein spots were excised from the gel, followed by in-gel digestion, and the peptide mappings were analyzed by liquid chromatography electrospray ion trap mass spectrometer. Nine proteins were identified via database searching, according to the molecular weights and amino acid sequences of peptides, among which two proteins have not been identified in the other liver-cell database. The sequence coverage was 21%-72%. Furthermore, the relationship between the expressed proteins and the liver carcinoma was discussed.

  14. Quantification of salsolinol enantiomers by stable isotope dilution liquid chromatography with tandem mass spectrometric detection

    OpenAIRE

    Cai, Min; Liu, Yi-Ming

    2008-01-01

    Salsolinol, 1-methyl-6,7-dihydroxy-2,3,4,5-tetrahydroisoquinoline (SAL), is a precursor of a Parkinsonian neurotoxin, N-methysalsolinol (N-methyl-SAL). Previous studies have shown that individual enantiomers of N-methyl-SAL possess distinct neurotoxicological properties. In this work, a chiral high-performance liquid chromatography (HPLC) method with electrospray ionization tandem mass spectrometric (ESI-MS/MS) detection was developed for the quantification of (R/S)-SAL enantiomers. Enantiose...

  15. Analysis of tear glucose concentration with electrospray ionization mass spectrometry.

    Science.gov (United States)

    Taormina, Christopher R; Baca, Justin T; Asher, Sanford A; Grabowski, Joseph J; Finegold, David N

    2007-02-01

    We have developed a mass spectrometry-based method that allows one to accurately determine the glucose concentration of tear fluid. We used a 1 microL micro-capillary to collect tear fluid from the tear meniscus with minimal irritation of the eye. We analyzed the 1 muL volume of collected tear fluid with liquid-chromatography electrospray ionization mass spectrometry with the use of D-glucose-6,6-d2 as an internal standard. Repeated measurements and a recovery experiment on pooled, onion-induced tears showed that the analysis of the glucose in tears was precise (4% relative standard deviation) and provided 100% recovery. We found the tear glucose concentration of one fasting nondiabetic subject to be 13 to 51 microM while the onion-induced tear glucose concentration of a different nondiabetic subject to be 211 to 256 microM. PMID:17084090

  16. Isolation and characterization of wild-type lipoxygenase LOX(Psa)1 from Pleurotus sapidus.

    Science.gov (United States)

    Plagemann, Ina; Krings, Ulrich; Berger, Ralf G

    2014-01-01

    The lipoxygenase LOX(Psa) 1 of Pleurotus sapidus, originally investigated because of its ability to oxidize (+)-valencene to the valuable grapefruit aroma (+)-nootkatone, was isolated from the peptidase-rich lyophilisate using a three-step purification scheme including preparative isoelectric focusing and chromatographic techniques. Nano-liquid chromatography electrospray ionization tandem mass spectrometry (nLC-ESI-MS/MS) of the purified enzyme and peptide mass fingerprint analysis gave 38 peptides of the lipoxygenase from P. sapidus. Nearly 50% of the 643 amino acids long sequence encoded by the cDNA was covered. Both terminal peptides of the native LOX(Psa) 1 were identified by de novo sequencing, and the postulated molecular mass of 72.5 kDa was confirmed. With linoleic acid as the substrate, the LOX(Psa)1 showed a specific activity of 113 U mg(-1) and maximal activity at pH 7.0 and 30 degrees C, respectively. PMID:24873036

  17. Biochemical characterization of novel bioactive protein from silkworm (Bombyx mori L) fecal matter.

    Science.gov (United States)

    Raghavendra, R; Neelagund, S E

    2012-07-01

    In this study, complete purification and biochemical characterization of protein is presented. The protein was purified by using Sephadex G-75 gel filtration column followed by reverse-phase high-performance liquid chromatography in a C18 column. The molecular weight of the protein was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis, mass spectrum matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS) and liquid chromatography-electrospray ionization tandem mass spectrometry. Protein was fragmented by trypsin based on the m/z values obtained by MALDI-TOF-MS analysis. The peptide fragments sequence showed homology with DEAD-box-ATP-dependent RNA helicase 45, present in a public domain, National Centre for Biotechnology Information. The protein exhibited antibacterial activity against selected Gram +/- bacteria. The analgesic activity was determined by conducting acetic-acid-induced writhing test in mice. PMID:22328263

  18. Structural elucidation of in vitro and in vivo metabolites of emodin in rats by LC -ESI-MS/MS

    International Nuclear Information System (INIS)

    Emodin is a widely occurring natural product and has been studied extensively for its varieties of pharmacological activity. In attempt to know more deeply about its metabolism, this paper investigated the metabolites of emodin in rats, including its in vitro conversion product by intestinal microflora and urinary metabolites. The detection of emodin metabolites was performed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) with negative ion mode. By comparing the changes of metabolites in molecular masses (delta M), product ions and retention times with those of the parent drug, six metabolites (8-O-methylemodin, omega-hydroxyemodin, x-hydroxyemodin, emodin glucuronide, hydroxyemodin glucuronide and emodin sulfate) were observed,and what is more, the metabolite hydroxyemodin glucuronide was first reported in this article. For some metabolites, identification of their precise structure needs to be confirmed by other techniques such as the 1H and 13C NMR. (author)

  19. A validated method for quantitation of psilocin in plasma by LC-MS/MS and study of stability.

    Science.gov (United States)

    Martin, Rafaela; Schürenkamp, Jennifer; Pfeiffer, Heidi; Köhler, Helga

    2012-11-01

    A liquid chromatography-electrospray ionization/tandem mass spectrometry method for the quantitation of psilocin in plasma is presented. Sample workup was performed with mixed-mode solid-phase extraction using ascorbic acid and nitrogen for drying to protect the unstable analyte. Calibration curves were linear from 2 to 100 ng/mL, and no selectivity problems occurred. The limit of detection was 0.1 ng/mL, and the limit of quantitation was 0.34 ng/mL. Recovery was >86% and matrix effects were fridge improved sample stability significantly. Freezing of blood samples led to a not reproducible loss of psilocin. PMID:22138681

  20. Capsaicin production by Alternaria alternata, an endophytic fungus from Capsicum annum; LC-ESI-MS/MS analysis.

    Science.gov (United States)

    Devari, Shekaraiah; Jaglan, Sundeep; Kumar, Manjeet; Deshidi, Ramesh; Guru, Santosh; Bhushan, Shashi; Kushwaha, Manoj; Gupta, Ajai P; Gandhi, Sumit G; Sharma, Jai P; Taneja, Subhash C; Vishwakarma, Ram A; Shah, Bhahwal Ali

    2014-02-01

    Alternaria alternata, an endophytic fungus capable of producing capsaicin (1) was isolated from Capsicum annum. The endophyte was found to produce capsaicin upto three generations. Upscaling of the fermentation broth led to the isolation of one known and one compound characterized as 2,4-di-tert-butyl phenol (2) and alternariol-10-methyl ether (3) respectively. Compound 1 and 3 were identified and quantified using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) system through multiple reaction monitoring (MRM). Furthermore, compound 3 displayed a range of cytotoxicity against a panel of human cancer cell lines and was found to induce apoptosis evidenced by Hoechst staining and loss of mitochondrial-membrane potential in HL-60 cells. PMID:24378219

  1. METHOD 521: DETERMINATION OF NITROSAMINES IN DRINKING WATER BY SOLID PHASE EXTRACTION AND CAPILLARY COLUMN GAS CHROMATOGRAPHY WITH LARGE VOLUME INJECTION AND CHEMICAL IONIZATION TANDEM MASS SPECTROMETRY (MS/MS)

    Science.gov (United States)

    NDMA is an emerging drinking water contaminant that is of interest to EPA and the environmental community. Its presence in drinking water is a potential health concern, because the EPA's IRIS data base lists the concentration of NDMA required to result in a one in one million li...

  2. 纺织品中致癌性芳香胺的质谱成像%Imaging Carcinogenic Aromatic Amines in Textiles by Surface Desorption Atmospheric Pressure Chemical Ionization Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    丁丽英; 胡斌; 杨水平; 李建强; 陈焕文

    2010-01-01

    表面解析常压化学电离串联质谱(SDAPCI-MS~n)可以在无需样品预处理的条件下直接检测纺织品中存在的致癌性邻甲苯胺.在此基础上,分别以质子化邻甲苯胺(m/z 108)及其特征峰碎片离子(m/z 91)为探针,对穿过的衣服袖口进行二维质谱扫描,用不同颜色表示袖口上芳香胺信号强度的高低,在无损衣服的情况下获得该袖口上邻甲苯胺的质谱影像,从分子层次上对衣袖中邻甲苯胺的分布进行可视化表达,所成像图的空间分辨率达0.2 mm~2,对了解致癌性芳香胺在纺织品中的分布具有重要意义.

  3. The Rapid Identification of Momordica Saponin I from Semen Momordicae Using Electrospray Ionization Tandem Mass Spectrometry (SPI-MSn)%电喷雾多级串联质谱快速鉴定木鳖子皂苷

    Institute of Scientific and Technical Information of China (English)

    郭明全; 宋凤瑞; 商慧娟; 王道武; 刘志强; 刘淑莹

    2002-01-01

    利用电喷雾正负离子多级串联质谱相结合的方法,并结合皂苷部分醇解产物和皂苷元的质谱数据,鉴定了木鳖子皂苷的结构,推断了木鳖子皂苷的电喷雾质谱机理.

  4. Determination of sialic acids in immune system cells (coelomocytes) of sea urchin, Paracentrotus lividus, using capillary LC-ESI-MS/MS.

    Science.gov (United States)

    İzzetoğlu, Savaş; Şahar, Umut; Şener, Ecem; Deveci, Remziye

    2014-01-01

    Coelomocytes are considered to be immune effectors of sea urchins. Coelomocytes are the freely circulating cells in the body fluid contained in echinoderm coelom and mediate the cellular defence responses to immune challenges by phagocytosis, encapsulation, cytotoxicity and the production of antimicrobial agents. Coelomocytes have the ability to recognize self from non-self. Considering that sialic acids play important roles in immunity, we determined the presence of sialic acid types in coelomocytes of Paracentrotus lividus. Homogenized coelomocytes were kept in 2 M aqueous acetic acid at 80 °C for 3 h to liberate sialic acids. Sialic acids were determined by derivatization with 1,2-diamino-4,5-methylenediaoxy-benzene dihydrochloride (DMB) followed by capillary liquid-chromatography-electrospray ionization/tandem mass spectrometry (CapLC-ESI-MS/MS). Standard sialic acids; Neu5Ac, Neu5Gc, KDN and bovine submaxillary mucin showing a variety of sialic acids were used to confirm sialic acids types. We found ten different types of sialic acids (Neu5Gc, Neu5Ac, Neu5Gc9Ac, Neu5Gc8Ac, Neu5,9Ac2, Neu5,7Ac2, Neu5,8Ac2, Neu5,7,9Ac3, Neu5Gc7,9Ac2, Neu5Gc7Ac) isolated in limited amounts from total coelomocyte population. Neu5Gc type of sialic acids in coelomocytes was the most abundant type sialic acid when compared with other types. This is the first report on the presence of sialic acid types in coelomocytes of P. lividus using CapLC-ESI-MS/MS-Ion Trap system (Capillary Liquid Chromatography-Electrospray Ionization/Tandem Mass Spectrometry). PMID:24215912

  5. Tandem mass spectrometry of kahalalides: Identification of two new cyclic depsipeptides, kahalalide R and S from Elysia grandifolia

    Digital Repository Service at National Institute of Oceanography (India)

    Tilvi, S.; Naik, C.G.

    depsipeptide anticancer drug kahalalide F in human plasma by high-performance liquid chromatography under basic conditions coupled to electrospray ionization tandem mass spectrometry. J. Mass Spectrom. 2002; 37: 992. 39. Hanno S, Bernhard K, Matthias M... voltage-5700 V; Declustering potential (DP)-120V; Focusing potential (FP)-365V; Declustering potential (DP2)-14V and Collision gas (CAD) 3 (arbitrary units). Full-scan data acquisition was performed, scanning from m/z 100 to m/z 2000 in profile mode...

  6. Glycosylation characterization of therapeutic mAbs by top- and middle-down mass spectrometry

    Directory of Open Access Journals (Sweden)

    Bao Quoc Tran

    2016-03-01

    Full Text Available A reference monoclonal antibody IgG1 and a fusion IgG protein were analyzed by top- and middle-down mass spectrometry with multiple fragmentation techniques including electron transfer dissociation (ETD and matrix-assisted laser desorption ionization in-source decay (MALDI-ISD to investigate heterogeneity of glycosylated protein species. Specifically, glycan structure, sites, relative abundance levels, and termini structural conformation were investigated by use of Fourier transform ion cyclotron resonance (FT-ICR or high performance liquid chromatography electrospray ionization (HPLC-ESI linked to an Orbitrap. Incorporating a limited enzymatic digestion by immunoglobulin G-degrading enzyme Streptococcus pyogenes (IdeS with MALDI-ISD analysis extended sequence coverage of the internal region of the proteins without pre-fractionation. The data in this article is associated with the research article published in Journal of Proteomics (Tran et al., 2015 [1].

  7. Identification of phenolic constituents in red chicory salads (Cichorium intybus) by high-performance liquid chromatography with diode array detection and electrospray ionisation tandem mass spectrometry.

    Science.gov (United States)

    Carazzone, Chiara; Mascherpa, Dora; Gazzani, Gabriella; Papetti, Adele

    2013-06-01

    Phenolic acids and flavonoids extracted from several types of Cichorium intybus var. silvestre salads ("Chioggia", "Treviso", "Treviso tardivo", and "Verona") were characterised by high-performance liquid chromatography-electrospray ionisation/mass spectrometry. Among the 64 compounds detected, several hydroxycinnamic acid derivatives including 8 mono- and dicaffeoylquinic acids, 3 tartaric acid derivatives, 31 flavonol and 2 flavone glycosides, as well as 10 anthocyanins were characterised based on UV spectra and MS(n) fragmentation patterns. Furthermore, several isomers of caffeic acid derivatives were distinguished for the first time by their specific mass spectral data. This is the first study reporting the glycosylation type and position of mono- and diglycosylated flavonoids in red salads. PMID:23411215

  8. 高效液相色谱-电喷雾质谱法测定枳壳中黄酮苷类化合物%Analysis of Flavonoid Glycosides in Fructus Aurantii by High Performance Liquid Chromatography-Electrospray Ionization Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    周大勇; 徐青; 薛兴亚; 章飞芳; 梁鑫淼

    2006-01-01

    利用高效液相色谱与电喷雾质谱联用技术研究了枳壳中的黄酮苷类化合物.实验采用反相C18色谱柱,二元线性梯度洗脱,分离并检测了枳壳中的6种黄酮苷类化合物;它们分别是新圣草苷(neoeriocitrin)、异柚皮苷(isonaringin)、柚皮苷(naringin)、橙皮苷(hesperidin)、新橙皮苷(neohesperidin)和新枸橘苷(neoponcirin);通过与电喷雾质谱联用获得了这6种黄酮苷的准分子离子峰([M+H]+)及分子加钠峰([M+Na]+),利用质谱的碰撞诱导解离技术获得了碎片裂解信息.通过这此质谱信息并结合文献,对这6种化合物进行了结构鉴定.

  9. The study of radiation induced DNA-protein crosslinks by electrospray ionization mass spectrometry

    International Nuclear Information System (INIS)

    The authors have used peptide-thymine and histone-thymine solutions to model protein-DNA cross-linking chemistry induced in intact chromatin by low dosage of g-irradiation. Induced thymine crosslinking to model peptide systems has been evaluated by on-line liquid chromatography-electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (MS-MS) with sensitivity comparable or superior to conventional GC-MS determinations. Radiation damage at doses as low as 0.1 Gy can be detected by this method. Additionally, thymine modified H2B can also be examined by ESI-MS and tandem-MS of the intact protein and proteinase digests. Limited information on the sites of thymine crosslinking can be obtained by tandem mass spectrometry on the intact multiply charged molecular species. More detailed information on the sites of thymine-protein crosslinking is obtained by on-line LC-ESI-MS of selective proteolysis products of the modified histones. Further MS-MS experiments on the selective proteolysis products will reveal specific modified amino acids and their sequence location. These methods reveal the nature, extent and site of radiation induced modification of the oligopeptides. Studies are being extended to the examination of the radiation induced covalent interactions between histones and oligonucleotides in higher states of organization. The eventual object is to study DNA-protein crosslinking interactions in model and native genomic nucleosome systems

  10. Characterization of gallotannins from Astronium species by flow injection analysis- electrospray ionization-ion trap-tandem mass spectrometry and matrix-assisted laser desorption/ionization time-of- flight mass spectrometry.

    Science.gov (United States)

    da Silva, Viviane Cândida; Napolitano, Assunta; Eletto, Daniela; Rodrigues, Clenilson Martins; Pizza, Cosimo; Vilegas, Wagner

    2011-01-01

    The species Astronium urundeuva (Allemao) Engl. and Astronium graveolens Jacq., which are used in Brazilian folk medicine to treat allergies, inflammation, diarrhea and ulcers, were investigated for their composition. The aim of this study was to define a rapid and reliable analytical approach, based on the flow-injection analysis-electrospray ionization-ion trap-tandem mass spectrometry (FIA-ESI-IT-MS-MS) and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-ToF-MS), to investigate the full range of hydrolyzable tannins present in the extracts of these Astronium species. The MALDI-ToF-MS analysis allowed us to ascertain the presence of hydrolysable tannins in both Astronium species as a series of gallotannins with degrees of polymerization of 7 to 13 galloyl units. Moreover, the analysis by FIA-ESI-IT-MS-MS, as well as confirming this result and chemically defining gallotannins as galloylglucose compounds, highlighted the presence of further classes of hydrolysable tannins, such as hexahydrodiphenoyl esters of glucose and some gallic acid derivatives, providing information about their structure by a careful study of their fragmentation patterns. Finally, the evaluation of the number of positional isomers of gallotannins occurring in both Astronium species was obtained by high-performance liquid chromatography-electrospray ionization-ion trap mass spectrometry (HPLC/ESI-IT-MS). This is the first mass spectrometric evidence relating to the existence of gallotannins in Astronium genus. PMID:22006629

  11. Simultaneous determination of four designer drugs and their major metabolites by liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Chen, Xueguo

    2015-06-15

    A sensitive liquid chromatography-electrospray ionization-ion trap mass spectrometry (LC-ESI-ITMS) method was utilized for the simultaneous analysis of four designer drugs and their in vitro metabolites in rat liver microsome S9 fraction. Four designer drugs, including methcathinone (MC), 3,4-methylenedioxymethcathinone (MDMC), 3,4-methylenedioxy-pyrovalerone (MDPV) and 4'-methyl-α-pyrrolidinopropiophenone (MPPP), were individually incubated with rat liver microsome S9 fraction, and the incubation mixtures were pooled together and analyzed by LC-ESI-ITMS simultaneously. Besides four designer drugs, five of their main metabolites were identified via the analysis of protonated molecules and tandem mass spectrometry data. Meanwhile, the quantification analysis of four designer drugs in rat liver microsome S9 fraction was performed, the calibration curves showed good linearity in the range of 0.01-5.0μg/mL and the detection limits were below 0.03μg/mL with RSDs less than 5.9% and recovery ratios above 77.4%. The experimental results not only showed that these designer drugs could be easily metabolized in rat liver microsome, and also displayed the superiorities of the method including time and cost saving, high efficiency, sensitivity and selectivity. The studies in this study indicated that the approach could be applied in the determination of illicit drugs and their metabolites in medical, pharmaceutical and forensic investigations. PMID:25939091

  12. Ultra performance liquid chromatography tandem mass spectrometry performance evaluation for analysis of antibiotics in natural waters.

    Science.gov (United States)

    Tamtam, Fatima; Mercier, Fabien; Eurin, Joëlle; Chevreuil, Marc; Le Bot, Barbara

    2009-03-01

    An ultra performance liquid chromatography electrospray tandem mass spectrometry (UPLC/MS/MS) method was developed and validated for the determination of 17 antibiotics in natural waters in one single extraction and chromatographic procedure. Gradient separation conditions were optimised for 17 compounds belonging to five different antibiotic groups: quinolones (oxolinic acid, nalidixic acid, pipemidic acid, flumequine), fluoroquinolones (enoxacin, ciprofloxacin, norfloxacin, ofloxacin, enrofloxacin, sarafloxacin, danofloxacin, difloxacin, lomefloxacin), sulphonamides (sulphamethoxazole, sulphamethazine), nitro-imidazole (ornidazole) and diaminopyrimidine (trimethoprim). The separation of all compounds, obtained using a 1.7 microm particle size column (100 mm x 2.1 mm), was achieved within 10 min time. Water samples were adjusted to pH 7 and extracted using Oasis hydrophilic-lipophilic balance (HLB) solid phase extraction cartridges. After elution with methanol and concentration, extracts were injected in a C18 column (Acquity UPLC BEH C18) and detected by tandem mass spectrometry. Average recovery from 100 ng L(-1) fortified samples was higher than 70% for most of the compounds, with relative standard deviations below 20%. Performances of the method (recoveries, detection limit, quantification limit and relative standard deviation) and matrix effects were studied, and results obtained showed that method was suitable for routine analysis of antibiotics in surface water. Samples analysis from Seine River (France) confirmed the interest of antibiotic contamination evaluation in that area. PMID:19148627

  13. Screening of the polyphenol content of tomato-based products through accurate-mass spectrometry (HPLC-ESI-QTOF).

    Science.gov (United States)

    Vallverdú-Queralt, Anna; Jáuregui, Olga; Di Lecce, Giuseppe; Andrés-Lacueva, Cristina; Lamuela-Raventós, Rosa M

    2011-12-01

    Tomatoes, the second most important vegetable crop worldwide, are a key component in the so-called "Mediterranean diet" and its consumption has greatly increased worldwide over the past 2 decades, mostly due to a growing demand for tomato-based products such as ketchups, gazpachos and tomato juices. In this work, tomato-based products were analysed after a suitable work-up extraction procedure using liquid chromatography/electrospray ionisation-time of flight-mass spectrometry (HPLC-ESI-QTOF) with negative ion detection using information-dependent acquisition (IDA) to determine their phenolic composition. The compounds were confirmed by accurate mass measurements in MS and MS(2) modes. The elemental composition was selected according to the accurate masses and isotopic pattern. In this way, 47 compounds (simple phenolic and hydroxycinnamoylquinic acids and flavone, flavonol, flavanone and dihydrochalcone derivatives) were identified in tomato-based products, five of them, as far as was known, were previously unreported in tomatoes. The phenolic fingerprint showed that tomato-based products differ in phenolic composition, principally in protocatechuic acid-O-hexoside, apigenin and its glycosylated forms, quercetin-O-dihexoside, kaempferol-C-hexoside and eriodictyol-O-dihexoside. Gazpacho showed the highest number of phenolic compounds due to the vegetables added for its production. PMID:25212313

  14. Affinity labeling coupled with matrix assistant laser desorption tandem time of flight mass spectrometry for quantitative proteomies research

    Institute of Scientific and Technical Information of China (English)

    MENG Qingfang; ZHANG Yangjun; CAI Yun; QIAN Xiaohong

    2007-01-01

    A relative quantitative method for differential proteomics by cleavable isotope-coded atTmity tag (cICAT)and matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF-MS) was estab-lished. The accuracy and reproducibility of the method were evaluated by bovine serum albumin (BSA) digest as having a relative standard deviation of less than 30% and good reproducibility. The dynamic range was als0 evaluated by analyzing two mixtures of several standard proteins with dif-ferent concentration. The experimental results showed that in the dynamic range of 1:30, the quantitation error of the method was less than 30%. Although the quantitation error becomes very large when used beyond this range, it does not affect the derivation of information on the differential proteins. All the work provides an alternative method for differential proteomics analysis in biological samples from different origins.

  15. Isocratic Solid Phase Extraction-Liquid Chromatography (SPE-LC) Interfaced to High-Performance Tandem Mass Spectrometry for Rapid Protein Identification

    DEFF Research Database (Denmark)

    Hørning, Ole B; Kjeldsen, Frank; Theodorsen, Søren; Vorm, Ole; Jensen, Ole Nørregaard

    2008-01-01

    Reversed-phase liquid chromatography interfaced to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) allows analysis of very complex peptide mixtures at great sensitivity, but it can be very time-consuming, typically using 60 min, or more, per sample analysis. We recently introduced...... the isocratic solid phase extraction-liquid chromatography (SPE-LC) technology for rapid separation ( approximately 8 min) of simple peptide samples. We now extend these studies to demonstrate the potential of SPE-LC separation in combination with a hybrid linear ion trap-Orbitrap tandem mass...... spectrometer for efficient analysis of peptide samples in proteomics research. The system performance of SPE-LC-MS/MS was evaluated in terms of sensitivity and efficiency for the analysis of tryptic peptide digests obtained from samples consisting of up to 12 standard proteins. The practical utility of the...

  16. Urinary profile of methylprednisolone acetate metabolites in patients following intra-articular and intramuscular administration.

    Science.gov (United States)

    Panusa, Alessia; Regazzoni, Luca; Aldini, Giancarlo; Orioli, Marica; Giombini, Arrigo; Minghetti, Paola; Tranquilli, Carlo; Carini, Marina

    2011-04-01

    A study on urinary metabolites of methylprednisolone acetate (MPA) has been performed by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) in precursor ion scanning (PIS) and neutral loss (NL) modes. Patients suffering from joint inflammation have been treated with Depo-Medrol® (MPA marketed suspension, 40 mg) intra-articularly (IA) and after a wash-out period, intramuscularly (IM) at the same dose. Urine samples have been collected after both the administration routes. Metabolites were identified in PIS mode by setting the fragment ion at m/z 161 which is specific for MPA, methylprednisolone (MP), methylprednisolone hemisuccinate, and in NL mode by selecting the losses of 54, 72, 176 and 194 Da. The MP-related structure of each target ion detected in both the MS modes was then confirmed by MS/MS acquisitions, and by accurate mass experiments. By using this approach, 13 MPA metabolites (M1-M13) have been identified, nine already reported in the literature and four unknown and for which the chemical structures have been proposed. No differences in the metabolic pattern of MPA when administered IM or IA were observed. The relative abundances of metabolites compared with the internal standard (MP-D2) were monitored by multiple reaction monitoring analysis for 19 days after both the administration routes. PMID:21336796

  17. Major Alterations of Phosphatidylcholine and Lysophosphotidylcholine Lipids in the Substantia Nigra Using an Early Stage Model of Parkinson’s Disease

    Science.gov (United States)

    Farmer, Kyle; Smith, Catherine A.; Hayley, Shawn; Smith, Jeffrey

    2015-01-01

    Parkinson’s disease (PD) is a progressive neurodegenerative disease affecting the nigrostriatal pathway, where patients do not manifest motor symptoms until >50% of neurons are lost. Thus, it is of great importance to determine early neuronal changes that may contribute to disease progression. Recent attention has focused on lipids and their role in pro- and anti-apoptotic processes. However, information regarding the lipid alterations in animal models of PD is lacking. In this study, we utilized high performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) and novel HPLC solvent methodology to profile phosphatidylcholines and sphingolipids within the substantia nigra. The ipsilateral substantia nigra pars compacta was collected from rats 21 days after an infusion of 6-hydroxydopamine (6-OHDA), or vehicle into the anterior dorsal striatum. We identified 115 lipid species from their mass/charge ratio using the LMAPS Lipid MS Predict Database. Of these, 19 lipid species (from phosphatidylcholine and lysophosphotidylcholine lipid classes) were significantly altered by 6-OHDA, with most being down-regulated. The two lipid species that were up-regulated were LPC (16:0) and LPC (18:1), which are important for neuroinflammatory signalling. These findings provide a first step in the characterization of lipid changes in early stages of PD-like pathology and could provide novel targets for early interventions in PD. PMID:26274953

  18. Major Alterations of Phosphatidylcholine and Lysophosphotidylcholine Lipids in the Substantia Nigra Using an Early Stage Model of Parkinson's Disease.

    Science.gov (United States)

    Farmer, Kyle; Smith, Catherine A; Hayley, Shawn; Smith, Jeffrey

    2015-01-01

    Parkinson's disease (PD) is a progressive neurodegenerative disease affecting the nigrostriatal pathway, where patients do not manifest motor symptoms until >50% of neurons are lost. Thus, it is of great importance to determine early neuronal changes that may contribute to disease progression. Recent attention has focused on lipids and their role in pro- and anti-apoptotic processes. However, information regarding the lipid alterations in animal models of PD is lacking. In this study, we utilized high performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) and novel HPLC solvent methodology to profile phosphatidylcholines and sphingolipids within the substantia nigra. The ipsilateral substantia nigra pars compacta was collected from rats 21 days after an infusion of 6-hydroxydopamine (6-OHDA), or vehicle into the anterior dorsal striatum. We identified 115 lipid species from their mass/charge ratio using the LMAPS Lipid MS Predict Database. Of these, 19 lipid species (from phosphatidylcholine and lysophosphotidylcholine lipid classes) were significantly altered by 6-OHDA, with most being down-regulated. The two lipid species that were up-regulated were LPC (16:0) and LPC (18:1), which are important for neuroinflammatory signalling. These findings provide a first step in the characterization of lipid changes in early stages of PD-like pathology and could provide novel targets for early interventions in PD. PMID:26274953

  19. Major Alterations of Phosphatidylcholine and Lysophosphotidylcholine Lipids in the Substantia Nigra Using an Early Stage Model of Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Kyle Farmer

    2015-08-01

    Full Text Available Parkinson’s disease (PD is a progressive neurodegenerative disease affecting the nigrostriatal pathway, where patients do not manifest motor symptoms until >50% of neurons are lost. Thus, it is of great importance to determine early neuronal changes that may contribute to disease progression. Recent attention has focused on lipids and their role in pro- and anti-apoptotic processes. However, information regarding the lipid alterations in animal models of PD is lacking. In this study, we utilized high performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS and novel HPLC solvent methodology to profile phosphatidylcholines and sphingolipids within the substantia nigra. The ipsilateral substantia nigra pars compacta was collected from rats 21 days after an infusion of 6-hydroxydopamine (6-OHDA, or vehicle into the anterior dorsal striatum. We identified 115 lipid species from their mass/charge ratio using the LMAPS Lipid MS Predict Database. Of these, 19 lipid species (from phosphatidylcholine and lysophosphotidylcholine lipid classes were significantly altered by 6-OHDA, with most being down-regulated. The two lipid species that were up-regulated were LPC (16:0 and LPC (18:1, which are important for neuroinflammatory signalling. These findings provide a first step in the characterization of lipid changes in early stages of PD-like pathology and could provide novel targets for early interventions in PD.

  20. Characterization of aroma-active and phenolic profiles of wild thyme (Thymus serpyllum) by GC-MS-Olfactometry and LC-ESI-MS/MS.

    Science.gov (United States)

    Sonmezdag, Ahmet Salih; Kelebek, Hasim; Selli, Serkan

    2016-04-01

    The present study was designed to characterize the volatile, aroma-active and phenolic compounds of wild thyme. Volatile components of T. serpyllum were extracted by use of the purge and trap technique with dichloromethane and analyzed by gas chromatography-mass spectrometry (GC-MS). The extraction method gave highly representative aromatic extract of the studied sample based on the sensory analysis. A total of 24 compounds were identified and quantified in Thymus serpyllum. Terpenes were qualitatively and quantitatively the most dominant volatiles in the sample. Aroma extract dilution analysis (AEDA) was used for the first time for the determination of aroma-active compounds of Thymus serpyllum. In total, 12 aroma-active compounds were detected in the aromatic extract by GC-MS-Olfactometry and terpenes were the most abundant compounds. High-performance liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method was used for the phenolic compounds analysis. 18 phenolic compounds were identified and quantified in the T. serpyllum. Luteolin 7-O-glucoside, luteolin and rosmarinic acid were the most abundant phenolics in this herb. PMID:27413222

  1. Proteomic signature of the murine intervertebral disc.

    Directory of Open Access Journals (Sweden)

    Matthew R McCann

    Full Text Available Low back pain is the most common musculoskeletal problem and the single most common cause of disability, often attributed to degeneration of the intervertebral disc. Lack of effective treatment is directly related to our limited understanding of the pathways responsible for maintaining disc health. While transcriptional analysis has permitted initial insights into the biology of the intervertebral disc, complete proteomic characterization is required. We therefore employed liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS protein/peptide separation and mass spectrometric analyses to characterize the protein content of intervertebral discs from skeletally mature wild-type mice. A total of 1360 proteins were identified and categorized using PANTHER. Identified proteins were primarily intracellular/plasma membrane (35%, organelle (30%, macromolecular complex (10%, extracellular region (9%. Molecular function categorization resulted in three distinct categories: catalytic activity (33%, binding (molecule interactions (29%, and structural activity (13%. To validate our list, we confirmed the presence of 14 of 20 previously identified IVD-associated markers, including matrix proteins, transcriptional regulators, and secreted proteins. Immunohistochemical analysis confirmed distinct localization patterns of select protein with the intervertebral disc. Characterization of the protein composition of healthy intervertebral disc tissue is an important first step in identifying cellular processes and pathways disrupted during aging or disease progression.

  2. Identification of two new keratinolytic proteases from a Bacillus pumilus strain using protein analysis and gene sequencing.

    Science.gov (United States)

    Fellahi, Soltana; Chibani, Abdelwaheb; Feuk-Lagerstedt, Elisabeth; Taherzadeh, Mohammad J

    2016-12-01

    The Bacillus strain (CCUG 66887) has a high capacity to excrete keratinase with the ability to degrade both alpha- and beta keratin. In this study we aimed to show the characteristics of the keratinolytic protease and to identify its gene by using liquid chromatography-electrospray ionization tandem mass spectrometry methods (nanoHPLC-ESI-MS/MS) followed by Mascot data base search. The results showed that the enzyme in fact consists of two different keratinases, both with a molecular mass of 38 kDa. Further, DNA sequencing generated the open reading frame (ORF) of one of the genes (Ker1), and de novo genome sequencing identified the ORF of the second gene (Ker2). The two keratinase genes contain 1153 base pairs each and have a gene similarity of 67 %. In addition, the Bacillus strain was classified as Bacillus pumilus and its genes were annotated in the GeneBank at NCBI (accession: CP011109.1). Amino acid sequences alignment with known B. pumilus proteases indicated that the two keratinases of B. pumilus strain C4 are subtilisin-like serine proteases belonging to the Protease S8 family. Taken together, these result suggest the two keratinases as promising candidates for enzymatic processing of keratinous wastes in waste refinery. PMID:27363997

  3. Mass spectrometric studies on the interaction of cisplatin and insulin.

    Science.gov (United States)

    Li, Jing; Yue, Lei; Liu, Yaqin; Yin, Xinchi; Yin, Qi; Pan, Yuanjiang; Yang, Lirong

    2016-04-01

    The interaction of antitumor drug, cisplatin (cis-[PtCl2(NH3)2], CDDP) with insulin from porcine pancreas has been investigated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and high resolution hybrid ion trap/time-of-flight mass spectrometry (MALIDI-TOF/TOF-MS and ESI-IT/TOF MS). The MALDI-TOF/TOF-MS results demonstrated that the presence of cisplatin complex resulted in the reduction of the disulfide bond in porcine pancreas after the incubations of the two substances were performed in vitro. It indicated that the presence of cisplatin would destroy the native configuration of insulin, which may lead to the inactivation of insulin. High resolution mass values and the characteristic isotopic pattern of the platinated insulin ions allowed the analysis of platinated mono-, di- and triadducts of cisplatin and insulin in the incubations under different conditions. The laser-induced dissociation of the monoadduct obtained in MALDI source was carried out and one platinum was found to bind to insulin B chain was determined. The platinum binding sites were further identified to be the N terminus (B chain), cysteine 7 (B chain) and cysteine 19 (B chain) residues by electrospray ionization tandem mass spectrometry. The identification of the interaction between insulin and cisplatin broadens the horizon of the knowledge in the interaction of the proteins and metallodrugs. PMID:26724920

  4. Distribution of Heparan Sulfate Oligosaccharides in Murine Mucopolysaccharidosis Type IIIA

    Science.gov (United States)

    Mason, Kerryn; Meikle, Peter; Hopwood, John; Fuller, Maria

    2014-01-01

    Heparan sulfate (HS) catabolism begins with endo-degradation of the polysaccharide to smaller HS oligosaccharides, followed by the sequential action of exo-enzymes to reduce these oligosaccharides to monosaccharides and inorganic sulfate. In mucopolysaccharidosis type IIIA (MPS IIIA) the exo-enzyme, N-sulfoglucosamine sulfohydrolase, is deficient resulting in an inability to hydrolyze non-reducing end glucosamine N-sulfate esters. Consequently, partially degraded HS oligosaccharides with non-reducing end glucosamine sulfate esters accumulate. We investigated the distribution of these HS oligosaccharides in tissues of a mouse model of MPS IIIA using high performance liquid chromatography electrospray ionization-tandem mass spectrometry. Oligosaccharide levels were compared to total uronic acid (UA), which was used as a measure of total glycosaminoglycan. Ten oligosaccharides, ranging in size from di- to hexasaccharides, were present in all the tissues examined including brain, spleen, lung, heart, liver, kidney and urine. However, the relative levels varied up to 10-fold, suggesting different levels of HS turnover and storage. The relationship between the di- and tetrasaccharides and total UA was tissue specific with spleen and kidney showing a different disaccharide:total UA ratio than the other tissues. The hexasaccharides showed a stronger correlation with total UA in all tissue types suggesting that hexasaccharides may more accurately reflect the storage burden in these tissues. PMID:25513953

  5. Pharmacokinetics/pharmacodynamic correlations of fluconazole in murine model of cryptococcosis.

    Science.gov (United States)

    Santos, Julliana Ribeiro Alves; César, Isabela Costa; Costa, Marliete Carvalho; Ribeiro, Noelly Queiroz; Holanda, Rodrigo Assunção; Ramos, Lais Hott; Freitas, Gustavo José Cota; Paixão, Tatiane Alves; Pianetti, Gerson Antônio; Santos, Daniel Assis

    2016-09-20

    The emergence of fluconazole-resistant Cryptococcus gattii is a global concern, since this azole is the main antifungal used worldwide to treat patients with cryptococcosis. Although pharmacokinetic (PK) and pharmacodynamic (PD) indices are useful predictive factors for therapeutic outcomes, there is a scarcity of data regarding PK/PD analysis of antifungals in cryptococcosis caused by resistant strains. In this study, PK/PD parameters were determined in a murine model of cryptococcosis caused by resistant C. gattii. We developed and validated a suitable liquid chromatography-electrospray ionization tandem mass spectrometry method for PK studies of fluconazole in the serum, lungs, and brain of uninfected mice. Mice were infected with susceptible or resistant C. gattii, and the effects of different doses of fluconazole on the pulmonary and central nervous system fungal burden were determined. The peak levels in the serum, lungs, and brain were achieved within 0.5h. The AUC/MIC index (area under the curve/minimum inhibitory concentration) was associated with the outcome of anti-cryptococcal therapy. Interestingly, the maximum concentration of fluconazole in the brain was lower than the MIC for both strains. In addition, the treatment of mice infected with the resistant strain was ineffective even when high doses of fluconazole were used or when amphotericin B was tested, confirming the cross-resistance between these drugs. Altogether, our novel data provide the correlation of PK/PD parameters with antifungal therapy during cryptococcosis caused by resistant C. gattii. PMID:27235581

  6. LC/ESI-MS/MS method for determination of salivary eicosapentaenoic acid concentration to arachidonic acid concentration ratio.

    Science.gov (United States)

    Ogawa, Shoujiro; Tomaru, Koki; Matsumoto, Nagisa; Watanabe, Shui; Higashi, Tatsuya

    2016-01-01

    A simple liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) method for determination of the eicosapentaenoic acid (EPA) concentration to arachidonic acid (AA) concentration ratio in human saliva has been developed. The EPA/AA ratio in serum or plasma is widely recognized as a useful indicator in identifying the risk of cardiovascular disease, especially atherosclerosis. The salivary EPA/AA ratio is expected to be a convenient alternative to the serum or plasma EPA/AA ratio, because saliva offers the advantages of easy and noninvasive sampling. The saliva was deproteinized with acetonitrile, purified using an Oasis HLB cartridge, and derivatized with 1-[(4-dimethylaminophenyl)carbonyl]piperazine (DAPPZ). The derivatized EPA and AA were subjected to LC/ESI-MS/MS, and the EPA/AA ratio was determined using the selected reaction monitoring mode. The DAPPZ-derivatization increased the ESI sensitivity by 100- and 300-fold for EPA and AA, respectively, and enabled the detection of trace fatty acids in saliva using a 200 μL sample. The assay reproducibility was satisfactory (relative standard deviation, <5.0%). The method was successfully applied to the measurement of the salivary EPA/AA ratios of healthy Japanese subjects and their changes owing to the supplementation of EPA. PMID:25620210

  7. A new LC-ESI-MS/MS method to measure long-chain acylcarnitine levels in cultured cells

    International Nuclear Information System (INIS)

    The quantitative evaluation of long-chain acylcarnitines in lipid extracts from cultured cells or tissues is a prerequisite to study carnitine palmitoyltransferase (CPT) activity. There is thus a need for the accurate measurement of the concentration of long-chain acylcarnitines at the lowest concentration present in lipid extracts. Here we report a fast and reliable quantitative method based on the use of weak acid extraction and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) to quantify acylcarnitines through hydrophilic interaction chromatography. The method was validated using isotopic dilution and the results allow the analysis of a large number of samples at low concentration levels (down to 0.35 nmol L-1 for palmitoylcarnitine) with good inter- and intra-day precision. The method was used for the quantitative study of changes in concentration of palmitoylcarnitine and other acylcarnitines in PC-12 cells over-expressing CPT1a gene. It was also used to measure CPT1 activity in mitochondria isolated from transfected cells, giving similar results to the more common radiometric method, but with higher sensitivity

  8. The Role of P-Glycoprotein in Transport of Danshensu across the Blood-Brain Barrier

    Directory of Open Access Journals (Sweden)

    Peng-Fei Yu

    2011-01-01

    Full Text Available Danshensu (3-(3, 4-dihydroxyphenyl lactic acid, a water-soluble active component isolated from the root of Salvia miltiorrhiza Bunge, is widely used for the treatment of cerebrovascular diseases. The present study aims to investigate the role of P-glycoprotein in transport of Danshensu across the blood-brain barrier. Sprague-Dawley rats were pretreated with verapamil at a dose of 20 mg kg−1 (verapamil group or the same volume of normal saline (control group. Ninety minutes later, the animals were administrated with Danshensu (15 mg kg−1 by intravenous injection. At 15 min, 30 min, and 60 min after Danshensu administration, the levels of Danshensu in the blood and brain were detected by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS. The results showed that Danshensu concentrations in the brain of the rats pretreated with verapamil were significantly increased. In addition, the brain-plasma ratios of the group pretreated with verapamil were much higher than that of the control group. There was no difference in Danshensu level in plasma between the verapamil group and control group. The findings indicated that Danshensu can pass the blood-brain barrier, and P-glycoprotein plays an important role in Danshensu transportation in brain.

  9. N-methylated tryptamine derivatives in citrus genus plants: identification of N,N,N-trimethyltryptamine in bergamot.

    Science.gov (United States)

    Servillo, Luigi; Giovane, Alfonso; Balestrieri, Maria Luisa; Cautela, Domenico; Castaldo, Domenico

    2012-09-19

    The occurrence of N-methylated tryptamine derivatives in bergamot plant (Citrus bergamia Risso et Poit) is reported for the first time. Interestingly, the most abundant of these substances is N,N,N-trimethyltryptamine, which has not been previously identified in any citrus plant. The N-methylated tryptamine derivatives were identified and quantitated in leaves, peel, juice, and seeds by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. N,N,N-Trimethyltryptamine was confirmed by MS(3) and comparison with the synthesized authentic standard. In addition, the study of the distribution of tryptophan, tryptamine, N-methyltryptamine, N,N-dimethyltryptamine, and N,N,N-trimethyltryptamine indicated that these compounds are differently expressed in the various tissues of the bergamot plant. Intriguingly, chemically synthesized N,N,N-trimethyltryptamine was reported to possess nicotine-like activity being a stimulant of parasympathetic ganglia by exerting its action on acetylcholine receptors. On this basis, the identification of N,N,N-trimethyltryptamine at a relatively high level in leaves suggests a possible role in a physiological mechanism of plant defense. PMID:22957740

  10. A sensitive LC-ESI-MS/MS method for the quantification of avobenzone in rat plasma and skin layers: Application to a topical administration study.

    Science.gov (United States)

    Kim, Min Gi; Kim, Tae Hwan; Shin, Beom Soo; Kim, Min Gyu; Seok, Su Hyun; Kim, Kyu-Bong; Lee, Jong Bong; Choi, Hyeon Gwan; Lee, Young Sung; Yoo, Sun Dong

    2015-10-15

    This study describes the development of a sensitive high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the quantification of avobenzone in rat plasma and skin layers. Separations were performed on a Zorbax SB C8 column using a binary gradient mobile phase composed of acetonitrile and 0.1% formic acid in water. The assay achieved LLOQ of 0.5ng/ml for plasma, 5ng/ml for stratum corneum, and 10ng/ml for epidermis and dermis. This method was applied to a percutaneous absorption study of avobenzone in rats. At 12h following topical application of emulsion and lotion (applied amount of avobenzone 11.7mg/kg), avobenzone was found primarily in the stratum corneum (16.3-17.8%) followed by epidermis (2.0-3.4%) and dermis (0.11-0.15%). Avobenzone was not quantifiable in the plasma samples collected over a 12h sampling period. Given the excellent plasma assay sensitivity, this study provides evidence that the systemic absorption of avobenzone is insignificant, if any, after topical application. PMID:26409261

  11. Phytohormone Involvement in the Ustilago maydis- Zea mays Pathosystem: Relationships between Abscisic Acid and Cytokinin Levels and Strain Virulence in Infected Cob Tissue.

    Directory of Open Access Journals (Sweden)

    Erin N Morrison

    Full Text Available Ustilago maydis is the causative agent of common smut of corn. Early studies noted its ability to synthesize phytohormones and, more recently these growth promoting substances were confirmed as cytokinins (CKs. Cytokinins comprise a group of phytohormones commonly associated with actively dividing tissues. Lab analyses identified variation in virulence between U. maydis dikaryon and solopathogen infections of corn cob tissue. Samples from infected cob tissue were taken at sequential time points post infection and biochemical profiling was performed using high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI MS/MS. This hormone profiling revealed that there were altered levels of ABA and major CKs, with a marked reduction in CK glucosides, increases in methylthiol CKs and a particularly dramatic increase in cisZ CK forms, in U. maydis infected tissue. These changes were more pronounced in the more virulent dikaryon relative to the solopathogenic strain suggesting a role for cytokinins in moderating virulence during biotrophic infection. These findings highlight the fact that U. maydis does not simply mimic a fertilized seed but instead reprograms the host tissue. Results underscore the suitability of the Ustilago maydis- Zea mays model as a basis for investigating the control of phytohormone dynamics during biotrophic infection of plants.

  12. Chemical derivatization for enhancing sensitivity during LC/ESI-MS/MS quantification of steroids in biological samples: a review.

    Science.gov (United States)

    Higashi, Tatsuya; Ogawa, Shoujiro

    2016-09-01

    Sensitive and specific methods for the detection, characterization and quantification of endogenous steroids in body fluids or tissues are necessary for the diagnosis, pathological analysis and treatment of many diseases. Recently, liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) has been widely used for these purposes due to its specificity and versatility. However, the ESI efficiency and fragmentation behavior of some steroids are poor, which lead to a low sensitivity. Chemical derivatization is one of the most effective methods to improve the detection characteristics of steroids in ESI-MS/MS. Based on this background, this article reviews the recent advances in chemical derivatization for the trace quantification of steroids in biological samples by LC/ESI-MS/MS. The derivatization in ESI-MS/MS is based on tagging a proton-affinitive or permanently charged moiety on the target steroid. Introduction/formation of a fragmentable moiety suitable for the selected reaction monitoring by the derivatization also enhances the sensitivity. The stable isotope-coded derivatization procedures for the steroid analysis are also described. PMID:26454158

  13. Fast Simultaneous Determination of 13 Nucleosides and Nucleobases in Cordyceps sinensis by UHPLC-ESI-MS/MS.

    Science.gov (United States)

    Zong, Shi-Yu; Han, Han; Wang, Bing; Li, Ning; Dong, Tina Ting-Xia; Zhang, Tong; Tsim, Karl W K

    2015-01-01

    A reliable ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS) method for the fast simultaneous determination of 13 nucleosides and nucleobases in Cordyceps sinensis (C. sinensis) with 2-chloroadenosine as internal standard was developed and validated. Samples were ultrasonically extracted in an ice bath thrice, and the optimum analyte separation was performed on an ACQUITY UPLC(TM) HSS C18 column (100 mm × 2.1 mm, 1.8 μm) with gradient elution. All targeted analytes were separated in 5.5 min. Furthermore, all calibration curves showed good linear regression (r > 0.9970) within the test ranges, and the limits of quantitation and detection of the 13 analytes were less than 150 and 75 ng/mL, respectively. The relative standard deviations (RSDs) of intra- and inter-day precisions were <6.23%. Recoveries of the quantified analytes ranged within 85.3%-117.3%, with RSD < 6.18%. The developed UHPLC-ESI-MS/MS method was successfully applied to determine nucleosides and nucleobases in 11 batches of C. sinensis samples from different regions in China. The range for the total content in the analyzed samples was 1329-2057 µg/g. PMID:26690105

  14. Analysis and occurrence of seven artificial sweeteners in German waste water and surface water and in soil aquifer treatment (SAT).

    Science.gov (United States)

    Scheurer, Marco; Brauch, Heinz-J; Lange, Frank T

    2009-07-01

    A method for the simultaneous determination of seven commonly used artificial sweeteners in water is presented. The analytes were extracted by solid phase extraction using Bakerbond SDB 1 cartridges at pH 3 and analyzed by liquid chromatography electrospray ionization tandem mass spectrometry in negative ionization mode. Ionization was enhanced by post-column addition of the alkaline modifier Tris(hydroxymethyl)amino methane. Except for aspartame and neohesperidin dihydrochalcone, recoveries were higher than 75% in potable water with comparable results for surface water. Matrix effects due to reduced extraction yields in undiluted waste water were negligible for aspartame and neotame but considerable for the other compounds. The widespread distribution of acesulfame, saccharin, cyclamate, and sucralose in the aquatic environment could be proven. Concentrations in two influents of German sewage treatment plants (STPs) were up to 190 microg/L for cyclamate, about 40 microg/L for acesulfame and saccharin, and less than 1 microg/L for sucralose. Removal in the STPs was limited for acesulfame and sucralose and >94% for saccharin and cyclamate. The persistence of some artificial sweeteners during soil aquifer treatment was demonstrated and confirmed their environmental relevance. The use of sucralose and acesulfame as tracers for anthropogenic contamination is conceivable. In German surface waters, acesulfame was the predominant artificial sweetener with concentrations exceeding 2 microg/L. Other sweeteners were detected up to several hundred nanograms per liter in the order saccharin approximately cyclamate > sucralose. PMID:19533103

  15. Development and validation of an LC-MS/MS method for the determination of SB-505124 in rat plasma: Application to pharmacokinetic study.

    Science.gov (United States)

    Jiang, Jiayu; Zhang, Yuandong; Zhang, Quan; Li, Yanping; Gong, Tao; Zhang, Zhirong; Ding, Rui; Sun, Xun

    2016-01-01

    A sensitive, selective and rapid liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-MS/MS) method has been developed for the quantification of the novel transforming growth factor-β (TGF-β) inhibitor SB-505124 in rat plasma and then validated. Plasma samples were prepared by simple protein precipitation. Separation was performed on a Diamonsil ODS chromatography column using a mobile phase of acetonitrile and 0.1% (v/v) aqueous formic acid. SB-505124 and the internal standard doxorubicin were detected in the positive ion mode using multiple reaction monitoring of the transitions at m/z 336.2→320.1 and 544.2→397.2, respectively. Calibration curve was linear (r>0.9996) over a concentration range of 10-5000 ng/mL with the lower quantification limit of 10 ng/mL. Both intra- and inter-day precision were within 6.5% and trueness were not more than 3.1%. Extraction recovery and matrix effect were within acceptable limits. Stability tests showed that SB-505124 and the IS remained stable throughout the analytical procedure. The validated LC-MS/MS method was then used to analyze the pharmacokinetics of SB-505124 administered to rats intravenously (8 mg/kg) or orally (10 mg/kg). Oral bioavailability of SB-505124 was calculated as 76.4%, indicating the potential of SB-505124 as an orally administered drug. PMID:26363490

  16. Lack of tissue accumulation of grape seed flavanols after daily long-term administration in healthy and cafeteria-diet obese rats.

    Science.gov (United States)

    Margalef, Maria; Pons, Zara; Iglesias-Carres, Lisard; Bravo, Francisca Isabel; Muguerza, Begoña; Arola-Arnal, Anna

    2015-11-18

    After ingestion flavanols are metabolized by phase-II enzymes and the microbiota and are distributed throughout the body depending on several factors. Herein we aim to evaluate whether flavanols are tissue-accumulated after the long-term administration of a grape seed polyphenol extract (GSPE) in rats and to study if compounds present in tissues differ in a cafeteria-diet obesity state. For that, plasma, liver, mesenteric white adipose tissue (MWAT), brain, and aorta flavanol metabolites from standard chow-diet-fed (ST) and cafeteria-diet-fed (CAF) rats were analyzed by high-performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) 21 h after the last 12-week-daily GSPE (100 mg/kg) dosage. Results showed that long-term GSPE intake did not trigger a flavanol tissue accumulation, indicating a clearance of products at each daily dosage. Therefore, results suggest that polyphenol benefits in a disease state would be due to a daily pulsatile effect. Moreover, obesity induced by diet also influences the metabolism and bioavailability of flavanols in rats. PMID:26496863

  17. Degradation of Swainsonine by the NADP-Dependent Alcohol Dehydrogenase A1R6C3 in Arthrobacter sp. HW08

    Directory of Open Access Journals (Sweden)

    Yan Wang

    2016-05-01

    Full Text Available Swainsonine is an indolizidine alkaloid that has been found in locoweeds and some fungi. Our previous study demonstrated that Arthrobacter sp. HW08 or its crude enzyme extract could degrade swainsonie efficiently. However, the mechanism of swainsonine degradation in bacteria remains unclear. In this study, we used label-free quantitative proteomics method based on liquid chromatography-electrospray ionization-tandem mass spectrometry to dissect the mechanism of swainsonine biodegradation by Arthrobacter sp. HW08. The results showed that 129 differentially expressed proteins were relevant to swainsonine degradation. These differentially expressed proteins were mostly related to the biological process of metabolism and the molecular function of catalytic activity. Among the 129 differentially expressed proteins, putative sugar phosphate isomerase/epimerase A1R5X7, Acetyl-CoA acetyltransferase A0JZ95, and nicotinamide adenine dinucleotide phosphate (NADP-dependent alcohol dehydrogenase A1R6C3 were found to contribute to the swainsonine degradation. Notably, NADP-dependent alcohol dehyrodgenase A1R6C3 appeared to play a major role in degrading swainsonine, but not as much as Arthrobacter sp. HW08 did. Collectively, our findings here provide insights to understand the mechanism of swainsonine degradation in bacteria.

  18. Morpho-physiological response of Populus alba to erythromycin: A timeline of the health status of the plant.

    Science.gov (United States)

    Pierattini, Erika Carla; Francini, Alessandra; Raffaelli, Andrea; Sebastiani, Luca

    2016-11-01

    Populus alba Villafranca clone was chosen for a proof of concept study to determine the potential uptake and accumulation of antibiotics by trees. Plants were grown hydroponically and irrigated with a recirculating Hoagland's nutrient solution (control) and Hoagland's nutrient solution fortified with erythromycin at 0.01, 0.1 and 1mgL(-1). After 3 and 28days of treatment, poplar plants were separated into roots, stem, and leaves. Plants showed good health all over the period of treatment, and no differences in poplar growth for all the concentrations of erythromycin tested were observed. Quantification of erythromycin was performed using liquid chromatography electrospray ionization tandem mass spectrometry (LC-MS/MS) in positive ion mode using multiple reaction ion monitoring. Erythromycin was detected in all organs analyzed. Roots showed an erythromycin concentration tenfold higher than leaves. The photochemical efficiency of photosystem II did not show a dose-dependant trend. From the quenching analysis of chlorophyll fluorescence, low nonphotochemical quenching (NPQ) and high photochemical quenching (qP) for the first week of erythromycin exposure was observed, depending on leaves position along the stem. Results suggest a short term adaptation of the photosynthetic apparatus of Populus alba in response to environmental realistic erythromycin concentrations. PMID:27366984

  19. A new LC-ESI-MS/MS method to measure long-chain acylcarnitine levels in cultured cells

    Energy Technology Data Exchange (ETDEWEB)

    Jauregui, Olga [Scientific and Technical Services, University of Barcelona (Spain); Sierra, Adriana Y.; Carrasco, Patricia; Gratacos, Esther [Molecular and Cellular Unit, School of Health Sciences, International University of Catalonia (Spain); Hegardt, Fausto G. [Department of Biochemistry and Molecular Biology, University of Barcelona, School of Pharmacy (Spain); Casals, Nuria [Molecular and Cellular Unit, School of Health Sciences, International University of Catalonia (Spain)], E-mail: ncasals@csc.uic.es

    2007-09-05

    The quantitative evaluation of long-chain acylcarnitines in lipid extracts from cultured cells or tissues is a prerequisite to study carnitine palmitoyltransferase (CPT) activity. There is thus a need for the accurate measurement of the concentration of long-chain acylcarnitines at the lowest concentration present in lipid extracts. Here we report a fast and reliable quantitative method based on the use of weak acid extraction and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) to quantify acylcarnitines through hydrophilic interaction chromatography. The method was validated using isotopic dilution and the results allow the analysis of a large number of samples at low concentration levels (down to 0.35 nmol L{sup -1} for palmitoylcarnitine) with good inter- and intra-day precision. The method was used for the quantitative study of changes in concentration of palmitoylcarnitine and other acylcarnitines in PC-12 cells over-expressing CPT1a gene. It was also used to measure CPT1 activity in mitochondria isolated from transfected cells, giving similar results to the more common radiometric method, but with higher sensitivity.

  20. Application of LC-MS/MS MRM to Determine Staphylococcal Enterotoxins (SEB and SEA) in Milk

    Science.gov (United States)

    Andjelkovic, Mirjana; Tsilia, Varvara; Rajkovic, Andreja; De Cremer, Koen; Van Loco, Joris

    2016-01-01

    Staphylococcus aureus is one of the important aetiological agents of food intoxications in Europe and can cause gastro-enteritis through the production of various staphylococcal enterotoxins (SEs) in foods. Due to their stability and ease of production and dissemination, some SEs have also been studied as potential agents for bioterrorism. Therefore, specific and accurate analytical tools are required to detect and quantify SEs. Online solid-phase extraction liquid chromatography electrospray ionization tandem mass spectrometry (online SPE-LC-ESI-MS/MS) based on multiple reaction monitoring (MRM) was used to detect and quantify two types of SE (A and B) spiked in milk and buffer solution. SE extraction and concentration was performed according to the European Screening Method developed by the European Reference Laboratory for Coagulase Positive Staphylococci. Trypsin digests were screened for the presence of SEs using selected proteotypic heavy-labeled peptides as internal standards. SEA and SEB were successfully detected in milk samples using LC-MS/MS in MRM mode. The selected SE peptides were proteotypic for each toxin, allowing the discrimination of SEA and SEB in a single run. The detection limit of SEA and SEB was approximately 8 and 4 ng/g, respectively. PMID:27104569

  1. Application of LC-MS/MS MRM to Determine Staphylococcal Enterotoxins (SEB and SEA in Milk

    Directory of Open Access Journals (Sweden)

    Mirjana Andjelkovic

    2016-04-01

    Full Text Available Staphylococcus aureus is one of the important aetiological agents of food intoxications in Europe and can cause gastro-enteritis through the production of various staphylococcal enterotoxins (SEs in foods. Due to their stability and ease of production and dissemination, some SEs have also been studied as potential agents for bioterrorism. Therefore, specific and accurate analytical tools are required to detect and quantify SEs. Online solid-phase extraction liquid chromatography electrospray ionization tandem mass spectrometry (online SPE-LC-ESI-MS/MS based on multiple reaction monitoring (MRM was used to detect and quantify two types of SE (A and B spiked in milk and buffer solution. SE extraction and concentration was performed according to the European Screening Method developed by the European Reference Laboratory for Coagulase Positive Staphylococci. Trypsin digests were screened for the presence of SEs using selected proteotypic heavy-labeled peptides as internal standards. SEA and SEB were successfully detected in milk samples using LC-MS/MS in MRM mode. The selected SE peptides were proteotypic for each toxin, allowing the discrimination of SEA and SEB in a single run. The detection limit of SEA and SEB was approximately 8 and 4 ng/g, respectively.

  2. Application of LC-MS/MS MRM to Determine Staphylococcal Enterotoxins (SEB and SEA) in Milk.

    Science.gov (United States)

    Andjelkovic, Mirjana; Tsilia, Varvara; Rajkovic, Andreja; De Cremer, Koen; Van Loco, Joris

    2016-01-01

    Staphylococcus aureus is one of the important aetiological agents of food intoxications in Europe and can cause gastro-enteritis through the production of various staphylococcal enterotoxins (SEs) in foods. Due to their stability and ease of production and dissemination, some SEs have also been studied as potential agents for bioterrorism. Therefore, specific and accurate analytical tools are required to detect and quantify SEs. Online solid-phase extraction liquid chromatography electrospray ionization tandem mass spectrometry (online SPE-LC-ESI-MS/MS) based on multiple reaction monitoring (MRM) was used to detect and quantify two types of SE (A and B) spiked in milk and buffer solution. SE extraction and concentration was performed according to the European Screening Method developed by the European Reference Laboratory for Coagulase Positive Staphylococci. Trypsin digests were screened for the presence of SEs using selected proteotypic heavy-labeled peptides as internal standards. SEA and SEB were successfully detected in milk samples using LC-MS/MS in MRM mode. The selected SE peptides were proteotypic for each toxin, allowing the discrimination of SEA and SEB in a single run. The detection limit of SEA and SEB was approximately 8 and 4 ng/g, respectively. PMID:27104569

  3. Distribution of Heparan Sulfate Oligosaccharides in Murine Mucopolysaccharidosis Type IIIA

    Directory of Open Access Journals (Sweden)

    Kerryn Mason

    2014-12-01

    Full Text Available Heparan sulfate (HS catabolism begins with endo-degradation of the polysaccharide to smaller HS oligosaccharides, followed by the sequential action of exo-enzymes to reduce these oligosaccharides to monosaccharides and inorganic sulfate. In mucopolysaccharidosis type IIIA (MPS IIIA the exo-enzyme, N-sulfoglucosamine sulfohydrolase, is deficient resulting in an inability to hydrolyze non-reducing end glucosamine N-sulfate esters. Consequently, partially degraded HS oligosaccharides with non-reducing end glucosamine sulfate esters accumulate. We investigated the distribution of these HS oligosaccharides in tissues of a mouse model of MPS IIIA using high performance liquid chromatography electrospray ionization-tandem mass spectrometry. Oligosaccharide levels were compared to total uronic acid (UA, which was used as a measure of total glycosaminoglycan. Ten oligosaccharides, ranging in size from di- to hexasaccharides, were present in all the tissues examined including brain, spleen, lung, heart, liver, kidney and urine. However, the relative levels varied up to 10-fold, suggesting different levels of HS turnover and storage. The relationship between the di- and tetrasaccharides and total UA was tissue specific with spleen and kidney showing a different disaccharide:total UA ratio than the other tissues. The hexasaccharides showed a stronger correlation with total UA in all tissue types suggesting that hexasaccharides may more accurately reflect the storage burden in these tissues.

  4. Methionine sulfoxide profiling of milk proteins to assess the influence of lipids on protein oxidation in milk.

    Science.gov (United States)

    Wüst, Johannes; Pischetsrieder, Monika

    2016-06-15

    Thermal treatment of milk and milk products leads to protein oxidation, mainly the formation of methionine sulfoxide. Reactive oxygen species, responsible for the oxidation, can be generated by Maillard reaction, autoxidation of sugars, or lipid peroxidation. The present study investigated the influence of milk fat on methionine oxidation in milk. For this purpose, quantitative methionine sulfoxide profiling of all ten methionine residues of β-lactoglobulin, α-lactalbumin, and αs1-casein was carried out by ultrahigh-performance liquid chromatography-electrospray ionization tandem mass spectrometry with scheduled multiple reaction monitoring (UHPLC-ESI-MS/MS-sMRM). Analysis of defatted and regular raw milk samples after heating for up to 8 min at 120 °C and analysis of ultrahigh-temperature milk samples with 0.1%, 1.5%, and 3.5% fat revealed that methionine oxidation of the five residues of the whey proteins and of residues M 123, M 135, and M 196 of αs1-casein was not affected or even suppressed in the presence of milk fat. Only the oxidation of residues M 54 and M 60 of αs1-casein was promoted by lipids. In evaporated milk samples, formation of methionine sulfoxide was hardly influenced by the fat content of the samples. Thus, it can be concluded that lipid oxidation products are not the major cause of methionine oxidation in milk. PMID:26927981

  5. Degradation of Swainsonine by the NADP-Dependent Alcohol Dehydrogenase A1R6C3 in Arthrobacter sp. HW08

    Science.gov (United States)

    Wang, Yan; Zhai, A’guan; Zhang, Yanqi; Qiu, Kai; Wang, Jianhua; Li, Qinfan

    2016-01-01

    Swainsonine is an indolizidine alkaloid that has been found in locoweeds and some fungi. Our previous study demonstrated that Arthrobacter sp. HW08 or its crude enzyme extract could degrade swainsonie efficiently. However, the mechanism of swainsonine degradation in bacteria remains unclear. In this study, we used label-free quantitative proteomics method based on liquid chromatography-electrospray ionization-tandem mass spectrometry to dissect the mechanism of swainsonine biodegradation by Arthrobacter sp. HW08. The results showed that 129 differentially expressed proteins were relevant to swainsonine degradation. These differentially expressed proteins were mostly related to the biological process of metabolism and the molecular function of catalytic activity. Among the 129 differentially expressed proteins, putative sugar phosphate isomerase/epimerase A1R5X7, Acetyl-CoA acetyltransferase A0JZ95, and nicotinamide adenine dinucleotide phosphate (NADP)-dependent alcohol dehydrogenase A1R6C3 were found to contribute to the swainsonine degradation. Notably, NADP-dependent alcohol dehyrodgenase A1R6C3 appeared to play a major role in degrading swainsonine, but not as much as Arthrobacter sp. HW08 did. Collectively, our findings here provide insights to understand the mechanism of swainsonine degradation in bacteria. PMID:27196926

  6. Trace analysis of antidepressant pharmaceuticals and their select degradates in aquatic matrixes by LC/ESI/MS/MS

    Science.gov (United States)

    Schultz, M.M.; Furlong, E.T.

    2008-01-01

    Treated wastewater effluent is a potential environmental point source for antidepressant pharmaceuticals. A quantitative method was developed for the determination of trace levels of antidepressants in environmental aquatic matrixes using solid-phase extraction coupled with liquid chromatography- electrospray ionization tandem mass spectrometry. Recoveries of parent antidepressants from matrix spiking experiments for the individual antidepressants ranged from 72 to 118% at low concentrations (0.5 ng/L) and 70 to 118% at high concentrations (100 ng/L) for the solid-phase extraction method. Method detection limits for the individual antidepressant compounds ranged from 0.19 to 0.45 ng/L. The method was applied to wastewater effluent and samples collected from a wastewater-dominated stream. Venlafaxine was the predominant antidepressant observed in wastewater and river water samples. Individual antidepressant concentrations found in the wastewater effluent ranged from 3 (duloxetine) to 2190 ng/L (venlafaxine), whereas individual concentrations in the waste-dominated stream ranged from 0.72 (norfluoxetine) to 1310 ng/L (venlafaxine). ?? 2008 American Chemical Society.

  7. Determination of Glimepiride in Human Plasma by Liquid Chromatography

    International Nuclear Information System (INIS)

    A sensitive method for quantitation of glimepiride in human plasma has been established using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS). Glipizide was used as an internal standard. Glimepiride and internal standard in plasma sample was extracted using diethyl etherethyl acetate (1 : 1). A centrifuged upper layer was then evaporated and reconstituted with the mobile phase of acetonitrile-5 mM ammonium acetate (60:40, pH 3.0). The reconstituted samples were injected into a C18 reversed-phase column. Using MS/MS in the multiple reaction monitoring (MRM) mode, glimepiride and glipizide were detected without severe interference from human plasma matrix. Glimepiride produced a protonated precursor ion ([M+H]+) at m/z 491 and a corresponding product ion at m/z 352. And the internal standard produced a protonated precursor ion ([M+H]+) at m/z 446 and a corresponding product ion at m/z 321. Detection of glimepiride in human plasma by the LC-ESI/MS/MS method was accurate and precise with a quantitation limit of 0.1 ng/mL. The validation, reproducibility, stability, and recovery of the method were evaluated. The method has been successfully applied to pharmacokinetic studies of glimepiride in human plasma

  8. Determination of Glimepiride in Human Plasma by Liquid Chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ho Hyun; Lee, Hee Joo [Seoul Clinical Laboratories, Seoul (Korea, Republic of); Chang, Kyu Young [Korean Biochip Society, Seoul (Korea, Republic of); Han, Sang Beom [ChungAng University, Seoul (Korea, Republic of)

    2004-01-15

    A sensitive method for quantitation of glimepiride in human plasma has been established using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS). Glipizide was used as an internal standard. Glimepiride and internal standard in plasma sample was extracted using diethyl etherethyl acetate (1 : 1). A centrifuged upper layer was then evaporated and reconstituted with the mobile phase of acetonitrile-5 mM ammonium acetate (60:40, pH 3.0). The reconstituted samples were injected into a C{sub 18} reversed-phase column. Using MS/MS in the multiple reaction monitoring (MRM) mode, glimepiride and glipizide were detected without severe interference from human plasma matrix. Glimepiride produced a protonated precursor ion ([M+H]{sup +}) at m/z 491 and a corresponding product ion at m/z 352. And the internal standard produced a protonated precursor ion ([M+H]{sup +}) at m/z 446 and a corresponding product ion at m/z 321. Detection of glimepiride in human plasma by the LC-ESI/MS/MS method was accurate and precise with a quantitation limit of 0.1 ng/mL. The validation, reproducibility, stability, and recovery of the method were evaluated. The method has been successfully applied to pharmacokinetic studies of glimepiride in human plasma

  9. Simultaneous determination of human plasma protein binding of bioactive flavonoids in Polygonum orientale by equilibrium dialysis combined with UPLC-MS/MS

    Institute of Scientific and Technical Information of China (English)

    Yong Huang; Yong-Lin Wang; Hui Chen; Feng He; Zhi-Rong Zhang; Lin Zheng; Yue Liu; Yan-Yu Lan; Shang-Gao Liao; Yong-Jun Li

    2013-01-01

    A simple and selective ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) assay was developed for the determination of the human plasma protein binding of four bioactive flavonoids (such as orientin and vitexin) in Polygonum orientale. Protein precipitation was used for sample preparation. Equilibrium dialysis technique was applied to determine the plasma protein binding under physiological conditions. The separation was achieved through a Waters C18 column with a mobile phase composed of 0.1%formic acid in acetonitrile and 0.1%aqueous formic acid using step gradient elution at a flow rate of 0.35 mL/min. A Waters ACQUITY™TQD system was operated under the multiple reaction monitoring (MRM) mode of positive electrospray ionization. All of the recovery, precision, accuracy and stability of the method met the requirements. Good correlations (r40.99) of the four compounds were found, which suggested that these compounds can be simultaneously determined with acceptable accuracy. Results showed that the plasma protein bindings of the four bioactive flavonoids were in the range of 74-89% over the six concentrations studied. The binding parameters containing protein binding affinity, protein binding dissociation constant, and protein binding site were studied. The maximum ability to bind with protein was also determined in the assay in order to understand the drug-protein binding of each compound better.

  10. Evaluation of analytical methodology for the detection of hormones and their attenuation during aquifer recharge and recovery cycles.

    Science.gov (United States)

    de Lima Stebbins, Daniela; Docs, Jon; Lowe, Paula; Cohen, Jason; Lei, Hongxia

    2016-05-18

    The hormones listed in the screening survey list 2 of the Unregulated Contaminant Monitoring Rule 3 (estrone, 17-β-estradiol, 17-α-ethynylestradiol, 16-α-hydroxyestradiol (estriol), equilin, testosterone and 4-androstene-3,17-dione) were analyzed by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Two analytical methods were compared: EPA method 539 and the isotope dilution method. EPA method 539 was successfully utilized in river and drinking water matrices with fortified recoveries of 98.9 to 108.5%. Samples from the Hillsborough River reflected levels below the method detection limit (MDL) for the majority of the analytes, except estrone (E1), which was detected at very low concentrations (aquifer storage and recovery (ASR) water samples as a result of strong matrix/solid phase extraction (SPE) losses observed in these more complex matrices. Most of the compounds were not detected or found at relatively low concentrations in the ASR samples. Attenuation of 50 to 99.1% was observed as a result of the ASR recharge/recovery cycles for most of the hormones, except for estriol (E3). Relatively stable concentrations of E3 were found, with only 10% attenuation at one of the sites and no measureable attenuation at another location. These results have substantiated that while EPA method 539 works well for most environmental samples, the isotope dilution method is more robust when dealing with complex matrices such as reclaimed and ASR samples. PMID:27146029

  11. Methods for determination of fingernail steroids by LC/MS/MS and differences in their contents between right and left hands.

    Science.gov (United States)

    Higashi, Tatsuya; Yamagata, Kenichiro; Kato, Yuina; Ogawa, Yu; Takano, Kaori; Nakaaze, Yutaro; Iriyama, Takashi; Min, Jun Zhe; Ogawa, Shoujiro

    2016-05-01

    Fingernail clipping is expected to be a specimen for steroid testing, because it has several advantages over blood; i.e., noninvasive collection, ease of storage, portability and handling, and possibility for an assessment of the steroid status over a relatively long and retrospective time window. In this study, we examined whether there is a difference in the nail contents between the right and left hands for five steroids [glycochenodeoxycholic acid (GCDCA), taurochenodeoxycholic acid (TCDCA), dehydroepiandrosterone sulfate (DHEAS), testosterone (TST) and cortisol (CRT)] using newly developed liquid chromatography/electrospray ionization-tandem mass spectrometry methods. The nail contents between the hands were significantly different for GCDCA, TCDCA and DHEAS, whereas those of TST and CRT only slightly differed. These results might be due to the difference in the binding affinity of each steroid for the nail keratin. The relatively hydrophilic steroids, GCDCA, TCDCA and DHEAS, may be lost from nails in daily life due to their low affinity for keratin, which would produce differences in the nail contents between the hands. Thus, the fingernail GCDCA, TCDCA and DHEAS contents may be influenced by factors other than the disease; the nail analysis is inefficient in the diagnosis of the disease associated with these steroids. On the other hand, the nail analysis looks promising for evaluation of the status of TST and CRT, which are lipophilic and inferred to be tightly bound to the keratin. In fact, the nail TST content showed a significant sex difference, just like its serum/plasma concentration. PMID:26898540

  12. Leukotrienes in exhaled breath condensate and fractional exhaled nitric oxide in workers exposed to TiO2 nanoparticles.

    Science.gov (United States)

    Pelclova, Daniela; Zdimal, Vladimir; Kacer, Petr; Fenclova, Zdenka; Vlckova, Stepanka; Komarc, Martin; Navratil, Tomas; Schwarz, Jaroslav; Zikova, Nadezda; Makes, Otakar; Syslova, Kamila; Belacek, Jaroslav; Zakharov, Sergey

    2016-01-01

    Human health data regarding exposure to nanoparticles are extremely scarce and biomonitoring of exposure is lacking in spite of rodent pathological experimental data. Potential markers of the health-effects of engineered nanoparticles were examined in 30 workers exposed to TiO2 aerosol, 22 office employees of the same plant, and 45 unexposed controls. Leukotrienes (LT) B4, C4, E4, and D4 were analysed in the exhaled breath condensate (EBC) and urine via liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Fractional exhaled nitric oxide (FeNO) and spirometry was also measured. The median particle number concentration of the aerosol in the production ranged from 1.98  ×  10(4) to 2.32  ×  10(4) particles cm(-3); about 80% of the particles were  spirometry significant impairment in the workers was seen only for %VCIN and %PEF (both p  Spirometry was not sensitive enough. PMID:27356965

  13. Evaluation of relative isotopic abundance measurements in a quadrupole time-of-flight mass spectrometer for elemental composition determination of natural products in traditional Chinese medicine.

    Science.gov (United States)

    Wu, Zhi-Jun; Huo, Jia-Li; Chen, Jian-Zhong; Li, Na; Fang, Dong-Mei; Chen, Xiao-Zhen; Zhang, Guo-Lin; Wang, Jian-Hua; Xu, Xiao-Ying

    2013-01-01

    The relative isotopic abundance (RIA) measurement errors of a quadrupole time-of-flight (Q-ToF) instrument incorporating analog-to-digital converter detectors were systemically evaluated by stochastically collecting about 200 data in positive ion mass spectrometry (MS) mode. Errors varied with peak intensities at definite spectral acquisition rates but were very close, even if peak intensities changed sharply at different spectral acquisition rates with the same concentration. Intensity thresholds were systematically defined at 1 Hz of spectral acquisition rates. RIA measurement errors were also evaluated using peak area. It seemed that peak area was better adapted for the high-intensity ions while peak intensity was suited for very low-intensity ions. Several known compounds were selected for RIA measurements for product ions in tandem mass spectropmetry (MS/MS) mode. An extract of a representative traditional Chinese medicinal, Paederia scandens was analyzed with high-performance liquid chromatography-electrospray ionization-QToF-MS/MS. The unique elemental compositions of some compounds could not be identified even with exact masses and MS/MS spectra of measured and reference compounds. RIA errors, especially of (M+2)M(-1), provided vital information for determining the elemental composition. PMID:24261081

  14. A new multiplex method for the diagnosis of peroxisomal disorders allowing simultaneous determination of plasma very-long-chain fatty acids, phytanic, pristanic, docosahexaenoic and bile acids by high-performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry.

    Science.gov (United States)

    Semeraro, Michela; Rizzo, Cristiano; Boenzi, Sara; Cappa, Marco; Bertini, Enrico; Antonetti, Giacomo; Dionisi-Vici, Carlo

    2016-07-01

    Peroxisomal disorders (PDs) present with wide phenotypic variability. An appropriate diagnosis requires a complete analysis of peroxisomal metabolites. We developed a multiplex LC-MS/MS method, using atmospheric pressure chemical ionization allowing the simultaneous determination in plasma of very-long-chain fatty acids, phytanic, pristanic, docosahexaenoic acids and di- and tri-hydroxycolestanoic bile acids. Two hundred microliters of plasma extracted with acetonitrile and 200μl extracted with hexane after an acid hydrolysis were combined, evaporated, dissolved in 10μl of methanol and analyzed. The acquisition was in negative-ion mode using multiple reaction monitoring. The method was validated analytically and clinically. Linearity was 0.1-200μmol/l for docosanoic, cis-13-docosenoic, tetracosanoic, cis-15-tetracosenoic and phytanic acids; 0.01-10μmol/l for hexacosanoic acid; 0.02-20μmol/l for di-hydroxycolestanoic, tri-hydroxycolestanoic and pristanic acids; 0.3-300μmol/l for docosahexaenoic acid. Intra-day and inter-day CVs were below 3.88 and 3.98 respectively for all compounds. Samples from patients with known peroxisomal disorders were compared with controls and the method allowed to confirm the diagnosis in all subjects with a 100% sensitivity. The advantage of this multiplex method is to allow in a single chromatographic run the simultaneous determination of a large number of peroxisome biomarkers with a simple preparative phase without derivatization. PMID:27189059

  15. Elucidating collision induced dissociation products and reaction mechanisms of protonated uracil by coupling chemical dynamics simulations with tandem mass spectrometry experiments.

    Science.gov (United States)

    Molina, Estefanía Rossich; Ortiz, Daniel; Salpin, Jean-Yves; Spezia, Riccardo

    2015-12-01

    In this study we have coupled mixed quantum-classical (quantum mechanics/molecular mechanics) direct chemical dynamics simulations with electrospray ionization/tandem mass spectrometry experiments in order to achieve a deeper understanding of the fragmentation mechanisms occurring during the collision induced dissociation of gaseous protonated uracil. Using this approach, we were able to successfully characterize the fragmentation pathways corresponding to ammonia loss (m/z 96), water loss (m/z 95) and cyanic or isocyanic acid loss (m/z 70). Furthermore, we also performed experiments with isotopic labeling completing the fragmentation picture. Remarkably, fragmentation mechanisms obtained from chemical dynamics simulations are consistent with those deduced from isotopic labeling. PMID:26634967

  16. Coupling Charge Reduction Mass Spectrometry to Liquid Chromatography for Complex Mixture Analysis.

    Science.gov (United States)

    Stutzman, John R; Crowe, Matthew C; Alexander, James N; Bell, Bruce M; Dunkle, Melissa N

    2016-04-01

    Electrospray ionization (ESI) of solution mixtures often generates complex mass spectra, even following liquid chromatography (LC), due to analyte multiple charging. Multiple charge state distributions can lead to isobaric interferences, mass spectral congestion, and ambiguous ion identification. As a consequence, data interpretation increases in complexity. Several charge reduction mass spectrometry (MS) approaches have been previously developed to reduce the average charge state of gaseous ions; however, all of these techniques have been restricted to direct infusion MS. In this study, synthetic polyols and surfactants separated by liquid chromatography and ionized by positive mode ESI have been subjected to polonium-210 α-particle radiation to reduce the average charge state to singly charged cations prior to mass analysis. LC/MS analysis of 5000 molecular weight poly(ethylene glycol) (PEG5000) generated an average charge state of 5.88+; whereupon, liquid chromatography/electrospray ionization/charge reduction/mass spectrometry (LC/CR/MS) analysis of PEG 5000 generated an average charge state of 1.00+. The PEG5000 results demonstrated a decrease in spectral complexity and enabled facile interpretation. Other complex solution mixtures representing specific MS challenges (i.e., competitive ionization and isobaric ion overlap) were explored and analyzed with LC/CR/MS to demonstrate the benefits of coupling LC to CR/MS. For example, polyol information related to initiator, identity/relative amount of monomer, and estimated molecular weight was characterized in random and triblock ethylene oxide/propylene oxide polyols using LC/CR/MS. LC/CR/MS is a new analytical technique for the analysis of complex mixtures. PMID:26971559

  17. Identification of degradation products of indigoids by tandem mass spectrometry.

    Science.gov (United States)

    Witkoś, Katarzyna; Lech, Katarzyna; Jarosz, Maciej

    2015-11-01

    The study concerns identification of photodegradation products of indigotin, indirubin and isoindigo. Experimental methodology consists of degradation of standard solutions of indigoids in a solar box and analysis of samples taken at different aging time by using capillary high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometric and spectrophotometric detectors. Identification of the formed compounds was based on careful interpretation of the electrospray ionization MS/MS spectra. Apart from the well-known degradation products of indigoids: isatin, isatoic anhydride and anthranilic acid, another seven species were also identified, and their proposed structures were confirmed by high-resolution molecular masses measurements; according to the best knowledge of authors, they have not been reported so far. The obtained results formed the basis for postulating mechanism of the process. Moreover, the MRM (Multiple Reaction Monitoring) method was developed for the identification of natural dyes and their degradation products in textiles of historical value. Apart from such colorants as indigotin and flavonoids, also presence of degradation products of indigoids was confirmed. PMID:26505769

  18. Quantitative Mass Spectrometry for Bacterial Protein Toxins — A Sensitive, Specific, High-Throughput Tool for Detection and Diagnosis

    Directory of Open Access Journals (Sweden)

    Suzanne Kalb

    2011-03-01

    Full Text Available Matrix-assisted laser-desorption time-of-flight (MALDI-TOF mass spectrometry (MS is a valuable high-throughput tool for peptide analysis. Liquid chromatography electrospray ionization (LC-ESI tandem-MS provides sensitive and specific quantification of small molecules and peptides. The high analytic power of MS coupled with high-specificity substrates is ideally suited for detection and quantification of bacterial enzymatic activities. As specific examples of the MS applications in disease diagnosis and select agent detection, we describe recent advances in the analyses of two high profile protein toxin groups, the Bacillus anthracis toxins and the Clostridium botulinum neurotoxins. The two binary toxins produced by B. anthracis consist of protective antigen (PA which combines with lethal factor (LF and edema factor (EF, forming lethal toxin and edema toxin respectively. LF is a zinc-dependent endoprotease which hydrolyzes specific proteins involved in inflammation and immunity. EF is an adenylyl cyclase which converts ATP to cyclic-AMP. Toxin-specific enzyme activity for a strategically designed substrate, amplifies reaction products which are detected by MALDI-TOF-MS and LC-ESI-MS/MS. Pre-concentration/purification with toxin specific monoclonal antibodies provides additional specificity. These combined technologies have achieved high specificity, ultrasensitive detection and quantification of the anthrax toxins. We also describe potential applications to diseases of high public health impact, including Clostridium difficile glucosylating toxins and the Bordetella pertussis adenylyl cyclase.

  19. Sequence characterization and glycosylation sites identification of donkey milk lactoferrin by multiple enzyme digestions and mass spectrometry.

    Science.gov (United States)

    Gallina, Serafina; Cunsolo, Vincenzo; Saletti, Rosaria; Muccilli, Vera; Di Francesco, Antonella; Foti, Salvatore; Lorenzten, Andrea Maria; Roepstorff, Peter

    2016-07-01

    Lactoferrin, a protein showing an array of biochemical properties, including immuno-modulation, iron-binding ability, as well as antioxidant, antibacterial and antiviral activities, but which may also represent a potential milk allergen, was isolated from donkey milk by ion exchange chromatography. The characterization of its primary structure, by means of enzymatic digestions, SPITC derivatization of tryptic digest, reversed-phase high performance liquid chromatography, electrospray and matrix-assisted laser desorption/ionization mass spectrometry, is reported. Our results allowed the almost complete characterization of donkey lactoferrin sequence, that, at least for the covered sequence, differs from the horse genomic deduced sequence (UniProtKB Acc. Nr. O77811) by five point substitutions located at positions 91 (Arg → His), 328 (Thr → Ile/Leu), 466 (Ala → Gly), 642 (Asn → Ser) and 668 (Ser → Ala). Analysis of the glycosylated protein showed that glycans in donkey lactoferrin are linked to the protein backbone via an amide bond to asparagine residues located at the positions 137, 281 and 476. PMID:27020775

  20. Global characterization of the photosynthetic glycerolipids from a marine diatom Stephanodiscus sp. by ultra performance liquid chromatography coupled with electrospray ionization-quadrupole-time of flight mass spectrometry.

    Science.gov (United States)

    Xu, Jilin; Chen, Deying; Yan, Xiaojun; Chen, Juanjuan; Zhou, Chengxu

    2010-03-17

    The photosynthetic glycerolipids composition of algae is crucial for structural and physiological aspects. In this work, a comprehensive characterization of the photosynthetic glycerolipids of the diatom Stephanodiscus sp. was carried out by ultra performance liquid chromatography-electrospray ionization-quadrupole-time of flight mass spectrometry (UPLC-ESI-Q-TOF MS). By use of the MS(E) data collection mode, the Q-TOF instrument offered a very viable alternative to triple quadrupoles for precursor ion scanning of photosynthetic glycerolipids and had the advantage of high efficiency, selectivity, sensitivity and mass accuracy. Characteristic fragment ions were utilized to identify the structures and acyl compositions of photosynthetic glycerolipids. Comparing the abundance of fragment ions, it was possible to determine the position of the sn-glycerol-bound fatty acyl chains. As a result, four classes of photosynthetic glycerolipid in the extract of Stephanodiscus sp. were unambiguously identified, including 16 monogalactosyldiacylglycerols (MGDGs), 9 digalactosyldiacylglycerols (DGDGs), 23 sulfoquinovosyldiacylglycerols (SQDGs) and 8 phosphatidylglycerols (PGs). As far as our knowledge, this is the first report on global identification of photosynthetic glycerolipids, including lipid classes, fatty acyl composition within lipids and the location of fatty acids in lipids (sn-1 vs. sn-2), in the extract of marine microalgae by UPLC-ESI-Q-TOF MS directly. PMID:20172098

  1. Structural Characterization of New Peptide Variants Produced by Cyanobacteria from the Brazilian Atlantic Coastal Forest Using Liquid Chromatography Coupled to Quadrupole Time-of-Flight Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Miriam Sanz

    2015-06-01

    Full Text Available Cyanobacteria from underexplored and extreme habitats are attracting increasing attention in the search for new bioactive substances. However, cyanobacterial communities from tropical and subtropical regions are still largely unknown, especially with respect to metabolite production. Among the structurally diverse secondary metabolites produced by these organisms, peptides are by far the most frequently described structures. In this work, liquid chromatography/electrospray ionization coupled to high resolution quadrupole time-of-flight tandem mass spectrometry with positive ion detection was applied to study the peptide profile of a group of cyanobacteria isolated from the Southeastern Brazilian coastal forest. A total of 38 peptides belonging to three different families (anabaenopeptins, aeruginosins, and cyanopeptolins were detected in the extracts. Of the 38 peptides, 37 were detected here for the first time. New structural features were proposed based on mass accuracy data and isotopic patterns derived from full scan and MS/MS spectra. Interestingly, of the 40 surveyed strains only nine were confirmed to be peptide producers; all of these strains belonged to the order Nostocales (three Nostoc sp., two Desmonostoc sp. and four Brasilonema sp..

  2. Optimized verification method for detection of an albumin-sulfur mustard adduct at Cys(34) using a hybrid quadrupole time-of-flight tandem mass spectrometer after direct plasma proteolysis.

    Science.gov (United States)

    John, Harald; Siegert, Markus; Gandor, Felix; Gawlik, Michael; Kranawetvogl, Andreas; Karaghiosoff, Konstantin; Thiermann, Horst

    2016-02-26

    The vesicant sulfur mustard (SM) is a banned chemical warfare agent that is controlled by the Organisation for the Prohibition of Chemical Weapons (OPCW). Bioanalytical procedures are mandatory for proving an alleged use and incorporation of SM into the body. We herein present the development and application of a novel optimized procedure suitable for qualitative verification analysis of plasma targeting the SM-adduct of human serum albumin (HSA) alkylated at the cysteine(34) residue. Diluted human plasma is directly mixed with pronase in an ultrafiltration device (10kDa cut-off) for proteolysis (4h, 37°C). Following ultrafiltration the filtrate is diluted and analyzed by microbore liquid chromatography-electrospray ionization high resolution tandem-mass spectrometry (μLC-ESI HR MS/MS) targeting the alkylated dipeptide hydroxyethylthioethyl-CysPro (HETE-CP). A hybrid quadrupole time-of-flight mass spectrometer provided high mass spectrometric resolution in the MS/MS mode enabling highest selectivity and sensitivity (lower limit of detection corresponding to 9.8nM SM in plasma). Kinetics of HETE-CP formation from heparin-, citrate-, and EDTA-plasma as well as serum are presented and the influence of different EDTA and pronase concentrations was characterized. The novel procedure was applied to plasma samples provided by the OPCW as well as to patientś plasma derived from real cases of SM-poisoning. PMID:26449527

  3. A sensitive and specific liquid chromatography mass spectrometry method for simultaneous determination of berberine, palmatine, coptisine, epiberberine and jatrorrhizine from Coptidis Rhizoma in rat plasma

    Science.gov (United States)

    Yu, Sen; Pang, Xiaoyan; Deng, Yuanxiong; Liu, Li; Liang, Yan; Liu, Xiaodong; Xie, Lin; Wang, Guangji; Wang, Xinting

    2007-11-01

    A sensitive and specific liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) method has been developed and validated for the identification and quantification of five protoberberine alkaloids, which are berberine, palmatine, coptisine, epiberberine and jatrorrhizine, in rat plasma using tetrahydroberberine as an internal standard. Following solid-phase extraction, the analytes were separated by linear gradient elution on a Shim-pack ODS (4.6 [mu]m, 150 mm × 2.0 mm i.d.) column and analyzed in selected ion monitoring (SIM) mode with a positive electrospray ionization (ESI) interface using the respective [M]+ and [M + H]+ ions, [M]+ = 336 for berberine; 320 for coptisine; 336 for epiberberine; 338 for jatrorrhizine; 352 for palmatine and [M + H]+ = 340 for the internal standard. The method was validated over the concentration range of 0.31-20 ng mL-1 for all the five protoberberine alkaloids. Within-batch and between-batch precisions (R.S.D.%) were all within 15% and accuracy (%Er) ranged from -5 to 5%. The lower limits of quantification were 0.31 ng mL-1 for all analytes. The extraction recoveries were on average 80.8% for berberine, 67E0% for coptisine, 66.2% for epiberberine, 71.8% for jatrorrhizine and 73E2% for palmatine. The validated method was used to study the pharmacokinetic profile of the five protoberberine alkaloids in rat plasma after oral administration of Coptidis Rhizoma extract.

  4. Quantitative and qualitative profiling of endocannabinoids in human plasma using a triple quadrupole linear ion trap mass spectrometer with liquid chromatography.

    Science.gov (United States)

    Thomas, Aurélien; Hopfgartner, Gérard; Giroud, Christian; Staub, Christian

    2009-03-01

    Owing to the large implication of endocannabinoids (ECs) in many physiological and pathophysiological processes, a rapid liquid chromatography/electrospray ionisation triple quadrupole linear ion trap mass spectrometric assay (LC/ESI-QqQ(LIT)) was developed for the detection and characterization of anandamide (AEA), 2-arachidonoyl glycerol (2-AG), virodhamine (VA), noladin ether (2-AGE), and N-arachidonoyl dopamine (NADA) in human plasma. The ECs were extracted from 500 microL of plasma by liquid-liquid extraction (LLE) and separated by using an XTerra C18 MS column (50 x 3.0 mm i.d., 3.5 microm) with gradient elution. The mobile phase was composed of a mixture of acetonitrile, water, and formic acid (0.1%). For confirmatory analysis, an information-dependent acquisition (IDA) experiment was performed with selected reaction monitoring (SRM) as survey scan and enhanced product ion (EPI) as dependent scan. The assay was found to be linear in the concentration range of 0.1-5 ng/mL for AEA, 0.3-5 ng/mL for VA, 2-AGE, and NADA and 1-20 ng/mL for 2-AG using a 0.5 mL aliquot of plasma. Repeatability and intermediate precision were found less than 15% over the tested concentration ranges. The developed method thus provided the rapid, highly sensitive and highly selective requirement for assess quantitation, and identification of ECs in plasma. PMID:19170046

  5. Simultaneous determination of drugs of abuse and their main metabolites using pressurized liquid extraction and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Arbeláez, Paula; Borrull, Francesc; Maria Marcé, Rosa; Pocurull, Eva

    2014-07-01

    An analytical method based on pressurized liquid extraction (PLE) and liquid chromatography-(electrospray)-tandem mass spectrometry was developed for the simultaneous determination of nicotine, four drugs of abuse (opiates and alkaloids) and four of their main metabolites in sewage sludge. The optimum PLE conditions were: cell volume 11 mL, dichloromethane as extraction solvent, 5 min preheating time, 100 °C temperature, 1500 psi pressure, 60% flush volume, 1 cycle, 15 min static extraction time, 120 s purge time and sample weight 1g. Absolute recoveries for all compounds were between 25% and 65%. Data acquisition was done by selective reaction monitoring and the two most abundant product ions were used for confirmation. Limits of detection were lower than 10 μg/kg dry weight (d.w.) and limits of quantification were between 2.5 and 25 μg/kg (d.w.). The highest concentrations found in sludge samples from two sewage treatment plants were for nicotine and cocaine in the range of 23-173 μg/kg (d.w.) and 9-232 μg/kg (d.w.) respectively. PMID:24840416

  6. Quantification of oxidative DNA lesions in tissues of Long-Evans Cinnamon rats by capillary high-performance liquid chromatography-tandem mass spectrometry coupled with stable isotope-dilution method.

    Science.gov (United States)

    Wang, Jin; Yuan, Bifeng; Guerrero, Candace; Bahde, Ralf; Gupta, Sanjeev; Wang, Yinsheng

    2011-03-15

    The purpose of our study was to develop suitable methods to quantify oxidative DNA lesions in the setting of transition metal-related diseases. Transition metal-driven Fenton reactions constitute an important endogenous source of reactive oxygen species (ROS). In genetic diseases with accumulation of transition metal ions, excessive ROS production causes pathophysiological changes, including DNA damage. Wilson's disease is an autosomal recessive disorder with copper toxicosis due to deficiency of ATP7B protein needed for excreting copper into bile. The Long-Evans Cinnamon (LEC) rat bears a deletion in Atp7b gene and serves as an excellent model for hepatic Wilson's disease. We used a sensitive capillary liquid chromatography-electrospray-tandem mass spectrometry (LC-ESI-MS/MS/MS) method in conjunction with the stable isotope-dilution technique to quantify several types of oxidative DNA lesions in the liver and brain of LEC rats. These lesions included 5-formyl-2'-deoxyuridine, 5-hydroxymethyl-2'-deoxyuridine, and the 5'R and 5'S diastereomers of 8,5'-cyclo-2'-deoxyguanosine and 8,5'-cyclo-2'-deoxyadenosine. Moreover, the levels of these DNA lesions in the liver and brain increased with age and correlated with age-dependent regulation of the expression of DNA repair genes in LEC rats. These results provide significant new knowledge for better understanding the implications of oxidative DNA lesions in transition metal-induced diseases, such as Wilson's disease, as well as in aging and aging-related pathological conditions. PMID:21323344

  7. Speciation analysis of calcium, iron, and zinc in casein phosphopeptide fractions from toddler milk-based formula by anion exchange and reversed-phase high-performance liquid chromatography-mass spectrometry/flame atomic-absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Miquel, Esther; Alegria, Amparo; Barbera, Reyes; Farre, Rosaura [University of Valencia, Nutrition and Food Chemistry, Faculty of Pharmacy, Burjassot, Valencia (Spain)

    2005-03-01

    Casein phosphopeptides (CPP) are phosphorylated casein-derived peptides that can be released by in-vitro or in-vivo enzymatic hydrolysis of {alpha}{sub s1}-casein, {alpha}{sub s2}-casein, and {beta}-casein (CN). Many of these peptides contain a highly polar acidic sequence of three phosphoseryl groups followed by two glutamic acid residues. These domains are binding sites for minerals such as calcium, iron, and zinc and play an important role in mineral bioavailability. The aim of this study was speciation analysis of calcium, iron, and zinc in CPP fractions from the soluble fraction of a toddler milk-based formula. Methods for CPP separation by anion-exchange high-performance liquid chromatography (AE-HPLC) were combined with CPP identification by reversed-phase high performance liquid chromatography-electrospray ionization mass spectrometry and determination of the calcium, iron, zinc, and phosphorus content of the fractions obtained by AE-HPLC. Calcium and phosphorus were detected in all the analyzed AE-HPLC fractions. Calcium and zinc could be bound to CPP derived from {alpha}{sub s1}-CN and {alpha}{sub s2}-CN in fraction 3. Iron could be bound to CPP in fraction 4 in which {beta}-CN(15-34)4P was present with the cluster sequence S(P)S(P)S(P)EE. The results obtained prove the different distribution of calcium, iron, and zinc in heterogeneous CPP fractions. (orig.)

  8. Rapid analysis of the skin irritant p-phenylenediamine (PPD) in henna products using atmospheric solids analysis probe mass spectrometry.

    Science.gov (United States)

    Chen, Weiyang; Nkosi, Thobile A N; Combrinck, Sandra; Viljoen, Alvaro M; Cartwright-Jones, Catherine

    2016-09-01

    Henna (Lawsonia inermis) is applied to stain keratin, present in hair, skin and fingernails, a red-orange or rust colour. Producers of temporary tattoos mix the aromatic amine compound, para-phenylenediamine (PPD) into natural henna to create 'black henna' that rapidly stains the skin black. However, PPD may cause severe delayed hypersensitivity reactions following skin contact. This study proposes a rapid direct-analysis method to detect and identify PPD using an atmospheric solids analysis probe (ASAP) coupled to a Q-ToF mass spectrometer (MS). Since laborious, multistep methods of analysis to determine PPD are undesirable, due to the instability of the compound in solution, a screening method involving no sample preparation steps was developed. Experiments were carried out to optimise the corona current, sample cone voltage, source temperature, and desolvation gas temperature to determine ideal ASAP-Q-ToF-MS analysing conditions. Eleven of the 109 henna samples, originating from various countries, tested positive for PPD when henna products were screened using ASAP-MS, without any form of sample preparation other than grinding. Ultra-performance liquid chromatography electrospray ionisation-mass spectrometry (UPLC-Q-ToF-MS) was subsequently used to confirm the results from ASAP and to determine the concentrations of PPD in henna products. The allergen was detected in the same eleven samples, with concentrations ranging from 0.05-4.21% (w/w). It can be concluded that the sensitivity of the ASAP-MS technique is sufficient (limit of detection=0.025% w/w) to allow screening of henna samples for the presence of PPD. This relatively new technique can be applied to commercial products without extraction, sample treatment or chromatographic separation. PMID:27243826

  9. Generic sample treatment method for simultaneous determination of multiclass pesticides and mycotoxins in wines by liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Pérez-Ortega, Patricia; Gilbert-López, Bienvenida; García-Reyes, Juan F; Ramos-Martos, Natividad; Molina-Díaz, Antonio

    2012-08-01

    In this work, a generic sample treatment method for simultaneous determination of multiclass pesticides and mycotoxins in wines is presented. The proposed method is based on solid-phase extraction (SPE) using polymeric-type SPE cartridges. To evaluate the proposed sample treatment, a liquid chromatography electrospray time-of-flight mass spectrometry method was used for testing 60 selected representative multiclass pesticides and 9 mycotoxins. Two different polymeric sorbents were evaluated, with hydrophilic-lipophilic-balanced (HLB) polymer cartridges being selected (Oasis HLB) as the most suitable for the present study. The identification and confirmation of the compounds was based on retention time and accurate mass measurements of the protonated molecules ([M+H](+)). Limits of detection were below 1 μg L(-1) for the 87% of the studied compounds. With the selected 4:1 preconcentration factor, 70% of the target compounds showed relatively low matrix effects, corresponding to signal suppressions lower than 30%. Recovery studies (n=10) were carried out at two concentration levels, 2.5 μg L(-1) and 25 μg L(-1), obtaining mean recovery rates between 70 and 120% for the 90% of studied analytes. The relative standard deviation (RSD%) values of the entire procedure were below 15% in most cases (97% of the studied analytes). The proposed method was successfully applied to 24 red wine samples produced in different regions of Spain. The concentration levels of the target compounds found in the studied samples were in compliance with the current regulations. Aflatoxin B(2) and metalaxyl were the most detected compounds (75% and 50% of the studied samples, respectively). PMID:22749361

  10. Linear quantification of a streptavidin-alkaline phosphatase probe for enzyme-linked immuno mass spectrometric assay.

    Science.gov (United States)

    Florentinus-Mefailoski, Angelique; Marshall, John G

    2016-06-15

    The alkaline phosphatase-streptavidin (AP-SA) probe released adenosine (∼267.2 Da) from the substrate adenosine monophosphate (AMP), where a signal may be detected from as little as 0.5 μl of a 0.1-pg/ml dilution of the probe (2.6 × 10(-22) mol). The signal from the AP-SA probe was linear from 1 to 50 pg/ml by monitoring adenosine release at 268 m/z (M + H) with liquid chromatography, electrospray ionization, and quadrupole mass spectrometry (LC-ESI-MS). The safe limit of detection and quantification of the AP-SA probe was approximately 0.5 pg/well or 5 pg/ml. Enzyme-linked immuno mass spectrometric assay (ELIMSA) using the AP-SA probe provided a linear signal response for prostate-specific antigen (PSA) against external standards from 1 to 500 pg/ml. The ELIMSA showed a safe limit of detection and quantification at 5 pg PSA/well or 50 pg/ml (false positive detection rate P ≤ 0.01). Female samples of 100 μl plasma/well were read against standards and blanks made in normal female plasma, and the lowest sample quantified was approximately 9.8 pg/well or 98 pg/ml. Here ELIMSA was applied to measure PSA in plasma from female, normal male, prostatectomy patient, and cancer patient samples that showed significant differences by analysis of variance (ANOVA). PMID:26944413

  11. Rapid metabolic profiling of Nicotiana tabacum defence responses against Phytophthora nicotianae using direct infrared laser desorption ionization mass spectrometry and principal component analysis

    Directory of Open Access Journals (Sweden)

    Weis Engelbert

    2010-06-01

    Full Text Available Abstract Background Successful defence of tobacco plants against attack from the oomycete Phytophthora nicotianae includes a type of local programmed cell death called the hypersensitive response. Complex and not completely understood signaling processes are required to mediate the development of this defence in the infected tissue. Here, we demonstrate that different families of metabolites can be monitored in small pieces of infected, mechanically-stressed, and healthy tobacco leaves using direct infrared laser desorption ionization orthogonal time-of-flight mass spectrometry. The defence response was monitored for 1 - 9 hours post infection. Results Infrared laser desorption ionization orthogonal time-of-flight mass spectrometry allows rapid and simultaneous detection in both negative and positive ion mode of a wide range of naturally occurring primary and secondary metabolites. An unsupervised principal component analysis was employed to identify correlations between changes in metabolite expression (obtained at different times and sample treatment conditions and the overall defence response. A one-dimensional projection of the principal components 1 and 2 obtained from positive ion mode spectra was used to generate a Biological Response Index (BRI. The BRI obtained for each sample treatment was compared with the number of dead cells found in the respective tissue. The high correlation between these two values suggested that the BRI provides a rapid assessment of the plant response against the pathogen infection. Evaluation of the loading plots of the principal components (1 and 2 reveals a correlation among three metabolic cascades and the defence response generated in infected leaves. Analysis of selected phytohormones by liquid chromatography electrospray ionization mass spectrometry verified our findings. Conclusion The described methodology allows for rapid assessment of infection-specific changes in the plant metabolism, in particular

  12. Semicarbazide is a minor thermal decomposition product of azodicarbonamide used in the gaskets of certain food jars.

    Science.gov (United States)

    Stadler, Richard H; Mottier, Pascal; Guy, Philippe; Gremaud, Eric; Varga, Natalia; Lalljie, Sam; Whitaker, Richard; Kintscher, Jurgen; Dudler, Vincent; Read, Wendy A; Castle, Laurence

    2004-03-01

    Evidence is presented for the first time showing that semicarbazide (SEM) is a minor thermal decomposition product of the blowing agent azodicarbonamide (ADC). A novel direct analytical method based on liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESIMS/MS) has been developed to determine SEM in foamed polyvinyl chloride (PVC) seals of metal lids, as well as in commercially available ADC. The direct LC-MS/MS method for gaskets entails extraction of the gaskets in hot water, addition of ((15)N(2)(13)C)-SEM as internal standard, and injection of an aliquot directly into the LC-MS system, achieving good sensitivity (S/N = 348 for 2 ng injected on-column) and monitoring three characteristic mass transitions (m/z 76-->31; 76 -->44; 76-->59). Semicarbazide can be detected in thermally treated ADC, reaching up to 0.93 mmol mol(-1) at 220 degrees C, as determined by the direct LC-MS/MS method. This new method is also compared to the classical derivatization method using 2-nitrobenzaldehyde (2-NBA) that is routinely employed to determine SEM as an indicator of the usage of the antimicrobial drug nitrofurazone, the use of which is not authorized in the European Union (EU). Both methods revealed proportional results, with approx. 3-fold higher levels recorded by the direct SEM approach, probably due to differences in the extraction procedures used. A limited survey of plastic seals from used press twist and twist-off metal lids on food jars (non-foamed and foamed) revealed levels of SEM ranging from 2 to 8689 microg kg(-1)(average = 1593 microg kg(-1), n= 57 determinations). PMID:14978533

  13. Development and validation of an LC-ESI-MS/MS method for the simultaneous quantification of naproxen and sumatriptan in human plasma: application to a pharmacokinetic study.

    Science.gov (United States)

    Brêtas, Juliana Machado; César, Isabela Costa; Brêtas, Camila Machado; Teixeira, Leonardo de Souza; Bellorio, Karini Bruno; Mundim, Iram Moreira; Pianetti, Gerson Antônio

    2016-06-01

    A sensitive and fast liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method was developed and validated for the simultaneous quantification of naproxen and sumatriptan in human plasma. A simple liquid-liquid extraction procedure, with a mixture of ethyl acetate, methyl tert-butyl ether, and dichloromethane (4:3:3, v/v), was used for the cleanup of plasma. Naratriptan and aceclofenac were employed as internal standards. The analyses were carried out using an ACE C18 column (50 × 4.6 mm i.d.; particle size 5 μm) and a mobile phase consisting of 2 mM aqueous ammonium acetate with 0.025 % formic acid and methanol (38:62, v/v). A triple-quadrupole mass spectrometer equipped with an electrospray source in the positive mode was set up in the selective reaction monitoring mode to detect the ion transitions m/z 231.67 → m/z 185.07, m/z 296.70 → m/z 157.30, m/z 354.80 → m/z 215.00, and m/z 336.80 → m/z 97.94 for naproxen, sumatriptan, aceclofenac, and naratriptan, respectively. The method was validated and proved to be linear, accurate, precise, and selective over the ranges of 2.5-130 μg mL(-1) for naproxen and 1-50 ng mL(-1) for sumatriptan. The validated method was successfully applied to a pharmacokinetic study with simultaneous administration of naproxen sodium and sumatriptan succinate tablet formulations in healthy volunteers. PMID:27020929

  14. Single Cell Proteomics Using Frog (Xenopus laevis) Blastomeres Isolated from Early Stage Embryos, Which Form a Geometric Progression in Protein Content.

    Science.gov (United States)

    Sun, Liangliang; Dubiak, Kyle M; Peuchen, Elizabeth H; Zhang, Zhenbin; Zhu, Guijie; Huber, Paul W; Dovichi, Norman J

    2016-07-01

    Single cell analysis is required to understand cellular heterogeneity in biological systems. We propose that single cells (blastomeres) isolated from early stage invertebrate, amphibian, or fish embryos are ideal model systems for the development of technologies for single cell analysis. For these embryos, although cell cleavage is not exactly symmetric, the content per blastomere decreases roughly by half with each cell division, creating a geometric progression in cellular content. This progression forms a ladder of single-cell targets for the development of successively higher sensitivity instruments. In this manuscript, we performed bottom-up proteomics on single blastomeres isolated by microdissection from 2-, 4-, 8-, 16-, 32-, and 50-cell Xenopus laevis (African clawed frog) embryos. Over 1 400 protein groups were identified in single-run reversed-phase liquid chromatography-electrospray ionization-tandem mass spectrometry from single balstomeres isolated from a 16-cell embryo. When the mass of yolk-free proteins in single blastomeres decreased from ∼0.8 μg (16-cell embryo) to ∼0.2 μg (50-cell embryo), the number of protein group identifications declined from 1 466 to 644. Around 800 protein groups were quantified across four blastomeres isolated from a 16-cell embryo. By comparing the protein expression among different blastomeres, we observed that the blastomere-to-blastomere heterogeneity in 8-, 16-, 32-, and 50-cell embryos increases with development stage, presumably due to cellular differentiation. These results suggest that comprehensive quantitative proteomics on single blastomeres isolated from these early stage embryos can provide valuable insights into cellular differentiation and organ development. PMID:27314579

  15. Trapping Methylglyoxal by Genistein and Its Metabolites in Mice.

    Science.gov (United States)

    Wang, Pei; Chen, Huadong; Sang, Shengmin

    2016-03-21

    Increasing evidence supports dicarbonyl stress such as methylglyoxal (MGO) as one of the major pathogenic links between hyperglycemia and diabetic complications. In vitro studies have shown that dietary flavonoids can inhibit the formation of advanced glycation end products (AGEs) by trapping MGO. However, whether flavonoids can trap MGO in vivo and whether biotransformation limits the trapping capacity of flavonoids remain virtually unknown. In this study, we investigated whether genistein (GEN), the major soy isoflavone, could trap MGO in mice by promoting the formation of MGO adducts of GEN and its metabolites. Two different mouse studies were conducted. In the acute study, a single dose of MGO and GEN were administered to mice via oral gavage. In the chronic study, MGO was given to mice in drinking water for 1 month and then GEN was given to mice for 4 consecutive days via oral gavage. Two mono-MGO adducts of GEN and six mono-MGO adducts of GEN phase I and microbial metabolites were identified in mouse urine samples from these studies using liquid chromatography/electrospray ionization tandem mass spectrometry. The structures of these MGO adducts were confirmed by analyzing their MS(n) (n = 1-4) spectra as well as by comparing them with the tandem mass spectra of authentic standards. All of the MGO adducts presented in their phase II conjugated forms in mouse urine samples in the acute and chronic studies. To our knowledge, this is the first in vivo evidence to demonstrate the trapping efficacy of GEN in mice and to show that the metabolites of GEN remain bioactive. PMID:26881724

  16. LC-MS/MS-based multibiomarker approaches for the assessment of human exposure to mycotoxins.

    Science.gov (United States)

    Warth, Benedikt; Sulyok, Michael; Krska, Rudolf

    2013-07-01

    Mycotoxins are toxic fungal secondary metabolites that frequently contaminate food and feed worldwide, and hence represent a major hazard for food and feed safety. To estimate human exposure arising from contaminated food, so-called biomarker approaches have been developed as a complementary biomonitoring tool besides traditional food analysis. The first methods based on radioimmunoassays and enzyme-linked immunosorbent assays as well as on liquid chromatography were developed in the late 1980s and early 1990s for the carcinogenic aflatoxins and in the last two decades further tailor-made methods for some major mycotoxins have been published. Since 2010, there has been a clear trend towards the development and application of multianalyte methods based on liquid chromatography-electrospray ionization tandem mass spectrometry for assessment of mycotoxin exposure made possible by the increased sensitivity and selectivity of modern mass spectrometry instrumentation and sophisticated sample cleanup approaches. With use of these advanced methods, traces of mycotoxins and relevant breakdown and conjugation products can be quantified simultaneously in human urine as so-called biomarkers and can be used to precisely describe the real exposure, toxicokinetics, and bioavailability of the toxins present. In this article, a short overview and comparison of published multibiomarker methods focusing on the determination of mycotoxins and relevant excretion products in human urine is presented. Special attention is paid to the main challenges when analyzing these toxic food contaminants in urine, i.e., very low analyte concentrations, appropriate sample preparation, matrix effects, and a lack of authentic, NMR-confirmed calibrants and reference materials. Finally, the progress in human exposure assessment studies facilitated by these analytical methods is described and an outlook on probable developments and possibilities is presented. PMID:23774829

  17. Symbiosis induces widespread changes in the proteome of the model cnidarian Aiptasia.

    Science.gov (United States)

    Oakley, Clinton A; Ameismeier, Michael F; Peng, Lifeng; Weis, Virginia M; Grossman, Arthur R; Davy, Simon K

    2016-07-01

    Coral reef ecosystems are metabolically founded on the mutualism between corals and photosynthetic dinoflagellates of the genus Symbiodinium. The glass anemone Aiptasia sp. has become a tractable model for this symbiosis, and recent advances in genetic information have enabled the use of mass spectrometry-based proteomics in this model. We utilized label-free liquid chromatography electrospray-ionization tandem mass spectrometry to analyze the effects of symbiosis on the proteomes of symbiotic and aposymbiotic Aiptasia. We identified and obtained relative quantification of more than 3,300 proteins in 1,578 protein clusters, with 81 protein clusters showing significantly different expression between symbiotic states. Symbiotic anemones showed significantly higher expression of proteins involved in lipid storage and transport, nitrogen transport and cycling, intracellular trafficking, endocytosis and inorganic carbon transport. These changes reflect shifts in host metabolism and nutrient reserves due to increased nutritional exchange with the symbionts, as well as mechanisms for supplying inorganic nutrients to the algae. Aposymbiotic anemones exhibited increased expression of multiple systems responsible for mediating reactive oxygen stress, suggesting that the host derives direct or indirect protection from oxidative stress while in symbiosis. Aposymbiotic anemones also increased their expression of an array of proteases and chitinases, indicating a metabolic shift from autotrophy to heterotrophy. These results provide a comprehensive Aiptasia proteome with more direct relative quantification of protein abundance than transcriptomic methods. The extension of "omics" techniques to this model system will allow more powerful studies of coral physiology, ecosystem function, and the effects of biotic and abiotic stress on the coral-dinoflagellate mutualism. PMID:26716757

  18. Rapid measurement of perchlorate in polar ice cores down to sub-ng L(-1) levels without pre-concentration.

    Science.gov (United States)

    Peterson, Kari; Cole-Dai, Jihong; Brandis, Derek; Cox, Thomas; Splett, Scott

    2015-10-01

    An ion chromatography-electrospray ionization-tandem mass spectrometry (IC-ESI-MS/MS) method has been developed for rapid and accurate measurement of perchlorate in polar snow and ice core samples in which perchlorate concentrations are expected to be as low as 0.1 ng L(-1). Separation of perchlorate from major inorganic species in snow is achieved with an ion chromatography system interfaced to an AB SCIEX triple quadrupole mass spectrometer operating in multiple reaction monitoring mode. Under optimized conditions, the limit of detection and lower limit of quantification without pre-concentration have been determined to be 0.1 and 0.3 ng L(-1), respectively, with a linear dynamic range of 0.3-10.0 ng L(-1) in routine measurement. These represent improvements over previously reported methods using similar analytical techniques. The improved method allows fast, accurate, and reproducible perchlorate quantification down to the sub-ng L(-1) level and will facilitate perchlorate measurement in the study of natural perchlorate production with polar ice cores in which perchlorate concentrations are anticipated to vary in the low and sub-ng L(-1) range. Initial measurements of perchlorate in ice core samples from central Greenland show that typical perchlorate concentrations in snow dated prior to the Industrial Revolution are about 0.8 ng L(-1), while perchlorate concentrations are significantly higher in recent (post-1980) snow, suggesting that anthropogenic sources are a significant contributor to perchlorate in the current environment. PMID:26297465

  19. Dynamic lipidomic insights into the adaptive responses of Saccharomyces cerevisiae to the repeated vacuum fermentation.

    Science.gov (United States)

    Zhou, Xiao; Zhou, Jian; Tian, Hongchi; Yuan, Yingjin

    2010-10-01

    Vacuum fermentation is utilized in a wide range of life science industries and biomedical R&D. Little is known, however, on the effects of the vacuum on the yeast, and in particular, on the yeast lipidome that plays a central role in maintaining cell membrane and other vital (yeast) cell functions. The present study evaluated the adaptive responses of Saccharomyces cerevisiae to repeated vacuum fermentation by lipidomic analysis. We employed gas chromatography coupled to time-of-flight mass spectrometry (GC-TOF-MS) and liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI/MS(n)) to quantify a total of 13 intermediate sterols and 139 phospholipid species of yeast cells. Principal components analysis found that the PI (phosphatidylinositol) 26:0, PI 28:0, PE (phosphatidylethanolamine) 32:1, and PE 34:1 were potential biomarkers to distinguish the vacuum fermentation process. Quantitative analysis showed that vacuum fermentation increased the synthesis of PI and the PC (phosphatidylcholine) species with short saturated acyl chains. The synthesis of PC via CDP-choline and turnover of PC were enhanced, instead of formation via methylation of PE. Additionally, increased PI at the expense of PE and PG (phosphatidylglycerol) was associated with enhancement of ethanol productivity. Vacuum fermentation caused eburicol accumulation, suggesting that vacuum can activate the branch of the ergosterol biosynthesis pathway. Eburicol decrease and PI increase contributed to recovery of cellular activities with oxygenating treatment. Ethanol productivity was increased by sixfold in vacuum-treated cells. These observations may allow the development of future mechanistic approaches to optimization of yeast fermentation under vacuum for bioindustry and life science applications. In particular, our findings on changes in lipid molecular species and the ergosterol biosynthesis pathway elucidate the defense responses of yeast cell membranes during the repeated

  20. Evaluation of Flow-Injection Tandem Mass Spectrometry for Rapid and High-Throughput Quantitative Determination of B-Vitamins in Nutritional Supplements

    Energy Technology Data Exchange (ETDEWEB)

    Bhandari, Deepak [ORNL; Van Berkel, Gary J [ORNL

    2012-01-01

    The use of flow-injection electrospray ionization tandem mass spectrometry for rapid and high-throughput mass spectral analysis of selected B-vitamins, viz. B1, B2, B3, B5, and B6, in nutritional formulations was demonstrated. A simple and rapid (~5 min) in-tube sample preparation was performed by adding extraction solvent to a powdered sample aliquot followed by agitation, centrifugation, and filtration to recover an extract for analysis. Automated flow injection introduced 1 L of the extracts directly into the mass spectrometer ion source without chromatographic separation. Sample-to-sample analysis time was 60 s representing significant improvement over conventional liquid chromatography approaches which typically require 25-45 min, and often require more significant sample preparation procedures. Quantitative capabilities of the flow-injection analysis were tested using the method of standard additions and NIST standard reference material (SRM 3280) multivitamin/multielement tablets. The quantity determined for each B-vitamin in SRM 3280 was within the statistical range provided for the respective certified values. The same sample preparation and analysis approach was also applied to two different commercial vitamin supplement tablets and proved to be successful in the quantification of the selected B-vitamins as evidenced by an agreement with the labels values and the results obtained using isotope dilution liquid chromatography/mass spectrometry.

  1. High resolution mass spectrometry coupled with multivariate data analysis revealing plasma lipidomic alteration in ovarian cancer in Asian women.

    Science.gov (United States)

    Zhang, Yangyang; Liu, Yingying; Li, Lin; Wei, Jinchao; Xiong, Shaoxiang; Zhao, Zhenwen

    2016-04-01

    Ovarian cancer (OC) is the most common cause of death from gynecologic malignancies in women. The identification of reliable diagnostic biomarkers for the early detection of this deadly disease is critical for reducing the mortality rate of OC. Plasma lysophosphatidic acid (LPA) levels were increased from OC patients vs. healthy controls. Therefore, lipidomics may represent an excellent developing prospect for the discovery of diagnostic biomarkers of OC. In this study, a nontargeted lipidomics approach based on ultra performance liquid chromatography-electrospray ionization-QTOF-mass spectrometry (UPLC-ESI-QTOF-MS) combined with multivariate data analysis, including principal component analysis (PCA) and (orthogonal) partial least squared discriminant analysis [(O)PLS-DA] was applied for the investigation of potential diagnostic biomarkers in plasma of OC patients. Patients with OC could be distinguished from healthy individuals and patients with benign gynecological tumor disease by this method, which shows a significant lipid perturbation in this disease. With the assistance of high resolution and high accuracy of MS and MS/MS data, the potential markers including lysophosphatidylcholines (LPCs), phosphatidylcholines (PCs) and triacylglycerols (TGs) with specific fatty acid chains, were identified. Interestingly, LPCs were up-regulated and PCs and TGs were down-regulated, compared OC group with benign tumor and normal control groups, and the glycerophospholipid metabolism emerged as a key pathway, in particular, the phospholipase A2 (PLA2) enzyme activity, that was disregulated in the disease. This study may provide new insight into underlying mechanisms for OC and proves that MS-based lipidomics is a powerful method in discovering new potential clinical biomarkers for diseases. PMID:26838385

  2. Untargeted metabolomic analysis using liquid chromatography quadrupole time-of-flight mass spectrometry for non-volatile profiling of wines

    International Nuclear Information System (INIS)

    Highlights: • An untargeted metabolomic method for the non-volatile profile of the Graciano wine was developed. • 411 different metabolites in Graciano Vitis vinifera red wine were identified. • 15 compounds could serve to differentiate Graciano and Tempranillo wines. • An enological database (WinMet) with 2080 compounds was constructed. - Abstract: The current study presents a method for comprehensive untargeted metabolomic fingerprinting of the non-volatile profile of the Graciano Vitis vinifera wine variety, using liquid chromatography/electrospray ionization time of flight mass spectrometry (LC–ESI-QTOF). Pre-treatment of samples, chromatographic columns, mobile phases, elution gradients and ionization sources, were evaluated for the extraction of the maximum number of metabolites in red wine. Putative compounds were extracted from the raw data using the extraction algorithm, molecular feature extractor (MFE). For the metabolite identification the WinMet database was designed based on electronic databases and literature research and includes only the putative metabolites reported to be present in oenological matrices. The results from WinMet were compared with those in the METLIN database to evaluate how much the databases overlap for performing identifications. The reproducibility of the analysis was assessed using manual processing following replicate injections of Vitis vinifera cv. Graciano wine spiked with external standards. In the present work, 411 different metabolites in Graciano Vitis vinifera red wine were identified, including primary wine metabolites such as sugars (4%), amino acids (23%), biogenic amines (4%), fatty acids (2%), and organic acids (32%) and secondary metabolites such as phenols (27%) and esters (8%). Significant differences between varieties Tempranillo and Graciano were related to the presence of fifteen specific compounds

  3. Untargeted metabolomic analysis using liquid chromatography quadrupole time-of-flight mass spectrometry for non-volatile profiling of wines

    Energy Technology Data Exchange (ETDEWEB)

    Arbulu, M. [Department of Analytical Chemistry, Faculty of Pharmacy, University of the Basque Country, 01006 Vitoria-Gasteiz (Spain); Sampedro, M.C. [Central Service of Analysis, SGIker, University of the Basque Country, 01006 Vitoria-Gasteiz (Spain); Gómez-Caballero, A.; Goicolea, M.A. [Department of Analytical Chemistry, Faculty of Pharmacy, University of the Basque Country, 01006 Vitoria-Gasteiz (Spain); Barrio, R.J., E-mail: r.barrio@ehu.es [Department of Analytical Chemistry, Faculty of Pharmacy, University of the Basque Country, 01006 Vitoria-Gasteiz (Spain)

    2015-02-09

    Highlights: • An untargeted metabolomic method for the non-volatile profile of the Graciano wine was developed. • 411 different metabolites in Graciano Vitis vinifera red wine were identified. • 15 compounds could serve to differentiate Graciano and Tempranillo wines. • An enological database (WinMet) with 2080 compounds was constructed. - Abstract: The current study presents a method for comprehensive untargeted metabolomic fingerprinting of the non-volatile profile of the Graciano Vitis vinifera wine variety, using liquid chromatography/electrospray ionization time of flight mass spectrometry (LC–ESI-QTOF). Pre-treatment of samples, chromatographic columns, mobile phases, elution gradients and ionization sources, were evaluated for the extraction of the maximum number of metabolites in red wine. Putative compounds were extracted from the raw data using the extraction algorithm, molecular feature extractor (MFE). For the metabolite identification the WinMet database was designed based on electronic databases and literature research and includes only the putative metabolites reported to be present in oenological matrices. The results from WinMet were compared with those in the METLIN database to evaluate how much the databases overlap for performing identifications. The reproducibility of the analysis was assessed using manual processing following replicate injections of Vitis vinifera cv. Graciano wine spiked with external standards. In the present work, 411 different metabolites in Graciano Vitis vinifera red wine were identified, including primary wine metabolites such as sugars (4%), amino acids (23%), biogenic amines (4%), fatty acids (2%), and organic acids (32%) and secondary metabolites such as phenols (27%) and esters (8%). Significant differences between varieties Tempranillo and Graciano were related to the presence of fifteen specific compounds.

  4. Qualitative and quantitative analysis of glucosinolates and nucleosides in Radix Isatidis by HPLC and liquid chromatography tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Xiuming Wang

    2013-09-01

    Full Text Available Multi-component fingerprinting and quantitation of the glucosinolates and nucleosides in samples of Radix Isatidis have been carried out using high-performance liquid chromatography with diode-array detection and electrospray ionization tandem mass spectrometry (HPLC–DAD–ESI/MS. Five nucleosides together with one glucosinolate were identified by comparing retention times, ultraviolet spectra, mass spectra and/or empirical molecular formulae of reference compounds. Quantitation of these six compounds was carried out simultaneously by HPLC on a Phenomenex Luna C18 column using gradient elution with methanol and water and detection at 254 nm. All calibration curves were linear (r>0.9994 within test ranges. Limits of detection and quantitation were 0.33 ng and 2.50 ng on column, respectively. Intra- and inter-day precision (as relative standard deviation for all analytes was <2.19% with recoveries in the range 99.6%–101.8% at three concentration levels. The validated method was successfully applied to fingerprinting and assay of 25 batches of Radix Isatidis sourced from different geographical regions of China. The method is simple and reliable and has potential value in the quality control of Radix Isatidis.

  5. Paired-ion electrospray ionization--triple quadrupole tandem mass spectrometry for quantification of anionic surfactants in waters.

    Science.gov (United States)

    Santos, Inês C; Guo, Hongyue; Mesquita, Raquel B R; Rangel, António O S S; Armstrong, Daniel W; Schug, Kevin A

    2015-10-01

    A new paired ion electrospray ionization tandem mass spectrometry method for determination of anionic surfactants in water samples was developed. In this method, dicationic ion-pairing reagents were complexed with monoanionic analytes to facilitate analyte detection in positive mode electrospray ionization - mass spectrometry. Single ion monitoring and selected reaction monitoring on a triple quadrupole instrument were performed and compared. Four dicationic reagents were tested for the determination of perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), sodium dodecyl sulfate (SDS), dodecylbenzene sulfonic acid (DBS), and stearic acid (SA), among other common anions. The obtained limits of detection were compared with those from previous literature. Solid phase extraction using a C18 cartridge was performed in order to eliminate matrix interferences. A literature review was compiled for the methods published between 2010 and 2015 for determination of anionic surfactants. The optimized method was more sensitive than previously developed methods with LOD values of 2.35, 35.4, 37.0, 1.68, and 0.675 pg for SDS, SA, DBS, PFOS, and PFOA, respectively. The developed method was effectively applied for the determination of anionic surfactants in different water samples such as bottled drinking water, cooking water, tap water, and wastewater. PMID:26078166

  6. Quantitative determination of capsaicin, a transient receptor potential channel vanilloid 1 agonist, by liquid chromatography quadrupole ion trap mass spectrometry: evaluation of in vitro metabolic stability.

    Science.gov (United States)

    Beaudry, Francis; Vachon, Pascal

    2009-02-01

    Capsaicin is the most abundant pungent molecule present in red peppers and it is widely used for food flavoring, in pepper spray in self-defense devices and more recently in ointments for the relief of neuropathic pain. Capsaicin is a selective agonist of transient receptor potential channel, vanilloid subfamily member 1. A selective and sensitive quantitative method for the determination of capsaicin by LC-ESI/MS/MS was developed. The method consisted of a protein precipitation extraction followed by analysis using liquid chromatography electrospray quadrupole ion trap mass spectrometry. The chromatographic separation was achieved using a 100 x 2 mm C(18) Waters Symmetry column combined with a gradient mobile phase composed of acetonitrile and 0.1% formic acid aqueous solution at a flow rate of 220 microL/min. The mass spectrometer was operating in full-scan MS/MS mode using two-segment analysis. An analytical range of 10-5000 ng/mL was used in the calibration curve constructed in rat plasma. The interbatch precision and accuracy observed were 6.5, 6.7, 5.3 and 101.2, 102.7, 103.5% at 50, 500 and 5000 ng/mL, respectively. An in vitro metabolic stability study was performed in rat, dog and mouse liver microsomes and the novel analytical method was adapted and used to determine intrinsic clearance of capsaicin. Results suggest very rapid degradation with T(1/2) ranging from 2.3 to 4.1 min and high clearance values suggesting that drug bioavailability will be considerably reduced, consequently affecting drug response and efficacy. PMID:18816461

  7. Determination of drugs in surface water and wastewater samples by liquid chromatography-mass spectrometry: Methods and preliminary results including toxicity studies with Vibrio fischeri

    Science.gov (United States)

    Farre, M.; Ferrer, I.; Ginebreda, A.; Figueras, M.; Olivella, L.; Tirapu, L.; Vilanova, M.; Barcelo, D.

    2001-01-01

    In the present work a combined analytical method involving toxicity and liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) was developed for the determination of pharmaceutical compounds in water samples. The drugs investigated were the analgesics: ibuprofen, ketoprofen, naproxen, and diclofenac, the decomposition product of the acetyl salicylic acid: salicylic acid and one lipid lowering agent, gemfibrozil. The selected compounds are acidic substances, very polar and all of them are analgesic compounds that can be purchased without medical prescription. The developed protocol consisted, first of all, on the use Microtox?? and ToxAlert??100 toxicity tests with Vibrio fischeri for the different pharmaceutical drugs. The 50% effective concentration (EC50) values and the toxicity units (TU) were determined for every compound using both systems. Sample enrichment of water samples was achieved by solid-phase extraction procedure (SPE), using the Merck LiChrolut?? EN cartridges followed by LC-ESI-MS. Average recoveries loading 1 l of samples with pH=2 varied from 69 to 91% and the detection limits in the range of 15-56 ng/l. The developed method was applied to real samples from wastewater and surface-river waters of Catalonia (north-east of Spain). One batch of samples was analyzed in parallel also by High Resolution Gas Chromatography coupled with Mass Spectrometry (HRGC-MS) and the results have been compared with the LC-ESI-MS method developed in this work. ?? 2001 Elsevier Science B.V. All rights reserved.

  8. Multi-residue method for the determination of over 400 priority and emerging pollutants in water and wastewater by solid-phase extraction and liquid chromatography-time-of-flight mass spectrometry.

    Science.gov (United States)

    Robles-Molina, José; Lara-Ortega, Felipe J; Gilbert-López, Bienvenida; García-Reyes, Juan F; Molina-Díaz, Antonio

    2014-07-11

    This article describes the development and validation of a liquid chromatography high-resolution mass spectrometry method for the simultaneous determination of over 400 multi-class priority and emerging pollutants with different physicochemical properties in environmental waters (surface water and wastewater). The proposed approach is based on the use of a database consisting of retention time/exact mass (of selected ions) pairs implemented with specific software for data analysis. The targeted list comprises 430 contaminants belonging to different compound categories, including 105 multiclass pharmaceuticals (analgesics/anti-inflammatories, antibiotics, lipid regulators, β-blockers, antiepileptic/psychiatrics ulcer healings, diuretics, hormones and bronchodilatadors), life-style products (caffeine, nicotine), 21 drugs of abuse and their metabolites, 279 pesticides and some of their more relevant metabolites, nitrosamines, flame retardants, plasticizers and perfluorinated compounds. The proposed approach included a simple offline solid phase extraction (SPE) step using polymeric cartridges (Oasis HLB) with 200mL of water sample loaded, followed by analysis by rapid resolution liquid chromatography electrospray time-of-flight mass spectrometry (LC-TOFMS) in both positive and negative modes. The identification of the positive findings is accomplished with the data from accurate masses of the target ions along with retention time data and characteristic in-source fragment ions. The overall method performance was satisfactory with limits of quantification lower than 10ngL(-1) for the 44% of studied compounds. Recoveries between 50% and 130% were obtained for the 65% of the analytes (281 compounds). Matrix effects occurring with wastewater matrices were also assessed. The developed method was applied to the determination of target analytes in real surface water and wastewater samples. PMID:24891157

  9. Moving pieces in a proteomic puzzle: mass fingerprinting of toxic fractions from the venom of Tityus serrulatus (Scorpiones, Buthidae).

    Science.gov (United States)

    Pimenta, A M; Stöcklin, R; Favreau, P; Bougis, P E; Martin-Eauclaire, M F

    2001-01-01

    Scorpion venoms are very complex mixtures of molecules, most of which are peptides that display different kinds of biological activity. These venoms have been studied in the light of their pharmacological targets and their constituents are able to bind specifically to a variety of ionic channels located in prey tissues, resulting in neurotoxic effects. Toxins that modulate Na(+), K(+), Ca(++) and Cl(-) currents have been described in scorpion venoms. Mass spectrometry was employed to analyze toxic fractions from the venom of the Brazilian scorpion Tityus serrulatus in order to shed light on the molecular composition of this venom and to facilitate the search for novel pharmacologically active compounds. T. serrulatus venom was first subjected to gel filtration to separate its constituents according to their molecular size. The resultant fractions II and III, which account for 90 and 10% respectively of the whole venom toxic effect, were further analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS), on-line liquid chromatography/electrospray mass spectrometry (LC/ESMS) and off-line LC/MALDI-TOFMS in order to establish their mass fingerprints. The molecular masses in fraction II were predominantly between 6500 and 7500 Da. This corresponds to long-chain toxins that mainly act on voltage-gated Na(+) channels. Fraction III is more complex and predominantly contained molecules with masses between 2500 and 5000 Da. This corresponds to the short-chain toxin family, most of which act on K(+) channels, and other unknown peptides. Finally, we were able to measure the molecular masses of 380 different compounds present in the two fractions investigated. To our knowledge, this is the largest number of components ever detected in the venom of a single animal species. Some of the toxins described previously from T. serrulatus venom could be detected by virtue of their molecular masses. The interpretation of this large set of data

  10. Simultaneous Determination of Eight Alkaloids in Rat Plasma by UHPLC-MS/MS after Oral Administration of Coptis deltoidea C. Y. Cheng et Hsiao and Coptis chinensis Franch.

    Science.gov (United States)

    Liu, Lu; Wang, Zhi-Bin; Song, Yang; Yang, Jing; Wu, Li-Jun; Yang, Bing-You; Wang, Qiu-Hong; Wang, Li-Qian; Wang, Ru-Xuan; Yang, Chun-Juan

    2016-01-01

    A ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) method was successfully developed and validated for the identification and determination of eight alkaloids: tetrahydropalmatine (A); palmatine (B); magnoflorine (C); columbamine (D); berberine (E); worenine (F); berberrubine (G) and coptisine (H) in rat plasma, which are the active components in Coptis deltoidea C. Y. cheng et Hsiao (CCY) and Coptis chinensis Franch (CF). The chromatographic separation of analytes was successfully achieved on an Agilent SB-C18 column (1.8 µm, 150 mm × 2.1 mm) using a programme with a mobile phase consisting of acetonitrile and water containing 0.3% acetic acid at a flow rate of 0.25 mL/min. The analytes were detected with a triple quadrupole tandem MS in multiple reaction monitoring (MRM) mode and an electrospray ionization (ESI) source in positive mode. The validated method showed good linearity over a wide concentration range (r² > 0.991), and lower limits of quantification (LLOQ) less than 1.1 ng/mL for all analytes, and matrix effects ranged from 85.2% to 106.8%. The mean extraction recoveries were no less than 86.4%, and the precision and accuracy were within the acceptable limits. All analytes were proven to be stable during sample storage and analysis procedures. The method validation results demonstrated that the proposed method was sensitive, specific, and reliable, which could lay a foundation for the pharmacokinetic study of eight analytes after oral administration of CCY and CF in subsequent studies. PMID:27428938

  11. Functional Promiscuity of Two Divergent Paralogs of Type III Plant Polyketide Synthases.

    Science.gov (United States)

    Pandith, Shahzad A; Dhar, Niha; Rana, Satiander; Bhat, Wajid Waheed; Kushwaha, Manoj; Gupta, Ajai P; Shah, Manzoor A; Vishwakarma, Ram; Lattoo, Surrinder K

    2016-08-01

    Plants effectively defend themselves against biotic and abiotic stresses by synthesizing diverse secondary metabolites, including health-protective flavonoids. These display incredible chemical diversity and ubiquitous occurrence and confer impeccable biological and agricultural applications. Chalcone synthase (CHS), a type III plant polyketide synthase, is critical for flavonoid biosynthesis. It catalyzes acyl-coenzyme A thioesters to synthesize naringenin chalcone through a polyketidic intermediate. The functional divergence among the evolutionarily generated members of a gene family is pivotal in driving the chemical diversity. Against this backdrop, this study was aimed to functionally characterize members of the CHS gene family from Rheum emodi, an endangered and endemic high-altitude medicinal herb of northwestern Himalayas. Two full-length cDNAs (1,179 bp each), ReCHS1 and ReCHS2, encoding unique paralogs were isolated and characterized. Heterologous expression and purification in Escherichia coli, bottom-up proteomic characterization, high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry analysis, and enzyme kinetic studies using five different substrates confirmed their catalytic potential. Phylogenetic analysis revealed the existence of higher synonymous mutations in the intronless divergents of ReCHS. ReCHS2 displayed significant enzymatic efficiency (Vmax/Km) with different substrates. There were significant spatial and altitudinal variations in messenger RNA transcript levels of ReCHSs correlating positively with metabolite accumulation. Furthermore, the elicitations in the form of methyl jasmonate, salicylic acid, ultraviolet B light, and wounding, chosen on the basis of identified cis-regulatory promoter elements, presented considerable differences in the transcript profiles of ReCHSs. Taken together, our results demonstrate differential propensities of CHS paralogs in terms of the accumulation of flavonoids and

  12. Proteomic Analysis of Sauvignon Blanc Grape Skin, Pulp and Seed and Relative Quantification of Pathogenesis-Related Proteins.

    Directory of Open Access Journals (Sweden)

    Bin Tian

    Full Text Available Thaumatin-like proteins (TLPs and chitinases are the main constituents of so-called protein hazes which can form in finished white wine and which is a great concern of winemakers. These soluble pathogenesis-related (PR proteins are extracted from grape berries. However, their distribution in different grape tissues is not well documented. In this study, proteins were first separately extracted from the skin, pulp and seed of Sauvignon Blanc grapes, followed by trypsin digestion and analysis by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS. Proteins identified included 75 proteins from Sauvignon Blanc grape skin, 63 from grape pulp and 35 from grape seed, mostly functionally classified as associated with metabolism and energy. Some were present exclusively in specific grape tissues; for example, proteins involved in photosynthesis were only detected in grape skin and proteins found in alcoholic fermentation were only detected in grape pulp. Moreover, proteins identified in grape seed were less diverse than those identified in grape skin and pulp. TLPs and chitinases were identified in both Sauvignon Blanc grape skin and pulp, but not in the seed. To relatively quantify the PR proteins, the protein extracts of grape tissues were seperated by HPLC first and then analysed by SDS-PAGE. The results showed that the protein fractions eluted at 9.3 min and 19.2 min under the chromatographic conditions of this study confirmed that these corresponded to TLPs and chitinases seperately. Thus, the relative quantification of TLPs and chitinases in protein extracts was carried out by comparing the area of corresponding peaks against the area of a thamautin standard. The results presented in this study clearly demonstrated the distribution of haze-forming PR proteins in grape berries, and the relative quantification of TLPs and chitinases could be applied in fast tracking of changes in PR proteins during grape growth and

  13. Determination of the highest no-effect dose (HNED) and of the elimination pattern for cocaine in horses.

    Science.gov (United States)

    Queiroz-Neto, A; Zamur, G; Lacerda-Neto, J C; Tobin, T

    2002-01-01

    Cocaine is one of the most widespread illegal stimulants utilized by the human population throughout the world. The aim of this study was to establish the highest no-effect dose (HNED) of cocaine on the spontaneous locomotor activity (SLA) of horses in a behavior chamber, and thereby to determine the maximal acceptable threshold of the urinary drug concentration in horses. Twelve English thoroughbred mares received 0.02, 0.03, 0.04, 0.08 or 0.12 mg kg(-1) cocaine i.v. or saline solution (control). It was noted that doses above 0.04 mg kg(-1) induced a significant increase in SLA (P horses in a behavior chamber is 0.02 mg kg(-1). After injection of this dose in five horses, urine samples were collected at predetermined intervals through vesical catheterization. The concentrations of cocaine, norcocaine, benzoylecgonine and ecgonine methyl ester were quantified by liquid chromatography/electrospray ionization tandem mass spectrometry. Cocaine and norcocaine concentrations remained consistently below the level of detection. Benzoylecgonine reached a mean (+/- SEM) maximum concentration of 531.9 +/- 168.7 ng ml(-1) after 4 h, whereas ecgonine methyl ester peaked 2 h after injection at a concentration of 97.2 +/- 26.5 ng ml(-1). The maximum admissible concentration for cocaine and/or metabolites in the urine of horses is difficult to establish unequivocally because of the substantial individual variation in the drug elimination pattern observed in horses, which can be inferred by the large standard error of the means obtained. PMID:11920936

  14. A novel liquid chromatography method using diode-array detector for the determination of oleuropein in dietary supplements.

    Science.gov (United States)

    Bertolini, Tiziana; Vicentini, Lorenza; Boschetti, Silvia; Andreatta, Paolo; Gatti, Rita

    2016-09-10

    A simple and fast chromatographic method using ultraviolet diode-array detector (UV-DAD) was developed for the automatic high performance liquid chromatography (HPLC) determination of the title of oleuropein in a new dietary supplements in form of effervescent granules. The chromatographic separations were performed on a C18 core-shell column with detection at λ=232nm. The mobile phase consisted of deionized water with 0.1% TFA and acetonitrile under gradient conditions at a flow-rate of 0.8mL/min. Oleuropein and oleuroside present in the raw material were characterized by high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The validation of the analytical procedure has been performed determining the following parameters: specificity, linearity, repeatability, reproducibility, accuracy, limit of quantification (LOQ), stability of the standard and sample solutions. Linear response was observed in fortified placebo solutions (determination coefficient: 0.9998). Intra-day precision (relative standard deviation, RSD) was ≤5.0% for peak area and for retention times (tR) without significant differences between intra- and inter-day data. The limits of quantitation (LOQ) was about 5μg/mL and 9pmol/inject. Oleuropein recovery studies gave good results (99.9%) with a R.S.D. of 0.5%. The speed of analysis and the stability of the solutions with a fluctuation Δ (%) ≤2.0 at room temperature means an undoubted advantage of the method allowing the simultaneous preparation of many samples and consecutive chromatographic analyses by using an autosampler. The developed method is suitable for the quality control of oleuropein in raw material and industrial products. The method can be applied in any analytical laboratory not requiring a sophisticated instrumentation. PMID:27429369

  15. The impact of stannous, fluoride ions and its combination on enamel pellicle proteome and dental erosion prevention.

    Directory of Open Access Journals (Sweden)

    A A Algarni

    Full Text Available To compare the effects of stannous (Sn and fluoride (F ions and their combination on acquired enamel pellicle (AEP protein composition (proteome experiment, and protection against dental erosion (functional experiment.In the proteome experiment, bovine enamel specimens were incubated in whole saliva supernatant for 24h for AEP formation. They were randomly assigned to 4 groups (n=10, according to the rinse treatment: Sn (800ppm/6.7mM, SnCl2, F (225ppm/13mM, NaF, Sn and F combination (Sn+F and deionized water (DIW, negative control. The specimens were immersed 3× in the test rinses for 2min, 2h apart. Pellicles were collected, digested, and analyzed for protein content using liquid chromatography electrospray ionization tandem mass spectrometry. In the functional experiment, bovine enamel specimens (n=10 were similarly treated for pellicle formation. Then, they were subjected to a five-day erosion cycling model, consisting of 5min erosive challenges (15.6 mM citric acid, pH 2.6, 6×/d and 2min treatment with the rinses containing Sn, F or Sn+F (3×/d. Between the treatments, all specimens were incubated in whole saliva supernatant. Surface loss was determined by profilometry.Our proteome approach on bovine enamel identified 72 proteins that were common to all groups. AEP of enamel treated with Sn+F demonstrated higher abundance for most of the identified proteins than the other groups. The functional experiment showed reduction of enamel surface loss for Sn+F (89%, Sn (67% and F (42% compared to DIW (all significantly different, p<0.05.This study highlighted that anti-erosion rinses (e.g. Sn+F can modify quantitatively and qualitatively the AEP formed on bovine enamel. Moreover, our study demonstrated a combinatory effect that amplified the anti-erosive protection on tooth surface.

  16. The impact of microbial biotransformation of catechin in enhancing the allelopathic effects of Rhododendron formosanum.

    Science.gov (United States)

    Wang, Chao-Min; Li, Tsai-Chi; Jhan, Yun-Lian; Weng, Jen-Hsien; Chou, Chang-Hung

    2013-01-01

    Rhododendron formosanum is distributed widely in the central mountains in Taiwan and the major allelopathic compound in the leaves has been identified as (-)-catechin, which is also a major allelochemical of an invasive spotted knapweed in North America. Soil microorganisms play key roles in ecosystems and influence various important processes, including allelopathy. However, no microorganism has been identified as an allelochemical mediator. This study focused on the role of microorganisms in the allelopathic effects of R. formosanum. The microorganism population in the rhizosphere of R. formosanum was investigated and genetic analysis revealed that the predominant genera of microorganisms in the rhizosphere of R. formosanum were Pseudomonas, Herbaspirillum, and Burkholderia. The dominant genera Pseudomonas utilized (-)-catechin as the carbon source and catalyzed the conversion of (-)-catechin into protocatechuic acid in vitro. The concentrations of allelochemicals in the soil were quantified by liquid chromatography-electrospray ionization/tandem mass spectrometry. The concentration of (-)-catechin in the soil increased significantly during the extreme rainfall in the summer season and suppressed total bacterial populations. Protocatechuic acid accumulation was observed while total bacterial populations increased abundantly in both laboratory and field studies. Allelopathic interactions were tested by evaluating the effects of different allelochemicals on the seed germination, radicle growth, and photosynthesis system II of lettuce. Protocatechuic acid exhibited higher phytotoxicity than (-)-catechin did and the effect of (-)-catechin on the inhibition of seed germination was enhanced by combining it with protocatechuic acid at a low concentration. This study revealed the significance of the allelopathic interactions between R. formosanum and microorganisms in the rhizosphere. These findings demonstrate that knowledge regarding the precise biotransformation

  17. Determination of 18 water-soluble artificial dyes by LC-MS in selected matrices.

    Science.gov (United States)

    Martin, Frédéric; Oberson, Jean-Marie; Meschiari, Marco; Munari, Caroline

    2016-04-15

    A multi-residue method based on two different extraction procedures was developed and compared with liquid chromatography electrospray ionization tandem mass spectrometry analysis of eighteen water-soluble artificial colours including Tartrazine (E102), Chrysoine (E103), Quinoline Yellow (E104), Yellow 2G (E107), Sunset Yellow (E110), Azorubine (E122), Amaranth (E123), Ponceau 4R (E124), Erythrosine (E127), Red 2G (E128), Allura Red (E129), Patent Blue V (E131), Indigo Carmine (E132), Brilliant Blue (E133), Green S (E142), Fast Green (E143), Brilliant Black (E151), and Black 7984 (E152) in sugar and gummy confectionary, ice-cream, and chocolate sweets. Sample preparation included SPE clean-up and liquid-liquid extraction for ice-cream and chocolate sweets. Accuracy was evaluated by recovery experiments. Correlation between response and concentration was obtained with R(2)>0.98 for all but six colours. Limits of quantification were within the 10-50 μg/kg range for E129; 20-200 μg/kg for E152; 10-250 μg/kg for E103; 10-500 μg/kg for E102, E104, E107, E110, E122, E123, E124, E127, E128, E131, E133; 20-800 μg/kg for E132, 142, 151; and 10-1000 μg/kg for E143. CV for repeatability ranged from 4.0% to 51.0%, while the CV for intermediate reproducibility ranged from 5.8% to 41.4%. Finally, recoveries varied from 84.3% to 166.0%. Together, these demonstrate that the method has been validated for complex matrices and is, thus, fit-for-purpose. PMID:26675864

  18. Mismatches outside exons 2 and 3 do not alter the peptide motif of the allele group B*44:02P.

    Science.gov (United States)

    Bade-Doeding, Christina; Cano, Pedro; Huyton, Trevor; Badrinath, Soumya; Eiz-Vesper, Britta; Hiller, Oliver; Blasczyk, Rainer

    2011-11-01

    Sequence variations outside exons 2 and 3 do not appear to affect the function of human leukocyte antigen (HLA) class I alleles. HLA-B*44:02:01:01 and -B*44:27 are considered functionally identical because they differ by a single amino acid substitution of Val > Ala at position 199, which is located in the α3 domain. To validate that HLA-B*44:02:01:01 and -B*44:27 represent functionally identical alleles that might reflect a permissive mismatch in hematopoetic stem cell transplantation (HSCT), we determined their peptide-binding features. B-lymphoblastic cells were lentivirally transduced with B*44:02 and B*44:27 constructs and soluble recombinant molecules were purified by affinity chromatography. Peptides were isolated and sequencing of single peptides was performed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LTQ-Orbitrap) technology. We demonstrate that the peptide motif of B*44:02(199Val) and B*44:27(199Ala) is identical. Both variants feature E at P2 and Y, F, or W at PΩ in their ligands. Most of the identified peptides are 9 to 11 amino acids in length and approximately 20% of these ligands are shared between the alleles. Our results lead to the conclusion that B*44:02:01:01 and B*44:27 might have the same immune function, validating a theory that is now being used in deciding which donors to select in HSCT when there is no identical donor available. PMID:21872626

  19. Development of an improved method for trace analysis of quinolones in eggs of laying hens and wildlife species using molecularly imprinted polymers.

    Science.gov (United States)

    Blasco, Cristina; Picó, Yolanda

    2012-11-01

    A sensitive, selective, and efficient method was developed for simultaneous determination of 11 fluoroquinolones (FQs), ciprofloxacin, danofloxacin, difloxacin, enrofloxacin, flumequine, marbofloxacin, norfloxacin, ofloxacin, oxolinic acid, pipemidic acid, and sarafloxacin, in eggs by molecularly imprinted polymer (MIP) and column liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Samples were diluted with 50 mM sodium dihydrogen phosphate at pH 7.4, followed by purification with a commercial MIP (SupelMIP SPE-Fluoroquinolones). Recoveries for the 11 quinolones were in the range of 90-106% with intra- and interday relative standard deviation ranging from 1 to 6% and from 3 to 8%, respectively. Limits of detection (LODs) were 0.12-0.85 ng/g, and limits of quantification (LOQs) were 0.36 and 2.59 ng/g, whereas the decision limit (CC(α)) and detection capability (CC(β)) ranged from 0.46 to 3.35 ng/g and from 0.59 to 4.12 ng/g, respectively. The calculated relevant validation parameters are in an acceptable range and in compliance with the requirements of Commission Decision 2002/657/EC. Moreover, a comparison to two other sample treatments [solid-phase extraction (SPE) and solvent extraction] has been carried out. The method was applied to lying hens, Japanese quail, and black-headed gull eggs, in which FQs were not found. The method was also applied to study the depletion of sarafloxacin in eggs. PMID:23009602

  20. Analyses of the spleen proteome of chickens infected with Marek's disease virus

    International Nuclear Information System (INIS)

    Marek's disease virus (MDV), which causes a lymphoproliferative disease in chickens, is known to induce host responses leading to protection against disease in a manner dependent on genetic background of chickens and virulence of the virus. In the present study, changes in the spleen proteome at 7, 14 and 21 days post-infection in response to MDV infection were studied using two-dimensional polyacrylamide gel electrophoresis. Differentially expressed proteins were identified using one-dimensional liquid chromatography electrospray ionization tandem mass spectrometry (1D LC ESI MS/MS). Comparative analysis of multiple gels revealed that the majority of changes had occurred at early stages of the disease. In total, 61 protein spots representing 48 host proteins were detected as either quantitatively (false discovery rate (FDR) ≤ 0.05 and fold change ≥ 2) or qualitatively differentially expressed at least once during different sampling points. Overall, the proteins identified in the present study are involved in a variety of cellular processes such as the antigen processing and presentation, ubiquitin-proteasome protein degradation (UPP), formation of the cytoskeleton, cellular metabolism, signal transduction and regulation of translation. Notably, early stages of the disease were characterized by changes in the UPP, and antigen presentation. Furthermore, changes indicative of active cell proliferation as well as apoptosis together with significant changes in cytoskeletal components that were observed throughout the experimental period suggested the complexity of the pathogenesis. The present findings provide a basis for further studies aimed at elucidation of the role of these proteins in MDV interactions with its host.

  1. Variations in plasma and urinary lipids in response to enzyme replacement therapy for Fabry disease patients by nanoflow UPLC-ESI-MS/MS.

    Science.gov (United States)

    Byeon, Seul Kee; Kim, Jin Yong; Lee, Jin-Sung; Moon, Myeong Hee

    2016-03-01

    A deficiency of α-galactosidase A causes Fabry disease (FD) by disrupting lipid metabolism, especially trihexosylceramide (THC). Enzyme replacement therapy (ERT) is clinically offered to FD patients in an attempt to lower the accumulated lipids. Studies on specific types of lipids that are directly or indirectly altered by FD are very scarce, even though they are crucial in understanding the biological process linked to the pathogenesis of FD. We performed a comprehensive lipid profiling of plasma and urinary lipids from FD patients with nanoflow liquid chromatography electrospray-ionization tandem mass spectrometry (nLC-ESI-MS/MS) and identified 129 plasma and 111 urinary lipids. Among these, lipids that exhibited alternations (>twofold) in patients were selected as targets for selected reaction monitoring (SRM)-based high-speed quantitation using nanoflow ultra-performance LC-ESI-MS/MS (nUPLC-ESI-MS/MS) and 31 plasma and 26 urinary lipids showed significant elevation among FD patients. Higher percentages of sphingolipids (SLs; 48 % for plasma and 42 % for urine) were highly elevated in patients; whereas, a smaller percentage of phospholipids (PLs; 15 % for plasma and 13 % for urine) were significantly affected. Even though α-galactosidase A is reported to affect THC only, the results show that other classes of lipids (especially SLs) are changed as well, indicating that FD not only alters metabolism of THC but various classes of lipids too. Most lipids showing significant increases in relative amounts before ERT decreased after ERT, but overall, ERT influenced plasma lipids more than urinary lipids. Graphical abstract Brief overview of lipidomic analysis for Fabry disease using nLC-ESI-MS/MS and nUPLC-ESI-MS/MS. PMID:26873218

  2. Curcumin inhibits advanced glycation end product-induced oxidative stress and inflammatory responses in endothelial cell damage via trapping methylglyoxal

    Science.gov (United States)

    SUN, YAN PING; GU, JUN FEI; TAN, XIAO BIN; WANG, CHUN FEI; JIA, XIAO BIN; FENG, LIANG; LIU, JI PING

    2016-01-01

    Methylglyoxal (MGO)-induced carbonyl stress and pro-inflammatory responses have been suggested to contribute to endothelial dysfunction. Curcumin (Cur), a polyphenolic compound from Curcuma longa L., may protect endothelial cells against carbonyl stress-induced damage by trapping dicarbonyl compounds such as MGO. However, Cur-MGO adducts have not been studied in depth to date and it remains to be known whether Cur-MGO adducts are able to attenuate endothelial damage by trapping MGO. In the present study, 1,2-diaminobenzene was reacted with MGO to ensure the reliability of the reaction system. Cur was demonstrated to trap MGO at a 1:1 ratio to form adducts 1, 2 and 3 within 720 min. The structures of these adducts were identified by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry. The kinetic curves of Cur (10−7, 10−6 and 10−5 M) were measured from 0–168 h by fluorescent intensity. Cur significantly inhibited the formation of advanced glycation end products (AGEs). The differences in oxidative damage and the levels of pro-inflammatory cytokines following MGO + HSA or Cur-MGO treatment were investigated in human umbilical vein endothelial cells (HUVECs). Exposure of HUVECs to the Cur-MGO reaction adducts significantly reduced the intracellular ROS levels and improved cell viability compared with MGO alone. Furthermore, there was a significant reduction in the expression levels of transforming growth factor-β1 and intercellular adhesion molecule-1 following treatment with Cur-MGO adducts compared with MGO alone. These results provide further evidence that the trapping of MGO by Cur inhibits the formation of AGEs. The current study indicates that the protective effect of Cur on carbonyl stress and pro-inflammatory responses in endothelial damage occurs via the trapping of MGO. PMID:26718010

  3. Application of zirconium dioxide nanoparticle sorbent for the clean-up step in post-harvest pesticide residue analysis.

    Science.gov (United States)

    Uclés, Ana; Herrera López, Sonia; Dolores Hernando, Maria; Rosal, Roberto; Ferrer, Carmen; Fernández-Alba, Amadeo R

    2015-11-01

    The use of yttria-stabilized zirconium dioxide nanoparticles as d-SPE clean-up sorbent for a rapid and sensitive liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the determination of post-harvest fungicides (carbaryl, carbendazim, chlorpropham, diphenylamine, ethoxyquin, flutriafol, imazalil, iprodione, methomyl, myclobutanil, pirimiphos-methyl, prochloraz, pyrimethanil, thiabendazole, thiophanate-methyl and tolclofos-methyl) in orange and pear samples has been evaluated and validated. The sample preparation was a modification of the QuEChERS extraction method using yttria-stabilized zirconium dioxide and multi-walled carbon nanotubes (MWCNTs) nanoparticles as the solid phase extraction (d-SPE) clean-up sorbents prior to injecting the ten-fold diluted extracts into the LC system. By using the yttria-stabilized zirconium dioxide extraction method, more recoveries in the 70-120% range were obtained - thus this method was used for the validation. Quantification was carried out using a matrix-matched calibration curve which was linear in the 1-500 µg kg(-1) range for almost all the pesticides studied. The validated limit of quantification was 10 µg kg(-1) for most of the studied compounds, except chlorpropham, ethoxyquin and thiophanate-methyl. Pesticide recoveries at the 10 and 100 µg kg(-1) concentration levels were satisfactory, with values between 77% and 120% and relative standard deviations (RSD) lower than 10% (n=5). The developed method was applied for the determination of selected fungicides in 20 real orange and pear samples. Four different pesticide residues were detected in 10 of these commodities; 20% of the samples contained pesticide residues at a quantifiable level (equal to or above the LOQs) for at least one pesticide residue. The most frequently-detected pesticide residues were: carbendazim, thiabendazole and imazalil-all were below the MRL. The highest concentration found was imazalil at 1175 µg kg

  4. Mycobacterium tuberculosis AtsG (Rv0296c), GlmU (Rv1018c) and SahH (Rv3248c) Proteins Function as the Human IL-8-Binding Effectors and Contribute to Pathogen Entry into Human Neutrophils.

    Science.gov (United States)

    Dziadek, Bozena; Brzostek, Anna; Grzybowski, Marcin; Fol, Marek; Krupa, Agnieszka; Kryczka, Jakub; Plocinski, Przemyslaw; Kurdowska, Anna; Dziadek, Jaroslaw

    2016-01-01

    Mycobacterium tuberculosis is an extremely successful intracellular pathogen that has evolved a broad spectrum of pathogenic mechanisms that enable its manipulation of host defense elements and its survival in the hostile environment inside phagocytes. Cellular influx into the site of mycobacterial entry is mediated by a variety of chemokines, including interleukin-8 (IL-8), and the innate cytokine network is critical for the development of an adaptive immune response and infection control. Using affinity chromatography, liquid chromatography electrospray ionization tandem mass spectrometry and surface plasmon resonance techniques, we identified M. tuberculosis AtsG arylsulphatase, bifunctional glucosamine-1-phosphate acetyltransferase and N-acetylglucosamine-1-phosphate uridyl transferase (GlmU) and S-adenosyl-L-homocysteine hydrolase (SahH) as the pathogen proteins that bind to human IL-8. The interactions of all of the identified proteins (AtsG, GlmU and SahH) with IL-8 were characterized by high binding affinity with KD values of 6.83x10-6 M, 5.24x10-6 M and 7.14x10-10 M, respectively. Furthermore, the construction of Mtb mutant strains overproducing AtsG, GlmU or SahH allowed determination of the contribution of these proteins to mycobacterial entry into human neutrophils. The significantly increased number of intracellularly located bacilli of the overproducing M. tuberculosis mutant strains compared with those of "wild-type" M. tuberculosis and the binding interaction of AtsG, GlmU and SahH proteins with human IL-8 may indicate that these proteins participate in the modulation of the early events of infection with tubercle bacilli and could affect pathogen attachment to target cells. PMID:26829648

  5. Determination of iron content and dispersity of intact ferritin by superconducting tunnel junction cryodetection mass spectrometry.

    Science.gov (United States)

    Plath, Logan D; Ozdemir, Abdil; Aksenov, Alexander A; Bier, Mark E

    2015-09-01

    Ferritin is a common iron storage protein complex found in both eukaryotic and prokaryotic organisms. Although horse spleen holoferritin (HS-HoloFt) has been widely studied, this is the first report of mass spectrometry (MS) analysis of the intact form, likely because of its high molecular weight ∼850 kDa and broad iron-core mass distribution. The 24-subunit ferritin heteropolymer protein shell consists of light (L) and heavy (H) subunits and a ferrihydrite-like iron core. The H/L heterogeneity ratio of the horse spleen apoferritin (HS-ApoFt) shell was found to be ∼1:10 by liquid chromatography-electrospray ionization mass spectrometry. Superconducting tunneling junction (STJ) cryodetection matrix-assisted laser desorption ionization time-of-flight MS was utilized to determine the masses of intact HS-ApoFt, HS-HoloFt, and the HS-HoloFt dimer to be ∼505 kDa, ∼835 kDa, and ∼1.63 MDa, respectively. The structural integrity of HS-HoloFt and the proposed mineral adducts found for both purified L and H subunits suggest a robust biomacromolecular complex that is internally stabilized by the iron-based core. However, cross-linking experiments of HS-HoloFt with glutaraldehyde, unexpectedly, showed the complete release of the iron-based core in a one-step process revealing a cross-linked HS-ApoFt with a narrow fwhm peak width of 31.4 kTh compared to 295 kTh for HS-HoloFt. The MS analysis of HS-HoloFt revealed a semiquantitative description of the iron content and core dispersity of 3400 ± 1600 (2σ) iron atoms. Commercially prepared HS-ApoFt was estimated to still contain an average of 240 iron atoms. These iron abundance and dispersity results suggest the use of STJ cryodetection MS for the clinical analysis of iron deficient/overload diseases. PMID:26266697

  6. Characterization of wheat gliadin proteins by combined two-dimensional gel electrophoresis and tandem mass spectrometry.

    Science.gov (United States)

    Mamone, Gianfranco; Addeo, Francesco; Chianese, Lina; Di Luccia, Aldo; De Martino, Alessandra; Nappo, Annunziata; Formisano, Annarita; De Vivo, Pasqualina; Ferranti, Pasquale

    2005-07-01

    A proteomics-based approach was used for characterizing wheat gliadins from an Italian common wheat (Triticum aestivum) cultivar. A two-dimensional gel electrophoresis (2-DE) map of roughly 40 spots was obtained by submitting the 70% alcohol-soluble crude protein extract to isoelectric focusing on immobilized pH gradient strips across two pH gradient ranges, i.e., 3-10 or pH 6-11, and to sodium dodecyl sulfate-polyacrylamide electrophoresis in the second dimension. The chymotryptic digest of each spot was characterized by matrix-assisted laser desorption/ionization-time of flight mass spectrometry and nano electrospray ionization-tandem mass spectrometry (MS/MS) analysis, providing a "peptide map" for each digest. The measured masses were subsequently sought in databases for sequences. For accurate identification of the parent protein, it was necessary to determine de novo sequences by MS/MS experiments on the peptides. By partial mass fingerprinting, we identified protein molecules such as alpha/beta-, gamma-, omega-gliadin, and high molecular weight-glutenin. The single spots along the 2-DE map were discriminated on the basis of their amino acid sequence traits. alpha-Gliadin, the most represented wheat protein in databases, was highly conserved as the relative N-terminal sequence of the components from the 2-DE map contained only a few silent amino acid substitutions. The other closely related gliadins were identified by sequencing internal peptide chains. The results gave insight into the complex nature of gliadin heterogeneity. This approach has provided us with sound reference data for differentiating gliadins amongst wheat varieties. PMID:15952231

  7. Use of specific peptide biomarkers for quantitative confirmation of hidden allergenic peanut proteins Ara h 2 and Ara h 3/4 for food control by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Careri, M; Costa, A; Elviri, L; Lagos, J-B; Mangia, A; Terenghi, M; Cereti, A; Garoffo, L Perono

    2007-11-01

    A liquid chromatography-electrospray-tandem mass spectrometry (LC-ESI-MS-MS) method based on the detection of biomarker peptides from allergenic proteins was devised for confirming and quantifying peanut allergens in foods. Peptides obtained from tryptic digestion of Ara h 2 and Ara h 3/4 proteins were identified and characterized by LC-MS and LC-MS-MS with a quadrupole-time of flight mass analyzer. Four peptides were chosen and investigated as biomarkers taking into account their selectivity, the absence of missed cleavages, the uniform distribution in the Ara h 2 and Ara h 3/4 protein isoforms together with their spectral features under ESI-MS-MS conditions, and good repeatability of LC retention time. Because of the different expression levels, the selection of two different allergenic proteins was proved to be useful in the identification and univocal confirmation of the presence of peanuts in foodstuffs. Using rice crisp and chocolate-based snacks as model food matrix, an LC-MS-MS method with triple quadrupole mass analyzer allowed good detection limits to be obtained for Ara h 2 (5 microg protein g(-1) matrix) and Ara h 3/4 (1 microg protein g(-1) matrix). Linearity of the method was established in the 10-200 microg g(-1) range of peanut proteins in the food matrix investigated. Method selectivity was demonstrated by analyzing tree nuts (almonds, pecan nuts, hazelnuts, walnuts) and food ingredients such as milk, soy beans, chocolate, cornflakes, and rice crisp. PMID:17899033

  8. Determination of seven benzoylphenylurea insecticides in processed fruit and vegetables using high-performance liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Sannino, Anna; Bandini, Mirella

    2005-01-01

    A liquid chromatographic method with electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) has been developed for the sensitive and selective determination of seven benzoylphenylurea insecticide residues (diflubenzuron, triflumuron, lufenuron, flufenoxuron, teflubenzuron, chlorfuazuron, hexaflumuron) in pear baby purée, concentrated lemon juice, and tomato pulp. The general sample extraction/partition method for our established multiresidue methods has been used. The entire procedure involves extraction of residues with acetone and partition into ethyl acetate/cyclohexane. Chromatographic determination was performed using a C18 column and isocratic elution. Fourteen MS/MS transitions of precursor ions were monitored (two for each pesticide) using negative ESI. The majority of mean recoveries at fortification levels of 0.002-0.020 and 0.020-0.200 mg/kg were in the range 77-102% with relative standard deviations between 2 and 10%. The excellent sensitivity and selectivity of this LC/MS/MS method allowed quantitation and identification at low levels in difficult matrices with a run time of 4 min. PMID:16136517

  9. Biomimetic oxidation studies of monensin A catalyzed by metalloporphyrins: identification of hydroxyl derivative product by electrospray tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    José N. Sousa-Junior

    2013-08-01

    Full Text Available Monensin A is an important commercially available natural product isolated from Streptomyces cinnamonensins that shows antibiotic and anti-parasitic activities. This molecule has a significant influence in the antibiotic market, but until now there are no studies on putative metabolite formations. Bioorganic catalysts applying metalloporphyrins and mono-oxygen donors are able to mimic the cytochrome P450 reactions. This model has been employed for natural product metabolism studies affording several new putative metabolites and in vivo experiments confirming the relevance of this procedure. In this work we evaluated the potential of 10,15,20-tetrakis (pentafluorophenyl porphyrin metal(III chloride [Fe(TFPPCl] catalyst models to afford a putative monensin A metabolite. Oxidation agents such as meta-chloroperoxy benzoic acid, iodosylbenzene, hydrogen peroxide 30 wt.% and tert-butyl hydroperoxide 70 wt.%, were used to investigate different reaction conditions, in addition to the analysis of the influence of the solvent. The quantification of total monensin A conversion and the structure of the new hydroxylated putative metabolite were proposed based on electrospray ionization tandem mass spectrometry analysis. The porphyrin tested, afforded moderate conversions of monensin A in all reaction conditions and the selectivity was found to be dependent on the oxidation/medium employed.

  10. Determination of Flavonoids and Anthocyanins in Nitraria tangutorum by High Performance Liquid Chromatography Coupled with Tandem Mass Spectrometry.

    Science.gov (United States)

    Zhe, Gao; Ying-Chun, Wang; Yan-Xu, Chang

    2016-01-01

    Using high-performance liquid chromatography coupled with diode array detection and electrospray ionization tandem mass spectrometry (HPLC-DAD-MSn) method, qualitative and quantitative analysis of flavonoids of stems, leaves, fruits and seeds, and anthocyanidin of fresh fruits in Nitraria tangutorum were performed. A total of 14 flavonoid components were identified from the seeds of N. tangutorum including three quercetin derivatives, three kaempferol derivatives, and eight isorhamnetin derivatives. A total of 12, 10, and 7 flavonoid components were identified from leaves, stems, and fruits of N. tangutorum, respectively; all were present in seeds also. The total content of flavonoids in leaves was the highest, up to 42.43 mg/g·dry weight. A total of 12 anthocyanidin components were identified from the fresh fruits of N. tangutorum, belonging to five anthocyanidin. The total content of anthocyanidin in fresh fruits was up to 45.83 mg/100 g· fresh weight, of which the acylated anthocyanidin accounted for 65.7%. The HPLC-DAD-MS(n) method can be operated easily, rapidly, and accurately, and is feasible for qualitative and quantitative analysis of flavone glycosides in N. tangutorum. PMID:26972973

  11. Determination of melamine in milk-based products and other food and beverage products by ion-pair liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ibanez, Maria; Sancho, Juan V. [Research Institute for Pesticides and Water, University Jaume I, E-12071, Castellon (Spain); Hernandez, Felix, E-mail: felix.hernandez@qfa.uji.es [Research Institute for Pesticides and Water, University Jaume I, E-12071, Castellon (Spain)

    2009-09-01

    This paper describes a fast method for the sensitive and selective determination of melamine in a wide range of food matrices, including several milk-based products. The method involves an extraction with aqueous 1% trichloroacetic acid before the injection of the 10-fold diluted extract into the liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) system, using labelled melamine as the internal standard. As melamine is present in aqueous media in the cationic form, the chromatographic separation in reversed-phase LC requires the use of anionic ion-pair reagents, such as tridecafluoroheptanoic acid (THFA). This allows a satisfactory chromatographic retention and peak shape in all the types of food samples investigated. The method has been validated in six food matrices (biscuit, dry pasta and four milk-based products) by means of recovery experiments in samples spiked at 1 and 5 mg kg{sup -1}. Average recoveries (n = 5) ranged from 77% to 100%, with excellent precision (RSDs lower than 5%) and limits of detection between 0.01 and 0.1 mg kg{sup -1}. In addition, accuracy and robustness of the method was proven in different soya-based matrices by means of quality control (QC) sample analysis. QC recoveries, at 1 and 2.5 mg kg{sup -1}, were satisfactory, ranging from 79% to 110%. The method developed in this work has been applied to the determination of melamine in different types of food samples. All detections were confirmed by acquiring two MS/MS transitions (127 > 85 for quantification; 127 > 68 for confirmation) and comparing their ion intensity ratio with that of reference standards. Accuracy of the method was also assessed by applying it to a milk-based product and a baking mix material as part of an EU proficiency test, in which highly satisfactory results were obtained.

  12. Determination of melamine in milk-based products and other food and beverage products by ion-pair liquid chromatography-tandem mass spectrometry

    International Nuclear Information System (INIS)

    This paper describes a fast method for the sensitive and selective determination of melamine in a wide range of food matrices, including several milk-based products. The method involves an extraction with aqueous 1% trichloroacetic acid before the injection of the 10-fold diluted extract into the liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) system, using labelled melamine as the internal standard. As melamine is present in aqueous media in the cationic form, the chromatographic separation in reversed-phase LC requires the use of anionic ion-pair reagents, such as tridecafluoroheptanoic acid (THFA). This allows a satisfactory chromatographic retention and peak shape in all the types of food samples investigated. The method has been validated in six food matrices (biscuit, dry pasta and four milk-based products) by means of recovery experiments in samples spiked at 1 and 5 mg kg-1. Average recoveries (n = 5) ranged from 77% to 100%, with excellent precision (RSDs lower than 5%) and limits of detection between 0.01 and 0.1 mg kg-1. In addition, accuracy and robustness of the method was proven in different soya-based matrices by means of quality control (QC) sample analysis. QC recoveries, at 1 and 2.5 mg kg-1, were satisfactory, ranging from 79% to 110%. The method developed in this work has been applied to the determination of melamine in different types of food samples. All detections were confirmed by acquiring two MS/MS transitions (127 > 85 for quantification; 127 > 68 for confirmation) and comparing their ion intensity ratio with that of reference standards. Accuracy of the method was also assessed by applying it to a milk-based product and a baking mix material as part of an EU proficiency test, in which highly satisfactory results were obtained.

  13. Rapid chemical profiling of saponins in the flower buds of Panax notoginseng by integrating MCI gel column chromatography and liquid chromatography/mass spectrometry analysis.

    Science.gov (United States)

    Yang, Wen-Zhi; Bo, Tao; Ji, Shuai; Qiao, Xue; Guo, De-An; Ye, Min

    2013-08-15

    The flower buds of Panax notoginseng (Notoginseng flower, FBP) are used as the traditional Chinese medicine San-Qi-Hua. In this study, we conducted column chromatography fractionation and liquid chromatography/mass spectrometry (LC/MS) analysis to comprehensively profile bioactive notoginseng saponins (ginsenosides) in FBP. MCI gel column chromatography allowed separation and enrichment of minor saponins. Electrospray ionization tandem mass spectrometry of [M-H](-) and [M+Na](+) precursor ions of the saponins provided reliable structural information for the sapogenin, and sequence of sugar chains. Confirmed by high-accuracy Q-TOF analysis, 170 notoginseng saponins were characterized from FBP, and 91 of them were reported from Panax species for the first time. The new ginsenosides contain acyl groups on α-chain, malonyl group at 20-OH, or di-malonyl groups. This study also indicated that the flower buds of P. notoginseng contained more protopanaxadiol-type but less protopanaxatriol-type ginsenosides than the roots. PMID:23561171

  14. Development of a multi-residue method for the determination of organic micropollutants in water, sediment and mussels using gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Sánchez-Avila, Juan; Fernandez-Sanjuan, María; Vicente, Joana; Lacorte, Silvia

    2011-09-23

    This study describes the development of a multiresidue method based on gas chromatography-electron ionization-tandem mass spectrometry (GC-EI-MS/MS) for the detection of sixteen polycyclic aromatic hydrocarbons (PAHs), five phthalate esters (PEs), seven polychlorinated biphenyls (PCBs), six polybrominated diphenyl ethers (PBDEs), six alkylphenols (APs), three organochlorined pesticides and their isomers or degradation products (OCPs) and bisphenol A in seawater, river water, wastewater treatment plant (WWTP) effluents, sediments and mussels. Solid phase extraction (SPE) was used for the extraction of target analytes in aqueous samples, and ultrasound assisted extraction for solid samples. GC-EI-MS/MS acquisition conditions in selected reaction monitoring (SRM) using two transitions per compound were optimized. In this way, quantification and unequivocal identification of organic micropollutants were performed in compliance with the Decision 2002/657/EC. Good linearity responses with coefficients of determination higher than 0.99 were obtained. Methodological detection limits (MDLs) in seawater ranged from 0.1 to 6 ng L(-1); in river water from 0.1 to 4.8 ng L(-1); in WWTP effluents from 1 to 75 ng L(-1); in sediments from 1 to 150 ng g(-1) and in mussels from 1 to 125 ng g(-1). MDLs and recovery yields were compared with other published methods and similarities or even improvements were achieved. The optimized method was applied to analyze five samples from each matrix collected in coastal areas, showing its potential use for marine pollution monitoring. PMID:21824622

  15. Pesticides residues in water treatment plant sludge: validation of analytical methodology using liquid chromatography coupled to Tandem mass spectrometry (LC-MS/MS)

    International Nuclear Information System (INIS)

    The evolving scenario of Brazilian agriculture brings benefits to the population and demands technological advances to this field. Constantly, new pesticides are introduced encouraging scientific studies with the aim of determine and evaluate impacts on the population and on environment. In this work, the evaluated sample was the sludge resulted from water treatment plant located in the Vale do Ribeira, Sao Paulo, Brazil. The technique used was the reversed phase liquid chromatography coupled to electrospray ionization tandem mass spectrometry. Compounds were previously liquid extracted from the matrix. The development of the methodology demanded data processing in order to be transformed into reliable information. The processes involved concepts of validation of chemical analysis. The evaluated parameters were selectivity, linearity, range, sensitivity, accuracy, precision, limit of detection, limit of quantification and robustness. The obtained qualitative and quantitative results were statistically treated and presented. The developed and validated methodology is simple. As results, even exploring the sensitivity of the analytical technique, the work compounds were not detected in the sludge of the WTP. One can explain that these compounds can be present in a very low concentration, can be degraded under the conditions of the water treatment process or are not completely retained by the WTP. (author)

  16. Development and validation of an ultra high performance liquid chromatography tandem mass spectrometry method for determination of 10 cephalosporins and desacetylcefapirin in milk.

    Science.gov (United States)

    Hou, Xiao-Lin; Wu, Yin-Liang; Lv, Yan; Xu, Xiu-Qin; Zhao, Jian; Yang, Ting

    2013-07-15

    A simple, sensitive and reliable analytical method was developed for the simultaneous determination of 10 cephalosporins and desacetylcefapirin in bovine milk by ultra high performance liquid chromatography-positive electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS). Samples were directly purified through HLB cartridge after dilution with 50mM phosphate buffer solution (pH 8.5). Then the eluate was dried under nitrogen and the residue was redissolved in mobile phase. Samples were analyzed by LC-MS/MS on an Acquity UPLC BEH Shield RP18 column with gradient elution. The samples were quantified using ceftiofur-D3 as internal standard. The proposed method was validated according to the European Commission Decision 2002/657/EC. The CCα values were 111, 0.04, 140, 55, 55, 67, 23, 23, 68, 0.10 and 113μg/kg for cefalexin, cefradine, cefacetrile, cefazolin, cefoperazone, cefapirin, cefalonium, cefquinome, desacetylcefapirin, cefotaxime and ceftiofur, respectively. The mean recoveries, repeatability (expressed as coefficient of variation, CVr), and reproducibility (CVR) varied from 94.6% to 117.1%, from 5.6% to 13.6% (CVr), and from 5.9% to 27.9% (CVR), respectively. The method is demonstrated to be suitable for the determination of 10 cephalosporins and desacetylcefapirin in bovine milk. The total time required for the analysis of one sample, including sample preparation, was about 40min. PMID:23747425

  17. In vitro Metabolism of Sodium 9-dehydro-17-hydro-andrographolide-19-yl Sulfate in Rat Liver S9 by Liquid Chromatography–Mass Spectrometry Method

    Science.gov (United States)

    Zheng, Dongkun; Shao, Jun; Chen, Weikang; Luo, Yuehua

    2016-01-01

    Background: Sodium 9-dehydro-17-hydro-andrographolide-19-yl sulfate (DHAS) is the active ingredient of Xiyanping injection, a traditional Chinese medicine in clinical use. However, there has been no report about the metabolic rate and metabolites of DHAS in vitro. Materials and Methods: In this article, DHAS was incubated with rat liver S9, and liquid chromatography/mass spectrometry (LC/MS) was used for the metabolism study. The residual concentrations of substrate were determined by ultra-high-performance liquid chromatography-electrospray ionization–tandem mass spectrometry method for the metabolic rate study of DHAS in liver S9. Metabolites were identified by the (UPLC-TOF-MSE) Ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry method. Results: The calibration curves of DHAS were linear over the concentration range from 0.75 μM to 75.22 μM with correlation coefficients >0.99. The lower limit of quantification was 0.150 μM for DHAS. The determination recoveries of DHAS were in the range of 84.9–90.6%. The t½ and CLint of DHAS in rat liver S9 were 98.6 ± 2.1 min and 3.5 ± 0.1 mL/min/g, respectively. Five metabolites were preliminarily identified based on the high resolution mass spectrum data in comparison with related references. These metabolites were mainly the products of dehydration and hydrogenation of DHAS. Conclusion: The present in vitro metabolic study of DHAS provided valuable information about the metabolic rate and potential metabolites of DHAS, which are important for future in vivo metabolism studies of DHAS and the discovery of more active andrographolide derivatives. SUMMARY In this paper, sodium 9-dehydro-17-hydro-andrographolide-19-yl sulfate (DHAS) metabolism in vitro has been investigated with rat liver S9 using liquid chromatography-mass spectrometry (LC-MS). The result of quantitative analysis showed that DHAS had a long t1/2, which indicated its high metabolic stability. Five metabolites of DHAS

  18. New method for caffeine quantification by planar chromatography coupled with electropray ionization mass spectrometry using stable isotope dilution analysis.

    Science.gov (United States)

    Aranda, Mario; Morlock, Gertrud

    2007-01-01

    A new high-performance thin-layer chromatography/electrospray ionization mass spectrometry (HPTLC/ESI-MS) method for the quantification of caffeine in pharmaceutical and energy drink samples was developed using stable isotope dilution analysis (SIDA). After sample preparation, samples and caffeine standard were applied on silica gel 60 F254 HPTLC plates and over-spotted with caffeine-d3 used for correction of the plunger positioning. After chromatography, densitometric detection was performed by UV absorption at 274 nm. The bands were then eluted by means of a plunger-based extractor into the ESI interface of a single-quadrupole mass spectrometer. For quantification by MS the [M+H]+ ions of caffeine and caffeine-d3 were recorded in the positive ion single ion monitoring (SIM) mode at m/z 195 and 198, respectively. The calibration showed a linear regression with a determination coefficient (R2) of 0.9998. The repeatability (RSD, n=6) in matrix wasbrand names were determined three times and ranged between RSD+/-0.68% and+/-2.64% (sample 1) and between+/-3.44% and+/-8.60% (sample 2). The method accuracy was evaluated by comparing the results obtained by HPTLC/SIDA-ESI-MS with those from the validated HPTLC/UV method. The results for pharmaceutical and energy drink samples were (ng/band) 99.82+/-3.75 and 338.09+/-4.87 by HPTLC/SIDA-ESI-MS and 104.74+/-1.51 and 334.86+/-5.63 by HPTLC/UV. According to the F-test (homogeneity of variances) and the t-test (comparison of means) the two methods show no significant difference. The detection and quantification limits were 75 and 250 microg L-1 (0.75 and 2.5 ng/band), respectively, which were a factor of 13 lower than those established for HPTLC/UV. The positioning error (RSD+/-6%) was calculated by comparing HPTLC/SIDA-ESI-MS with HPTLC/ESI-MS. However, using SIDA the positioning error was nullified. HPTLC/SIDA-ESI-MS was demonstrated to be a highly reliable method for the quantification of compounds by planar chromatography

  19. Quantification of clenbuterol at trace level in human urine by ultra-high pressure liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Nicoli, Raul; Petrou, Michael; Badoud, Flavia; Dvorak, Jiri; Saugy, Martial; Baume, Norbert

    2013-05-31

    Clenbuterol is a β2 agonist agent with anabolic properties given by the increase in the muscular mass in parallel to the decrease of the body fat. For this reason, the use of clenbuterol is forbidden by the World Anti-Doping Agency (WADA) in the practice of sport. This compound is of particular interest for anti-doping authorities and WADA-accredited laboratories due to the recent reporting of risk of unintentional doping following the eating of meat contaminated with traces of clenbuterol in some countries. In this work, the development and the validation of an ultra-high pressure liquid chromatography coupled to electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) method for the quantification of clenbuterol in human urine is described. The analyte was extracted from urine samples by liquid-liquid extraction (LLE) in basic conditions using tert butyl-methyl ether (TBME) and analyzed by UHPLC-MS/MS with a linear gradient of acetonitrile in 9min only. The simple and rapid method presented here was validated in compliance with authority guidelines and showed a limit of quantification at 5pg/mL and a linearity range from 5pg/mL to 300pg/mL. Good trueness (85.8-105%), repeatability (5.7-10.6% RSD) and intermediate precision (5.9-14.9% RSD) results were obtained. The method was then applied to real samples from eighteen volunteers collecting urines after single oral doses administration (1, 5 and 10μg) of clenbuterol-enriched yogurts. PMID:23294994

  20. Enzyme-assisted extraction and liquid chromatography mass spectrometry for the determination of arsenic species in chicken meat.

    Science.gov (United States)

    Liu, Qingqing; Peng, Hanyong; Lu, Xiufen; Le, X Chris

    2015-08-12

    Chicken is the most consumed meat in North America. Concentrations of arsenic in chicken range from μg kg(-1) to mg kg(-1). However, little is known about the speciation of arsenic in chicken meat. The objective of this research was to develop a method enabling determination of arsenic species in chicken breast muscle. We report here enzyme-enhanced extraction of arsenic species from chicken meat, separation using anion exchange chromatography (HPLC), and simultaneous detection with both inductively coupled plasma mass spectrometry (ICPMS) and electrospray ionization tandem mass spectrometry (ESIMS). We compared the extraction of arsenic species using several proteolytic enzymes: bromelain, papain, pepsin, proteinase K, and trypsin. With the use of papain-assisted extraction, 10 arsenic species were extracted and detected, as compared to 8 detectable arsenic species in the water/methanol extract. The overall extraction efficiency was also improved using a combination of ultrasonication and papain digestion, as compared to the conventional water/methanol extraction. Detection limits were in the range of 1.0-1.8 μg arsenic per kg chicken breast meat (dry weight) for seven arsenic species: arsenobetaine (AsB), inorganic arsenite (As(III)), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), inorganic arsenate (As(V)), 3-nitro-4-hydroxyphenylarsonic acid (Roxarsone), and N-acetyl-4-hydroxy-m-arsanilic acid (NAHAA). Analysis of breast meat samples from six chickens receiving feed containing Roxarsone showed the presence of (mean±standard deviation μg kg(-1)) AsB (107±4), As(III) (113±7), As(V) (7±2), MMA (51±5), DMA (64±6), Roxarsone (18±1), and four unidentified arsenic species (approximate concentration 1-10 μg kg(-1)). PMID:26320952

  1. Simultaneous determination and pharmacokinetic study of four phenol compounds in rat plasma by ultra-high performance liquid chromatography with tandem mass spectrometry after oral administration of Echinacea purpurea extract.

    Science.gov (United States)

    Gan, Chunli; Liu, Lu; Du, Yan; Wang, Liqian; Gao, Mingjie; Wu, Lijun; Yang, Chunjuan

    2016-05-01

    A rapid and sensitive assay based on ultra-high performance liquid chromatography with electrospray ionization tandem mass spectrometry was established and validated for the simultaneous determination of cichoric acid, chlorogenic acid, quinic acid, and caffeic acid in rat plasma after oral administration of Echinacea purpurea extract using butylparaben as the internal standard. Samples were pretreated by liquid-liquid extraction with ethyl acetate. The separations for analytes were performed on an ACQUITY UPLC HSS C18 column (1.8 μm 2.1 × 100 mm) using a gradient elution program with acetonitrile/10 mM ammonium acetate (pH 5.6) at a flow rate of 0.3 mL/min. The analytes were detected in multiple reaction monitoring mode with negative electrospray ionization. The lower limit of quantification of each analyte was not higher than 10.85 ng/mL. The relative standard deviation of the intraday and interday precisions was less than 14.69%. The relative errors of accuracies were in the range of -13.80 to 14.91%. The mean recoveries for extraction recovery and matrix effect were higher than 80.79 and 89.98%, respectively. The method validation results demonstrated that the proposed method was sensitive, specific, and reliable, which was successfully applied to the pharmacokinetic study of four components after oral administration of Echinacea purpurea extract. PMID:26924074

  2. [Determination of 32 sulfonylurea herbicide residues in sweet corns and green soybeans by QuEChERS-liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Wang, Lianzhu; Huang, Xiaoyan; Wang, Dengfei; Chen, Yong; Xu, Dunming; Zhou, Yu

    2015-05-01

    A fast method based on QuEChERS methodology for the simultaneous determination of 32 sulfonylurea herbicide residues in sweet corns and green soybeans was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The clean-up effects of three dispersive sorbents were evaluated in terms of the residue mass for extracts after evaporation and recoveries. The three sorbents were C18, a mixture of two sorbents--silica coated with zirconium dioxide (Z-Sep) and C18, a bonded C18 zirconia-coated silica (Z-Sep+). As a result, the best effects were obtained from using Z-Sep/C18 sorbents. The samples were extracted with acetonitrile, and salted out with anhydrous magnesium sulphate and sodium chloride. The extracts were cleaned up with dispersive solid phase extraction using Z-Sep/C18 sorbents. Chromatographic analysis was carried out using a CSH C18 column with gradient elution. The pesticides were analyzed by negative electrospray ionization tandem mass spectrometry under scheduled multiple reaction monitoring mode. The quantification was achieved using matrix-matched standard calibrations as the external standard. The recoveries at fortification levels of 10, 20, 100 µg/kg in sweet corns and green beans ranged from 80.0% to 108.2% with the relative standard deviations of 1.2%-13.0%. The limits of quantification (S/N ≥ 10) were 0.2-5.0 µg/kg. The method has been proven to be simple, sensitive, environmental, and thus suitable for the determination of the 32 sulfonylurea herbicide residues in sweet corns and green soy- beans. PMID:26387208

  3. [Simultaneous determination and screening of five pigments in marine phytoplanktons by high performance liquid chromatography-triple quadrupole mass spectrometry].

    Science.gov (United States)

    Zheng, Liyang; Chen, Juanjuan; Xu, Jilin; Zhou, Chengxu; Yan, Xiaojun

    2014-09-01

    A quantitative method based on high performance liquid chromatography coupled with electrospray ionization tandem triple-quadrupole mass spectrometry (HPLC-ESI-QqQ-MS) has been established for five pigments in marine phytoplanktons. The HPLC method used ternary solvent systems and a reversed-phase C16-amide column. In addition, methanol, acetonitrile and aqueous ammonium acetate were used as mobile phases. Five pigments (chlorophyll a, chlorophyll b, β, β-carotene, lutein and fucoxanthin) were quantified in selective reaction mode. As results, good linear relationships were achieved between the concentrations and the peak areas of the five pigment standards. And their correlation coefficients (r2) were higher than 0.996. The recoveries of the pigment standards were between 82.77% and 99.83%. The inter-day and intra-day precisions were lower than 5% (n = 5). The detection limits of the pigments for this method were between 0.02 and 0.16 μg/L and the quantification limits were in the range from 0.06 to 0.54 μg/L. According to the above method, eleven algae (Heterosigma akashiwo (NMBRah03-2), Heterosigma akashiwo (NMBRah03-2-2), Karlodinium veneficum (NMBjah047-1), Prorocentrum minimum ( NMBjah042), Nannochloropsis oceanic (NMBluh014), Chlorella pyrenoidosa (NMBluh015-1), Pleurochrysis sp. (NMBjih026-1), Prymnesium sp. (NMBjih029), Skeletonema costatum (NMBguh004-1), Thalassiosira weiss- flogii (NMBguh021) and Thalassiosira pseudonana) (NMBguh005)) have been investigated for comparing the pigment distributions. The method is sensitive, accurate, reproducible, and useful for the study of alga compositions. PMID:25752094

  4. Quantification of melamine in human urine using cation-exchange based high performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Panuwet, Parinya; Nguyen, Johnny V; Wade, Erin L; D'Souza, Priya E; Ryan, P Barry; Barr, Dana Boyd

    2012-03-01

    Melamine and cyanuric acid have been implicated as adulterants in baby formula in China and pet foods in North America. In China, the effect of melamine or melamine-cyanuric acid adulteration lead to kidney stone development and acute renal failure in thousands of Chinese infants. A selective and sensitive analytical method was developed to measure melamine in human urine in order to evaluate the extent of potential health implications resulting from the consumption of these types of adulterated products in the general US population. This method involves extracting melamine from human urine using cation-exchange solid-phase extraction, chromatographically separating it from its urinary matrix co-extractants on a silica-based, strong-cation exchange analytical column using high performance liquid chromatography, and analysis using positive mode electrospray ionization tandem mass spectrometry. Quantification was performed using modified, matrix-based isotope dilution calibration covering the concentration range of 0.50-100 ng/mL. The limit of detection, calculated using replicates of blank and low level spiked samples, was 0.66 ng/mL and the relative standard deviations were between 6.89 and 14.9%. The relative recovery of melamine was 101-106%. This method was tested for viability by analyzing samples collected from the general US population. Melamine was detected in 76% of the samples tested, with a geometric mean of 2.37 ng/mL, indicating that this method is suitable for reliably detecting background exposures to melamine or other chemicals from which it can be derived. PMID:22309774

  5. Neutrino masses

    CERN Document Server

    Buccella, F

    2004-01-01

    By requiring the lower limit for the lightest right-handed neutrino mass, obtained in the baryogenesis from leptogenesis scenario, and a Dirac neutrino mass matrix similar to the up-quark mass matrix we predict small values for the $\

  6. Using positive-ion electrospray ionization mass spectrometry and H/D exchange study phosphoryl group transfer reactions involved in amino acid ester isopropyl phosphoramidates of Brefeldin A

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Mei-Juan; Zhang, He; Liao, Chao; Qiu, Ying-Kun [School of Pharmaceutical Sciences and the Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiang-An South Road, Xiamen 361102 (China); Fang, Hua [The Third Institute of Oceanography of the State Oceanic Administration, Xiamen 361005 (China); Zheng, Zhen-Yu [College of Chemistry and Chemical Engineering, Department of Chemistry, Xiamen University, Xiamen 361005 (China); Gao, Xiang [School of Pharmaceutical Sciences and the Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiang-An South Road, Xiamen 361102 (China); Zhao, Yu-Fen [School of Pharmaceutical Sciences and the Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiang-An South Road, Xiamen 361102 (China); College of Chemistry and Chemical Engineering, Department of Chemistry, Xiamen University, Xiamen 361005 (China); Wu, Zhen, E-mail: wuzhen@xmu.edu.cn [School of Pharmaceutical Sciences and the Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiang-An South Road, Xiamen 361102 (China)

    2015-01-01

    Highlights: • ESI-MS{sup n}, HRMS and H/D exchange were used. • The fragmentation pathways of NPAAE-BFA in ESI-MS{sup n} were described. • Fragment ions involved in phosphorus group’s rearrangement reactions were observed. • Two rearrangement mechanisms about phosphorylation–dephosphorylation were proposed. - Abstract: As mini-chemical models, amino acid ester isopropyl phosphoramidates of Brefeldin A (compounds 2a–2d) were synthesized and investigated by electrospray ionization tandem mass spectrometry in combination with H/D exchange. To further confirm the fragments’s structures, off-line Fourier transform resonance tandem mass spectrometry (FT-ICR-MS/MS) was also performed. The fragmentation rules of compounds 2a–2d have been summarized and the plausible schemes for the fragmentation pathways were proposed. In this study, one dephosphorylated ion and two phosphorylated ions were observed in ESI-MS{sup 2} spectra of [M + Na]{sup +} ions for compounds 2a–2d. The possible mechanisms about phosphorylation and dephosphorylation were proposed and confirmed by H/D exchange. For the “dephosphorylation” rearrangement, a nitrogen atom was migrated from the phosphoryl group to the carbon atom of Brefeldin A’s backbone with losing a molecule of C{sub 3}H{sub 7}PO{sub 3} (122 Da). For the “phosphorylation” rearrangement, an oxygen atom of one phosphoryl group attacked the sideward phosphorus atom to form a nine-member ring intermediate, then two steps of C-H covalent bond cleavage with consecutive migration of hydrogen atom to lose a molecule of C{sub 16}H{sub 20}O{sub 2} (244 Da). The two proposed rearrangement mechanisms about phosphoryl group transfer might be valuable for the structure analysis of other analogs and provide insights into elucidating the dynamic process of the phosphorylation–dephosphorylation of proteins.

  7. Liquid chromatography-tandem mass spectrometry for the determination of sphingomyelin species from calf brain, ox liver, egg yolk, and krill oil.

    Science.gov (United States)

    Zhou, Li; Zhao, Minjie; Ennahar, Saïd; Bindler, Françoise; Marchioni, Eric

    2012-01-11

    In this study, molecular species of sphingomyelin (SM) in egg yolk, calf brain, ox liver, and krill oil were investigated. Classes of phospholipids (PLs) were purified, identified, and quantified by normal phase semipreparative high-performance liquid chromatography (HPLC) combined with evaporative light scattering detectors (ELSD). For SM molecular species identification, pure SM collected through a flow splitter was loaded to HPLC-electrospray ionization-tandem mass spectrometry (LC-ESI-MS(2)), with 100% methanol containing 5 mM ammonium formate as mobile phase. In addition to classes of PLs, the used approach allowed the determination of profiles of SM species in egg yolk, ox liver, and calf brain, whereas krill oil turned out not to contain any SM. It also allowed the separation and identification of SM subclasses, as well as tentative identification of species with the same molecular mass, including isomers. The results showed that egg yolk contained the highest proportion of (d18:1-16:0)SM (94.1%). The major SM molecular species in ox liver were (d18:1-16:0)SM (25.5%), (d18:1-23:0)SM (19.7%), (d18:1-24:0)SM (13.2%), and (d18:1-22:0)SM (12.5%). Calf brain SM was rich in species such as (d18:1-18:0)SM (40.7%), (d18:1-24:1)SM (17.1%), and (d18:1-20:0)SM (10.8%). PMID:22148474

  8. [Determination of 51 carbamate pesticide residues in vegetables by liquid chromatography-tandem mass spectrometry based on optimization of QuEChERS sample preparation method].

    Science.gov (United States)

    Wang, Lianzhu; Zhou, Yu; Huang, Xiaoyan; Wang, Ruilong; Lin, Zixu; Chen, Yong; Wang, Dengfei; Lin, Dejuan; Xu, Dunming

    2013-12-01

    The raw extracts of six vegetables (tomato, green bean, shallot, broccoli, ginger and carrot) were analyzed using gas chromatography-mass spectrometry (GC-MS) in full scan mode combined with NIST library search to confirm main matrix compounds. The effects of cleanup and adsorption mechanisms of primary secondary amine (PSA) , octadecylsilane (C18) and PSA + C18 on co-extractives were studied by the weight of evaporation residue for extracts before and after cleanup. The suitability of the two versions of QuEChERS method for sample preparation was evaluated for the extraction of 51 carbamate pesticides in the six vegetables. One of the QuEChERS methods was the original un-buffered method published in 2003, and the other was AOAC Official Method 2007.01 using acetate buffer. As a result, the best effects were obtained from using the combination of C18 and PSA for extract cleanup in vegetables. The acetate-buffered version was suitable for the determination of all pesticides except dioxacarb. Un-buffered QuEChERS method gave satisfactory results for determining dioxacarb. Based on these results, the suitable QuEChERS sample preparation method and liquid chromatography-positive electrospray ionization-tandem mass spectrometry under the optimized conditions were applied to determine the 51 carbamate pesticide residues in six vegetables. The analytes were quantified by matrix-matched standard solution. The recoveries at three levels of 10, 20 and 100 microg/kg spiked in six vegetables ranged from 58.4% to 126% with the relative standard deviations of 3.3%-26%. The limits of quantification (LOQ, S/N > or = 10) were 0.2-10 microg/kg except that the LOQs of cartap and thiofanox were 50 microg/kg. The method is highly efficient, sensitive and suitable for monitoring the 51 carbamate pesticide residues in vegetables. PMID:24669707

  9. Determination of ultra-trace organic acids in Masson pine (Pinus massoniana L.) by accelerated solvent extraction and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wang, Shuiliang; Fan, China Q; Wang, Ping

    2015-02-15

    An accelerated solvent extraction (ASE)-solid-phase extraction (SPE)-liquid chromatography with electrospray ionization-tandem mass spectrometry (ASE-SPE-LC-ESI-MS/MS) methodology was developed for the extraction, cleanup and quantification of ultra-trace organic acids in Masson pine (Pinus massoniana L.) tissues. The separation was carried out on a Bio-Rad Aminex HPX-87H sulfonic column with an eluent containing 5 mmol L(-1) H₂SO₄ at a flow rate of 0.5 mL min(-1). A linear ion trap mass spectrometer equipped with electrospray ionization (ESI) source was operated in negative ion mode, and the six organic acids were eluted within 20 min. ASE extraction, SPE cleanup and LC-ESI-MS/MS analysis conditions were optimized to obtain reliable information about plant organic acid composition. Selective reaction monitoring (SRM) was employed for quantitative measurement. Intra-day precisions averaged 6.7%, and inter-day precisions were 2.1-10.7% for organic acid measurements in the pine samples. External standard calibration curves were linear over the range of 16.5-5000 ng L(-1), and detection limits based on a signal-to-noise ratio of three were at 0.5-5.0 ng L(-1). The results obtained showed the sensibility of the method was better than that of previously described HPLC methodology, and had no significant matrix effect. The proposed ASE-SPE-LC-ESI-MS/MS method is sensitive and reliable for the determination of ultra-trace organic acids in plant samples, despite the presence of the particularly complex matrix. PMID:25594951

  10. Using positive-ion electrospray ionization mass spectrometry and H/D exchange study phosphoryl group transfer reactions involved in amino acid ester isopropyl phosphoramidates of Brefeldin A

    International Nuclear Information System (INIS)

    Highlights: • ESI-MSn, HRMS and H/D exchange were used. • The fragmentation pathways of NPAAE-BFA in ESI-MSn were described. • Fragment ions involved in phosphorus group’s rearrangement reactions were observed. • Two rearrangement mechanisms about phosphorylation–dephosphorylation were proposed. - Abstract: As mini-chemical models, amino acid ester isopropyl phosphoramidates of Brefeldin A (compounds 2a–2d) were synthesized and investigated by electrospray ionization tandem mass spectrometry in combination with H/D exchange. To further confirm the fragments’s structures, off-line Fourier transform resonance tandem mass spectrometry (FT-ICR-MS/MS) was also performed. The fragmentation rules of compounds 2a–2d have been summarized and the plausible schemes for the fragmentation pathways were proposed. In this study, one dephosphorylated ion and two phosphorylated ions were observed in ESI-MS2 spectra of [M + Na]+ ions for compounds 2a–2d. The possible mechanisms about phosphorylation and dephosphorylation were proposed and confirmed by H/D exchange. For the “dephosphorylation” rearrangement, a nitrogen atom was migrated from the phosphoryl group to the carbon atom of Brefeldin A’s backbone with losing a molecule of C3H7PO3 (122 Da). For the “phosphorylation” rearrangement, an oxygen atom of one phosphoryl group attacked the sideward phosphorus atom to form a nine-member ring intermediate, then two steps of C-H covalent bond cleavage with consecutive migration of hydrogen atom to lose a molecule of C16H20O2 (244 Da). The two proposed rearrangement mechanisms about phosphoryl group transfer might be valuable for the structure analysis of other analogs and provide insights into elucidating the dynamic process of the phosphorylation–dephosphorylation of proteins

  11. Ultra-trace determination of phthalate ester metabolites in seawater, sediments, and biota from an urbanized marine inlet by LC/ESI-MS/MS.

    Science.gov (United States)

    Blair, Joel D; Ikonomou, Michael G; Kelly, Barry C; Surridge, Blair; Gobas, Frank A P C

    2009-08-15

    This study presents results of an analytical method developed for the quantification of monoalkyl phthalate esters (MPEs) in seawater, sediments, and biota. The method uses accelerated solvent extraction, solid-phase extraction, and liquid chromatography electrospray ionization tandem mass spectrometry (LC/ ESI-MS/MS). Results show the method is robust and can provide trace measurement of several MPE analytes at low parts per trillion levels in water and low parts per billion levels in sediments and biological tissues. Analyte recoveries varied between 70% and 110%. Method detection limits (MDLs) varied between 0.19 and 3.98 ng/L in seawater and between 0.024 and 0.99 ng/g in sediment and biota, which is approximately 10-50 times lower than previously reported MDLs using gas chromatography mass spectrometry. We applied the method to field collected samples of seawater, sediments, and tissues of mussels, crabs, and fish from False Creek an urbanized marine inlet near Vancouver, Canada. The results indicate residues of several MPEs can be found in surface waters, sediments, and organism tissues of this marine system. Monoethyl phthalate (MEP), mono-n-butyl phthalate (MnBP), and mono-(2-ethylhexyl)-phthalate (MEHP) were frequently detected in all matrices. MnBP generally exhibited the highest concentrations among MPEs analyzed. Detectable concentrations of MPEs varied from 1 to 600 ng/L in seawater, 0.1 to 20 ng/g dry wt in sediments, and 0.1 to 600 ng/g wet wt in biota. Observed concentrations of low molecular weight MPEs in mussels were found to be significantly higher (P DBP). Mono-iso-nonyl-phthalate (MoC9) and mono-iso-decyl phthalate (MoC10), which were routinely detected in water and sediments, were not detected in False Creek biota, indicating negligible uptake and/or in vivo bioformation of these high molecular weight MPEs. The ability to measure MPEs in complex environmental samples provided by this LC/ESI-MS/MS method expands the capability for future

  12. Axino mass

    CERN Document Server

    Kim, Jihn E

    2012-01-01

    I will talk on my recent works. Axino, related to the SUSY transformation of axion, can mix with Goldstino in principle. In this short talk, I would like to explain what is the axino mass and its plausible mass range. The axino mass is known to have a hierarchical mass structure depending on accidental symmetries. With only one axino, if G_A=0 where G=K+ 2ln|W|, we obtain axino mass= gravitino mass. For G_A nonzero, the axino mass depends on the details of the Kaehler potential. I also comment on the usefulness of a new parametrization of the CKM matrix.

  13. Metabolomics approach to explore the effects of Kai-Xin-San on Alzheimer's disease using UPLC/ESI-Q-TOF mass spectrometry.

    Science.gov (United States)

    Chu, Hang; Zhang, Aihua; Han, Ying; Lu, Shengwen; Kong, Ling; Han, Jinwei; Liu, Zhidong; Sun, Hui; Wang, Xijun

    2016-03-15

    Alzheimer's disease (AD) is a multifactorial neurodegenerative disease that influences elderly populations, with no effective method for its treatment so far. To improve its diagnosis and treatment, changes of small molecule metabolite during AD should be elucidated. Kai-Xin-San (KXS) is an herbal formulae that has been widely used to treat mental disorders, especially amnesia and depression in China. Experimental AD was induced in rats by an intraperitoneal injection of d-galactose (d-gal) and administered intragastrically with aluminum chloride (AlCl3) simultaneously for 105 days. Morris water maze task as a behavior test was used for testing the effects of KXS on AD model and pathological changes to the brain were assessed by hematoxylin-eosin staining and immunohistochemistry. The levels of Bcl-2 and ChAT in hippocampus were evaluated by western-blot. Furthermore, metabolite profiling of AD was performed through ultra-performance liquid chromatography/electrospray ionization quadruple time-of- flight-high-definition mass spectrometry (UPLC/ESI-Q-TOF/HDMS) combined with pattern recognition approaches and pathway analysis. d-gal and AlCl3-treated caused a decline in spatial learning and memory, hippocampal histopathological abnormalities and increased Aβ1-40 levels in the brain cortex and hippocampus along with decreased Bcl-2 and ChAT expression in the hippocampus. KXS significantly improved the cognitive impairment induced by d-gal and AlCl3, attenuated hippocampal histopathological abnormalities, reduced Aβ1-40 levels and increased Bcl-2 and ChAT expression in the hippocampus. A total of 48 metabolites were considered as potential biomarkers of AD, and 36 metabolites may correlate with the regulation of KXS treatment on AD. Changes in AD metabolic profiling were close to normal states through regulating multiple perturbed pathways after KXS treatment. This study has revealed the potential biomarkers and metabolic networks of AD, illuminated the biochemistry

  14. PHOSPHOLIPIDS OF FIVE PSEUDOMONAD ARCHETYPES FOR DIFFERENT TOLUENE DEGRADATION PATHWAYS

    Science.gov (United States)

    Liquid chromatography/electrospray ionization/mass spectrometry (LC/ESI/MS) was used to determine phospholipid profiles for five reference pseudomonad strains harboring distinct toluene catabolic pathways: Pseudomonas putida mt-2, Pseudomonas putida F1, Burkholderia cepacia G4, B...

  15. Isolation and Purification of Anthocyanins from Black Bean Wastewater Using Macroporous Resins

    OpenAIRE

    Wang, Xiaoxi

    2012-01-01

    Isolation and purification of anthocyanins from black bean canning wastewater by column chromatography with macroporous resins were investigated in this study. Different adsorption materials and adsorption conditions were compared and the most effective material and adsorption conditions were selected to purify anthocyanins. Purified anthocyanins then were identified by high performance liquid chromatography electrospray tandem mass spectrometry. The most effective macroporous resin was selec...

  16. Development and validation of an LC-MS/MS method for simultaneous determination of piperaquine and 97-63, the active metabolite of CDRI 97-78, in rat plasma and its application in interaction study.

    Science.gov (United States)

    Wahajuddin, Muhammad; Singh, Sheelendra Pratap; Taneja, Isha; Raju, Kanumuri Siva Rama; Gayen, Jiaur Rahman; Siddiqui, Hefazat Hussain; Singh, Shio Kumar

    2016-02-01

    Piperaquine-dihydroartemisinin combination is the latest addition to the repertoire of ACTs recommended by the World Health Organization (WHO) for treatment of falciparum malaria. Due to the increasing resistance to artemisinin derivatives, CSIR-CDRI has developed a prospective short acting, trioxane antimalarial derivative, CDRI 97-78. In the present study, a liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the simultaneous quantification of piperaquine (PPQ) and 97-63, the active metabolite of CDRI 97-78 found in vivo, was developed and validated in 100 μL rat plasma using halofantrine as internal standard. PPQ and 97-63 were separated using acetonitrile:methanol (50:50, v/v) and ammonium formate buffer (10 mM, pH 4.5) in the ratio of 95:5(v/v) as mobile phase under isocratic conditions at a flow rate of 0.65 mL/min on Waters Atlantis C18 (4.6 × 50 mm, 5.0 µm) column. The extraction recoveries of PPQ and 97-63 ranged from 90.58 to 105.48%, while for the internal standard, it was 94.27%. The method was accurate and precise in the linearity range 3.9-250 ng/mL for both the analytes, with a correlation coefficient (r) of ≥ 0.998. The intra- and inter-day assay precision ranged from 2.91 to 8.45% and; intra- and inter-day assay accuracy was between 92.50 and 110.20% for both the analytes. The method was successfully applied to study the effect of oral co-administration of PPQ on the pharmacokinetics of CDRI 97-78 in Sprague-dawley rats and vice versa. The co-administration of CDRI 97-78 caused significant decrease in AUC0-∞ of PPQ from 31.52 ± 2.68 to 14.84 ± 4.33 h*µg/mL. However, co-administration of PPQ did not have any significant effect on the pharmacokinetics of CDRI 97-78. PMID:25975936

  17. Immunogenic salivary proteins of Triatoma infestans: development of a recombinant antigen for the detection of low-level infestation of triatomines.

    Directory of Open Access Journals (Sweden)

    Alexandra Schwarz

    Full Text Available BACKGROUND: Triatomines are vectors of Trypanosoma cruzi, the etiological agent of Chagas disease in Latin America. The most effective vector, Triatoma infestans, has been controlled successfully in much of Latin America using insecticide spraying. Though rarely undertaken, surveillance programs are necessary in order to identify new infestations and estimate the intensity of triatomine bug infestations in domestic and peridomestic habitats. Since hosts exposed to triatomines develop immune responses to salivary antigens, these responses can be evaluated for their usefulness as epidemiological markers to detect infestations of T. infestans. METHODOLOGY/PRINCIPAL FINDINGS: T. infestans salivary proteins were separated by 2D-gel electrophoresis and tested for their immunogenicity by Western blotting using sera from chickens and guinea pigs experimentally exposed to T. infestans. From five highly immunogenic protein spots, eight salivary proteins were identified by nano liquid chromatography-electrospray ionization-tandem mass spectrometry (nanoLC-ESI-MS/MS and comparison to the protein sequences of the National Center for Biotechnology Information (NCBI database and expressed sequence tags of a unidirectionally cloned salivary gland cDNA library from T. infestans combined with the NCBI yeast protein sub-database. The 14.6 kDa salivary protein [gi|149689094] was produced as recombinant protein (rTiSP14.6 in a mammalian cell expression system and recognized by all animal sera. The specificity of rTiSP14.6 was confirmed by the lack of reactivity to anti-mosquito and anti-sand fly saliva antibodies. However, rTiSP14.6 was recognized by sera from chickens exposed to four other triatomine species, Triatoma brasiliensis, T. sordida, Rhodnius prolixus, and Panstrongylus megistus and by sera of chickens from an endemic area of T. infestans and Chagas disease in Bolivia. CONCLUSIONS/SIGNIFICANCE: The recombinant rTiSP14.6 is a suitable and promising

  18. Endogenous melatonin and oxidatively damaged guanine in DNA

    Directory of Open Access Journals (Sweden)

    Poulsen Henrik E

    2009-10-01

    Full Text Available Abstract Background A significant body of literature indicates that melatonin, a hormone primarily produced nocturnally by the pineal gland, is an important scavenger of hydroxyl radicals and other reactive oxygen species. Melatonin may also lower the rate of DNA base damage resulting from hydroxyl radical attack and increase the rate of repair of that damage. This paper reports the results of a study relating the level of overnight melatonin production to the overnight excretion of the two primary urinary metabolites of the repair of oxidatively damaged guanine in DNA. Methods Mother-father-daughter(s families (n = 55 were recruited and provided complete overnight urine samples. Total overnight creatinine-adjusted 6-sulphatoxymelatonin (aMT6s/Cr has been shown to be highly correlated with total overnight melatonin production. Urinary 8-oxo-7,8-dihydro-guanine (8-oxoGua results from the repair of DNA or RNA guanine via the nucleobase excision repair pathway, while urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG may possibly result from the repair of DNA guanine via the nucleotide excision repair pathway. Total overnight urinary levels of 8-oxodG and 8-oxoGua are therefore a measure of total overnight guanine DNA damage. 8-oxodG and 8-oxoGua were measured using a high-performance liquid chromatography-electrospray ionization tandem mass spectrometry assay. The mother, father, and oldest sampled daughter were used for these analyses. Comparisons between the mothers, fathers, and daughters were calculated for aMT6s/Cr, 8-oxodG, and 8-oxoGua. Regression analyses of 8-oxodG and 8-oxoGua on aMT6s/Cr were conducted for mothers, fathers, and daughters separately, adjusting for age and BMI (or weight. Results Among the mothers, age range 42-80, lower melatonin production (as measured by aMT6s/CR was associated with significantly higher levels of 8-oxodG (p Conclusion Low levels of endogenous melatonin production among older individuals may lead to

  19. Tandem anion and cation exchange solid phase extraction for the enrichment of micropollutants and their transformation products from ozonation in a wastewater treatment plant.

    Science.gov (United States)

    Deeb, Ahmad A; Schmidt, Torsten C

    2016-06-01

    The presence of organic micropollutants and their transformation products (TPs) from biotic and abiotic processes in aquatic environments is receiving intense public and scientific attention. Yet a suitable sample preparation method that would enable extraction and enrichment of a wide range of such compounds from water is missing. The focus of this paper was to develop an enhanced solid phase extraction (SPE) protocol which enabled isolation of parent compounds and low molecular weight transformation products (that are produced after treatment of water with ozone) from different water matrices. Ten SPE sorbents were evaluated with regard to their ability to extract acidic, neutral, and basic compounds from water at several pH values. Highest recoveries (91-99 %) for all analytes in pure water were obtained by combining strong anion and cation exchangers of two manufacturers in a tandem mode without pH adjustment. Tandem Oasis (MAX+MCX) was finally applied to extract the spiked analytes from tap water, surface water, and several wastewater samples. The efficiency of the used SPE procedure was examined using an optimized liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method using multiple reaction monitoring (MRM) mode. The occurrence of some of the investigated TPs in environmental water matrices was proven for the first time in this study. Method quantification limits (MQLs) for all compounds ranged from 3.7 to 15.3 ng/L in all matrices. Recoveries (%RE) were between 90 and 110 %. Intraday and interday precision, expressed as relative standard deviation, varied from 0.7 to 5.9 % and 1.8 to 10.3 %, respectively. Matrix effect (%ME) evaluation demonstrated that even complex sample matrices did not show significant ion suppression or enhancement. The applicability of the method was shown during two sampling campaigns at Ruhr river and a wastewater treatment plant (WWTP) equipped with an ozonation step after regular

  20. Top-down and bottom-up lipidomic analysis of rabbit lipoproteins under different metabolic conditions using flow field-flow fractionation, nanoflow liquid chromatography and mass spectrometry.

    Science.gov (United States)

    Byeon, Seul Kee; Kim, Jin Yong; Lee, Ju Yong; Chung, Bong Chul; Seo, Hong Seog; Moon, Myeong Hee

    2015-07-31

    This study demonstrated the performances of top-down and bottom-up approaches in lipidomic analysis of lipoproteins from rabbits raised under different metabolic conditions: healthy controls, carrageenan-induced inflammation, dehydration, high cholesterol (HC) diet, and highest cholesterol diet with inflammation (HCI). In the bottom-up approach, the high density lipoproteins (HDL) and the low density lipoproteins (LDL) were size-sorted and collected on a semi-preparative scale using a multiplexed hollow fiber flow field-flow fractionation (MxHF5), followed by nanoflow liquid chromatography-ESI-MS/MS (nLC-ESI-MS/MS) analysis of the lipids extracted from each lipoprotein fraction. In the top-down method, size-fractionated lipoproteins were directly infused to MS for quantitative analysis of targeted lipids using chip-type asymmetrical flow field-flow fractionation-electrospray ionization-tandem mass spectrometry (cAF4-ESI-MS/MS) in selected reaction monitoring (SRM) mode. The comprehensive bottom-up analysis yielded 122 and 104 lipids from HDL and LDL, respectively. Rabbits within the HC and HCI groups had lipid patterns that contrasted most substantially from those of controls, suggesting that HC diet significantly alters the lipid composition of lipoproteins. Among the identified lipids, 20 lipid species that exhibited large differences (>10-fold) were selected as targets for the top-down quantitative analysis in order to compare the results with those from the bottom-up method. Statistical comparison of the results from the two methods revealed that the results were not significantly different for most of the selected species, except for those species with only small differences in concentration between groups. The current study demonstrated that top-down lipid analysis using cAF4-ESI-MS/MS is a powerful high-speed analytical platform for targeted lipidomic analysis that does not require the extraction of lipids from blood samples. PMID:26087967

  1. Rapid Quantitation of Ascorbic and Folic Acids in SRM 3280 Multivitamin/Multielement Tablets using Flow-Injection Tandem Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bhandari, Deepak [ORNL; Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

    2013-01-01

    RATIONALE: Ascorbic acid (AA) and folic acid (FA) are water-soluble vitamins and are usually fortified in food and dietary supplements. For the safety of human health, proper intake of these vitamins is recommended. Improvement in the analysis time required for the quantitative determination of these vitamins in food and nutritional formulations is desired. METHODS: A simple and fast (~5 min) in-tube sample preparation was performed, independently for FA and AA, by mixing extraction solvent with a powdered sample aliquot followed by agitation, centrifugation, and filtration to recover an extract for analysis. Quantitative detection was achieved by flow-injection (1 L injection volume) electrospray ionization tandem mass spectrometry (ESI-MS/MS) in negative ion mode using the method of standard addition. RESULTS: Method of standard addition was employed for the quantitative estimation of each vitamin in a sample extract. At least 2 spiked and 1 non-spiked sample extract were injected in triplicate for each quantitative analysis. Given an injection-to-injection interval of approximately 2 min, about 18 min was required to complete the quantitative estimation of each vitamin. The concentration values obtained for the respective vitamins in the standard reference material (SRM) 3280 using this approach were within the statistical range of the certified values provided in the NIST Certificate of Analysis. The estimated limit of detections of FA and AA were 13 and 5.9 ng/g, respectively. CONCLUSIONS: Flow-injection ESI-MS/MS was successfully applied for the rapid quantitation of FA and AA in SRM 3280 multivitamin/multielement tablets.

  2. Neutrino Masses

    CERN Document Server

    Weinheimer, Christian

    2013-01-01

    The various experiments on neutrino oscillation evidenced that neutrinos have indeed non-zero masses but cannot tell us the absolute neutrino mass scale. This scale of neutrino masses is very important for understanding the evolution and the structure formation of the universe as well as for nuclear and particle physics beyond the present Standard Model. Complementary to deducing constraints on the sum of all neutrino masses from cosmological observations two different methods to determine the neutrino mass scale in the laboratory are pursued: the search for neutrinoless double $\\beta$-decay and the direct neutrino mass search by investigating single $\\beta$-decays or electron captures. The former method is not only sensitive to neutrino masses but also probes the Majorana character of neutrinos and thus lepton number violation with high sensitivity. Currently quite a few experiments with different techniques are being constructed, commissioned or are even running, which aim for a sensitivity on the neutrino ...

  3. Mass spectrometry.

    Science.gov (United States)

    Burlingame, A. L.; Johanson, G. A.

    1972-01-01

    Review of the current state of mass spectrometry, indicating its unique importance for advanced scientific research. Mass spectrometry applications in computer techniques, gas chromatography, ion cyclotron resonance, molecular fragmentation and ionization, and isotope labeling are covered. Details are given on mass spectrometry applications in bio-organic chemistry and biomedical research. As the subjects of these applications are indicated alkaloids, carbohydrates, lipids, terpenes, quinones, nucleic acid components, peptides, antibiotics, and human and animal metabolisms. Particular attention is given to the mass spectra of organo-inorganic compounds, inorganic mass spectrometry, surface phenomena such as secondary ion and electron emission, and elemental and isotope analysis. Further topics include mass spectrometry in organic geochemistry, applications in geochronology and cosmochemistry, and organic mass spectrometry.

  4. A straightforward, quantitative ultra-performance liquid chromatography-tandem mass spectrometric method for heparan sulfate, dermatan sulfate and chondroitin sulfate in urine: an improved clinical screening test for the mucopolysaccharidoses.

    Science.gov (United States)

    Zhang, Haoyue; Wood, Tim; Young, Sarah P; Millington, David S

    2015-02-01

    Mucopolysaccharidoses (MPS) are complex storage disorders that result in the accumulation of glycosaminoglycans (GAGs) in urine, blood, brain and other tissues. Symptomatic patients are typically screened for MPS by analysis of GAG in urine. Current screening methods used in clinical laboratories are based on colorimetric assays that lack the sensitivity and specificity to reliably detect mild GAG elevations that occur in some patients with MPS. We have developed a straightforward, reliable method to quantify chondroitin sulfate (CS), dermatan sulfate (DS) and heparan sulfate (HS) in urine by stable isotope dilution tandem mass spectrometry. The GAGs were methanolyzed to uronic acid-N-acetylhexosamine or iduronic acid-N-glucosamine dimers and mixed with stable isotope labeled internal standards derived from deuteriomethanolysis of GAG standards. Specific dimers derived from HS, DS and CS were separated by ultra-performance liquid chromatography and analyzed by electrospray ionization tandem mass spectrometry using selected reaction monitoring for each targeted GAG product and its corresponding internal standard. The method was robust with a mean inaccuracy from 1 to 15%, imprecision below 11%, and a lower limit of quantification of 0.4mg/L for CS, DS and HS. We demonstrate that the method has the required sensitivity and specificity to discriminate patients with MPS III, MPS IVA and MPS VI from those with MPS I or MPS II and can detect mildly elevated GAG species relative to age-specific reference intervals. This assay may also be used for the monitoring of patients following therapeutic intervention. Patients with MPS IVB are, however, not detectable by this method. PMID:25458519

  5. Separation and analysis of phenolic acids from Salvia miltiorrhiza and its related preparations by off-line two-dimensional hydrophilic interaction chromatography×reversed-phase liquid chromatography coupled with ion trap time-of-flight mass spectrometry.

    Science.gov (United States)

    Sun, Wanyang; Tong, Ling; Miao, Jingzhuo; Huang, Jingyi; Li, Dongxiang; Li, Yunfei; Xiao, Hongting; Sun, Henry; Bi, Kaishun

    2016-01-29

    Salvia miltiorrhiza (SM) is one of the most widely used Traditional Chinese Medicine. Active constituents of SM mainly contain hydrophilic phenolic acids (PAs) and lipophilic tanshinones. However, due to the existing of multiple ester bonds and unsaturated bonds in the structures, PAs have numerous chemical conversion products. Many of them are so low-abundant that hard to be separated using conventional methods. In this study, an off-line two-dimensional liquid chromatography (2D-LC) method was developed to separate PAs in SM and its related preparations. In the first dimension, samples were fractionated by hydrophilic interaction chromatography (HILIC) (Acchrom×Amide, 4.6×250mm, 5μm) mainly based on the hydrogen bonding effects. The fractions were then separated on reversed-phase liquid chromatography (RP-LC) (Acquity HSS T3, 2.1×50mm, 1.7μm) according to hydrophobicity. For the selective identification of PAs, diode array detector (DAD) and electrospray ionization tandem ion trap time-of-flight mass spectrometry (ESI-IT-TOF-MS) were employed. Practical and effective peak capacities of all the samples were greater than 2046 and 1130, respectively, with the orthogonalities ranged from 69.7% to 92.8%, which indicated the high efficiency and versatility of this method. By utilizing the data post-processing techniques, including mass defect filter, neutral loss filter and product ion filter, a total of 265 compounds comprising 196 potentially new PAs were tentatively characterized. Twelve kinds of derivatives, mainly including glycosylated compounds, O-alkylated compounds, condensed compounds and hydrolyzed compounds, constituted the novelty of the newly identified PAs. The HILIC×RP-LC/TOF-MS system expanded our understanding on PAs of S. miltiorrhiza and its related preparations, which could also benefit the separation and characterization of polar constituents in complicated herbal extracts. PMID:26792448

  6. 液相色谱-串联质谱法检测贝类产品中腹泻性贝类毒素%Determination of Diarrhetic Shellfish Poisoning in Shellfishes by Liquid Chromatography with Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    母清林; 方杰; 万汉兴; 王晓华; 曹柳燕; 张庆红

    2011-01-01

    建立了贝类组织中2种腹泻性贝毒(Diamletic shellfish Poisobing,DSP)聚醚类毒素-大田软海绵酸(Okadaic acid,OA)和鳍藻毒素(Dinophysistoxin-1,DTX-1)的高效液相色谱-串联质谱分析方法.贝类样品经80%甲醇溶液提取,经正己烷脱脂和HLB固相萃取柱净化,采用Pursuit C18(150 mm×3.0 mm,3 μm,varian公司)色谱柱分离,以80%(V/V)甲醇水溶液为流动相等度洗脱,负离子扫描,在多反应监测(MRM)模式下进行定性与定量分析.在4~200 μg/L范围内线性关系良好,OA和DTX-1的最低定量限均为2 μg/kg.添加水平在2,25和50 μg/kg时的平均回收率大于80%,相对标准偏差小于11%(n=6).%A liquid chromatography-electrospray ionization triple-quadruple tandem.mass spectrometric method has been established for the determination of two kinds of diarrhetic shellfish poisoning including okadaic acid (QA) and dinophysistoxin-1 (DTX-1). After being extracted using methanol and water(80∶20, V/V ), the solution was extracted with n-hexane to remove lipid components and then cleaned-up by solid phase extraction (SPE) on an Oasis HLB cartridge. The analytes were eluted with methanol-water (80:20, V/V) on a Pursuit C18 column (150 mm×3.0 mm, 3 μm). The quantitative and confirmatory determination of OA and DTX-1 was performed by multiple reactions monitoring (MRM) mode. OA and DTX-1 were determined in the negative ion mode. The calibration curve was linear in the range of 4- 200 μg/L. The quantification limits of OA and DTX-1 were 2 μg/kg. The mean recoveries at spiked concentration of 2-100 μg/kg were more than 80% and the relative standard deviations were less than 11% (n=6).

  7. Neutrino masses

    Energy Technology Data Exchange (ETDEWEB)

    Weinheimer, Christian [Institut fuer Kernphysik, Westfaelische Wilhelms-Universitaet Muenster, Wilhelm-Klemm-Str. 9, D-48149 Muenster (Germany); Zuber, Kai [Institut fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, Zellescher Weg 19, D-01069 Dresden (Germany)

    2013-09-15

    The various experiments on neutrino oscillation evidence that neutrinos have indeed non-zero masses but cannot provide the absolute neutrino mass scale. This scale of neutrino masses is very important for understanding the evolution and the structure formation of the universe as well as for nuclear and particle physics beyond the present Standard Model. Complementary to deducing constraints on the sum of all neutrino masses from cosmological observations, two different methods to determine the neutrino mass scale in the laboratory are pursued: the search for neutrinoless double {beta}-decay and the direct neutrino mass search by investigating single {beta}-decays or electron captures. The former method is not only sensitive to neutrino masses but also probes the Majorana character of neutrinos and thus lepton number violation with high sensitivity. Currently quite a few experiments using different techniques are being constructed, commissioned, or are even running, which aim for a sensitivity on the neutrino mass of O(100) meV. The principal methods and these experiments are discussed in this short review. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Determination of apurinic/apyrimidinic lesions in DNA with high-performance liquid chromatography and tandem mass spectrometry.

    Science.gov (United States)

    Roberts, Kenneth P; Sobrino, Justin A; Payton, Julie; Mason, Lavinnia B; Turesky, Robert J

    2006-02-01

    A new method has been developed to accurately measure apurinic and apyrimidinic (AP) DNA damage sites, which are lesions in DNA formed by loss of a nucleobase from oxidative stress or carcinogen adducts. If AP sites are left unrepaired (or if improperly repaired), these sites can lead to DNA mutations that may ultimately result in the formation of cancer. Hence, detection of AP sites may provide a useful indicator of exposure and susceptibility to chemical carcinogens and oxidative stress. AP detection is currently accomplished by immunodetection methods using an aldehyde reactive probe [Nakamura, J., Walker, V. E., Upton, P. B., Chiang, S.-Y., Kow, Y. W., and Swenberg, J. A. (1998) Cancer Res. 58, 222-225; Atamna, H., Cheung, I., and Ames, B. N. (2000) Proc. Natl. Acad. Sci. U.S.A. 97, 686-691]; however, these approaches lack the specificity required for unequivocal identification of the AP site. Therefore, we have developed an accurate method based on mass spectrometry detection of AP sites from AP DNA that have been prelabeled with O-4-nitrobenzylhydroxylamine (NBHA). Once labeled and once the excess labeling agent has been removed, enzymatic digestion of DNA to monomeric subunits can be accomplished, followed by isolation and detection with high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Optimization and validation of the experimental procedures and detection limits have been established using a model DNA oligomer (11-mer) containing uracil. Enzymatic removal of uracil with uracil glycosylase generates well-defined AP sites in both single- and double-stranded DNA. The addition of NBHA labels the AP site in the oligomer, creating a labeled 11-mer. HPLC-ESI-MS/MS in the negative ionization mode was used to monitor and confirm binding of NBHA to the AP oligomer. The NBHA-tagged oligomer underwent endo- and exonuclease digestion to the 5'-deoxyribose monophosphate (5'-dRp) level, thereby releasing

  9. Mass hysteria

    CERN Document Server

    Hellemans, Alexander

    2004-01-01

    Considerable research is being undertaken to identify the Higgs particle that is believed to give things their mass. According to the standard model, what we call mass is really an indication of how strongly particles interact with an invisible syrupy substance called the Higgs field. Quantum mechanics say that the mass-giving field can also be thought of as a sea of electrically neutral Higgs particles that should be dislodged in collisions between subatomic particles with high enough energies. Particle physicists expect the Higgs to exist only for a fleeting moment before decaying into other particles, which are caught in a detector. (Edited abstract).

  10. A novel method for the rapid determination of polyethoxylated tallow amine surfactants in water and sediment using large volume injection with high performance liquid chromatography and tandem mass spectrometry.

    Science.gov (United States)

    Ross, Andrew R S; Liao, Xiangjun

    2015-08-19

    Polyethoxylated tallow amine (POEA) surfactants have been used in many glyphosate-based herbicide formulations for agricultural, industrial and residential weed control. The potential for release of these compounds into the environment is of increasing concern due to their toxicity towards aquatic organisms. Current methods for analysis of POEA surfactants require significant time and effort to achieve limits of quantification that are often higher than the concentrations at which biological effects have been observed (as low as 2 ng mL(-1)). We have developed a rapid and robust method for quantifying the POEA surfactant mixture MON 0818 at biologically relevant concentrations in fresh water, sea water and lake sediment using reversed phase high-performance liquid chromatography and electrospray ionization-tandem mass spectrometry. Water samples preserved by 1:1 v/v dilution with methanol are analyzed directly following centrifugation. Sediment samples undergo accelerated solvent extraction in aqueous methanol prior to analysis. Large volume (100 μL) sample injection and multiple reaction monitoring of a subset of the most abundant POEA homologs provide limits of quantification of 0.5 and 2.9 ng mL(-1) for MON 0818 in fresh water and sea water, respectively, and 2.5 ng g(-1) for total MON 0818 in lake sediment. Average recoveries of 93 and 75% were achieved for samples of water and sediment, respectively spiked with known amounts of MON 0818. Precision and accuracy for the analysis of water and sediment samples were within 10 and 16%, respectively based upon replicate analyses of calibration standards and representative samples. Results demonstrate the utility of the method for quantifying undegraded MON 0818 in water and sediment, although a more comprehensive method may be needed to identify and determine other POEA mixtures and degradation profiles that might occur in the environment. PMID:26343437

  11. Mass metrology

    CERN Document Server

    Gupta, S V

    2012-01-01

    This book presents the practical aspects of mass measurements. Concepts of gravitational, inertial and conventional mass and details of the variation of acceleration of gravity are described. The Metric Convention and International Prototype Kilogram and BIPM standards are described. The effect of change of gravity on the indication of electronic balances is derived with respect of latitude, altitude and earth topography. The classification of weights by OIML is discussed. Maximum permissible errors in different categories of weights prescribed by national and international organizations are p

  12. Mass spectrometry

    DEFF Research Database (Denmark)

    Nyvang Hartmeyer, Gitte; Jensen, Anne Kvistholm; Böcher, Sidsel;

    2010-01-01

    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is currently being introduced for the rapid and accurate identification of bacteria. We describe 2 MALDI-TOF MS identification cases - 1 directly on spinal fluid and 1 on grown bacteria. Rapidly obtained...

  13. Scrotal masses

    Science.gov (United States)

    ... your provider to determine if it may be testicular cancer. Prevention You can prevent scrotal masses caused by sexually ... 21095426 . U.S. Preventive Services Task Force. Screening for Testicular Cancer: U.S. Preventive Services Task Force reaffirmation recommendation statement. Ann Intern ...

  14. Mass Spectrometry for the Masses

    Science.gov (United States)

    Persinger, Jared D.; Hoops, Geoffrey, C.; Samide, Michael J.

    2004-01-01

    A simple, qualitative experiment is developed for implementation, where the gas chromatography-mass spectrometry (GC-MS) plays an important role, into the laboratory curriculum of a chemistry course designed for nonscience majors. This laboratory experiment is well suited for the students as it helps them to determine the validity of their…

  15. Mass Media

    Institute of Scientific and Technical Information of China (English)

    叶全荣

    2006-01-01

    @@ Every day,we are all influenced by the mass media.Although some critics of the media claim that these means of communication are used mainly to control our thinking and get us to buy products that we don't need,the media also contribute to keeping people informed.In other words,while dangers do exist,the benefits of the media far outweigh(超过)the disadvantages.Most of the messages brought to viewers,listeners,and readers are designed either to inform or to entertain,and neither of these goals can be considered dangerous or harmful.

  16. Identification of Plasma Metabolomic Profiling for Diagnosis of Esophageal Squamous-Cell Carcinoma Using an UPLC/TOF/MS Platform

    OpenAIRE

    Lihong Yin; Enchun Pan; Wei Guo; Yuepu Pu; Yi Wang; Xiaobo Li; Yuan Peng; Ran Liu

    2013-01-01

    Epidemiological studies indicated that esophageal squamous-cell carcinoma (ESCC) is still one of the most common causes of cancer incidence in the world. Searching for valuable markers including circulating endogenous metabolites associated with the risk of esophageal cancer, is extremely important A comparative metabolomics study was performed by using ultraperformance liquid chromatography-electrospray ionization-accurate mass time-of-flight mass spectrometry to analyze 53 pairs of plasma s...

  17. Fate of Organohalogens in U.S. Wastewater Treatment Plants and Estimated Chemical Releases to Soils Nationwide from Biosolids Recycling

    OpenAIRE

    Heidler, Jochen; Halden, Rolf U.

    2009-01-01

    This study examined the occurrence in wastewater of 11 aromatic biocides, pesticides and degradates, and their fate during passage through U.S. treatment plants, as well as the chemical mass contained in sewage sludge (biosolids) destined for land application. Analyte concentrations in wastewater influent, effluent and sludge from 25 facilities in 18 U.S. states were determined by liquid chromatography electrospray (tandem) mass spectrometry. Dichlorocarbanilide, fipronil, triclocarban, and t...

  18. Analysis of phospholipids in microalga Nitzschia closterium by UPLC-Q-TOF-MS

    Institute of Scientific and Technical Information of China (English)

    严小军; 李海英; 徐继林; 周成旭

    2010-01-01

    Precise structural identification of phospholipids in the microalga Nitzschia closterium has been established using ultra performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry (UPLC-ESI-Q-TOF-MS) for direct analysis of total lipid extracts.Mass spectrometry was performed in reflective time-of-flight using electron spraying ionization in negative mode.Phospholipid molecular species identification was based on the characteristic product ions and neutral loss yie...

  19. Mass discrimination

    International Nuclear Information System (INIS)

    The pertinent and well-known problem of the discriminative effect produced by small orifices used in mass-spectrometric ion sampling from gas discharges is one which is unfortunately not well understood. The problem has been investigated experimentally by Kingsman and Rees and by Milloy and Elford for particular experimental conditions. Parkes has investigated the problem theoretically for high-pressure discharges, where convective flow through the hole dominates. The present communication seeks to provide a simple method for calculating ion transmission coefficients through such orifices for the special case where the gas mean free path is greater than the orifice diameter and the ions have ab imposed additional axial velocity component due either to an electric-field drift velocity or to a flow velocity (flowing afterglows). (orig.)

  20. Liquid Chromatography Tandem mass spectrometry method for Quantification of Buproprion and Hydroxy Buproprion in Human Plasma and its application to Bioequivalence Study

    Directory of Open Access Journals (Sweden)

    Peeyush Jain

    2012-06-01

    Full Text Available A rapid, specific and robust assay based on solid phase extraction and liquid chromatography-electronspray ionization tandem mass spectrometry (LC-ESI MS-MS has been developed and validated for the quantitative analysis of Buproprion (a drug used for smoking cessation in human plasma using Buproprion D9 as internal standard (ISTD. The precursors to product ion transitions of m/z 240.20/183.90 and m/z 256.10/237.90 were used to measure the analyte (Buproprion and hydroxy Buproprion and the precursor to product ion transition of m/z 249.20/131.00 was used to measure the ISTD. The method was validated over a concentration range of 1.00ng mL-1 to 304.65ng mL-1 for Bupropion and 3.00ng mL-1 to 801.78ng mL-1 for hydroxy Bupropion. The method was validated over the various parameters like selectivity, matrix effect, sensitivity, linearity, precision, accuracy, stabilities (bench-top stability, standard stock solution stability in refrigerator and at room temperature, stock dilution stability, auto-sampler stability, freeze thaw stability, long-term stability at -65°C ± 10°C & -22°C ± 5°C, reagent stability, dry-extract stability, wet-extract stability and blood stability, effect of potentially interfering drugs, dilution integrity, recovery, reinjection reproducibility, ruggedness, extended batch verification, ion-suppression through infusion and inter-conversion check etc. The mean percent recovery of Bupropion was found 58.443% with a precision of 1.01% whereas the mean percent recoveries of hydroxy Bupropion and Bupropion D9 were found 62.327% and 66.513% with a precision of 2.99% and 3.91% respectively. The RSD percent of intra-day and inter-day assay was ;15%. The application of this assay was demonstrated in a bioequivalence study and it was found suitable for a study of sample size as big as sixty enrolled volunteers.

  1. Development of a high performance liquid chromatography tandem mass spectrometry based analysis for the simultaneous quantification of various Alternaria toxins in wine, vegetable juices and fruit juices.

    Science.gov (United States)

    Zwickel, Theresa; Klaffke, Horst; Richards, Keith; Rychlik, Michael

    2016-07-15

    An analytical method based on high performance liquid chromatography (HPLC) and tandem mass spectrometry (MS/MS) detection for the simultaneous quantification of 12 Alternaria toxins in wine, vegetable juices and fruit juices was developed. Excellent chromatographic performance was demonstrated for tenuazonic acid (TeA) in a multi-analyte method. This comprehensive study is also the first to report the determination of TeA, alternariol (AOH), alternariol monomethyl ether (AME), tentoxin (TEN) and altenuene (ALT), altertoxin I (ATX-I), altertoxin II (ATX-II), altenuisol (ATL), iso-altenuene (isoALT), altenuic acid III (AA-III) and the AAL toxins TB1 und TB2 in samples from the German market. Several types of HPLC columns were tested for the liquid chromatographic separation of the toxins of interest that widely differ in their polarities. The focus was on gaining suitable retention while avoiding derivatization steps especially for TeA and AA-III. Three atmospheric pressure ionization techniques used with liquid chromatography (electrospray, chemical and photo ionization) were tested to obtain the best selectivity and sensitivity. Samples were diluted with sodium hydrogen carbonate buffer and extracted on a diatomaceous earth solid phase extraction cartridge. Method validation was carried out by using tomato juice, citrus juice and white wine as blank matrices. Limits of detection ranged from 0.10 to 0.59μgL(-1) and limits of quantification ranged from 0.4-3.1μgL(-1) depending on the toxin and matrix. Recoveries were around 100±9% for all toxins except stemphyltoxin III (STTX-III) and altenusin (ALS) due to instability during sample clean up. Matrix-induced effects leading to ion suppression especially for ATX-I, ATX-II and AA-III were investigated. Relative standard deviations of repeatability (RSDr) and intermediate reproducibility (RSDR) were ≤9.3 and ≤17.1, respectively, for the toxins in different matrices at levels of 5 and 30μgL(-1). Finally, 103

  2. Elucidation of Phosphatidylcholine Composition in Krill Oil Extracted from Euphausia superba

    OpenAIRE

    Winther, Bjørn; Hoem, Nils; Berge, Kjetil; Reubsaet, Léon

    2010-01-01

    High performance liquid chromatography-electrospray tandem mass spectrometry was used to elucidate the phospholipids in krill oil extracted from Euphausia superba, an emerging source for human nutritional supplements. The study was carried out in order to map the species of the choline-containing phospholipid classes: phosphatidylcholine and lyso-phosphatidylcholine. In addition, the prevalent phosphatidylcholine class was quantified and the results compared with prior analysis. The qualifica...

  3. A Survey of Membrane Proteins in Human Serum

    OpenAIRE

    Dung, Nguyen Tien; Chi, Phan Van

    2012-01-01

    Serum and membrane proteins are two of the most attractive targets for proteomic analysis. Previous membrane protein studies tend to focus on tissue sample, while membrane protein studies in serum are still limited. In this study, an analysis of membrane proteins in normal human serum was carried out. Nano-liquid chromatography-electrospray ionization mass spectrometry (NanoLC-ESI-MS/MS) and bioinformatics tools were used to identify membrane proteins. Two hundred and seventeen membrane prote...

  4. Identification of phenolic constituents of cytisus multiflorus

    OpenAIRE

    Olívia R. Pereira; Silva, Artur; Domingues, M. R. M.; Cardoso, Susana M.

    2012-01-01

    The phenolic composition of the ethanolic extract obtained from the flowers of the medicinal plant Cytisus multiflorus has been elucidated by high performance liquid chromatography, electrospray mass spectrometry and nuclear magnetic resonance analysis. The extract was mainly composed of flavones, including the common chrysin, orientin, luteolin-5-O-glucoside, luteolin-7-O-glucoside, apigenin and apigenin-7-O-glucoside, which appeared as minor components. The major flavone in the ...

  5. The polyphenolic profiles of common bean (Phaseolus vulgaris L.)

    OpenAIRE

    Lin, Long-Ze; HARNLY, JAMES M.; Pastor-Corrales, Marcial S.; Luthria, Devanand L.

    2008-01-01

    Based on the phenolic profiles obtained by high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-DAD-ESI/MS), 24 common bean samples, representing 17 varieties and 7 generic off-the-shelf items, belonging to ten US commercial market classes can be organized into six different groups. All of them contained the same hydroxycinnaminic acids, but the flavonoid components showed distinct differences. Black beans contained primarily the 3-O-glucosides of delphinidin...

  6. Application of pressurized solvents for ultra fast trypsin hydrolysis in proteomics: Proteomics on the fly

    OpenAIRE

    López-Ferrer, Daniel; Petritis, Konstantinos; Hixson, Kim K.; Heibeck, Tyler H.; Moore, Ronald J.; Belov, Mikhail E.; Camp, David G; Smith, Richard D.

    2008-01-01

    A new method for rapid proteolytic digestion of proteins under high pressure that uses pressure cycling technology in the range of 5 to 35 kpsi was demonstrated for proteomic analysis. Successful in-solution digestions of single proteins and complex protein mixtures were achieved in 60 s and then analyzed by reversed phase liquid chromatography-electrospray ionization ion trap-mass spectrometry. Method performance in terms of the number of Shewanella oneidensis peptides and proteins identifie...

  7. Selenium speciation analysis of Misgurnus anguillicaudatus selenoprotein by HPLC-ICP-MS and HPLC-ESI-MS/MS

    Science.gov (United States)

    Analytical methods for selenium (Se) speciation were developed using high performance liquid chromatography (HPLC) coupled to either inductively coupled plasma mass spectrometry (ICP-MS) or electrospray ionization tandem mass spectrometry (ESI-MS/MS). Separations of selenomethionine (Se-Met) and sel...

  8. Mass Customization Services

    DEFF Research Database (Denmark)

    Friedrich, Gerhard

    Topics of the IMCM’08 & PETO’08 and this book are: Mass customization in service, mass customizing financial services, mass customization in supply networks, implementation issues in logistics, product life cycle and mass customization. The research field of mass customization is more than 15 years...

  9. 两种黄酮醇苷同分异构体的电喷雾质谱区分

    Institute of Scientific and Technical Information of China (English)

    窦建鹏; 刘志强; 刘淑莹

    2004-01-01

    Two flavonol glycoside isomers of Icariside I and Caohuoside C were differentiated by electrospray ionization tandem mass spectrometry (ESI-MSn) method. In the negative ion mode, the two compounds with different glycosyl moieties showed the same ESI-MS spectrum, but obvious different MS2 spectra and thus they can be distinguished rapidly, accurately and easily by ESI-MS.

  10. Determination of aflatoxins in food using LC/MS/MS

    DEFF Research Database (Denmark)

    Vahl, Martin; Jørgensen, Kevin

    1998-01-01

    A liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometric method is described for the determination of aflatoxins B-1, B-2, G(1) and G(2) in food with the use of aflatoxin M-1 as an internal standard. The method works well with matrices such as those of figs and p...

  11. LC-MS/MS method for the determination of the fungal pigment bikaverin in maize kernels as an indicator of ear rot

    Science.gov (United States)

    Bikaverin is a polyketide metabolite produced by multiple species of the fungus Fusarium that infects plant crops, including maize. A technique was developed for the analysis of bikaverin by high performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry. The quant...

  12. Radical Mechanism in the Elimination of 2-Arylsulfinyl Esters

    OpenAIRE

    LaTorre, Antonio; López Martín, Irakusne; Ramírez, Victoria; Rodríguez Pastor, Santiago; Izquierdo Ferrer, Javier; González Adelantado, Florenci Vicent; Vicent Barrera, Cristian

    2012-01-01

    The mechanism of the dehydrosulfenylation of 2-arylsulfinyl esters was investigated. The reaction was found to follow a homolytic cleavage mechanism as verified by electrospray ionization tandem mass spectrometry and experimental work. Rearranged sulfoxides are obtained as byproduct during the elimination reaction.

  13. Determination of aflatoxins in food using LC/MS/MS

    DEFF Research Database (Denmark)

    Vahl, Martin; Jørgensen, Kevin

    1998-01-01

    A liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometric method is described for the determination of aflatoxins B-1, B-2, G(1) and G(2) in food with the use of aflatoxin M-1 as an internal standard. The method works well with matrices such as those of figs and...

  14. Mass spectrometric immunoassay

    Science.gov (United States)

    Nelson, Randall W; Williams, Peter; Krone, Jennifer Reeve

    2007-12-04

    Rapid mass spectrometric immunoassay methods for detecting and/or quantifying antibody and antigen analytes utilizing affinity capture to isolate the analytes and internal reference species (for quantification) followed by mass spectrometric analysis of the isolated analyte/internal reference species. Quantification is obtained by normalizing and calibrating obtained mass spectrum against the mass spectrum obtained for an antibody/antigen of known concentration.

  15. UPLC-MS/MS同时检测染发剂中三种二氨基酚类物质%Determinauon of 3 diaminopnenols in hair dyes by ultra performance liquid chromatography tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    曹鹏; 耿金培; 许红岩; 李晓玉; 李金强; 梁君妮; 沙美兰

    2011-01-01

    建立了超高效液相色谱-串联质谱( UPLC-MS/MS)同时检测染发剂中三种二氨基酚类物质(2,4-二氨基苯酚盐酸盐、2,4-二氨基苯甲醚盐酸盐、2,3-二氨基苯酚)含量的方法.样品经0.1%甲酸水溶液提取,正己烷净化后,用Waters ACQUITY BEH Shield RP18色谱柱进行分离,流动相为甲醇和5 mmol/L乙酸铵-0.1%甲酸溶液.分离后采用多反应监测模式进行检测,外标法定量.在优化实验条件下,三种化合物的线性范围为10 ~ 500.μg/L,相关系数均大于0.998.三种二氨基酚类化合物的检出限为3μg/kg,定量下限为10μg/kg,加标平均回收率为80.3%~113.5%,相对标准偏差均不高于8.6%.该方法适用于染发剂中三种二氨基酚类物质的定量及确证分析.%An ultra performance liquid chromatography-electrospray ionization triple-quadruple tandem mass speetrometric ( UPLC-ESI MS/MS) method has been established for the simultaneous determination of three diaminophenols, including 2,4-diaminophenol dihydrochloride, 2,4-diaminoanisole dihydrochloride, and 2,3-Diaminophenol, in hair dyes. The diaminophenols were extracted by water - 0. 1 % formic acid and cleaned up by n-hexane. The separation was carried out by an ACQUITY? BEH Shield RP18 column using methanol and 5 mmol/L ammonium acetate - 0. 1 % formic acid as the mobile phase. The target compounds were confirmed and quantified by MS-MS under multiple-reaction monitering ( MRM) mode with external standard method. Extraction and chromatographic conditions were optimized and the best separation was obtained. Under the optimal conditions, the calibration curves were linear in the range of 10 ~ 500 jxg/L for the three compounds with correlation coefficients more than 0.998. The limits of detection (LOD) were 3 fig/kg, and the limits of quantitation (LOQ) were 10 jxg/kg. The average recoveries of 3 diaminophenols were between 80.3% and 113. 5% with the relative standard deviations (RSDs) no more than 8

  16. Determination of Paralytic Shellfish Poisoning Toxins in Shellfish by Liquid Chromatography with Tandem Mass Spectrometry%液相色谱-串联质谱法检测贝类产品中麻痹性贝类毒素

    Institute of Scientific and Technical Information of China (English)

    母清林; 方杰; 王晓华; 胡颢琰; 曹柳燕; 张庆红

    2013-01-01

    建立了贝类组织中11种麻痹性贝类毒素的高效液相色谱-串联质谱分析方法,包括STX、dcSTX、NEO、dcNEO、GTX1-4、dcGTX2,3和GTX5(B1).贝类样品经含0.1%甲酸的80%(体积分数)乙腈水溶液超声提取后,经过冷冻分层,下层固体融化后通过HLB固相萃取小柱富集净化和10 000MWCO(Molecular Weight Cutoff)超滤管超滤截留,超滤液用于仪器分析.采用Zwitterionic亲水性相互作用色谱柱(250 mm×4.6 mm,5μm,德国)分离,在多反应监测模式下进行定性和定量分析.各组分在一定的范围内具有良好的线性关系,平均回收率大于60%,相对标准偏差小于20%(n=7).用该方法分析染毒的栉孔扇贝样品,证实了对PSP毒素具有良好的分析测定效果.%A liquid chromatography-electrospray ionization triple-quadruple tandem mass spectrometric method has been established for the determination of eleven kinds of paralytic shellfish poisoning toxins including STX, dcSTX, NEO, dcNEO, GTX1 -4, dcGTX2,3 andGTX5(B1). After being extracted using acetonitrile and water (80:20, V/V) including 0. 1 % formic acid, the solution was frozen to separate into two layers. To melt the solid, then the solution would be cleaned-up by solid phase extraction (SPE) on an Oasis HLB cartridge. In order to get rid of macromolecule compound, the sample was ultra filtrated with 10 000 MWCO ( Molecular Weight Cutoff) ultra-filtration device. The ultra-filtration solution would be analyzed. The sample would be separated on a Zwitterionic hydrophilic interaction liquid chromatography column ( 250 mm × 4. 6 mm, 5 μm ). The quantitative and confirmatory determinations of PSP were performed by multiple reactions monitoring mode. All components showed good linear relation in the suitable range. The mean recoveries were more than 60% and the relative standard deviations were less than 20% ( n = 7 ). The method has been applied to the analysis of samples contaminated with PSP toxins with

  17. Precision mass measurements

    Science.gov (United States)

    Gläser, M.; Borys, M.

    2009-12-01

    Mass as a physical quantity and its measurement are described. After some historical remarks, a short summary of the concept of mass in classical and modern physics is given. Principles and methods of mass measurements, for example as energy measurement or as measurement of weight forces and forces caused by acceleration, are discussed. Precision mass measurement by comparing mass standards using balances is described in detail. Measurement of atomic masses related to 12C is briefly reviewed as well as experiments and recent discussions for a future new definition of the kilogram, the SI unit of mass.

  18. Mass Customization Services

    OpenAIRE

    Friedrich, Gerhard

    2008-01-01

    Topics of the IMCM’08 & PETO’08 and this book are: Mass customization in service, mass customizing financial services, mass customization in supply networks, implementation issues in logistics, product life cycle and mass customization. The research field of mass customization is more than 15 years old but as the topics illustrate, quite a diverse field. This is expected to continue as long as all fields continue to evolve in their own direction. From a research point of view this provide...

  19. Neutrino masses and oscillations

    International Nuclear Information System (INIS)

    New effects related to refraction of neutrinos in different media are reviewed and implication of the effects to neutrino mass and mixing are discussed. Patterns of neutrino masses and mixing implied by existing hints/bounds are described. Recent results on neutrino mass generation are presented. They include neutrino masses in SO(10) GUT's and models with anomalous U(1), generation of neutrino mass via neutrino-neutralino mixing, models of sterile neutrino. (author). 95 refs, 9 figs

  20. Heavy quark masses

    Science.gov (United States)

    Testa, Massimo

    1990-01-01

    In the large quark mass limit, an argument which identifies the mass of the heavy-light pseudoscalar or scalar bound state with the renormalized mass of the heavy quark is given. The following equation is discussed: m(sub Q) = m(sub B), where m(sub Q) and m(sub B) are respectively the mass of the heavy quark and the mass of the pseudoscalar bound state.

  1. Imaging mass spectrometer with mass tags

    Science.gov (United States)

    Felton, James S.; Wu, Kuang Jen J.; Knize, Mark G.; Kulp, Kristen S.; Gray, Joe W.

    2013-01-29

    A method of analyzing biological material by exposing the biological material to a recognition element, that is coupled to a mass tag element, directing an ion beam of a mass spectrometer to the biological material, interrogating at least one region of interest area from the biological material and producing data, and distributing the data in plots.

  2. Alienation, Mass Society and Mass Culture.

    Science.gov (United States)

    Dam, Hari N.

    This monograph examines the nature of alienation in mass society and mass culture. Conceptually based on the "Gemeinschaft-Gesellschaft" paradigm of sociologist Ferdinand Tonnies, discussion traces the concept of alienation as it appears in the philosophies of Hegel, Marx, Kierkegaard, Sartre, and others. Dwight Macdonald's "A Theory of Mass…

  3. UPLC-MS/MS法测定Beagle犬血浆中S-奥拉西坦浓度%A sensitive and specific UPLC-MS/MS analysis and preliminary pharmacokinetic characterization of S-oxiracetam in Beagle dogs

    Institute of Scientific and Technical Information of China (English)

    汪五三; 季晖; 谢海棠; 戴敏; 贾元威; 梁大虎; 叶雷; 荣祖元

    2012-01-01

    目的:建立灵敏、准确的Beagle犬血浆中S-奥拉西坦浓度的UPLC-MS/MS检测方法,并用于该药在Beagle犬体内的药动学研究.方法:血浆样品经甲醇沉淀蛋白后,以甲醇-水溶液(85∶15,V/V,内加10 mmoL乙酸铵和0.1%甲酸)为流动相,用HP Amide LC-MS/MS Column(100 mm×3 mm ID,5μm)分离,采用电喷雾离子源,以多反应监测(MRM)方式进行正离子检测,定量分析的离子反应分别为m/z 159.0/114.1(S-奥拉西坦)和m/z 143.0/126.1(内标,吡拉西坦).结果:S-奥拉西坦线性范围为0.05~50 μg/mL,定量下限为0.05μg/mL,日内、日间精密度(RSD)均小于15%.S-奥拉西坦大鼠血浆样品在储存、预处理、分析期间均显示良好的稳定性.应用此法研究了6只Beagle犬单剂量口服S-奥拉西坦50 mg/kg后的药动学特点.结论:该方法快速、专属、灵敏、适用性强,可应用于5-奥拉西坦的临床前药动学研究.%AIM:To develop a sensitive and specific ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) method for the identification and quantification of S-oxiracetamin in Beagle dog plasma.METHODS:The method involved the addition of piracetam as internal standards,protein-precipitation,UPLC separation,and quantification by MS/MS system using positive electrospray ionization in the multiple reaction monitoring mode (MRM).An HP Amide C18 column (100 mm×3.00 mm,5 μm) was used as the analytical column,while a mixture of methanol-water was used as the mobile phase.The precursor/product ion transitions selected were m/z 159.0/114.1 for S-oxiracetam and m/z 143.0/126.1 for I.S.RESULTS:The lower limit of quantification of S-oxiracetam was 0.05μg/mL.The method was linear in the concentration range of 0.05 - 50 μg/mL.The intra-day and inter-day precisions (RSD) were within 15.0% for the analytes. S-oxiracetam was proved to be stable during all sample storage,preparation and analytical periods.The method was

  4. UHPLC-MS/MS分析腹泻性贝毒在文蛤体内的积累与排出%UHPLC-MS/MS analysis of the accumulation and elimination of DSP in Meretrix meretrix

    Institute of Scientific and Technical Information of China (English)

    饶涛; 张勇; 杜霞; 张洋; 贾睿; 陶妍; 何培民

    2012-01-01

    采用超高压液相色谱-四极杆串联质谱法建立了腹泻性贝毒(diarrhetic shellfish poisoning,DSP)、大田软海绵酸(okadaicacid,OA)和鳍藻毒素1(dinophysistoxin-1,DTX1)的检测方法。样品经80%甲醇提取后,经正己烷脱脂和C18固相萃取柱净化,采用Hypersil GOLD C18色谱柱分离,以50%(体积分数)乙腈水(0.2%甲酸)溶液为流动相等度洗脱,电喷雾电离,在选择反应监测(SRM)模式下进行定性与定量分析。OA和DTX1在25~400μg/kg范围内线性关系良好,OA和DTX1最低定量限(LOQ,S/N〉10)分别为5μg/kg和1μg/kg。样品平均回收率大于80%,相对标准偏差小于10%(n=6)。应用该检测方法研究了利玛原甲藻(Pivrocentrurn lima)产生的DSP毒素在文蛤(Meretrixmeretrix)体内累积与排出规律。结果表明,DSP在文蛤体内积累迅速,摄食48 h,贝类肌肉中和消化腺中的DTX1含量即超过了食用安全限量。文蛤消化腺中的毒素含量大约是肌肉中的10倍。经96 h排出实验,贝体内的DSP毒素排除量大于80%。%Okadaic acid(OA) and dinophysistoxins-1(DTX1) of diarrhetic shellfish poisoning(DSP) toxins were detected by ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry(UHPLC-MS/MS).After the toxins being extracted using methanol and water(80∶ 20,V/V),the solution was further extracted with n-hexane to remove lipid components and then cleaned up by solid phase extraction(SPE) on an C18 cartridge.The analytes were eluted with 50%(V/V)acetonitral water containing 0.2% formic acid on a Hypersil GOLD C18 column.The qualitative and quantitative determination of the toxins was performed by selective reaction monitoring(SRM) mode.OA and DTX1 were determined in the negative ion mode.The calibration curve was linear in the ranges of 25-400 μg/kg.The quantification limits of OA and DTX1were 5 μg/kg and 1 μg/kg,respectively.The mean recoveries at spiked

  5. Determination of medroxyprogesterone acetate residues in eels by ultra performance liquid chromatography with tandem mass spectrometric detection%超高效液相色谱-串联质谱法测定鳗鱼中醋酸甲羟孕酮含量

    Institute of Scientific and Technical Information of China (English)

    张秀珍; 田秀慧; 徐英江; 宫向红; 邢红艳; 张世娟; 刘慧慧

    2011-01-01

    The solid phase extraction-ultra performance liquid chromatography with electrospray ionization tandem mass spectrometry(UPLC-ESI-MS/MS) method for determination of medroxyprogesterone acetate in eels has been established in our work.The drugs were extracted by ethyl acetate,and then on the solid phase extraction cartridges,and the extraction was evaporated at 40 ℃ by nitrogen blow.The residue was dissolved and separated by ACQUITYTM UPLC BEH C18 column,and mobile phase was A(acetonitrile) and B(0.1% formic acid in water) and finally was confirmed and quantified using a MS/MS system in the multiple reaction mode with tandem mass analyzer using positive polarity mode.The LOD of medroxyprogesterone acetate was 0.03 μg/kg,and the LOQ was 0.10 μg/kg,and the average recovery was more than 80% with spiked residues from 0.10 μg/kg to 5.0 μg/kg.The intra-day relative standard derivation(RSD) and the inter-day RSD were less than 10%.The method has merits of simplicity,sensitivity and rapidity,and it can be used for determination in eels.%研究了鳗鱼中醋酸甲羟孕酮的固相萃取-超高效液相色谱-串联质谱分析方法。样品用乙酸乙酯提取,经固相萃取柱净化后,40℃水浴氮气吹至近干;以乙腈和含有0.1%甲酸的水溶液为流动相,经ACQUITYTM UPLC BEH C18柱分离后进行超高效液相色谱-串联质谱多反应监测模式下的定性定量分析。醋酸甲羟孕酮检出限为0.03μg/kg、定量限为0.10μg/kg,添加量为0.10~5.0μg/kg时,醋酸甲羟孕酮在鳗鱼中的平均回收率大于80%,相对标准偏差小于10%。

  6. Duplicity and Masses

    Science.gov (United States)

    Pourbaix, D.

    2005-01-01

    Duplicity is still the only hypothesis-free method to derive stellar masses. Whereas other techniques such as asteroseismology rely upon some stellar model, orbits of binary stars yield quantities directly related to either the sum of the masses or the individual masses of the two components. However, in order to derive those individual masses, it is necessary to combine at least two types of observations, e.g., visual and spectroscopic or photometric and spectroscopic. Gaia will make the three of them available but their combination will be an efficient source of masses for sub-groups of binaries only. For instance, given the precision of the radial velocities, how many orbital visual binaries (for which the mass sum is therefore accessible) will lead to a spectroscopic orbit required to derive the mass ratio and thus the individual masses?

  7. Body mass index

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/007196.htm Body mass index To use the sharing features on this ... your height is to figure out your body mass index (BMI). You and your health care provider ...

  8. Competition among mass media

    OpenAIRE

    Kwiek, Maksymilian

    2010-01-01

    This paper investigates how mass media provide information to readers or viewers who have diverse interests. The problem of a mass medium comes from the fact that there is a constraint on how much information can be delivered. It is shown that the mass medium optimally provides information that is somewhat useful to all agents, but not perfect to anybody in particular. This benchmark model is then used to investigate competition among mass media with differentiated products. In the equilibriu...

  9. Mass Customization Measurements Metrics

    DEFF Research Database (Denmark)

    Nielsen, Kjeld; Brunø, Thomas Ditlev; Jørgensen, Kaj Asbjørn;

    2014-01-01

    A recent survey has indicated that 17 % of companies have ceased mass customizing less than 1 year after initiating the effort. This paper presents measurement for a company’s mass customization performance, utilizing metrics within the three fundamental capabilities: robust process design, choice...... navigation, and solution space development. A mass customizer when assessing performance with these metrics can identify within which areas improvement would increase competitiveness the most and enable more efficient transition to mass customization....

  10. Baryon masses with dynamical twisted mass fermions

    CERN Document Server

    Alexandrou, C; Koutsou, G; Baron, R; Guichon, P; Brinet, M; Carbonell, J; Drach, V; Liu, Z; Pène, O; Urbach, C

    2007-01-01

    We present results on the mass of the nucleon and the $\\Delta$ using two dynamical degenerate twisted mass quarks. The evaluation is performed at four quark masses corresponding to a pion mass in the range of 690-300 MeV on lattices of size 2.1 fm and 2.7 fm. We check for cutoff effects by evaluating these baryon masses on lattices of spatial size 2.1 fm with lattice spacings $a(\\beta=3.9)=0.0855(6)$ fm and $a(\\beta=4.05)=0.0666(6)$ fm, determined from the pion sector and find them to be within our statistical errors. Lattice results are extrapolated to the physical limit using continuum chiral perturbation theory. The nucleon mass at the physical point provides a determination of the lattice spacing. Using heavy baryon chiral perturbation theory at ${\\cal O}(p^3)$ we find $a(\\beta=3.9)=0.0879(12)$ fm, with a systematic error due to the chiral extrapolation estimated to be about the same as the statistical error. This value of the lattice spacing is in good agreement with the value determined from the pion se...

  11. What masses for Cepheids

    International Nuclear Information System (INIS)

    To understand the evolution of giant stars, it is important to pin down the masses for Cepheids. The 7- to 10-day bump Cepheids imply lower than evolutionary mass (60%). Recent theoretical work, though, indicates that for Cepheids with periods of 15 to 16 days, the best understanding of the light curves results from using evolutionary masses

  12. On Defining Mass

    Science.gov (United States)

    Hecht, Eugene

    2011-01-01

    Though central to any pedagogical development of physics, the concept of mass is still not well understood. Properly defining mass has proven to be far more daunting than contemporary textbooks would have us believe. And yet today the origin of mass is one of the most aggressively pursued areas of research in all of physics. Much of the excitement…

  13. Direct Neutrino Mass Searches

    Science.gov (United States)

    VanDevender, B. A.

    2009-12-01

    Neutrino flavor oscillation experiments have demonstrated that the three Standard Model neutrino flavor eigenstates are mixed with three mass eigenstates whose mass eigenvalues are nondegenerate. The oscillation experiments measure the differences between the squares of the mass eigenvalues but tell us nothing about their absolute values. The unknown absolute neutrino mass scale has important implications in particle physics and cosmology. Beta decay endpoint measurements are presented as a model-independent method to measure the absolute neutrino mass. The Karlsruhe Tritium Neutrino Experiment (KATRIN) is explored in detail.

  14. Digital Imaging Mass Spectrometry

    Science.gov (United States)

    Bamberger, Casimir; Renz, Uwe; Bamberger, Andreas

    2011-06-01

    Methods to visualize the two-dimensional (2D) distribution of molecules by mass spectrometric imaging evolve rapidly and yield novel applications in biology, medicine, and material surface sciences. Most mass spectrometric imagers acquire high mass resolution spectra spot-by-spot and thereby scan the object's surface. Thus, imaging is slow and image reconstruction remains cumbersome. Here we describe an imaging mass spectrometer that exploits the true imaging capabilities by ion optical means for the time of flight mass separation. The mass spectrometer is equipped with the ASIC Timepix chip as an array detector to acquire the position, mass, and intensity of ions that are imaged by matrix-assisted laser desorption/ionization (MALDI) directly from the target sample onto the detector. This imaging mass spectrometer has a spatial resolving power at the specimen of (84 ± 35) μm with a mass resolution of 45 and locates atoms or organic compounds on a surface area up to ~2 cm2. Extended laser spots of ~5 mm2 on structured specimens allows parallel imaging of selected masses. The digital imaging mass spectrometer proves high hit-multiplicity, straightforward image reconstruction, and potential for high-speed readout at 4 kHz or more. This device demonstrates a simple way of true image acquisition like a digital photographic camera. The technology may enable a fast analysis of biomolecular samples in near future.

  15. The Point Mass Concept

    Directory of Open Access Journals (Sweden)

    Lehnert B.

    2011-04-01

    Full Text Available A point-mass concept has been elaborated from the equations of the gravitational field. One application of these deductions results in a black hole configuration of the Schwarzschild type, having no electric charge and no angular momentum. The critical mass of a gravitational collapse with respect to the nuclear binding energy is found to be in the range of 0.4 to 90 solar masses. A second application is connected with the spec- ulation about an extended symmetric law of gravitation, based on the options of positive and negative mass for a particle at given positive energy. This would make masses of equal polarity attract each other, while masses of opposite polarity repel each other. Matter and antimatter are further proposed to be associated with the states of positive and negative mass. Under fully symmetric conditions this could provide a mechanism for the separation of antimatter from matter at an early stage of the universe.

  16. On Defining Mass

    Science.gov (United States)

    Hecht, Eugene

    2011-01-01

    Though central to any pedagogical development of physics, the concept of mass is still not well understood. Properly defining mass has proven to be far more daunting than contemporary textbooks would have us believe. And yet today the origin of mass is one of the most aggressively pursued areas of research in all of physics. Much of the excitement surrounding the Large Hadron Collider at CERN is associated with discovering the mechanism responsible for the masses of the elementary particles. This paper will first briefly examine the leading definitions, pointing out their shortcomings. Then, utilizing relativity theory, it will propose—for consideration by the community of physicists—a conceptual definition of mass predicated on the more fundamental concept of energy, more fundamental in that everything that has mass has energy, yet not everything that has energy has mass.

  17. Origins of Mass

    CERN Document Server

    Wilczek, Frank

    2012-01-01

    Newtonian mechanics posited mass as a primary quality of matter, incapable of further elucidation. We now see Newtonian mass as an emergent property. Most of the mass of standard matter, by far, arises dynamically, from back-reaction of the color gluon fields of quantum chromodynamics (QCD). The equations for massless particles support extra symmetries - specifically scale, chiral, and gauge symmetries. The consistency of the standard model relies on a high degree of underlying gauge and chiral symmetry, so the observed non-zero masses of many elementary particles ($W$ and $Z$ bosons, quarks, and leptons) requires spontaneous symmetry breaking. Superconductivity is a prototype for spontaneous symmetry breaking and for mass-generation, since photons acquire mass inside superconductors. A conceptually similar but more intricate form of all-pervasive (i.e. cosmic) superconductivity, in the context of the electroweak standard model, gives us a successful, economical account of $W$ and $Z$ boson masses. It also al...

  18. The Point Mass Concept

    Directory of Open Access Journals (Sweden)

    Lehnert B.

    2011-04-01

    Full Text Available A point-mass concept has been elaborated from the equations of the gravitational field. One application of these deductions results in a black hole configuration of the Schwarzschild type, having no electric charge and no angular momentum. The critical mass of a gravitational collapse with respect to the nuclear binding energy is found to be in the range of 0.4 to 90 solar masses. A second application is connected with the speculation about an extended symmetric law of gravitation, based on the options of positive and negative mass for a particle at given positive energy. This would make masses of equal polarity attract each other, while masses of opposite polarity repel each other. Matter and antimatter are further proposed to be associated with the states of positive and negative mass. Under fully symmetric conditions this could provide a mechanism for the separation of antimatter from matter at an early stage of the universe.

  19. Mass Spectrometric Analysis of Glyoxal and Methylglyoxal-Induced Modifications in Human Hemoglobin from Poorly Controlled Type 2 Diabetes Mellitus Patients.

    Science.gov (United States)

    Chen, Hauh-Jyun Candy; Chen, Yu-Chin; Hsiao, Chiung-Fong; Chen, Pin-Fan

    2015-12-21

    Glyoxal and methylglyoxal are oxoaldehydes derived from the degradation of glucose-protein conjugates and from lipid peroxidation, and they are also present in the environment. This study investigated the site-specific reaction of glyoxal and methylglyoxal with the amino acid residues on human hemoglobin using a shot-gun proteomic approach with nanoflow liquid chromatography/nanospray ionization tandem mass spectrometry (nanoLC-NSI/MS/MS). In human hemoglobin incubated with glyoxal, modification on 8 different sites, including lysine residues at α-Lys-11, α-Lys-16, α-Lys-56, β-Lys-17, β-Lys-66, β-Lys-144, and arginine residues at α-Arg-92 and β-Arg-30, was observed using a data-dependent scan. In methylglyoxal-treated hemoglobin, there were specific residues, namely, α-Arg-92, β-Lys-66, β-Arg-30, and β-Lys-144, forming carboxyethylation as well as the dehydrated product hydroimidazolone at α-Arg-92 and β-Arg-30. These lysine and arginine modifications were confirmed by accurate mass measurement and the MS(2) and MS(3) spectra. The most intensive signal of each modified peptide was used as the precursor ion to perform the product ion scan. The relative extent of modifications was semiquantified simultaneously relative to the native reference peptide by nanoLC-NSI/MS/MS under the selected reaction monitoring (SRM) mode. The extent of these modifications increased dose-dependently with increasing concentrations of glyoxal or methylglyoxal. Six out of the eight modifications induced by glyoxal and three out of the six modifications induced by methylglyoxal were detected in hemoglobin freshly isolated from human blood samples. The relative extent of modification of these post-translational modifications was quantified in poorly controlled type 2 diabetes mellitus patients (n = 20) and in nondiabetic control subjects (n = 21). The results show that the carboxymethylated peptides at α-Lys-16, α-Arg-92, β-Lys-17, β-Lys-66, and the peptide at α-Arg-92

  20. Lepton and meson masses

    CERN Document Server

    Gonzalez-Martin, Gustavo R

    2004-01-01

    The lepton mass ratios are calculated using a geometric unified theory, taking the leptons as the only three possible families of topological excitations of the electron or the neutrino. The theoretical results give 107.5916 Mev for the muon mass and 1770.3 Mev for the tau mass using the mass ratios. Using the additional geometric interaction energy in a muon-neutrino system, the main leptonic mass contribution to the pion and kaon mass is calculated to be, respectively, 140.88 Mev and 494.76 Mev. The necessary first order corrections, due to the interaction of the excitations, should be of the order of the discrepancies with experimental values. The three geometric families of leptonic excitations may be related to a quark structure.

  1. Gluino Stransverse Mass

    CERN Document Server

    Cho, Won Sang; Kim, Yeong Gyun; Park, Chan Beom

    2007-01-01

    We introduce a new observable, 'gluino stransverse mass', which is an application of the Cambridge $m_{T2}$ variable to the process where gluinos are pair produced in proton-proton collision and each gluino subsequently decays into two quarks and one LSP, $i.e. \\tilde{g}\\tilde{g} \\to qq\\tilde\\chi_1^0\\ qq\\tilde\\chi_1^0$. We show that the gluino stransverse mass can be utilized to measure the gluino and the lightest neutralino masses separately, and also the (1st and 2nd generation) squark masses if lighter than the gluino mass, thereby providing a good first look at the pattern of sparticle masses experimentally.

  2. Is Mass Customization Sustainable?

    DEFF Research Database (Denmark)

    Petersen, Thomas Ditlev; Jørgensen, Kaj Asbjørn; Nielsen, Kjeld;

    2011-01-01

    Mass customizers are like other companies currently experiencing an increasing customer demand for environmentally sustainable products as well as an increasingly strict legislation regarding environmental sustainability. This paper addresses the issue whether the concepts mass customization...... and sustainability are fundamentally compatible by asking the question: can a mass customized product be sustainable? Several factors could indicate that mass customized products are less sustainable than standardized products; however other factors suggest the opposite. This paper explores these factors during...... three life cycle phases for a product: Production, Use and End of Life. It is concluded that there is not an unambiguous causal relationship between mass customization and sustainability; however several factors unique to mass customized products are essential to consider during product and process...

  3. Expedient preparative isolation and tandem mass spectrometric characterization of C-seco triterpenoids from Neem oil.

    Science.gov (United States)

    Haldar, Saikat; Mulani, Fayaj A; Aarthy, Thiagarayaselvam; Dandekar, Devdutta S; Thulasiram, Hirekodathakallu V

    2014-10-31

    C-seco triterpenoids are widely bioactive class of natural products with high structural complexity and diversity. The preparative isolation of these molecules with high purity is greatly desirable, although restricted due to the complexity of natural extracts. In this article we have demonstrated a Medium Pressure Liquid Chromatography (MPLC) based protocol for the isolation of eight major C-seco triterpenoids of salannin skeleton from Neem (Azadirachta indica) oil. Successive application of normal phase pre-packed silica-gel columns for the fractionation followed by reverse phase in automated MPLC system expedited the process and furnished highly pure metabolites. Furthermore, eight isolated triterpenoids along with five semi-synthesized derivatives were characterized using ultra performance liquid chromatography-electrospray ionization-quadrupole/orbitrap-MS/MS spectrometry as a rapid and sensitive identification technique. The structure-fragment relationships were established on the basis of plausible mechanistic pathway for the generation of daughter ions. The MS/MS spectral information of the triterpenoids was further utilized for the identification of studied molecules in the complex extract of stem and bark tissues from Neem. PMID:25267707

  4. Mass spectrometry in oceanography

    International Nuclear Information System (INIS)

    Mass spectrometry plays an important role in oceanography for various applications. Different types of inorganic as well as organic mass spectrometric techniques are being exploited world-wide to understand the different aspects of marine science, for palaeogeography, palaeoclimatology and palaeoecology, for isotopic composition and concentrations of different elements as well as for speciation studies. The present paper reviews some of the applications of atomic mass spectrometric techniques in the area of oceanography

  5. The Point Mass Concept

    OpenAIRE

    Lehnert B.

    2011-01-01

    A point-mass concept has been elaborated from the equations of the gravitational field. One application of these deductions results in a black hole configuration of the Schwarzschild type, having no electric charge and no angular momentum. The critical mass of a gravitational collapse with respect to the nuclear binding energy is found to be in the range of 0.4 to 90 solar masses. A second application is connected with the spec- ulation about an extended symmetric ...

  6. Gluino Stransverse Mass

    OpenAIRE

    Cho, Won Sang; Choi, Kiwoon; Kim, Yeong Gyun; Park, Chan Beom

    2007-01-01

    We introduce a new observable, 'gluino stransverse mass', which is an application of the Cambridge $m_{T2}$ variable to the process where gluinos are pair produced in proton-proton collision and each gluino subsequently decays into two quarks and one LSP, $i.e. \\tilde{g}\\tilde{g} \\to qq\\tilde\\chi_1^0\\ qq\\tilde\\chi_1^0$. We show that the gluino stransverse mass can be utilized to measure the gluino and the lightest neutralino masses separately, and also the (1st and 2nd generation) squark mass...

  7. Digital Imaging Mass Spectrometry

    CERN Document Server

    Bamberger, Casimir; Bamberger, Andreas

    2011-01-01

    Methods to visualize the two-dimensional distribution of molecules by mass spectrometric imaging evolve rapidly and yield novel applications in biology, medicine, and material surface sciences. Most mass spectrometric imagers acquire high mass resolution spectra spot-by-spot and thereby scan the object's surface. Thus, imaging is slow and image reconstruction remains cumbersome. Here we describe an imaging mass spectrometer that exploits the true imaging capabilities by ion optical means for the time of flight mass separation. The mass spectrometer is equipped with the ASIC Timepix chip as an array detector to acquire the position, mass, and intensity of ions that are imaged by MALDI directly from the target sample onto the detector. This imaging mass spectrometer has a spatial resolving power at the specimen of (84\\pm35) \\mu m with a mass resolution of 45 and locates atoms or organic compounds on a surface area up to ~2 cm2. Extended laser spots of ~5 mm2 on structured specimens allowed parallel imaging of s...

  8. MassAI

    DEFF Research Database (Denmark)

    2011-01-01

    A software tool for general analysis and data-mining of mass-spectrometric datasets. The program features a strong emphasis on scan-by-scan identification and results-transparency. MassAI also accommodates residue level analysis of labelled runs, e.g. HDX.......A software tool for general analysis and data-mining of mass-spectrometric datasets. The program features a strong emphasis on scan-by-scan identification and results-transparency. MassAI also accommodates residue level analysis of labelled runs, e.g. HDX....

  9. Does Information Have Mass?

    CERN Document Server

    Kish, Laszlo B

    2013-01-01

    Does information have mass? This question has been asked many times and there are many answers even on the Internet, including on Yahoo Answers. Usually the answer is "no". Attempts have been made to assess the physical mass of information by estimating the mass of electrons feeding the power-guzzling computers and devices making up the Internet, the result being around 50 gram. Other efforts to calculate the mass of information have assumed that each electron involved in signal transfer carries one bit of information, which makes the corresponding mass to be about 10^-5 gram. We address the fundamental question of minimum mass related to a bit of information from the angles of quantum physics and special relativity. Our results indicate that there are different answers depending on the physical situation, and sometimes the mass can even be negative. We tend to be skeptical about the earlier mass estimations, mentioned above, because our results indicate that the electron's mass does not play a role in any on...

  10. Cyclotrons as mass spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Clark, D.J.

    1984-04-01

    The principles and design choices for cyclotrons as mass spectrometers are described. They are illustrated by examples of cyclotrons developed by various groups for this purpose. The use of present high energy cyclotrons for mass spectrometry is also described. 28 references, 12 figures.

  11. "Mass" in Communication Research.

    Science.gov (United States)

    Corner, John

    1979-01-01

    Summarizes the arguments against the use of the term "mass" in communication research based on confusions which relate it to the theses of mass society theory or the notion that the term is too simple for the complex nature of communication. (JMF)

  12. Mass Preserving Image Registration

    DEFF Research Database (Denmark)

    Gorbunova, V.; Sporring, J.; Lo, P.;

    2010-01-01

    The paper presents results the mass preserving image registration method in the Evaluation of Methods for Pulmonary Image Registration 2010 (EMPIRE10) Challenge. The mass preserving image registration algorithm was applied to the 20 image pairs. Registration was evaluated using four different...

  13. ABSOLUTE NEUTRINO MASSES

    DEFF Research Database (Denmark)

    Schechter, J.; Shahid, M. N.

    2012-01-01

    We discuss the possibility of using experiments timing the propagation of neutrino beams over large distances to help determine the absolute masses of the three neutrinos.......We discuss the possibility of using experiments timing the propagation of neutrino beams over large distances to help determine the absolute masses of the three neutrinos....

  14. Thermal mass goes beautiful

    Energy Technology Data Exchange (ETDEWEB)

    Sjostrand, D.C.

    1980-01-01

    This presentation takes a look at architectural treatment of interior concrete masonry used for thermal mass. The effects on performance of a thermal mass of various combinations of concrete masonry and architectural treatments are studied. Alternatives to a black Trombe wall are presented along with thermal performance comparisons.

  15. Measurements of neutrino mass

    International Nuclear Information System (INIS)

    Direct experimental information of neutrino mass as derived from the study of nuclear and elementary-particle weak decays is reviewed. Topics include tritium beta decay; the 3He-T mass difference; electron capture decay of 163Ho and 158Tb; and limits on massive neutrinos from cosmology. 38 references

  16. Quantum view of Mass

    CERN Document Server

    Ramachandran, R

    2012-01-01

    The classical view of mass is that it quantifies the amount of substance and is a kinematical parameter. All matter has an attribute of mass and is a conserved quantity in any interaction. With the advent of special relativity, mass became no longer a conserved quantity, since energy and momenta had the status of conserved variables. Nevertheless, the expression for relativistic mass gives a Poincare invariant measure that can be associated as the mass, a useful attribute of the body or system. In the quantum regime, mass becomes truly dynamical. Higgs field is said to provide mass to all the species of elementary constituents - as widely popularized by the media in connection with the recent (most likely) discovery of the Higgs meson at CERN. However, we emphasize that the most abundant component of matter - Nucleons - derives its mass largely as a consequence of quantum effects of (color gluonic QCD) radiation. Further, interestingly this arises out of literally nothing, save the QCD scale determined experi...

  17. Cyclotrons as mass spectrometers

    International Nuclear Information System (INIS)

    The principles and design choices for cyclotrons as mass spectrometers are described. They are illustrated by examples of cyclotrons developed by various groups for this purpose. The use of present high energy cyclotrons for mass spectrometry is also described. 28 references, 12 figures

  18. Geometry of mass.

    Science.gov (United States)

    Dietrich, D D

    2015-08-01

    We study the effect of mass on geometric descriptions of gauge field theories. In an approach in which the massless theory resembles general relativity, the introduction of the mass entails non-zero torsion and the generalization to Einstein-Cartan-Sciama-Kibble theories. The relationships to pure torsion formulations (teleparallel gravity) and to higher gauge theories are also discussed. PMID:26124248

  19. Miniature mass analyzer

    CERN Document Server

    Cuna, C; Lupsa, N; Cuna, S; Tuzson, B

    2003-01-01

    The paper presents the concept of different mass analyzers that were specifically designed as small dimension instruments able to detect with great sensitivity and accuracy the main environmental pollutants. The mass spectrometers are very suited instrument for chemical and isotopic analysis, needed in environmental surveillance. Usually, this is done by sampling the soil, air or water followed by laboratory analysis. To avoid drawbacks caused by sample alteration during the sampling process and transport, the 'in situ' analysis is preferred. Theoretically, any type of mass analyzer can be miniaturized, but some are more appropriate than others. Quadrupole mass filter and trap, magnetic sector, time-of-flight and ion cyclotron mass analyzers can be successfully shrunk, for each of them some performances being sacrificed but we must know which parameters are necessary to be kept unchanged. To satisfy the miniaturization criteria of the analyzer, it is necessary to use asymmetrical geometries, with ion beam obl...

  20. Direct Neutrino Mass Experiments

    CERN Document Server

    Mertens, Susanne

    2016-01-01

    With a mass at least six orders of magnitudes smaller than the mass of an electron -- but non-zero -- neutrinos are a clear misfit in the Standard Model of Particle Physics. On the one hand, its tiny mass makes the neutrino one of the most interesting particles, one that might hold the key to physics beyond the Standard Model. On the other hand this minute mass leads to great challenges in its experimental determination. Three approaches are currently pursued: An indirect neutrino mass determination via cosmological observables, the search for neutrinoless double $\\beta$-decay, and a direct measurement based on the kinematics of single $\\beta$-decay. In this paper the latter will be discussed in detail and the status and scientific reach of the current and near-future experiments will be presented.