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Sample records for chromatography-electrospray ionization mass

  1. Identification of phosphorylation sites of proteins by high performance liquid chromatography-electrospray ionization-quadrupole ion trap mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    车发云; 邵晓霞; 夏其昌

    2000-01-01

    The phosphorylation sites of two phosphorylated proteins, bovine β-casein and myelin basic protein (MBP), were identified by high performance liquid chromatography-electrospray ionization-quadrupole ion trap mass spectrometry (HPLC-ESI-QITMS). The tryptic digest of each protein was separated by HPLC, the molecular weight of each peptide was determined by ESI-QITMS on line, and MS/MS spectrum of each peptide was simultaneously obtained by the combination of collision-induced desorption (CID) technique and tandem mass spectrometry (MS/MS) of QITMS. The phosphorylated peptide was identified by looking into whether the difference between the observed and predicted molecular weights of a peptide is 80 u or its integral multiple. Then the phosphorylation site was identified through manual interpretation of the MS/MS spectrum of the phosphorylated peptide or automatic SEQUEST data base-searching.

  2. Identification of phosphorylation sites of proteins by high performance liquid chromatography-electrospray ionization-quadrupole ion trap mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The phosphorylation sites of two phosphorylated proteins, bovine b-casein and myelin basic protein (MBP), were identified by high performance liquid chromatography-electrospray ionization-quadrupole ion trap mass spectrometry (HPLC-ESI-QITMS). The tryptic digest of each protein was separated by HPLC, the molecular weight of each peptide was determined by ESI-QITMS on line, and MS/MS spectrum of each peptide was simultaneously obtained by the combination of collision-induced desorption (CID) technique and tandem mass spectrometry (MS/MS) of QITMS. The phosphorylated peptide was identified by looking into whether the difference between the observed and predicted molecular weights of a peptide is 80 u or its integral multiple. Then the phosphorylation site was identified through manual interpretation of the MS/MS spectrum of the phosphorylated peptide or automatic SEQUEST data base-searching.

  3. 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.

  4. Simultaneous quantitative analysis of metabolites using ion-pair liquid chromatography-electrospray ionization mass spectrometry

    NARCIS (Netherlands)

    Coulier, L.; Bas, R.; Jespersen, S.; Verheij, E.; Werf, M.J. van der; Hankemeier, T.

    2006-01-01

    We have developed an analytical method, consisting of ion-pair liquid chromatography coupled to electrospray ionization mass spectrometry (IP-LC-ESI-MS), for the simultaneous quantitative analysis of several key classes of polar metabolites, like nucleotides, coenzyme A esters, sugar nucleotides, an

  5. 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

  6. 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...

  7. Liquid chromatography/electrospray ionization mass spectrometric characterization of Harpagophytum in equine urine and plasma.

    Science.gov (United States)

    Colas, Cyril; Garcia, Patrice; Popot, Marie-Agnès; Bonnaire, Yves; Bouchonnet, Stéphane

    2006-01-01

    A method has been developed for the analysis and characterization in equine urine and plasma of iridoid glycosides: harpagide, harpagoside and 8-para-coumaroyl harpagide, which are the main active principles of Harpagophytum, a plant with antiinflammatory properties. The method involves liquid chromatography coupled with positive electrospray ionization mass spectrometry. The addition of sodium or lithium chloride instead of formic acid in the eluting solvent has been studied in order to enhance the signal and to modify the ion's internal energy. Fragmentation pathways and associated patterns are proposed for each analyte. A comparison of three types of mass spectrometer: a 3D ion trap, a triple quadrupole and a linear ion trap, has been conducted. The 3D ion trap was selected for drug screening analysis whereas the linear ion trap was retained for identification and quantitation analysis. PMID:17044124

  8. 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

  9. Liquid Chromatography-Electrospray Ionization Mass Spectrometry Method for Determination of Protopanaxadiol in Rat Plasma

    Institute of Scientific and Technical Information of China (English)

    WU Yi; TENG Guo-sheng; LIANG Yong-tao; ZHONG Da-fang; LIU Bing

    2009-01-01

    A simple, rapid and sensitive method for the determination of protopanaxadiol in rat plasma with ginse-noside Rh2 as internal standard was developed and validated. The analyte and internal standard were extracted from plasma with ether-dichloromethane(3:2, volume ratio) and then were analyzed by reversed-phase HPLC on a short Zorbax Extend C_(18) column(50 mm×2.1 mm, 3.5 μm i.d.) eluted with a mobile phase consisting of acetoni-trile/methanol 0.10 mmol/L ammonium acetate(45:45:10, volume ratio) at 0.4 mL/min. Detection was performed on an Applied Biosystems Sciex API 4000 mass spectrometer set at unit resolution in the multiple reaction monitoring mode. Electrospray ionization was used for ion production. The assay method shows linear over a range of 5-2000 ng/mL and intra- and inter-day precisions over this range were <10.0% with accuracy ranged from 86.3% to 114.1%. The limit of detection was 500 pg/mL in the plasma. The method was successfully applied to a preclinical pharmaco-kinetic study of protopanaxadiol(17.5 mg/kg) administered as a single oral dose.

  10. 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......-colours. The method was validated in-house for water and 3% acetic acid food simulants using spiked migrates from plastic laminates. Detection limits ranged from 0.27 to 3 mu g amine/L food simulants, and RSD values of within-laboratory reproducibility at the 2 mu g PAA/L level ranged from 3.9 to 19%. PAA migration...... of PAA migration from food contact materials....

  11. 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.

  12. 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.

    Science.gov (United States)

    Tala, Viviane Raïssa Sipowo; Candida da Silva, Viviane; Rodrigues, Clenilson Martins; Nkengfack, Augustin Ephrem; dos Santos, Lourdes Campaner; Vilegas, Wagner

    2013-03-01

    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.

  13. Development and validation of an ultra high performance liquid chromatography electrospray ionization tandem mass spectrometry method for the simultaneous determination of selected flavonoids in Ginkgo biloba.

    Science.gov (United States)

    Pandey, Renu; Chandra, Preeti; Arya, Kamal Ram; Kumar, Brijesh

    2014-12-01

    A rapid and sensitive ultra high performance liquid chromatography electrospray ionization tandem mass spectrometry method was developed and validated for the simultaneous determination of 13 flavonoids in leaf, stem, and fruit extracts of male and female trees of Ginkgo biloba to investigate gender- and age-related variations of flavonoids content. Chromatographic separation was accomplished on an Acquity UPLC BEH C18 column (50 mm × 2.1 mm id, 1.7 μm) in 5 min. Quantitation was performed using negative electrospray ionization mass spectrometry in multiple reaction monitoring mode. The calibration curves of all analytes showed a good linear relationship (r(2) ≥ 0.9977) over the concentration range of 1-1000 ng/mL. The precision evaluated by an intra- and interday study showed RSD ≤ 1.98% and good accuracy with overall recovery in the range from 97.90 to 101.09% (RSD ≤ 1.67%) for all analytes. The method sensitivity expressed as the limit of quantitation was typically 0.25-3.57 ng/mL. The results showed that the total content of 13 flavonoids was higher in the leaf extract of an old male Ginkgo tree compared to young female Ginkgo trees.

  14. Simultaneous determination of quetiapine and three metabolites in human plasma by high-performance liquid chromatography-electrospray ionization mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    Kun-yanLI; Ze-nengCHENG; XinLI; Xue-lianBAI; Bi-kuiZHANG; FengWANG; Huan-deLI

    2004-01-01

    AIM:To develop a high performance liquid chromatography-electrospray mass spectrometry (HPLC-MS/ESI)method for simultaneous determination of quetiapine and its sulfoxide-, 7-hydroxy-, 7-hydroxy-N-dealkyl-metabolites in human plasma. METHODS: The HPLC separation of the compounds was performed on a Kromasil C18, (5μm, 4.6 mm×150 mm) column, using water (formic acid: 1.70 mmol/L, ammonium acetate: 5.8 mmol/L)-acetoni-trile (65:35) as mobile phase, with a flow-rate of 0.95 mL/min. The compounds were ionized in the electrospray ionization (ESI) ion source of the mass spectrometer and detected in the selected ion recording (SIR) mode. The samples were extracted using solid-phase extraction columns. RESULTS: The calibration curves were linear in theranges of 10-2000 μg/L for quetiapine, 1-200 μg/L for its metabolites, respectively. The average extraction recoveries for all the four samples were above 85 %. The methodology recoveries were much higher than 95 %. Theintra-day and inter-day RSD are less than 15 %. CONCLUSION: The method is accurate, sensitive, and simple for study of pharmacokinetics and metabolic mechanism of quetiapine in patients at therapeutic dose.

  15. 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.

  16. Analysis of iodinated haloacetic acids in drinking water by reversed-phase liquid chromatography/electrospray ionization/tandem mass spectrometry with large volume direct aqueous injection.

    Science.gov (United States)

    Li, Yongtao; Whitaker, Joshua S; McCarty, Christina L

    2012-07-01

    A large volume direct aqueous injection method was developed for the analysis of iodinated haloacetic acids in drinking water by using reversed-phase liquid chromatography/electrospray ionization/tandem mass spectrometry in the negative ion mode. Both the external and internal standard calibration methods were studied for the analysis of monoiodoacetic acid, chloroiodoacetic acid, bromoiodoacetic acid, and diiodoacetic acid in drinking water. The use of a divert valve technique for the mobile phase solvent delay, along with isotopically labeled analogs used as internal standards, effectively reduced and compensated for the ionization suppression typically caused by coexisting common inorganic anions. Under the optimized method conditions, the mean absolute and relative recoveries resulting from the replicate fortified deionized water and chlorinated drinking water analyses were 83-107% with a relative standard deviation of 0.7-11.7% and 84-111% with a relative standard deviation of 0.8-12.1%, respectively. The method detection limits resulting from the external and internal standard calibrations, based on seven fortified deionized water replicates, were 0.7-2.3 ng/L and 0.5-1.9 ng/L, respectively.

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. Development of a liquid chromatography-electrospray ionization-tandem mass spectrometry method for the simultaneous analysis of intact glucosinolates and isothiocyanates in Brassicaceae seeds and functional foods.

    Science.gov (United States)

    Franco, P; Spinozzi, S; Pagnotta, E; Lazzeri, L; Ugolini, L; Camborata, C; Roda, A

    2016-01-01

    A new high pressure liquid chromatography-electrospray ionization-tandem mass spectrometry method for the simultaneous determination of glucosinolates, as glucoraphanin and glucoerucin, and the corresponding isothiocyanates, as sulforaphane and erucin, was developed and applied to quantify these compounds in Eruca sativa defatted seed meals and enriched functional foods. The method involved solvent extraction, separation was achieved in gradient mode using water with 0.5% formic acid and acetonitrile with 0.5% formic acid and using a reverse phase C18 column. The electrospray ion source operated in negative and positive mode for the detection of glucosinolates and isothiocyanates, respectively, and the multiple reaction monitoring (MRM) was selected as acquisition mode. The method was validated following the ICH guidelines. Replicate experiments demonstrated a good accuracy (bias%<10%) and precision (CV%<10%). Detection limits and quantification limits are in the range of 1-400ng/mL for each analytes. Calibration curves were validated on concentration ranges from 0.05 to 50μg/mL. The method proved to be suitable for glucosinolates and isothiocyanates determination both in biomasses and in complex matrices such as food products enriched with glucosinolates, or nutraceutical bakery products. In addition, the developed method was applied to the simultaneous determination of glucosinolates and isothiocyanates in bakery product enriched with glucosinolates, to evaluate their thermal stability after different industrial processes from cultivation phases to consumer processing.

  2. 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

  3. 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

  4. 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

  5. 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.

  6. [Determination of 49 drugs and 5 metabolites in drinking water samples using ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry].

    Science.gov (United States)

    Wang, Shuo; Zhang, Xiangming; Zhang, Jing; Shao, Bing; Li, Shuming

    2015-07-01

    A method for the determination of 54 drugs in drinking water samples was developed by using ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI MS/MS). The target drugs in drinking water samples were enriched and cleaned-up by HLB solid-phase extraction (SPE) cartridges and then eluted with 5 mL methanol. The elute was collected, concentrated under a gentle stream of nitrogen gas, diluted with 0.4 mL 0.1% formic acid solution, and analyzed by UPLC-ESI MS/MS. The separation of the 54 drugs was performed on an ACQUITY UPLC™ BEH C18 column using mobile phases of 0.1% formic acid and methanol by gradient elution. The multiple reaction monitoring (MRM) mode was employed in mass spectrometry acquisition. The matrix-matched external standard calibration was used for quantitation. The results showed that the average recoveries of the drugs in ground water, tap water and surface water were 58.7%-104.4%, 53.1%-109.5%, and 50.7%-118.8%, respectively, and the corresponding relative standard deviations (RSD, n=6) were 0.3%-12.8%, 1.0%-15.5%, and 0.4%-19.3%, respectively. The method quantification limits (MQL) for target compounds were in the range of 0.002-5.000 ng/L. The developed method was applied to analyze the water samples from Beijing. The results showed that 26 drugs were detected in ground water samples.

  7. Determination of tamsulosin in human aqueous humor and serum by liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Keski-Rahkonen, Pekka; Pärssinen, Olavi; Leppänen, Esa; Mauriala, Timo; Lehtonen, Marko; Auriola, Seppo

    2007-01-17

    A simple, sensitive and selective LC-MS/MS method was developed for the determination of tamsulosin in human aqueous humor and serum to study the recently reported eye-related adverse effects of this alpha(1)-blocker drug. Aqueous humor samples were analyzed by direct injection, after addition of the internal standard, labetalol. Liquid-liquid extraction with ethyl acetate was used for serum sample preparation. The chromatographic separation was performed on a reversed phase column by gradient elution with acetonitrile -0.1% formic acid at a flow-rate of 0.2 ml/min. Detection and quantification of the analytes were carried out with a linear ion trap mass spectrometer, using positive electrospray ionization (ESI) and multiple reaction monitoring (MRM). The limit of quantification was 0.1 ng/ml for both aqueous humor and serum samples and linearity was obtained over the concentration ranges of 0.1-4.7 ng/ml and 0.1-19.3 ng/ml for aqueous humor and serum samples, respectively. Acceptable accuracy and precision were obtained for concentrations within the standard curve ranges. The method has been used for the determination of tamsulosin in aqueous humor and serum samples from patients that were on tamsulosin medication and underwent cataract surgery.

  8. 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.

  9. 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

  10. 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

  11. Determination of cocaine and benzoylecgonine in nails by liquid chromatography-electrospray ionization-tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Marzena Sykutera

    2015-02-01

    Full Text Available Nails and hair are a biological matrix which can be analyzed to confirm the use of a xenobiotic even several months after intake. Results of nail analysis can be used, for example, as evidence in civil and criminal law cases in which a history of drug use can influence the court’s decision. The paper presents results of analysis of a nail sample taken from a man who was suspected of trafficking cocaine. The suspect pleaded guilty to the possession of the drug for his own use because, as he claimed, he was addicted to cocaine. A nail sample was taken. Detection and quantification were carried out using liquid chromatography-mass spectrometry (LC-ESI-MS. The concentration of cocaine in nails was found to be 47 ng/mg, and benzoylecgonine – 14 ng/mg.

  12. Comparison of direct infusion and on-line liquid chromatography/electrospray ionization mass spectrometry for the analysis of nucleic acids.

    Science.gov (United States)

    Huber, C G; Krajete, A

    2000-07-01

    The applicability of ion-pair reversed-phase high-performance liquid chromatography/electrospray ionization mass spectrometry (IP-RP-HPLC/ESI-MS) and direct infusion/ESI-MS to the characterization of nucleic acid mixtures was evaluated by the analysis of the reaction products obtained from solid-phase synthesis of a 39-mer oligonucleotide. IP-RP-HPLC/ESI-MS was performed using 200 microm i.d. capillary columns packed with octadecylated, micropellicular poly(styrene-divinylbenzene) particles and applying gradients of acetonitrile in 50 mM triethylammonium bicarbonate (TEAB). Three different solvent systems were utilized for direct infusion/ESI-MS with removal of metal cations by on-line cation exchange: (1) 10 mM triethylamine (TEA) in 50% aqueous acetonitrile, (2) 2.2 mM TEA, 400 mM hexafluoro-2-propanol (HFIP) in 20% aqueous methanol and (3) 50 mM TEAB in 10% aqueous acetonitrile. Owing to its separation capability, the highest selectivity and specificity were achieved with IP-RP-HPLC/ESI-MS, which, apart form the 39-mer target sequence, allowed the identification of two isobutyryl-protected target sequences and a 10-mer and 20-mer failure sequence. Direct infusion/ESI-MS with TEA-acetonitrile or TEA-HFIP-methanol as solvent revealed signals for the 39-mer in the m/z range 700-1600. The presence of derivatives containing one, two, three and four isobutyryl groups indicated that the hydrolysis of the protecting groups after solid-phase synthesis was not complete. Failure sequences could not be identified by direct infusion/ESI-MS under conditions favoring multiple charging of the analytes owing to the high chemical background and coincidental overlapping of m/z signals. However, efficient charge state reduction upon addition of carbonic acid to the electrosprayed solvent shifted the signals of the 39-mer and derivatives to m/z values >2400 and allowed the detection of seven different failure sequences, ranging from the 8-mer to the 23-mer, in the mixture.

  13. Characterization of phosphoantigens by high-performance anion-exchange chromatography-electrospray ionization ion trap mass spectrometry and nanoelectrospray ionization ion trap mass spectrometry.

    Science.gov (United States)

    Pont, F; Luciani, B; Belmant, C; Fournié, J J

    2001-08-01

    New phosphorylated microbial metabolites referred to as phosphoantigens activate immune responses in humans. Although these molecules have leading applications in medical research, no direct method allows their rapid and unambiguous structural identification. Here, we interfaced online HPAEC (high performance anion-exchange chromatography) with ESI-ITMS (electrospray ionization ion trap mass spectrometry) to identify such pyrophosphorylated molecules. A self-regenerating anion suppressor located upstream of electrospray ionization enabled the simultaneous detection of pyrophosphoester by conductimetry, UV and MS. By HPAEC-ITMS and HPAEC-ITMS2, a single run permitted characterization of reference phosphoantigens and of related structures. Although all compounds were resolved by HPAEC, MS enabled their detection and identification by [M-H]- and fragment ions. Isobaric phosphoantigen analogues were also separated by HPAEC and distinguished by MS2. The relevance of this device was demonstrated for phosphoantigens analysis in human urine and plasma. Furthermore, identification of natural phosphoantigens by automatically generated 2D mass spectra from nano-ESI-ITMS is presented. This last technique permits the simultaneous performance of molecular screening of natural phosphoantigen extracts and their identification.

  14. 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).

  15. 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

  16. Liquid chromatography electrospray ionization and matrix-assisted laser desorption ionization tandem mass spectrometry for the analysis of lipid raft proteome of monocytes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Nan [Department of Chemistry, University of Alberta, Edmonton, Alberta (Canada); Shaw, Andrew R.E. [Department of Chemistry, University of Alberta, Edmonton, Alberta (Canada)], E-mail: andrewsh@cancerboard.ab.ca; Li Nan; Chen Rui [Department of Chemistry, University of Alberta, Edmonton, Alberta (Canada); Mak, Allan; Hu Xiuying [Department of Oncology, University of Alberta, Edmonton, Alberta (Canada); Young, Nelson; Wishart, David [Department of Computing Science, University of Alberta, Edmonton, Alberta (Canada); Li Liang, E-mail: Liang.Li@ualberta.ca

    2008-10-03

    Lipid rafts are dynamic assemblies of cholesterol and glycolipid that form detergent-insoluble microdomains within membrane lipid bilayers. Because rafts can be separated by flotation on sucrose gradients, interrogation by mass spectrometry (MS) provides a valuable new insight into lipid raft function. Here we combine liquid chromatography (LC) electrospray ionization (ESI) and matrix-assisted laser desorption ionization (MALDI) MS/MS to corroborate and extend our previous description of lipid raft proteomes derived from the monocytic cell line THP-1. Interestingly, LC-ESI and MALDI MS/MS identify largely non-overlapping, and therefore, potentially complementary protein populations. Using the combined approach, we detected 277 proteins compared to 52 proteins obtained with the original gel-based MALDI MS. We confirmed the presence of 47 of the original 52 proteins demonstrating the consistency of the lipid raft preparations. We demonstrated by immunoblotting that Rac 1 and Rac 2, two of the 52 proteins we failed to confirm, were indeed absent from the lipid raft fractions. The majority of new proteins were cytoskeletal proteins and their regulators, proteins implicated in membrane fusion and vesicular trafficking or signaling molecules. Our results therefore, confirm and extend previous evidence indicating lipid rafts of monocytic cells are specialized for cytoskeletal assembly and vesicle trafficking. Of particular interest, we detected SNAP-23, basigin, Glut-4 and pantophysin in lipid rafts. Since these proteins are implicated in both vesicular trafficking and gamete fusion, lipid rafts may play a common role in these processes. It is evident that the combination of LC-ESI and LC-MALDI MS/MS increases the proteome coverage which allows better understanding of the lipid raft function.

  17. 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

  18. 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.

  19. 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).

    Science.gov (United States)

    Liu, Guo-Ling; Guo, Hong-Hui; Sun, Yuan-Ming

    2012-01-01

    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 (R(2) = 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.

  20. 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

  1. 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

    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......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...... + 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...

  2. 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

  3. Determination of benzothiazole and benzotriazole derivates in tire and clothing textile samples by high performance liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Avagyan, Rozanna; Sadiktsis, Ioannis; Thorsén, Gunnar; Östman, Conny; Westerholm, Roger

    2013-09-13

    A high performance liquid chromatography-tandem mass spectrometry method utilizing electrospray ionization in positive and negative mode has been developed for the separation and detection of benzothiazole and benzotriazole derivates. Ultra-sonication assisted solvent extraction of these compounds has also been developed and the overall method demonstrated on a selected clothing textile and an automobile tire sample. Matrix effects and extraction recoveries, as well as linearity and limits of detection have been evaluated. The calibration curves spanned over more than two orders of magnitude with coefficients of correlation R(2)>0.99 and the limits of detection and the limits of quantification were in the range 1.7-58pg injected and 18-140pg/g, respectively. The extraction recoveries ranged between 69% and 102% and the matrix effects between 75% and 101%. Benzothiazole and benzotriazole derivates were determined in the textile sample and benzothiazole derivatives determined in the tire sample with good analytical performance.

  4. 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

  5. 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.

  6. 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

  7. 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

  8. 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

  9. Ceramide lipids in alive and thermally stressed mussels: an investigation by hydrophilic interaction liquid chromatography-electrospray ionization Fourier transform mass spectrometry.

    Science.gov (United States)

    Facchini, Laura; Losito, Ilario; Cataldi, Tommaso R I; Palmisano, Francesco

    2016-09-01

    Hydrophilic interaction liquid chromatography coupled to electrospray ionization-Fourier transform mass spectrometry was employed to study ceramide lipids occurring in mussels of sp. Mytilus galloprovincialis. Lipid extracts from alive mussels and mussels deliberately subjected to specific thermal treatments were analyzed. In particular, single and tandem MS measurements were performed on a hybrid quadrupole-Orbitrap mass spectrometer and then complemented by MS(n) analyses (n = 2, 3) achieved by a linear ion trap mass spectrometer. This approach enabled the characterization of 66 ceramide lipids, encompassing ceramide phosphoethanolamines (CPE), ceramide aminoethylphosphonates (CAEP) and N-monomethylated CAEP. The sphingoid and acyl chains of each ceramide lipid could be distinctly recognized in terms of numbers of carbon atoms and C=C bonds, and indications on the possible location of the latter on the sphingoid chain could be often inferred from fragmentation patterns. The occurrence of several species hydroxylated on the α carbon of the acyl chain was also discovered. On the other hand, the sphingoid chain of ceramide lipids was never found to be involved in oxidation processes, unless forced exposure of the mussel lipid extracts to atmospheric oxygen was performed. CPE(d19:3/16:0) and its hydroxylated form, CPE(d19:3/2-OH-16:0), were found to be the prevailing species among CPE, whereas CAEP(d18:2/16:0), CAEP(d19:3/16:0) and CAEP(d19:3/2-OH-16:0) were the most abundant CAEP. Finally, ceramide lipids showed a remarkably higher stability, compared with glycerophospholipids, in mussels subjected to different thermal treatments. This finding opens interesting perspectives on the role of ceramide-based lipids in the adaptation of aquatic organisms to thermal stresses. Copyright © 2016 John Wiley & Sons, Ltd.

  10. 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

  11. 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

  12. Reduction of matrix effects in liquid chromatography-electrospray ionization-mass spectrometry by dilution of the sample extracts: how much dilution is needed?

    Science.gov (United States)

    Stahnke, Helen; Kittlaus, Stefan; Kempe, Günther; Alder, Lutz

    2012-02-01

    In this study, the relationship between matrix concentration and suppression of electrospray ionization (matrix effects) was investigated. Ion suppression of pesticides present in QuEChERS extracts was used as an example. Residue-free extracts of four different commodities, avocado, black tea, orange, and rocket (arugula), were fortified with 39 pesticides each. For many of the resulting 156 pesticide/matrix combinations, considerable matrix effects were observed if the coextracted matrix of 8 mg of equivalent sample (in the case of tea: 1.6 mg) was injected with the undiluted extracts. The reduction of these matrix effects was measured at 10 levels of dilution up to 1000-fold. The results obtained indicate a linear correlation between matrix effects and the logarithm of matrix concentration (or dilution factor) until the zero-effect level of further dilution was reached. Using the logarithmic equations, it could be shown that a dilution of extracts by a factor of 25-40 reduces ion suppression to less than 20% if the initial suppression is ≤80%. For stronger matrix effects or complete elimination of suppression, higher dilution factors were needed. The observed correlation was independent from the two instrument platforms used, but the degree of matrix effects differed slightly between the two mass spectrometers in this study.

  13. 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

  14. Simultaneous determination of human and veterinary antibiotics in various environmental matrices by rapid resolution liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Zhou, Li-Jun; Ying, Guang-Guo; Liu, Shan; Zhao, Jian-Liang; Chen, Feng; Zhang, Rui-Quan; Peng, Fu-Qiang; Zhang, Qian-Qian

    2012-06-29

    A robust and sensitive analytical method is presented in which 11 classes of antibiotics are simultaneously extracted and determined in surface water, lagoon wastewater, influent, effluent, sediment, manure and sludge. Water samples with different volumes were adjusted to pH 3, added with 0.2g Na₂EDTA and then extracted using Oasis hydrophilic-lipophilic balance (HLB) cartridges. Extraction of solid samples was carried out by a combination of ultrasonic and vortex mixing using a mixture of acetonitrile and citric buffer at pH 3 as the extraction solution. The extracts of the solid samples were then cleaned-up by a tandem solid phase extraction (SPE) method using a strong anion exchange cartridge (SAX) and a HLB cartridge, followed by analysis using rapid resolution liquid chromatography-tandem mass spectrometry (RRLC-MS/MS) equipped with electrospray ionization source. Among the 50 target compounds, the recoveries in the range of 50-150% were obtained for 39, 40, 36, 40, 38, 33 and 36 antibiotics in the spiked samples of surface water, lagoon wastewater, influent, effluent, sediment, manure and sludge with three concentrations, respectively. Method quantification limits (MQLs) for the target compounds (except sulfaguanidine and sulfanilamide) were in the range of 0.52-5.88 ng/L, 2.36-65.8 ng/L, 1.73-20 ng/L, 1.42-9.52 ng/L, 0.64-6.67 ng/g (except bacitracin and cloxacillin), 1.33-17.4 ng/g (except salinomycin, narasin, monensin, cloxacillin and novobiocin) and 1.50-28.6 ng/g (except salinomycin, narasin, monensin and cloxacillin) in surface water, lagoon wastewater, influent, effluent, sediment, manure and sludge, respectively. The developed analytical method was successfully applied in the determination of target compounds in wastewater and sludge samples from Huiyang wastewater treatment plants, and in ground water, lagoon wastewater, manure and sediment collected from a pig farm, in South China. PMID:22625208

  15. 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

  16. 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

  17. 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.

  18. 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...

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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.

  6. Liquid chromatography/electrospray ionization/isotopic dilution mass spectrometry analysis of n-(phosphonomethyl) glycine and mass spectrometry analysis of aminomethyl phosphonic acid in environmental water and vegetation matrixes.

    Science.gov (United States)

    Grey, L; Nguyen, B; Yang, P

    2001-01-01

    A liquid chromatography/electrospray/mass spectrometry (LC/ES/MS) method was developed for the analysis of glyphosate (n-phosphonomethyl glycine) and its metabolite, aminomethyl phosphonic acid (AMPA) using isotope-labelled glyphosate as a method surrogate. Optimized parameters were achieved to derivatize glyphosate and AMPA using 9-fluorenylmethyl chloroformate (FMOC-Cl) in borate buffer prior to a reversed-phase LC analysis. Method spike recovery data obtained using laboratory and real world sample matrixes indicated an excellent correlation between the recovery of the native and isotope-labelled glyphosate. Hence, the first performance-based, isotope dilution MS method with superior precision, accuracy, and data quality was developed for the analysis of glyphosate. There was, however, no observable correlation between the isotope-labelled glyphosate and AMPA. Thus, the use of this procedure for the accurate analysis of AMPA was not supported. Method detection limits established using standard U.S. Environmental Protection Agency protocol were 0.06 and 0.30 microg/L, respectively, for glyphosate and AMPA in water matrixes and 0.11 and 0.53 microg/g, respectively, in vegetation matrixes. Problems, solutions, and the method performance data related to the analysis of chlorine-treated drinking water samples are discussed. Applying this method to other environmental matrixes, e.g., soil, with minimum modifications is possible, assuring accurate, multimedia studies of glyphosate concentration in the environment and the delivery of useful multimedia information for regulatory applications.

  7. Sheath liquid effects in capillary high-performance liquid chromatography-electrospray mass spectrometry of oligonucleotides.

    Science.gov (United States)

    Huber, C G; Krajete, A

    2000-02-18

    Fused-silica capillary columns of 200 microm inner diameter were packed with micropellicular, octadecylated, 2.3 microm poly(styrene-divinylbenzene) particles and applied to the separation of oligonucleotides by ion-pair reversed-phase high-performance liquid chromatography. Oligonucleotides were eluted at 50 degrees C with gradients of 3-13% acetonitrile in 50 mM triethylammonium bicarbonate. Addition of sheath liquid to the column effluent allowed the detection of oligonucleotides by electrospray ionization mass spectrometry using full-scan data acquisition with a detectability comparable to that obtained with UV detection. The signal-to-noise ratios with different sheath liquids increased in the order isopropanolmass spectra mainly because of increased background noise. Only a few charge states were observed in the mass spectra of oligonucleotides because of charge state reduction due to the presence of carbonic acid in the eluent. With triethylammonium hydrogencarbonate as chromatographic eluent and acetonitrile as sheath liquid, very few cation adducts of oligonucleotides were observed in the mass spectra. However, the presence of small amounts of monopotassium adducts enabled the calculation of the charge state of multiply charged ions. With acetonitrile as sheath liquid, 710 amol of a 16-mer oligonucleotide were detected using selected ion monitoring data acquisition with a signal-to-noise ratio of 3:1. Finally, capillary ion-pair reversed-phase high-performance liquid chromatography-electrospray ionization mass spectrometry was

  8. 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...

  9. 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.

  10. 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

  11. Simultaneous determination of quetiapine and three metabolites in human plasma by high-performance liquid chromatography electrospray ionization mass spectrometry%高效液相色谱-电喷雾电离质谱联用法同时测定人血浆中喹硫平及其三个代谢产物

    Institute of Scientific and Technical Information of China (English)

    李坤艳; 程泽能; 李鑫; 白雪莲; 张毕奎; 王峰; 李焕德

    2004-01-01

    AIM: To develop a high performance liquid chromatography-electrospray mass spectrometry (HPLC-MS/ESI)method for simultaneous determination of quetiapine and its sulfoxide-, 7-hydroxy-, 7-hydroxy-N-dealkyl-metabolites in human plasma. METHODS: The HPLC separation of the compounds was performed on a Kromasil C18, (5 μm, 4.6 mm× 150 mm) column, using water (formic acid: 1.70 mmol/L, ammonium acetate: 5.8 mmol/L)-acetonitrile (65:35) as mobile phase, with a flow-rate of 0.95 mL/min. The compounds were ionized in the electrospray ionization (ESI) ion source of the mass spectrometer and detected in the selected ion recording (SIR) mode. The samples were extracted using solid-phase extraction columns. RESULTS: The calibration curves were linear in the ranges of 10-2000 μg/L for quetiapine, 1-200 μg/L for its metabolites, respectively. The average extraction recoveries for all the four samples were above 85 %. The methodology recoveries were much higher than 95 %. The intra-day and inter-day RSD are less than 15 %. CONCLUSION: The method is accurate, sensitive, and simple for study of pharmacokinetics and metabolic mechanism of quetiapine in patients at therapeutic dose.

  12. 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.

  13. 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.

  14. 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

  15. 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)

  16. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lua, Ahai C. [Department of Laboratory Medicine and Biotechnology and Graduate Institute of Medical Biotechnology, Tzu Chi University, 701, Chung Yang Road Section 3, Hualien, 970, Taiwan (China); Sutono, Yenny [Department of Laboratory Medicine and Biotechnology and Graduate Institute of Medical Biotechnology, Tzu Chi University, 701, Chung Yang Road Section 3, Hualien, 970, Taiwan (China); Chou, T.-Y. [Department of Laboratory Medicine and Biotechnology and Graduate Institute of Medical Biotechnology, Tzu Chi University, 701, Chung Yang Road Section 3, Hualien, 970, Taiwan (China)]. E-mail: cty@mail.tcu.edu.tw

    2006-08-18

    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-d{sub 14}) 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-d{sub 14} (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{sup -3} X + 0.034, correlation coefficient: r {sup 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.

  19. Identification of active compounds and their metabolites by high-performance liquid chromatography/electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry from Xiao-xu-ming decoction (XXMD).

    Science.gov (United States)

    Wang, Yilin; Ding, Chunguang; Du, Kehe; Xiao, Yao; Wu, Caisheng; Zhang, Jinlan; Qin, Hailin; Du, Guanhua

    2009-09-01

    Xiao-xu-ming decoction (XXMD) prescription is a traditional Chinese prescription that has been widely used to treat theoplegia and the sequela of theoplegia. Modern pharmacological research has also indicated that the active fraction from XXMD is able to treat cardiovascular diseases and Alzheimer's disease. In the study reported here, high-performance liquid chromatography coupled with Fourier transform ion cyclotron resonance mass spectrometry (HPLC/FTICR-MS) was developed to identify active compounds and their metabolites after oral administration of active fraction from Xiao-xu-ming decoction to rats, using parent mass list triggered data-dependent multiple-stage mass analysis at a resolving power of 100,000 in the external calibration mode. The mass accuracies obtained for full-scan MS were within 2 ppm in most cases. Fifteen constituents were identified in the active fraction from XXMD and the biological samples of rats. The fragmentation behaviors of these constituents were summarized which would be helpful for structural characterization. The profiles of the constituents in the active fraction and biological samples of rats were obtained which provided us with much information for a better understanding of the chemical basis of the pharmacologic actions of XXMD.

  20. 女贞子化学成分的UPLC-ESI-Q-TOF-MS分析%Analysis on chemical components of Ligustrum lucidum by ultra performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    蒋叶娟; 姚卫峰; 张丽; 丁安伟

    2012-01-01

    目的:采用UPLC-ESI-Q-TOF-MS技术对女贞子中的化学成分进行定性分析.方法:采用ACQUITY UPLC BEHC18色谱柱(2.1mm×100 mm,1.7 μm),以乙腈-0.1%甲酸溶液为流动相梯度洗脱;质谱使用ESI离子源,正离子与负离子模式下采集数据.结果:通过正、负离子质谱信息及元素组成分析并结合对照品与相关文献数据对照,共鉴定出14个化合物.结论:通过超高效液相色谱分离,质谱测定相对分子质量及相关文献数据信息检索确定女贞子中的化学成分,为阐明女贞子的药效物质基础提供有力的证据.%Objective: To make a qualitative analysis on chemical components in Ligustrum lucidum by UPLC-ESI-Q-TOF-MS. Method; ACQUITY UPLC BEH C18 (2. 1 mm × 100 mm, 1. 7 μm) column was adopted, with methyl cyanides-0. 1% formic acid as the mobile phase for gradient elution; ESI ion source was used for mass spectra, and data were collected in positive and negative mode. Result: Fourteen compounds of L lucidum were identified by analyzing positive and negative ion mass spectra information and element composition and comparing controls with data from relevant literature. Conclusion: After the separation by ultra high performance liquid chromatography, relative molecular mass was determined by mass spectra, and chemical compounds in L. lucidum were determined by information search through relevant literature data, in order to provide powerful therapeutic material basis for L. lucidum.

  1. Reduction of in-source collision-induced dissociation and thermolysis of sulopenem prodrugs for quantitative liquid chromatography/electrospray ionization mass spectrometric analysis by promoting sodium adduct formation.

    Science.gov (United States)

    Wujcik, Chad E; Kadar, Eugene P

    2008-10-01

    Six chromatographically resolved sulopenem prodrugs were monitored for their potential to undergo both in-source collision-induced dissociation (CID) and thermolysis. Initial Q1 scans for each prodrug revealed the formation of intense [Prodrug2 + H]+, [Prodrug2 + Na]+, [Prodrug + Na]+, and [Sulopenem + Na]+ ions. Non-adduct-associated sulopenem ([Sulopenem + H]+) along with several additional lower mass ions were also observed. Product ion scans of [Prodrug3 + Na]+ showed the retention of the sodium adduct in the collision cell continuing down to opening of the beta-lactam ring. In-source CID and temperature experiments were conducted under chromatographic conditions while monitoring several of the latter ion transitions (i.e., adducts, dimers and degradants/fragments) for a given prodrug. The resulting ion profiles indicated the regions of greatest stability for temperature and declustering potential (DP) that provided the highest signal intensity for each prodrug and minimized in-source degradation. The heightened stability of adduct ions, relative to their appropriate counterpart (i.e., dimer to dimer adduct and prodrug to prodrug adduct ions), was observed under elevated temperature and DP conditions. The addition of 100 microM sodium to the mobile phase further enhanced the formation of these more stable adduct ions, yielding an optimal [Prodrug + Na]+ ion signal at temperatures from 400 to 600 degrees C. A clinical liquid chromatography/tandem mass spectrometry (LC/MS/MS) assay for sulopenem prodrug PF-04064900 in buffered whole blood was successfully validated using sodium-fortified mobile phase and the [PF-04064900 + Na]+ ion for quantitation. A conservative five-fold increase in sensitivity from previously validated preclinical assays using the [PF-04064900 + H]+ precursor ion was achieved.

  2. 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

  3. Quantitation of repaglinide and metabolites in mouse whole-body thin tissue sections using droplet-based liquid microjunction surface sampling-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Chen, Weiqi; Wang, Lifei; Van Berkel, Gary J; Kertesz, Vilmos; Gan, Jinping

    2016-03-25

    Herein, quantitation aspects of a fully automated autosampler/HPLC-MS/MS system applied for unattended droplet-based surface sampling of repaglinide dosed thin tissue sections with subsequent HPLC separation and mass spectrometric analysis of parent drug and various drug metabolites were studied. Major organs (brain, lung, liver, kidney and muscle) from whole-body thin tissue sections and corresponding organ homogenates prepared from repaglinide dosed mice were sampled by surface sampling and by bulk extraction, respectively, and analyzed by HPLC-MS/MS. A semi-quantitative agreement between data obtained by surface sampling and that by employing organ homogenate extraction was observed. Drug concentrations obtained by the two methods followed the same patterns for post-dose time points (0.25, 0.5, 1 and 2 h). Drug amounts determined in the specific tissues was typically higher when analyzing extracts from the organ homogenates. In addition, relative comparison of the levels of individual metabolites between the two analytical methods also revealed good semi-quantitative agreement. PMID:26589943

  4. 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.

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. Determination of 5 polyether antibiotics in chicken tissues by liquid chromatography-electrospray ionization tandem mass spectrometry%液相色谱-电喷雾串联质谱法检测鸡组织中5种聚醚类药物残留

    Institute of Scientific and Technical Information of China (English)

    梁春来; 程林丽; 沈建忠; 张玉洁; 张素霞

    2009-01-01

    A liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI MS/MS) method for the determination of 5 polyether antibiotics (lasalocid, salinomycin, mon-ensin, narasin and maduramicin) in chicken tissues was developed. The polyether antibiotics were extracted from chicken tissues with methanol. The extract was evaporated to dry, and re-dissolved in hexane, then cleaned up on a Sep-Pak Silica solid-phase extraction cartridge. The target drugs were eluted with 6 mL methylene chloride-methanol (90= 10, v/v), and the eluate was collected and dried under a gentle stream of nitrogen gas, then the residue was dissolved with 1 mL acetonitrile (containing 0. 1% formic acid) and analyzed by LC-MS/MS. The LC sep-aration was performed on a Symmetry Shield reversed phase C18 bonded silica column with acetonitrile (containing 0. 1% formic acid) - 0. 1% formic acid (97:3, v/v) as mobile phase. The quantification was carried out by positive electrospray ionization and multiple reaction mo-nitoring (MRM) mode. The validation was carried out on spiked chicken muscle (spiked at 0. 1 -1 500 μg/kg) and chicken liver (spiked at 0. 2-4 500 μg/kg), the average recoveries of tar-get drugs ranged from 71. 6%-99. 1% with intra-day relative standard deviations (RSDs) of 3. 2%-10. 7% and inter-day RSDs of 4. 6%-14. 7%. The limits of quantification ( LOQs) in chicken muscle and liver were 0. 1 - 1. 0 μg/kg. The results demonstrated that the sensitivity, accuracy and precision of this method meet the requirements of veterinary drug residue analy-sis. The method is applicable to detect 5 polyether antibiotics in chicken muscle and liver.%建立了鸡组织中聚醚类药物多残留检测的高效液相色谱-电喷雾串联质谱方法.采用甲醇提取鸡组织中的拉沙洛菌素、盐霉素、莫能菌素、甲基盐霉素和马杜霉素,经硅胶柱净化,以乙腈(含0.1%甲酸)-0.1%甲酸水溶液(体积比为97∶3)为流动相,Symmetry Shield RP18作为色谱分

  11. 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.

  12. Determination of citric acid in wine samples by ion chromatography-electrospray ionization tandem mass spectrometry (IC/MS)%离子色谱-质谱联用(IC/MS)法检测葡萄酒样品中的柠檬酸

    Institute of Scientific and Technical Information of China (English)

    周海波; 陈林; 闫永利

    2013-01-01

    目的:建立了离子色谱-质谱联用技术测定葡萄酒样品中柠檬酸的分析方法。方法以高容量、强亲水性的IonPac AS20型阴离子交换柱为分析柱, EGC在线产生梯度浓度KOH为淋洗液,淋洗液经捕获柱、抑制器成水后将样品带入质谱检测器。ESI-SIM监测模式监控柠檬酸根离子(m/z=191),并以峰面积进行定量。结果该方法对柠檬酸的检出限(S/N=3)为17.6μg/L,且柠檬酸浓度在50~1000μg/L范围内具有良好的线性,线性相关系数r=0.9992。200μg/L标准溶液重复进样8次,柠檬酸峰面积的相对标准偏差即精密度为0.77%。运用该方法测定市售5种不同品牌葡萄酒样品中柠檬酸的含量,并对样品加标回收,得回收率大于95%。结论该方法可以满足葡萄酒中柠檬酸定量分析的要求,且有效改善了分析的灵敏度和准确性。%Objective To establish a rapid method for determination of citric acid in wine samples by ion chromatography-electrospray ionization tandem mass spectrometry (IC/ESI-MS) in the negative ESI and se-lected ion monitor (SIM) mode. Methods Citric acid was separated by high capacity and hydroxide selective column IonPac AS20 with KOH eluent generated from EGC. Peak area of citrate ion (m/z=191) was monitored for quantifying. Results The limit of detection was 17.6μg/L for citric acid. A linear calibration was obtained over the range from 50 to 1000μg/L with a correlation coefficient of 0.9992. The relative standard deviation for 8 injections of standard solution (200 μg/L) was 0.77%. This method was applied to detect the citric acid in different kinds of wine samples which were purchased in market, and the rates of recovery were higher than 95%. Conclusion The method could meet the requirements of quantitative analysis of citric acid in wine samples, and also could improve the sensitivity and accuracy of the analysis.

  13. 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

  14. Quantification of Docetaxel in Serum Using Turbulent Flow Liquid Chromatography Electrospray Tandem Mass Spectrometry (TFC-HPLC-ESI-MS/MS).

    Science.gov (United States)

    Crutchfield, Christopher A; Marzinke, Mark A; Clarke, William A

    2016-01-01

    Docetaxel is a second-generation taxane and is used clinically as an anti-neoplastic agent in cancer chemotherapy via an anti-mitotic mechanism. Its efficacy is limited to a narrow therapeutic window. Inappropriately high concentrations may cause erythema, fluid retention, nausea, diarrhea, and neutropenia. As a result, dosing recommendations have changed from high dosage loading every 3 weeks to lower dosage loading weekly. We describe a method that can be used for therapeutic drug monitoring of docetaxel levels using turbulent flow liquid chromatography electrospray tandem mass spectrometry (TFC-HPLC-ESI-MS/MS). The method is rapid, requiring only 6.3 min per analytical run following a simple protein crash. The method requires only 100 μL of serum. Concentrations of docetaxel were quantified by a calibration curve relating the peak-area ratio of docetaxel to a deuterated internal standard (docetaxel-D9). The method was linear from 7.8 to 1000 ng/mL, with imprecision ≤6.2 %.

  15. Simultaneous determination of seven bisphenols in environmental water and solid samples by liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Yang, Yunjia; Lu, Libin; Zhang, Jing; Yang, Yi; Wu, Yongning; Shao, Bing

    2014-02-01

    This article presents a simple and universal analytical method for the simultaneous analysis of bisphenol S (BPS), bisphenol F (BPF), bisphenol A (BPA), bisphenol B (BPB), bisphenol AF (BPAF), tetrachlorobisphenol A (TCBPA), and tetrabromobisphenol A (TBBPA) in environmental water (river water, sewage) and solid samples (sediment, sludge) based on liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS). Analytes were extracted from water samples using hydrophilic lipophilic balanced (HLB) solid-phase extraction (SPE) cartridges, and the extracts were further purified using MAX SPE cartridges. For the solid samples, a combination of ultrasonic extraction with the same SPE clean-up procedures used for the water samples was employed. The absolute recoveries for all analytes in the water and solid samples ranged from 57.1 to 114.3%. Good method reproducibility was achieved in terms of intra- and inter-day precision, yielding relative standard deviations (RSDs) less than 16.9 and 18.1%, respectively. The method limits of quantitation (MLOQ) for the seven compounds in environmental water and solid samples ranged from 0.05 to 4.35ng/L and from 0.06 to 2.83ng/g (dry weight, d.w.), respectively. Finally, this method was successfully applied to real environmental sample analysis, which revealed that all of the tested BPs were present, with the exception of BPB.

  16. 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

  17. 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.

  18. 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

  19. 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). The chromatographic separation, ionisation and detection of PFASs mixtures, was achieved at high pH (pH=9.7) with NH4OH as additive. To distinguish PFASs from other chemicals we used the characteristic negative mass defects of PFASs, their specific losses of 20Da (HF) and the presence of series of chromatographic...

  20. 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

  1. Investigation of alkaloids in Coptids Rhizoma by reversed-phase high performance liquid chromatography-electrospray ionization ion trap tandem mass spectrometry%黄连生物碱的反相高效液相-电喷雾离子阱串联质谱的研究

    Institute of Scientific and Technical Information of China (English)

    王道武; 庞雪; 赵全成; 张龙

    2011-01-01

    The alkaloids in Coptids Rhizoma were studied by reversed-phase HPLC-electrospray ionization ion trap tandem mass spectrometry. The conditions of HPLC separation were optimized with mobile phase comprised of 70% acetonitrile and 30% H2O(contained of 2 mmol/L triethylamine) at a flow rate of 0.5 mL/min and column temperature was 30 ℃. The main compounds of berberine, jatrorrhizine, Palmatine, coptisine and the trace of epiberberine and magnoflorine were detected with the electrospray ionization ion trap tandem mass spectrometry. The structures of berberine and epiberberine were confirmed by the CID spectra. Magnoflorine was studied by electrospray ionization ion trap tandem mass spectrometry,and the fragmentation mechanism was discussed.%采用反相高效液相-电喷雾离子阱串联质谱法对由乙醇提取的黄连生物碱进行了研究.优化出了反相高效液相色谱分离黄连生物碱的条件:流动相为V(乙腈):V(H2O)(三乙胺2 mmol/L)=30:70;柱温为30℃;流速为0.5 mL/min,并结合电喷雾串联质谱检测出了黄连生物碱中的小檗碱、药根碱、巴马汀、黄连碱以及微量的表小檗碱和木兰碱,利用小檗碱和表小檗碱的CID数据分析确证了它们的结构,并利用电喷雾离子阱串联质谱研究了木兰碱在正离子检测方式的多级串联质谱,对其碎裂机理进行了解释.

  2. 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

  3. 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

  4. 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

  5. Application of a rapid and selective method for the simultaneous determination of carebastine and pseudoephedrine in human plasma by liquid chromatography-electrospray mass spectrometry for bioequivalence study in Korean subjects.

    Science.gov (United States)

    Lee, Myung-Jae; Lee, Heon-Woo; Kang, Jong-Min; Seo, Ji-Hyung; Tak, Seong-Kun; Shim, Wangseob; Yim, Sung-Vin; Hong, Seung Jae; Lee, Kyung-Tae

    2010-10-01

    We describe a simple, rapid and sensitive high-performance liquid chromatography-electrospray ionization tandem mass spectrometric method that was developed for the simultaneous determination of carebastine and pseudoephedrine in human plasma using cisapride as an internal standard. Acquisition was performed in multiple-reaction monitoring mode by monitoring the transitions: m/z 500.43 > 167.09 for carebastine and m/z 166.04 > 147.88 for pseudoephedrine. The devised method involves a simple single-step liquid-liquid extraction with ethyl acetate. Chromatographic separation was performed on a C(18) reversed-phase chromatographic column at 0.2  mL/min by isocratic elution with 10  mM ammonium formate buffer-acetonitrile (30:70, v/v; adjusted to pH 3.3 with formic acid). The devised method was validated over 0.5-100  ng/mL of carebastine and 5-1000  ng/mL of pseudoephedrine with acceptable accuracy and precision, and was successfully applied to a bioequivalence study involving a single oral dose (10  mg of ebastine plus 120  mg of pseudoephedrine complex) to healthy Korean volunteers.

  6. Quantification of Tricyclic Antidepressants in Serum Using Liquid Chromatography Electrospray Tandem Mass Spectrometry (HPLC-ESI-MS/MS).

    Science.gov (United States)

    Crutchfield, Christopher A; Breaud, Autumn R; Clarke, William A

    2016-01-01

    Tricyclic antidepressants (TCA) are used to treat major depressive disorder and other psychological conditions. The efficacy of these drugs is tied to a narrow therapeutic window. Inappropriately high drug concentrations can result in serious side effects such as hypotension, tachycardia, or coma. As a result, concentrations of tricyclic antidepressants are routinely monitored to ensure compliance and to prevent adverse side effects by dose adjustments. We describe a method for the determination of concentrations of amitriptyline, desipramine, imipramine, and nortriptyline in human serum using high-performance liquid chromatography coupled to a tandem mass spectrometer with electrospray ionization (HPLC-ESI-MS/MS). The method is rapid, requiring only 3.5 min per analysis. The method requires 100 μL of serum. Concentrations of each TCA were quantified by a calibration curve relating the peak area ratio of each TCA analyte to a deuterated internal standard (amitriptyline-D3, desipramine-D3, imipramine-D3, and nortriptyline-D3). The method was linear from ~70 ng/mL to ~1000 ng/mL for all TCAs, with imprecision ≤ 12%.

  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. 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

  9. Analysis of advanced glycation endproducts in dairy products by isotope dilution liquid chromatography-electrospray tandem mass spectrometry. The particular case of carboxymethyllysine.

    Science.gov (United States)

    Delatour, Thierry; Hegele, Jörg; Parisod, Véronique; Richoz, Janique; Maurer, Sarah; Steven, Matthew; Buetler, Timo

    2009-03-20

    A fully validated multiple-transition recording isotope dilution liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantitative determination of N(epsilon)-carboxymethyllysine (CML) and lysine in dairy products is described. Internal standards were [N-1',2'-(13)C(2)]CML and [1,2,3,4,5,6-(13)C(6)-2,6-(15)N(2)]lysine, and the method was validated by evaluating the selectivity, linearity, precision (repeatability and reproducibility) and trueness, using both powder and liquid products. For liquid dairy products, the repeatability and reproducibility was 2.79% and 11.0%, while 4.85% and 4.92% were determined for powder dairy products, respectively. The trueness of the method ranged from -9.6% to -3.6% for powder and from -0.99% to 6.8% for liquid dairy products. The limit of detection for CML was estimated to be 8 ng CML per mg protein while the limit of quantification was 27 ng CML per mg protein. The method encompasses a proteolytic cleavage mediated by enzymatic digestion to reach a complete release of the amino acids prior to a sample cleanup based on solid phase extraction, and followed by LC-MS/MS analysis of CML and lysine residues. To ensure a suitable performance of the enzymatic digestion, CML measurements were compared to values obtained with an acid hydrolysis-mediated proteolysis. Finally, the method was employed for the analysis of CML in various dairy products. The values compare well to the data available in the literature when similar methods were used, even if some discrepancies were observed upon comparison with the results obtained by other techniques such as enzyme-linked immunosorbent assay and GC-MS.

  10. High-performance liquid chromatography-electrospray ionization-tandem mass spectrometry method for determination of active ingredients in technical zhongshengmycin%中生菌素原药有效成分高效液相色谱-串联质谱分析方法的建立

    Institute of Scientific and Technical Information of China (English)

    乔港; 魏少鹏; 姬志勤

    2012-01-01

    建立了采用高效液相色谱-串联质谱(HPLC-ESI-MS/MS)分析中生菌素(zhongshengmycins)原药中各有效成分(链丝菌素A~F)的方法.原药用去离子水超声辅助提取后经离心过滤,反相离子对高效液相色谱分离,二级质谱检测,标准样品定量离子外标法定量.结果表明:在15.63~500μg/mL质量浓度范围内,中生菌素原药各组分的仪器响应值与进样质量浓度之间呈良好的线性关系,相关系数R2>0.990 5;方法具有较好的精密度和准确度,6次重复进样,其相对标准偏差(RSD)在0.33% ~ 1.96%之间;在0.1、0.5和1μg/mg 3个添加水平下,各组分的回收率在98.2%~101.1%之间.样品实测结果表明:供试原药中链丝菌素D的含量最高,为297.65 μg/g;其次是链丝菌素B、C和F,含量分别为247.77、285.64和115.92 μg/g;链丝菌素A和E的含量较低,分别为15.63和19.60 μg/g.该方法能满足中生菌素原药中各有效成分定性及定量分析的要求.%A reliable method for determination of active ingredients in technical zhongshengmycin material was established using high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-ESI-MS/MS). The active ingredients in technique material were extracted by the ultrasound-assisted method, and then the aqueous extract was cleaned up by centrifugation and filtration. After separated by reverse-phase ion-pair chromatography, the characteristic MS/MS ions were detected by mass spectrometer and quantified with external standard method. A good linear relationship between response and concentration was obtained in the range of 15.63 -500 μg/mL,and its correlation coefficient was above 0.990 5. The relative standard derivations for different ingredients were in the range of 0. 33% - 1. 96%. The recovery rates for different ingredients were 98. 2% -101. 1% in the spiking levels of 0. 1,0. 5 and 1 μg/mg. The contents of streptothricins D,B,C,F,A and E in the tested technical

  11. 分散固相萃取-超高压液相色谱-串联质谱法测定黄瓜中的嗪胺灵%Determination of triforine in cucumber by dispersive solid phase extraction-ultra perssure liquid chromatography-electrospray ionization tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    陈武瑛; 张德咏; 李宗云; 何明远; 罗香文; 刘建宇; 刘绍文; 刘勇

    2013-01-01

    目的:建立黄瓜中嗪胺灵残留的液质串联快速分析检测方法。方法样品中的嗪胺灵经乙腈提取用 N-丙基乙二胺(PSA)和石墨化碳黑(GCB)净化,利用超高压液相色谱-串联质谱(UPLC-MS/MS)在多反应监测模式下进行检测。结果以碎片离子对432.8>212.9、432.8>82.9定性、离子对432.8>97.8进行外标法定量。仪器在0.01~1.00 mg/kg范围内,具有良好线性关系。在0.02~1.00 mg/kg添加水平范围内,嗪胺灵在黄瓜中的平均回收率为85.3%~92.2%,其相对标准偏差为2.8%~7.5%。该方法的检出限(LOD)为2.0μg/kg,定量限为(LOQ)为20μg/kg。结论本方法简便、快速、准确,能满足国内外法规的要求,可用于黄瓜样品中嗪胺灵的农药残留确证检测。%Objective A rapid method has been developed for the determination of germicide triforine re-sidues in cucumber. Methods The triforine from cucumber sample, which was extracted by acetonitrile and cleaned up by primary secondary amine (PSA) and graphitized carbon black (GCB), was determined by ultra perssure liquid chromatography-mass spectrometry under multiple reaction monitoring mode, then quantified by matrix-match standard solution. Results The qualitative results were obtained based on retention time, the precursor ion and three daughter ions, and the quantitation results were on the characteristic 432.8>212.9 ion, 432.8>82.9 ion and 432.8>97.8 ion. Average recoveries of triforine in cucumber samples were found in the range of 85.3%~92.2% at four spiking levels from 0.02 mg/kg to 1.0 mg/kg with relative standard deviations of 2.8%~7.5%. Limit of detections of triforine were 2.0 μg/kg, while limit of quantifications were 20 μg/kg, respectively. Conclusion The method is simple, rapid, and accurate, and it can meet the requirements of the domestic and international legislation. The method adapts to confirm residues of triforine pesticides in cu-cumber samples.

  12. 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...

  13. 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

  14. 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

  15. 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/...

  16. Screening and quantitation of multiclass drugs of abuse and pharmaceuticals in hair by fast liquid chromatography electrospray time-of-flight mass spectrometry.

    Science.gov (United States)

    Domínguez-Romero, Juan C; García-Reyes, Juan F; Molina-Díaz, Antonio

    2011-07-15

    In this work, an automated screening method for the simultaneous identification and quantitation of 30 representative multiclass drugs (including opiates, cocaine and its main metabolite, cannabinoids, amphetamines and other stimulants in hair samples) has been developed using fast liquid-chromatography time-of-flight mass spectrometry (LC-TOFMS). The identification and quantitation of the drugs were carried out by liquid chromatography using a C(18) column (4.6×50 mm) with 1.8 μm particle size. Accurate mass measurements of ions of interest (typically [M+H](+)) by electrospray time-of-flight mass spectrometry in the positive ionization mode were used for unambiguous confirmation of the targeted species. Three sample preparation methodologies were evaluated: (a) direct methanolic extraction by sonication, (b) acidic extraction, and (c) alkaline digestion. Direct methanolic extraction showed better recoveries and cleaner extracts. The limits of detection obtained in hair matrix were as low as 5 pg mg(-1) for cocaine and cannabidiol, ranging from 5 to 75 pg mg(-1) for the studied species while the LOQ ranged from 15 to 250 pg mg(-1). The method has been applied to six hair samples from drug consumer volunteers, where the presence of at least one drug was confirmed by accurate mass measurements within 2 ppm (mass error) in most cases. The present study demonstrates the usefulness of LC-TOFMS for both screening and quantitation purposes in drug testing in hair. In addition, the possibility of non-target or a posteriori data analysis of samples or the extension of the procedure for testing for additional compounds offers interesting features for forensic analysis.

  17. Simultaneous determination of acrylamide, its metabolite glycidamide and antipyrine in human placental perfusion fluid and placental tissue by liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Annola, Kirsi; Keski-Rahkonen, Pekka; Vähäkangas, Kirsi; Lehtonen, Marko

    2008-12-15

    A rapid and sensitive method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the simultaneous determination of acrylamide (AA) and its genotoxic metabolite glycidamide (GA) with a test marker antipyrine (AP) in placental tissue and perfusion medium used in human placental perfusion studies. An internal standard ((13)C-acrylamide) was added to the samples which were then deproteinized with acetonitrile. Chromatographic separation was performed on a reversed phase column with a gradient elution of acetonitrile and 0.01% formic acid at a flow rate of 0.3 mL/min. Detection and quantification of the analytes were carried out with a triple quadrupole mass spectrometer using positive electrospray ionization (ESI) and multiple reaction monitoring (MRM). The method was validated and linear over a concentration range of 0.5-20 microg/mL for acrylamide and glycidamide and 5-200 microg/mL for antipyrine. The lower limit of quantification for acrylamide and glycidamide was 0.5 microg/mL and for antipyrine 5 microg/mL. The method was selective, and good accuracy, precision, recovery, and stability were obtained for concentrations within the standard curve. The method was successfully used to analyze the placental perfusion medium and tissue samples in a toxicokinetic study for transplacental transfer of acrylamide and glycidamide. This is the first time that acrylamide, glycidamide and antipyrine are measured simultaneously.

  18. A generic and rapid strategy for determining trace multiresidues of sulfonamides in aquatic products by using an improved QuEChERS method and liquid chromatography-electrospray quadrupole tandem mass spectrometry.

    Science.gov (United States)

    Kung, Te-An; Tsai, Chung-Wei; Ku, Bing Chang; Wang, Wei-Hsien

    2015-05-15

    A rapid and efficient multiresidue method that involves using improved QuEChERS method and liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) was developed to measure trace levels of sulfonamides in fish tissue. This proposed method was proven to be a powerful, highly sensitive, and environmentally friendly analytical tool that requires minimal sample preparation. The typical MS/MS fragmentation patterns of the [M+H](+) were 156 m/z, 108 m/z, and 92 m/z. Separation was performed on HC-C18 columns with a gradient elution by using methanol -5mM ammonium acetate containing formic acid (pH 3.5). This method was validated and exhibited favorable performance as well as acceptable accuracy (80.2-93.5%), precision (3.82-8.71%), sensitivity (limits of detection (LODs) 0.43-1.22 μg kg(-1), limits of quantification (LOQs) 1.27-3.71 μg kg(-1); decision limit (CCα) 1.49-10.9 μg kg(-1), detection capability (CCβ) 1.71-11.4 μg kg(-1)), and an acceptable matrix effect (-18.2-18.4%). This methodology has been successfully applied in analyzing various fish tissue from local markets.

  19. Application of a liquid chromatography-electrospray mass spectrometry (LC/MS) method to the biodistribution and excretion studies of novel 5'-chloro-2, 3-didehydroindolo (2', 3': 2, 3) betulinic acid (DRF-4012) in tumour-bearing mice.

    Science.gov (United States)

    Mishra, Gautam; Singh, Manoj Kumar; Awasthi, Anshumali; Singh, Anu T; Jaggi, Manu; Ahmad, Farhan J

    2013-06-01

    Novel betulinic acid derivative 5'-chloro-2, 3-didehydroindolo [2', 3': 2, 3] betulinic acid (DRF-4012) is a new effective lupane type triterpenes with greater anticancer activity and efficacy than betulinic acid and currently under advanced preclinical investigation phase. In this study, a sensitive and rapid liquid chromatography-electrospray mass spectrometric (LC/MS) method has been developed for the determination of DRF-4012 in tumour-bearing mice plasma, urine, feces and tissues (liver, brain, lungs, heart, spleen, stomach, thigh muscle, kidneys, urinary bladder, small intestine and tumour). Biodistribution and excretion studies were performed for DRF-4012 nanoparticle (30 mg/kg body weight) after intravenous (i.v.) injection in tumour-bearing mice. DRF-4012 rapidly distributed throughout the body. After 0.5 h, tumour showed the second highest concentration, which was nearly half of the liver. After 4 and 24 h, the highest concentration of DRF-4012 was found in tumour indicating its retention in tumour site for a longer time. Excretion studies revealed that very low amount of unchanged DRF-4012 was observed in urine and primarily excreted through fecal route. This study may be useful to explain the manner in which DRF-4012 can inhibit tumour growth without apparent toxicity and preclinical/clinical evaluation of this potential antitumour agent.

  20. 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.

  1. Determination of therapeutic γ-aminobutyric acid analogs in forensic whole blood by hydrophilic interaction liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Sørensen, Lambert K; Hasselstrøm, Jørgen B

    2014-05-01

    Vigabatrin, pregabalin, gabapentin and baclofen are γ-aminobutyric acid analogs that are used in the treatment of epileptic seizures (vigabatrin, pregabalin and gabapentin) and spasticity (baclofen). The intake of these drugs may induce adverse reactions and impair the ability of an individual to drive a vehicle. There have also been reports of cases of intoxication and fatalities from overdoses. For rapid and accurate quantification of these drugs in forensic cases, an ultraperformance liquid chromatography tandem mass spectrometry method using pneumatically assisted electrospray ionization has been developed. The technique has been validated on both ante- and postmortem human whole blood. The protein in the blood samples was removed by the addition of a mixture of methanol and acetonitrile, and the extract was ultrafiltered and diluted with acetonitrile. The separation was performed by hydrophilic interaction liquid chromatography. Calibration of the system was achieved through use of matrix-matched calibrants combined with isotope dilution. The lower limits of quantification were 0.02-0.04 mg/L, and the relative intra-laboratory reproducibility standard deviations were 89%. The trueness expressed as the relative bias of the test results was within ±7% at concentrations of 1-40 mg/L for vigabatrin, pregabalin and gabapentin and of 0.1-4 mg/L for baclofen.

  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.

  3. 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...

  4. Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometric Analysis of 2-Alkylcyclobutanones in Irradiated Chicken by Precolumn Derivatization with Hydroxylamine

    NARCIS (Netherlands)

    Ye, Yuran; Liu, Hanxia; Horvatovich, Peter; Chan, Wan

    2013-01-01

    Food irradiation is a common preservation method that is used in many countries. The ability to identify irradiated food is important for assuring compliance with regulatory policies, such as food labeling requirements, and for informed consumer choice. There is thus a significant demand for analyti

  5. 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

  6. Multiresidue analysis of beta-agonists in bovine and porcine unrine, feed and hair using liquid chromatography electrospray ionisation tandem mass spectrometry

    NARCIS (Netherlands)

    Nielen, M.W.F.; Lasaroms, J.J.P.; Essers, M.L.; Oosterink, J.E.; Meijer, T.; Sanders, M.B.; Zuidema, T.; Stolker, A.A.M.

    2008-01-01

    The use of ß-agonists as growth promoters in cattle breeding is forbidden in many countries for reasons of fair trade and consumer protection. In recent years the use of liquid chromatography (LC) tandem mass spectrometry (MS/MS) has been shown to be the method of choice for the control of ß-agonist

  7. 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.

  8. 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.

  9. Efficient and sensitive detection of residues of nine coccidiostats in egg and muscle by liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Dubois, M; Pierret, G; Delahaut, Ph

    2004-12-25

    We present a method based on electrospray liquid chromatography tandem mass spectrometry (LC-MS/MS) for determining in muscle and eggs the following nine coccidiostats: halofuginone, diclazuril, dinitrocarbanilide (the main metabolite of nicarbazin), robenidine, monensin, lasalocid, narasin, salinomycin, and maduramicin. Dinitrocarbanilide-d8, nigericin, and diclazuril-bis were used as internal standards. The method uses extraction in acetonitrile followed by a clean-up on an SiOH solid-phase extraction column. High-performance liquid chromatography (HPLC) separation was performed on a Purospher C(18) column (125 mm x 3 mm i.d.) protected by a guard column, the mobile phase being a water-acetonitrile gradient (each gradient component containing 0.1% formic acid) at a flow rate of 1 ml min(-1). For unequivocal identification of each analyte, two ions were detected and chosen for multiple reaction monitoring (MRM). Validation was carried out on spiked muscle and egg samples. The method described meets all the criteria of Decision 2002/657/EC and is easy to use in routine analysis. Validation results are presented with the measured CCalpha and CCbeta values. This whole method allows extraction and analysis of up to 24 samples per day.

  10. Liquid chromatography-electrospray linear ion trap mass spectrometry analysis of targeted neuropeptides in Tac1(-/-) mouse spinal cords reveals significant lower concentration of opioid peptides.

    Science.gov (United States)

    Saidi, Mouna; Beaudry, Francis

    2015-08-01

    Tachykinin and opioid peptides play a central role in pain transmission, modulation and inhibition. The treatment of pain is very important in medicine and many studies using NK1 receptor antagonists failed to show significant analgesic effects in humans. Recent investigations suggest that both pronociceptive tachykinins and the analgesic opioid systems are important for normal pain sensation. The analysis of opioid peptides in Tac1(-/-) spinal cord tissues offers a great opportunity to verify the influence of the tachykinin system on specific opioid peptides. The objectives of this study were to develop an HPLC-MS/MRM assay to quantify targeted peptides in spinal cord tissues. Secondly, we wanted to verify if the Tac1(-/-) mouse endogenous opioid system is hampered and therefore affects significantly the pain modulatory pathways. Targeted neuropeptides were analyzed by high performance liquid chromatography linear ion trap mass spectrometry. Our results reveal that EM-2, Leu-Enk and Dyn A were down-regulated in Tac1(-/-) spinal cord tissues. Interestingly, Dyn A was almost 3 fold down-regulated (p<0.0001). No significant concentration differences were observed in mouse Tac1(-/-) spinal cords for Met-Enk and CGRP. The analysis of Tac1(-/-) mouse spinal cords revealed noteworthy decreases of EM-2, Leu-Enk and Dyn A concentrations which strongly suggest a significant impact on the endogenous pain-relieving mechanisms. These observations may have insightful impact on future analgesic drug developments and therapeutic strategies.

  11. Analysis of anthocyanins in commercial fruit juices by using nano-liquid chromatography-electrospray-mass spectrometry and high-performance liquid chromatography with UV-vis detector.

    Science.gov (United States)

    Fanali, Chiara; Dugo, Laura; D'Orazio, Giovanni; Lirangi, Melania; Dachà, Marina; Dugo, Paola; Mondello, Luigi

    2011-01-01

    Nano-LC and conventional HPLC techniques were applied for the analysis of anthocyanins present in commercial fruit juices using a capillary column of 100 μm id and a 2.1 mm id narrow-bore C(18) column. Analytes were detected by UV-Vis at 518 nm and ESI-ion trap MS with HPLC and nano-LC, respectively. Commercial blueberry juice (14 anthocyanins detected) was used to optimize chromatographic separation of analytes and other analysis parameters. Qualitative identification of anthocyanins was performed by comparing the recorded mass spectral data with those of published papers. The use of the same mobile phase composition in both techniques revealed that the miniaturized method exhibited shorter analysis time and higher sensitivity than narrow-bore chromatography. Good intra-day and day-to-day precision of retention time was obtained in both methods with values of RSD less than 3.4 and 0.8% for nano-LC and HPLC, respectively. Quantitative analysis was performed by external standard curve calibration of cyanidin-3-O-glucoside standard. Calibration curves were linear in the concentration ranges studied, 0.1-50 and 6-50 μg/mL for HPLC-UV/Vis and nano-LC-MS, respectively. LOD and LOQ values were good for both methods. In addition to commercial blueberry juice, qualitative and quantitative analysis of other juices (e.g. raspberry, sweet cherry and pomegranate) was performed. The optimized nano-LC-MS method allowed an easy and selective identification and quantification of anthocyanins in commercial fruit juices; it offered good results, shorter analysis time and reduced mobile phase volume with respect to narrow-bore HPLC. PMID:21246720

  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

    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

  13. 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

  14. 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

  15. 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 ...

  16. "Magic" Ionization Mass Spectrometry.

    Science.gov (United States)

    Trimpin, Sarah

    2016-01-01

    The systematic study of the temperature and pressure dependence of matrix-assisted ionization (MAI) led us to the discovery of the seemingly impossible, initially explained by some reviewers as either sleight of hand or the misinterpretation by an overzealous young scientist of results reported many years before and having little utility. The “magic” that we were attempting to report was that with matrix assistance, molecules, at least as large as bovine serum albumin (66 kDa), are lifted into the gas phase as multiply charged ions simply by exposure of the matrix:analyte sample to the vacuum of a mass spectrometer. Applied heat, a laser, or voltages are not necessary to achieve charge states and ion abundances only previously observed with electrospray ionization (ESI). The fundamentals of how solid phase volatile or nonvolatile compounds are converted to gas-phase ions without added energy currently involves speculation providing a great opportunity to rethink mechanistic understanding of ionization processes used in mass spectrometry. Improved understanding of the mechanism(s) of these processes and their connection to ESI and matrix-assisted laser desorption/ionization may provide opportunities to further develop new ionization strategies for traditional and yet unforeseen applications of mass spectrometry. This Critical Insights article covers developments leading to the discovery of a seemingly magic ionization process that is simple to use, fast, sensitive, robust, and can be directly applied to surface characterization using portable or high performance mass spectrometers. PMID:26486514

  17. "Magic" Ionization Mass Spectrometry

    Science.gov (United States)

    Trimpin, Sarah

    2016-01-01

    The systematic study of the temperature and pressure dependence of matrix-assisted ionization (MAI) led us to the discovery of the seemingly impossible, initially explained by some reviewers as either sleight of hand or the misinterpretation by an overzealous young scientist of results reported many years before and having little utility. The "magic" that we were attempting to report was that with matrix assistance, molecules, at least as large as bovine serum albumin (66 kDa), are lifted into the gas phase as multiply charged ions simply by exposure of the matrix:analyte sample to the vacuum of a mass spectrometer. Applied heat, a laser, or voltages are not necessary to achieve charge states and ion abundances only previously observed with electrospray ionization (ESI). The fundamentals of how solid phase volatile or nonvolatile compounds are converted to gas-phase ions without added energy currently involves speculation providing a great opportunity to rethink mechanistic understanding of ionization processes used in mass spectrometry. Improved understanding of the mechanism(s) of these processes and their connection to ESI and matrix-assisted laser desorption/ionization may provide opportunities to further develop new ionization strategies for traditional and yet unforeseen applications of mass spectrometry. This Critical Insights article covers developments leading to the discovery of a seemingly magic ionization process that is simple to use, fast, sensitive, robust, and can be directly applied to surface characterization using portable or high performance mass spectrometers.

  18. 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.

  19. 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

  20. Electrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Ryan T.; Marginean, Ioan; Tang, Keqi

    2014-06-13

    Electrospray Ionization (ESI) is a process whereby gas phase ions are created from molecules in solution. As a solution exits a narrow tube in the presence of a strong electric field, an aerosol of charged droplets are is formed that produces gas phase ions as they it desolvates. ESI-MS comprises the creation of ions by ESI and the determination of their mass to charge ratio (m/z) by MS.

  1. 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...

  2. 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...

  3. 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...

  4. 液相色谱-串联质谱法测定生鲜乳中氯噻嗪残留量%Determination of Residue in Raw Milk by Liquid Chromatography-Electrospray Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    田素润; 蒋俊树; 丁磊

    2013-01-01

      A new method of ultra-performance liquid chromatography–electrospray ionization tandem mass spectrometry (LC–ESI–MS/MS) for the analysis of chlorothiazide in raw milk was developed. After degreasing purification, the sample was extracted by ethyl acetate, and then chlorothiazide in which was determined by LC–ESI–MS/MS. Separated analytes were determined using multiple reaction monitoring (MRM). The quantitative analysis of target compounds was performed by the external standard method. The result indicated that the calibration curves were linear in the range of 5–100μg/L for chlorothiazide. The correlation coefficients was 0.999. The quantification limit was 5μg/L (S/N=10). The recoveries of chlorothiazide at three spiked levels of 0.01,0.05,0.1 mg/kg were in the range of 86%–105%with RSDs (n=6) less than 8%.This method shortened the time of pre-treatment process, and the result was credible. It could satisfy the requirement of mass and fast analysis in the laboratory.%  采用液相色谱–串联质谱(HPLC–ESI–MS/MS)法测定生鲜乳中氯噻嗪含量。样品经去脂净化后,用乙酸乙酯提取,采用液相色谱–串联质谱法分析,多反应监测模式下(MRM)外标法定量。结果表明氯噻嗪的质量浓度与定量离子的峰面积在5~100μg/L范围内线性良好,线性相关系数为r=0.999,定量限为5μg/kg(S/N=10),在0.01,0.05,0.1 mg/kg的添加水平下,回收率在86%~105%之间,测定结果的相对标准偏差小于8%(n=6)。该方法前处理过程简便快捷,可满足实验室大量、快速分析的需求。

  5. 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

  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. Laser ionization mass spectroscopy

    Science.gov (United States)

    Bernardez, Luis J., III; Siekhaus, W. J.

    1989-10-01

    Laser Ionization Mass Spectroscopy (LIMS) is a simple technique with several advantages and disadvantages over standard mass spectroscopy techniques. The LIMS technique uses a laser to vaporize a small portion of a sample. The vapor from the sample consists of a mixture of charged and neutral atoms or fragments. Using electrostatic grids, the ions (positive or negative) are given a known amount of kinetic energy and sent down a time-of-flight tube. The time it takes the ions to travel down the flight tube is recorded. Knowing the ions' energy, the length of the flight tube, and the time it takes the ions to travel that distance, the masses of the ions can be calculated. The instrument used is a LIMA 3 made by Cambridge Mass Spectrometry. It has a Quanta Ray DCR-11 Nd:YAG laser, which was frequency-quadrupled to 266 nm. The laser spot size is typically between 2 and 5 microns in diameter and the pulse width is between 5 and 10 nanoseconds. The energy of the laser is continually variable between 0.1 and 3.0 millijoules. The detector is a 17-stage venetian-blind multiplier made by Thorn EMI. The analysis is carried out under vacuum, usually between 10(exp -8) and 10(exp -9) Torr. The LIMA 3 has several useful features such as: a He-Ne pilot laser used to target the Nd:YAG laser; a microscope (which is used to view the sample through the laser optics); and a precision sample stage for accurate sample alignment.

  8. 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

  9. Development and validation of a fast and uniform approach to quantify β-lactam antibiotics in human plasma by solid phase extraction-liquid chromatography-electrospray-tandem mass spectrometry.

    Science.gov (United States)

    Colin, Pieter; De Bock, Lies; T'jollyn, Huybrecht; Boussery, Koen; Van Bocxlaer, Jan

    2013-01-15

    Monitoring of plasma antibiotic concentrations is necessary for individualization of antimicrobial chemotherapy dosing in special patient populations. One of these special populations of interest are the post-bariatric surgery patients. Until today, little is known on the effect of this procedure on drug disposition and efficacy. Therefore, close monitoring of antimicrobial plasma concentrations in these patients is warranted. A fast and uniform ultra-high-performance liquid chromatography (UPLC) method with tandem mass spectrometric detection (MS/MS) has been developed and qualified for the simultaneous quantification of β-lactam antibiotics in human plasma. Compounds included in this multi-component analysis are: amoxicillin, ampicillin, phenoxymethylpenicillin, piperacillin, cefuroxime, cefadroxil, flucloxacillin, meropenem, cefepime, ceftazidime, tazobactam, linezolid and cefazolin. After spiking of five different stable isotope labelled internal standards, plasma samples were prepared for UPLC-MS/MS analysis by mixed-mode solid phase extraction. The developed method was proven to be free of (relative) matrix effects and proved to be reliable for the quantification of 12 out of 13 β-lactam antibiotics. As a proof of concept the method has been applied to plasma samples obtained from a healthy volunteer treated with amoxicillin. The analytical method is suitable for use in a therapeutic drug monitoring setting, providing the clinician with reliable measurements on β-lactam antibiotic plasma concentrations in a timely manner.

  10. Simultaneous determination of propofol and its glucuronide in whole blood by liquid chromatography-electrospray tandem mass spectrometry and the influence of sample storage conditions on the reliability of the test results.

    Science.gov (United States)

    Sørensen, Lambert K; Hasselstrøm, Jørgen B

    2015-05-10

    Propofol (2,6-diisopropylphenol) is commonly used as an anaesthetic agent but is also abused for recreational purposes. Several cases of fatalities involving self-administered propofol have been reported. For rapid quantification of propofol and propofol β-d-glucuronide (propofol G) in clinical and forensic cases, an ultra-performance liquid chromatography-tandem mass spectrometry method using pneumatically assisted electrospray ionisation has been developed. The technique has been validated on both ante-mortem and post-mortem human whole blood. The proteins in the blood samples were removed by the addition of a mixture of methanol and acetonitrile, and the extract was cleaned up by solid phase extraction. The extract was concentrated in dimethyl sulphoxide. The system was calibrated using matrix-matched calibrants combined with isotope dilution. The lower limits of quantification were 0.01 and 0.02mg/L for propofol and 0.02 and 0.04mg/L for propofol G in ante-mortem and post-mortem whole blood, respectively. The relative intra-laboratory reproducibility standard deviation was less than 10% at concentrations of 0.2mg/L or higher. The mean true extraction recovery was 85% for propofol and 81% for propofol G. The trueness of the propofol determination expressed as the relative bias of the test results was within ±6% at concentration levels of 0.01-8.5mg/L. Propofol was less stable in blood stabilised with a citrate-EDTA-fluoride mixture than in blood stabilised with an oxalate-fluoride mixture. The stability was lower at -20°C than at 5°C and -80°C. Propofol G did not show instability under the storage conditions tested.

  11. 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.

  12. Negative chemical ionization mass spectrometry

    International Nuclear Information System (INIS)

    This thesis describes some aspects of Negative Chemical Ionization (NCI) mass spectrometry. The reasons for the growing interest in NCI are: (i) to extend the basic knowledge of negative ions and their reactions in the gas phase; (ii) to investigate whether or not this knowledge of negative ions can be used successfully to elucidate the structure of molecules by mass spectrometry. (Auth.)

  13. 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

  14. Laser resonance ionization mass spectrometer

    International Nuclear Information System (INIS)

    The setup is elaborated for the trace detection of transuranium elements by the three-step laser resonance ionization combined with the time-of-flight mass spectrometry. The setup efficiency for detection of plutonium was measured to be about 0.5 centre dot 10-8 ion/atom, and its selectivity relative to atoms of another elements has the order of 1013 atom/atom

  15. 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

  16. Ambient ionization mass spectrometry: A tutorial

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Min-Zong; Cheng, Sy-Chi; Cho, Yi-Tzu [Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Shiea, Jentaie, E-mail: jetea@fac.nsysu.edu.tw [Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Cancer Center, Kaohsiung Medical University, Kaohsiung, Taiwan (China)

    2011-09-19

    Highlights: {yields} Ambient ionization technique allows the direct analysis of sample surfaces with little or no sample pretreatment. {yields} We sort ambient ionization techniques into three main analytical strategies, direct ionization, direct desorption/ionization, and two-step ionization. {yields} The underlying principles of operation, ionization processes, detecting mass ranges, sensitivity, and representative applications of these techniques are described and compared. - Abstract: Ambient ionization is a set of mass spectrometric ionization techniques performed under ambient conditions that allows the direct analysis of sample surfaces with little or no sample pretreatment. Using combinations of different types of sample introduction systems and ionization methods, several novel techniques have been developed over the last few years with many applications (e.g., food safety screening; detection of pharmaceuticals and drug abuse; monitoring of environmental pollutants; detection of explosives for antiterrorism and forensics; characterization of biological compounds for proteomics and metabolomics; molecular imaging analysis; and monitoring chemical and biochemical reactions). Electrospray ionization and atmospheric pressure chemical ionization are the two main ionization principles most commonly used in ambient ionization mass spectrometry. This tutorial paper provides a review of the publications related to ambient ionization techniques. We describe and compare the underlying principles of operation, ionization processes, detecting mass ranges, sensitivity, and representative applications of these techniques.

  17. Analysis of nucleic acids by capillary ion-pair reversed-phase HPLC coupled to negative-ion electrospray ionization mass spectrometry.

    Science.gov (United States)

    Huber, C G; Krajete, A

    1999-09-01

    Ion-pair reversed-phase high-performance liquid chromatography was successfully coupled to negative-ion electrospray ionization mass spectrometry by using 60 × 0.20 mm i.d. capillary columns packed with 2.3-μm micropellicular, octadecylated poly(styrene/divinylbenzene) particles as stationary phase and gradients of acetonitrile in 50 mM aqueous triethylammonium bicarbonate as mobile phase. Systematic variation of the eluent composition, such as concentration of ion-pair reagent, anion in the ion-pair reagent, solution pH, and acetonitrile concentration led to the conclusion that most parameters have opposite effects on chromatographic and mass spectrometric performances. The use of acetonitrile as sheath liquid enabled the rapid and highly efficient separation and detection of phosphorylated and nonphosphorylated oligonucleotides ranging in size from 8 to 40 nucleotides. High-quality full-scan mass spectra showing little cation adduction were acquired from which the molecular masses of the separated oligonucleotides were calculated with an accuracy of 0.011%. With calibration curves being linear over at least 2 orders of magnitude, the lower limits of detection for a oligodeoxythymidine 16-mer were 104 fmol with full scan and 710 amol with selected-ion-monitoring data acquisition. The potential of ion-pair reversed-phase high-performance liquid chromatography-electrospray ionization mass spectrometry was demonstrated for mixed-sequence oligomers by the characterization of a reaction mixture from solid-phase synthesis of a 40-mer oligonucleotide.

  18. 甲醇提取印楝种仁成份的HPLC-MS分析%Analysis of Azadirachtin Related Triterpenoids from Methanol Extraction Neem by Liquid Chromatography - Electrospray Ionization Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    王秋芬; 赵淑英; 宋湛谦

    2004-01-01

    以反相高效液相色谱法分离测定甲醇萃取印楝中的印楝素及三萜类物质,利用质谱研究十种印楝主要萃取成分.讨论其质谱的裂解特征,利用液-质联用(HPLC-MS)方法对印楝萃取物的主要成分进行定性结构分析,讨论萃取物中九种主要成分的结构,它们分别是:(1)azadirachtin A;(2) azadirachtin D; (3) azadirachtin B; (4) salannolactame - 21; (5)21- oxo - ochinolide; (6) 6 - desacetylnimbin; (7) nimbin; ( 8 )salannol; (9) salannin.

  19. Determination of putrescine, cadaverine, spermidine and spermine in different chemical matrices by high performance liquid chromatography-electrospray ionization-ion trap tandem mass spectrometry (HPLC-ESI-ITMS/MS).

    Science.gov (United States)

    Ibarra, Alan Alexander González; Wrobel, Katarzyna; Escobosa, Alma Rosa Corrales; Elguera, Julio Cesar Torres; Garay-Sevilla, Ma Eugenia; Wrobel, Kazimierz

    2015-10-01

    The goal of this work was to establish a simple HPLC-ESI-ITMS/MS procedure, suitable for the determination of four common aliphatic polyamines in two different types of biological matrices. To this end, 1,6-diaminohexane was used as the internal standard (IS) and 4-fluoro-3-nitrobenzenotrifluoride (FNBT) as the derivatizing agent. Formation of fully derivatized compounds was confirmed by high resolution ESI-QTOFMS and MS/MS analysis. Reversed phase chromatographic separation was carried out by gradient elution with 0.1% (v/v) formic acid and methanol. In a positive ESI mode, the following pairs of precursor/quantifier ions were used for multiple reaction monitoring: 467.4/261.0 for PUT, 481.2/461.1 for CAD, 713.7/261.0 for SPD, 959.8/507.2 for SPM and 495.3/475.2 for IS. On-column instrumental detection limits of four polyamines were in the range 0.62-2.14fmol (0.039-0.215ng/ml). Versatility was demonstrated by analyzing plant extracts and human urine; prior to derivatization, all samples were cleaned-up by dichloromethane extraction. The evaluated signal suppression/enhancement was in the range 82.3-115.4% and the percentage recoveries obtained in the method of standard addition were in the range 83.7-114.4%. Statistically significant differences in polyamines concentrations were found in garden cress exposed to Cd(II) versus control seedlings (t-test, p<0.05); results obtained for urine from healthy volunteers and diabetic patients at different clinical conditions suggested possible utility of free polyamines as biomarkers of progressive diabetes.

  20. 超声波萃取-液相色谱-质谱法测定蔬菜中的酞酸酯%Determination of phthalates in vegetables by liquid chromatography-electrospray ionization mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    丛惠芳; 王丽霞; 邵蕾

    2008-01-01

    采用超声波萃取-液相色谱-质谱法测定保护地蔬菜中4种酞酸酯(PAEs)含量,研究保护地不同品种蔬菜中PAEs的污染状况.PAEs的添加回收率为82.7%~106.9%,RSD为1.9%~6.7%,检出限酞酸二甲酯(DMP)为0.988 ng,酞酸二乙酯(DEP)为0.749 ng,酞酸二丁酯(DBP)为0.702 ng,酞酸二异辛酯(DEHP)为1.920 ng.该方法前处理简单,具有较高的准确度和灵敏度.

  1. Capillary electrophoresis electrospray ionization mass spectrometry interface

    Science.gov (United States)

    Smith, Richard D.; Severs, Joanne C.

    1999-01-01

    The present invention is an interface between a capillary electrophoresis separation capillary end and an electrospray ionization mass spectrometry emitter capillary end, for transporting an anolyte sample from a capillary electrophoresis separation capillary to a electrospray ionization mass spectrometry emitter capillary. The interface of the present invention has: (a) a charge transfer fitting enclosing both of the capillary electrophoresis capillary end and the electrospray ionization mass spectrometry emitter capillary end; (b) a reservoir containing an electrolyte surrounding the charge transfer fitting; and (c) an electrode immersed into the electrolyte, the electrode closing a capillary electrophoresis circuit and providing charge transfer across the charge transfer fitting while avoiding substantial bulk fluid transfer across the charge transfer fitting. Advantages of the present invention have been demonstrated as effective in providing high sensitivity and efficient analyses.

  2. 重组L-天门冬酰胺酶II的液相色谱/电喷雾离子化质谱法分析%HIGH PERFORMANCE LIQUID CHROMATOGRAPHY / ELECTROSPRAY IONIZATON MASS SPECTROMETRIC CHARACTERIZATION OF RECOMBINANT L-ASPARAGINASE II

    Institute of Scientific and Technical Information of China (English)

    韩俊; 盛龙生; 杨仲元; 相秉仁; 安登魁

    2001-01-01

    AIM To characterize the primary structure of recombinant L-asparaginase II product. METHODS The molecular weight of the protein was measured by pneumatically-assisted electrospray ionization mass spectrometry with flow injection mode. Subsequently, tryptic peptide mapping was performed by high performance liquid chromatography on a C8 column with tandem UV and MS detection. An easy-to-use and simple denaturation process with trichloroacetic acid was conducted prior to tryptic digest so as to release the digest resistance from the protein structure. The amino acid sequences of the tryptic peptides were elucidated based on their in-source collision-induced dissociation spectra. RESULTS The measured molecular mass was different from the theoretical value. Three amino acid variations were unambiguously detected along the peptide backbone derived from the gene-encoding sequence. CONCLUSION This paper revealed that LC/ESI/MS had provided a promising and robust technique in primary structure analysis and quality control of DNA-derived recombinant protein pharmaceuticals.%目的 对基因重组L-天门冬酰胺酶II产品进行一级结构分析。方法 采用流动注射方式,电喷雾离子化质谱法测定分子量;三氯乙酸变性,胰蛋白酶水解后,HPLC测定肽图谱;结合质谱源内碰撞诱导解离技术,解析酶解肽段的氨基酸顺序。结果 分子量测定值与理论值不符,质谱解析表明样品中存在3个氨基酸变异现象,由此计算的分子量与测定值吻合。结论 液相色谱/电喷雾质谱法为基因重组蛋白质药物的一级结构分析和质量控制提供了新途径。

  3. Resonance ionization mass spectroscopy of uranium

    International Nuclear Information System (INIS)

    Resonance ionization mass spectroscopy (RIMS) has been used for the sensitive detection of uranium. The apparatus consists of a laser system with three dye lasers and two pulsed copper vapour lasers and a time-of-flight (TOF) mass spectrometer. The uranium atoms are ionized in a three step excitation with the third step leading to an autoionizing state. Several excitation schemes were investigated and for two schemes all three transitions could be saturated with the available laser power. The hyperfine structure splitting (HFS) of 235U, the isotopic shift (IS) between 235U and 238U as well as isotopic ratios in uranium samples were determined. (Author)

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

    Science.gov (United States)

    Giebułtowicz, Joanna; Kojro, Grzegorz; Buś-Kwaśnik, Katarzyna; Rudzki, Piotr J; Marszałek, Ryszard; Leś, Andrzej; Wroczyński, Piotr

    2015-12-01

    Cloud-point extraction (CPE) draws increasing interest in a number of analytical fields including bioanalysis, but combining CPE and LC-MS with electrospray ionization (ESI) in the determination of drugs in biological fluids such as plasma, serum or blood has not been reported so far. Bisoprolol was determined in human plasma by CPE using Trition X-114 as a surfactant and metoprolol as the internal standard. NaOH concentration, temperature and Trition X-114 concentration were optimized. All analyses were performed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). All validation experiments met international acceptance criteria and no significant matrix effect was observed. The compatibility of CPE and LC-ESI-MS/MS was confirmed using clinical plasma samples and appropriate statistical tests. The determination of bisoprolol concentration in human plasma in the range 1.0-70ngmL(-1) by the CPE method leads to the results which are equivalent to those obtained by the widely used liquid-liquid extraction method. The results revealed that a structural analogue may be an appropriate internal standard when CPE is used as the extraction technique. CPE offers significant practical advantages over the classical extraction methods, including a positive impact on the environment, therefore its wider application in future pharmacokinetic studies is justifiable.

  5. 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

  6. 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

  7. Electrospray Ionization Mass Spectra of Dipeptide Derivatives

    Institute of Scientific and Technical Information of China (English)

    LUO, Zaigang; ZENG, Chengchu; YANG, Daoshan; HUANG, Yali; WANG, Fang; DU, Hongguang; HU, Liming

    2009-01-01

    Based on the structure of the HIV integrase core domain, dipeptide derivatives, as a type of HIV integrase in- hibitor, were synthesized, and their fragmentation pathways were investigated by electrospray ionization mass spec- trometry (ESI-MSN) in conjunction with tandem mass spectrometry (MS/MS). In order to better understand the fragmentation pathways, the MS2 and MS3 spectra of the title compound were obtained. The main fragmentation pathways occur by the cleavage of the C-CO bonds between N-(benzothiazol-2-yl)aminocarbonyl and methylene, NH-CO bonds between the NH groups and carbonyl groups. Electrospray ionization was proven to be a good method for the structural characterization and identification of this kind of compound.

  8. 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

  9. 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.

  10. Reverse-phase liquid chromatography with electrospray ionization/mass spectrometry for the quantification of pseudoephedrine in human plasma and application to a bioequivalence study.

    Science.gov (United States)

    Kim, Jin-Ki; Jee, Jun-Pil; Park, Jeong-Sook; Kim, Hyung Tae; Kim, Chong-Kook

    2011-01-01

    A sensitive and selective reverse-phase liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) method was developed and validated to quantify pseudoephedrine (CAS 90-82-4) in human plasma. Phenacetin was used as the internal standard (I.S.). Sample preparation was performed with a deproteinization step using acetonitrile. Pseudoephedrine and I.S. were successfully separated using gradient elution with 0.5% trifluoroacetic acid (TFA) in water and 0.5% TFA in methanol at a flow-rate of 0.2 mL/min. Detection was performed on a single quadrupole mass spectrometer by a selected ion monitoring (SIM) mode via electrospray ionization (ESI) source. The ESI source was set at positive ionization mode. The ion signals of m/z 166.3 and 180.2 were measured for the protonated molecular ions of pseudoephedrine and I.S., respectively. The lower limit of quantification (LLOQ) of pseudoephedrine in human plasma was 10 ng/mL and good linearity was observed in the range of concentrations 10-500 ng/mL (R2 = 1). The intra-day accuracy of the drug containing plasma samples was more than 97.60% with a precision of 3.99-11.82%. The inter-day accuracy was 99.36% or more, with a precision of 7.65-18.42%. By using this analytical method, the bioequivalence study of the pseudoephedrine preparation was performed and evaluated by statistical analysis of the log transformed mean ratios of pharmacokinetic parameters. All the results fulfilled the standard criteria of bioequivalence, being within the 80-125% range which is required by the Korea FDA, US FDA, and EMEA to conclude bioequivalence. Consequently, the developed reverse-phase LC-ESI-MS method was successfully applied to bioequivalence studies of pseudoephedrine in healthy male volunteers.

  11. Electrostatic-spray ionization mass spectrometry.

    Science.gov (United States)

    Qiao, Liang; Sartor, Romain; Gasilova, Natalia; Lu, Yu; Tobolkina, Elena; Liu, Baohong; Girault, Hubert H

    2012-09-01

    An electrostatic-spray ionization (ESTASI) method has been used for mass spectrometry (MS) analysis of samples deposited in or on an insulating substrate. The ionization is induced by a capacitive coupling between an electrode and the sample. In practice, a metallic electrode is placed close to but not in direct contact with the sample. Upon application of a high voltage pulse to the electrode, an electrostatic charging of the sample occurs leading to a bipolar spray pulse. When the voltage is positive, the bipolar spray pulse consists first of cations and then of anions. This method has been applied to a wide range of geometries to emit ions from samples in a silica capillary, in a disposable pipet tip, in a polymer microchannel, or from samples deposited as droplets on a polymer plate. Fractions from capillary electrophoresis were collected on a polymer plate for ESTASI MS analysis. PMID:22876737

  12. 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.

  13. Determination of potato glycoalkaloids using high-pressure liquid chromatography-electrospray ionisation/mass spectrometry.

    Science.gov (United States)

    Matsuda, Fumio; Morino, Keiko; Miyazawa, Haruna; Miyashita, Masahiro; Miyagawa, Hisashi

    2004-01-01

    A method for quantifying two toxic glycoalkaloids, alpha-solanine and alpha-chaconine, in potato (Solanum tuberosum) tuber tissue was developed using HPLC-electrospray ionisation (ESI)/MS. Potato samples were extracted with 5% aqueous acetic acid, and the extracts were subjected directly to HPLC-ESI/MS after filtration. By determining the intensities of the protonated molecules of alpha-solanine (m/z 868) and alpha-chaconine (m/z 852) using selected ion monitoring (positive ion mode), a sensitive assay was attained with detection limits of 38 and 14 ppb for the two glycoalkaloids, respectively. The high sensitivity and selectivity of MS detection effectively reduced the time of analysis thus enabling a high throughput assay of glycoalkaloids in potato tubers.

  14. 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...

  15. Substrate-Enhanced Micro Laser Desorption Ionization Mass Spectrometry Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aerodyne Research, Inc. and the University of Massachusetts at Amherst will collaborate to develop laser desorption ionization (LDI) mass spectrometric analysis of...

  16. Ionization energy of acetone by vacuum ultraviolet mass-analyzed threshold ionization spectrometry

    International Nuclear Information System (INIS)

    Mass-analyzed threshold ionization (MATI) time-of-flight mass spectrometer using coherent vacuum ultraviolet (VUV) laser generated by four-wave difference frequency mixing (FWDFM) in Kr has been constructed and utilized to obtain the accurate ionization energy of acetone. From the MATI onsets measured from various applied pulsed fields, the ionization energy to the ionic ground state of acetone has been determined to be 9.7074 ± 0.0019 eV.

  17. Direct and Convenient Mass Spectrometry Sampling with Ambient Flame Ionization

    OpenAIRE

    Xiao-Pan Liu; Hao-Yang Wang; Jun-Ting Zhang; Meng-Xi Wu; Wan-Shu Qi; Hui Zhu; Yin-Long Guo

    2015-01-01

    Recent innovations in ambient ionization technology for the direct analysis of various samples in their native environment facilitate the development and applications of mass spectrometry in natural science. Presented here is a novel, convenient and flame-based ambient ionization method for mass spectrometric analysis of organic compounds, termed as the ambient flame ionization (AFI) ion source. The key features of AFI ion source were no requirement of (high) voltages, laser beams and spray g...

  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. Electron ionization mass spectrum of tellurium hexafluoride.

    Science.gov (United States)

    Clark, Richard A; McNamara, Bruce K; Barinaga, Charles J; Peterson, James M; Govind, Niranjan; Andersen, Amity; Abrecht, David G; Schwantes, Jon M; Ballou, Nathan E

    2015-05-18

    The electron ionization mass spectrum of tellurium hexafluoride (TeF6) is reported for the first time. The starting material was produced by direct fluorination of Te metal or TeO2 with nitrogen trifluoride. Formation of TeF6 was confirmed through cryogenic capture of the tellurium fluorination product and analysis through Raman spectroscopy. The eight natural abundance isotopes were observed for each of the set of fragment ions: TeF5(+), TeF4(+) TeF3(+), TeF2(+), TeF1(+), and Te(+), Te2(+). A trend in increasing abundance was observed for the odd fluoride bearing ions, TeF1(+) TeF2(+) > TeF4(+) > TeF6(+), with the molecular ion TeF6(+) not observed at all. Density functional theory based electronic structure calculations were used to calculate optimized ground state geometries of these gas phase species, and their relative stabilities explain the trends in the data and the lack of observed signal for TeF6(+).

  20. Electron Ionization Mass Spectrum of Tellurium Hexafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Richard A.; McNamara, Bruce K.; Barinaga, Charles J.; Peterson, James M.; Govind, Niranjan; Andersen, Amity; Abrecht, David G.; Schwantes, Jon M.; Ballou, Nathan E.

    2015-05-18

    The first electron ionization mass spectrum of tellurium hexafluoride (TeF6) is reported. The starting material was produced by direct fluorination of Te metal or TeO2 with nitrogen trifluoride. Formation of TeF6 was confirmed through cryogenic capture of the tellurium fluorination product and analysis through Raman spectroscopy. The eight natural abundance isotopes were observed for each of the set of fragment ions: TeF5+, TeF4+ TeF3+, TeF2+, TeF1+, and Te+, Te2+. A trend in increasing abundance was observed for the even fluoride bearing ions: TeF1+ < TeF3+ < TeF5+, and a decreasing abundance was observed for the even fragment series: Te(0)+ > TeF2+ > TeF4+ > TeF6+, with the molecular ion TeF6+ not observed at all. Density functional theory based electronic structure calculations were used to calculate optimized ground state geometries of these gas phase species and their relative stabilities explain the trends in the data and the lack of observed signal for TeF6+.

  1. Comparison of liquid chromatography-microchip/mass spectrometry to conventional liquid chromatography-mass spectrometry for the analysis of steroids.

    Science.gov (United States)

    Ahonen, Linda; Keski-Rahkonen, Pekka; Saarelainen, Taija; Paviala, Jenni; Ketola, Raimo A; Auriola, Seppo; Poutanen, Matti; Kostianen, Risto

    2012-04-01

    The feasibility of a microfluidic-based liquid chromatography-electrospray ionization/mass spectrometric system (HPLC-Chip/ESI/MS) was studied and compared to a conventional narrow-bore liquid chromatography-electrospray ionization/mass spectrometric (LC-ESI/MS) system for the analysis of steroids. The limits of detection (LODs) for oxime derivatized steroids, expressed as concentrations, were slightly higher with the HPLC-Chip/MS system (50-300 pM) using an injection volume of 0.5 μL than with the conventional LC-ESI/MS (10-150 pM) using an injection volume of 40 μL. However, when the LODs are expressed as injected amounts, the sensitivity of the HPLC-Chip/MS system was about 50 times higher than with the conventional LC-ESI/MS system. The results indicate that the use of HPLC-Chip/MS system is clearly advantageous only in the analysis of low-volume samples. Both methods showed good linearity and good quantitative and chromatographic repeatability. In addition to the instrument comparisons with oxime derivatized steroids, the feasibility of the HPLC-Chip/MS system in the analysis of non-derivatized and oxime derivatized steroids was compared. The HPLC-Chip/MS method developed for non-derivatized steroids was also applied to the quantitative analysis of 15 mouse plasma samples.

  2. Resonance ionization mass spectrometry at Los Alamos National Laboratory

    International Nuclear Information System (INIS)

    Two approaches to Resonance Ionization Mass Spectrometry (RIMS) at Los Alamos National Laboratory are discussed. The first is the use of continuous-wave dye lasers as the ionization source, and the use of pulse counting detection; and results are presented for lutetium and technetium. The second approach is the use of multiphoton resonances in the pulsed laser excitation of atoms. Experiments with 2 + 1 [photons to resonance plus photons to ionize] RIMS schemes for several elements are discussed. (author)

  3. Tissue Imaging Using Nanospray Desorption Electrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Laskin, Julia; Heath, Brandi S.; Roach, Patrick J.; Cazares, Lisa H.; Semmes, O. John

    2012-01-03

    We present the first results showing the ambient imaging of biological samples in their native environment using nanospray desorption ionization (nanoDESI) mass spectrometry. NanoDESI is an ambient pressure ionization technique that enables precise control of ionization of molecules from substrates. We demonstrate highly sensitive and robust analysis of tissue samples with high spatial resolution (<12 {mu}m) without sample preparation, which will be essential for applications in clinical diagnostics, drug discovery, molecular biology, and biochemistry.

  4. Electrospray ionization and matrix assisted laser desorption/ionization mass spectrometry: powerful analytical tools in recombinant protein chemistry

    DEFF Research Database (Denmark)

    Andersen, Jens S.; Svensson, B; Roepstorff, P

    1996-01-01

    Electrospray ionization and matrix assisted laser desorption/ionization are effective ionization methods for mass spectrometry of biomolecules. Here we describe the capabilities of these methods for peptide and protein characterization in biotechnology. An integrated analytical strategy is presen......Electrospray ionization and matrix assisted laser desorption/ionization are effective ionization methods for mass spectrometry of biomolecules. Here we describe the capabilities of these methods for peptide and protein characterization in biotechnology. An integrated analytical strategy...

  5. Mass spectrometry of solid samples in open air using combined laser ionization and ambient metastable ionization

    Science.gov (United States)

    He, X. N.; Xie, Z. Q.; Gao, Y.; Hu, W.; Guo, L. B.; Jiang, L.; Lu, Y. F.

    2012-01-01

    Mass spectrometry of solid samples in open air was carried out using combined laser ionization and metastable ionization time-of-flight mass spectrometry (LI-MI-TOFMS) in ambient environment for qualitative and semiquantitative (relative analyte information, not absolute information) analysis. Ambient metastable ionization using a direct analysis in realtime (DART) ion source was combined with laser ionization time-of-flight mass spectrometry (LI-TOFMS) to study the effects of combining metastable and laser ionization. A series of metallic samples from the National Institute of Standards and Technology (NIST 494, 495, 498, 499, and 500) and a pure carbon target were characterized using LI-TOFMS in open air. LI-MI-TOFMS was found to be superior to laser-induced breakdown spectroscopy (LIBS). Laser pulse energies between 10 and 200 mJ at the second harmonic (532 nm) of an Nd:YAG laser were applied in the experiment to obtain a high degree of ionization in plasmas. Higher laser pulse energy improves signal intensities of trace elements (such as Fe, Cr, Mn, Ni, Ca, Al, and Ag). Data were analyzed by numerically calculating relative sensitivity coefficients (RSCs) and limit of detections (LODs) from mass spectrometry (MS) and LIBS spectra. Different parameters, such as boiling point, ionization potential, RSC, LOD, and atomic weight, were shown to analyze the ionization and MS detection processes in open air.

  6. Highly efficient ionization of phosphopeptides at low pH by desorption electrospray ionization mass spectrometry†

    OpenAIRE

    Pan, Ning; Liu, Pengyuan; Cui, Weidong; Tang, Bo; Shi, Jingmin; Chen, Hao

    2013-01-01

    A fast and novel strategy for efficient ionization of phosphopeptides in mixtures is reported, in which the sample is acidified to low pH to suppress the deprotonation of phosphate groups and then followed by direct analysis using liquid sample desorption electrospray ionization mass spectrometry (DESI-MS).

  7. Liquid chromatography/negative electrospray ionization ion trap MS(2) mass spectrometry application for the determination of microcystins occurrence in Southern Portugal water reservoirs.

    Science.gov (United States)

    Rodrigues, M A; Reis, M P; Mateus, M C

    2013-11-01

    Microcystins (MCs) are toxins produced by cyanobacteria which are common organisms in the phytoplankton of eutrophic lakes, rivers and freshwater reservoirs. In the present work, a novel method of liquid chromatography-electrospray ion trap tandem mass spectrometry (LC/ESI/Ion trap-MS/MS), operated in the negative ionization mode, was developed for the analysis of these cyanotoxins. The method was applied to determine the amounts of total microcystins-LR, -YR and -RR in two water reservoirs in Southern Portugal, namely Alqueva and Beliche. A total of 30 water samples were analysed along 2011. Solid phase extraction (SPE) was used for sample cleaning-up and analyte enrichment. The extracted toxins were separated on a C18 column with a gradient of acetonitrile/water with 0.1% formic acid. Detection of microcystins was carried out using multiple reaction monitoring (MRM) in the negative polarity mode, as this method gave a higher selectivity. The MC-RR, YR and LR quantification limits were 17.9, 31.7 and 15.8 ng/L, respectively; quite below the limits recommended by WHO guidelines for drinking water (1 μg/L). Total MC highest concentrations were found in the warm months of June, July and September in Alqueva sampling sites, with concentrations of MC LR and RR ranging 17-344 and 25-212 ng/L, respectively, showing comparable results for MC-RR and LR and slightly lower concentration of MC-YR. Detected values for Beliche reservoir were below quantification limits.

  8. Matrix Assisted Ionization Vacuum (MAIV), a New Ionization Method for Biological Materials Analysis Using Mass Spectrometry*

    OpenAIRE

    Inutan, Ellen D.; Trimpin, Sarah

    2012-01-01

    The introduction of electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) for the mass spectrometric analysis of peptides and proteins had a dramatic impact on biological science. We now report that a wide variety of compounds, including peptides, proteins, and protein complexes, are transported directly from a solid-state small molecule matrix to gas-phase ions when placed into the vacuum of a mass spectrometer without the use of high voltage, a laser, or adde...

  9. Desorption electrospray ionization-mass spectrometry of proteins

    Science.gov (United States)

    Desorption electrospray ionization-mass spectrometry (DESI-MS) was evaluated for the detection of proteins ranging in molecular mass from 12 to 66 kDa. Proteins were uniformly deposited on a solid surface without pretreatment and analyzed with a DESI source coupled to a quadrupole ion trap mass spec...

  10. Principle and analytical applications of resonance ionization mass spectrometry

    International Nuclear Information System (INIS)

    Resonance ionization mass spectrometry (RIMS) is a very sensitive analytical technique for the detection of trace elements. This method is based on the excitation and ionization of atoms with resonant laser light followed by mass analysis. It allows element and, in some cases, isotope selective ionization and is applicable to most of the elements of the periodic table. A high selectivity can be achieved by applying three step photoionization of the elements under investigation and an additional mass separation for an unambiguous isotope assignment. An effective facility for resonance ionization mass spectrometry consists of three dye lasers which are pumped by two copper vapor lasers and of a linear time-of-flight spectrometer with a resolution better than 2500. Each copper vapor laser has a pulse repetition rate of 6,5 kHz and an average output power of 30 W. With such an apparatus measurements with lanthanide-, actinide-, and technetium-samples have been performed. By saturating the excitation steps and by using autoionizing states for ionization step a detection efficiency of 4 x 10-6 and 2,5 x 10-6 has been reached for plutonium and technetium, respectively, leading to a detection limit of less than 107 atoms in the sample. Measurements of isotope ratios of plutonium samples were in good agreement with mass-spectrometric data. The high elemental selectivity of the resonance ionization spectrometry could be demonstrated. (Authors)

  11. Matrix Assisted Ionization in Vacuum, a Sensitive and Widely Applicable Ionization Method for Mass Spectrometry

    Science.gov (United States)

    Trimpin, Sarah; Inutan, Ellen D.

    2013-05-01

    An astonishingly simple new method to produce gas-phase ions of small molecules as well as proteins from the solid state under cold vacuum conditions is described. This matrix assisted ionization vacuum (MAIV) mass spectrometry (MS) method produces multiply charged ions similar to those that typify electrospray ionization (ESI) and uses sample preparation methods that are nearly identical to matrix-assisted laser desorption/ionization (MALDI). Unlike these established methods, MAIV does not require a laser or voltage for ionization, and unlike the recently introduced matrix assisted ionization inlet method, does not require added heat. MAIV-MS requires only introduction of a crystalline mixture of the analyte incorporated with a suitable small molecule matrix compound such as 3-nitrobenzonitrile directly to the vacuum of the mass spectrometer. Vacuum intermediate pressure MALDI sources and modified ESI sources successfully produce ions for analysis by MS with this method. As in ESI-MS, ion formation is continuous and, without a laser, little chemical background is observed. MAIV, operating from a surface offers the possibility of significantly improved sensitivity relative to atmospheric pressure ionization because ions are produced in the vacuum region of the mass spectrometer eliminating losses associated with ion transfer from atmospheric pressure to vacuum. Mechanistic aspects and potential applications for this new ionization method are discussed.

  12. ATMOSPHERIC-PRESSURE-IONIZATION MASS-SPECTROMETRY .1. INSTRUMENTATION AND IONIZATION TECHNIQUES

    NARCIS (Netherlands)

    BRUINS, AP

    1994-01-01

    Mass spectrometer ion sources are normally located inside a high-vacuum envelope. Such low-pressure ion sources can make use of a range of different ionization methods and are in routine use in analytical mass spectrometers. An ion source operating at atmospheric pressure is better suited, and may b

  13. Resonance ionization mass spectroscopy for trace analysis of plutonium

    International Nuclear Information System (INIS)

    Trace amounts of plutonium are determined by means of resonance ionization mass spectroscopy (RIMS). Plutonium atoms evaporated from a heated filament are ionized via a three-step excitation leading to an autoionizing state. The ions are mass-selectively detected with a time-of-flight (TOF) mass spectrometer. Several types of filaments have been tested with respect to atomic yield after evaporation and reproducibility. The best results have been obtained using tantalum as backing and titanium as covering. An overall detection efficiency of 1·10-5 could be determined with such filaments yielding a detection limit of 2·106 atoms of 239Pu

  14. Resonance ionization mass spectroscopy for trace analysis of plutonium

    Science.gov (United States)

    Erdmann, N.; Albus, F.; Deiβenberger, R.; Eberhardt, K.; Funk, H.; Hasse, H.-U.; Herrmann, G.; Huber, G.; Kluge, H.-J.; Köhler, S.; Nunnemann, M.; Passler, G.; Trautmann, N.; Urban, F.-J.

    1995-04-01

    Trace amounts of plutonium are determined by means of resonance ionization mass spectroscopy (RIMS). Plutonium atoms evaporated from a heated filament are ionized via a three-step exciation leading to an autoionizing state. The ions are mass-selectively detected with a time-of-flight (TOF) mass spectrometer. Several types of filaments have been tested with respect to atomic yield after evaporation and reproducibility. The best results have been obtained using tantalum as backing and titanium as covering. An overall detection efficiency of 1ṡ10-5 could be determined with such filaments yielding a detection limit of 2ṡ106 atoms of 239Pu.

  15. Desorption electrospray ionization mass spectrometry of intact bacteria

    Science.gov (United States)

    Desorption electrospray ionization (DESI) mass spectrometry (MS) was used to differentiate 7 bacterial species based on their measured DESI-mass spectral profile. Both Gram positive and Gram negative bacteria were tested and included Escherichia coli, Staphyloccocus aureus, Enterococcus sp., Bordete...

  16. Advanced quantification of plutonium ionization potential to support nuclear forensic evaluations by resonance ionization mass spectrometry

    OpenAIRE

    Lensegrav, Craig T.

    2015-01-01

    Approved for public release; distribution is unlimited Ongoing work seeks to apply the technology of resonance ionization mass spectrometry (RIMS) to problems related to nuclear forensics and, in particular, to the analysis and quantification of the debris from nuclear detonations. As part of this effort, modeling and simulation methods are being applied to analyze and predict the potential for ionization by laser excitation of isotopes of both uranium and plutonium. Early work focused on ...

  17. Laser post-ionization secondary neutral mass spectroscopy

    International Nuclear Information System (INIS)

    Three different instruments using laser ionization techniques will be described. Results from the SARISA instrument with a demonstrated figure of merit of .05 (atoms detected/atoms sputtered) for resonance ionization; detection of Fe at the sub-part-per-billion level in ultrapure Si; and features of the instrument such as energy and angle refocusing time-of-flight (EARTOF) mass spectrometer and multiplexing for simultaneous detection of secondary ions and neutrals. 12 refs., 3 figs

  18. Direct and Convenient Mass Spectrometry Sampling with Ambient Flame Ionization

    Science.gov (United States)

    Liu, Xiao-Pan; Wang, Hao-Yang; Zhang, Jun-Ting; Wu, Meng-Xi; Qi, Wan-Shu; Zhu, Hui; Guo, Yin-Long

    2015-11-01

    Recent innovations in ambient ionization technology for the direct analysis of various samples in their native environment facilitate the development and applications of mass spectrometry in natural science. Presented here is a novel, convenient and flame-based ambient ionization method for mass spectrometric analysis of organic compounds, termed as the ambient flame ionization (AFI) ion source. The key features of AFI ion source were no requirement of (high) voltages, laser beams and spray gases, but just using small size of n-butane flame (height approximately 1 cm, about 500 oC) to accomplish the rapid desorption and ionization for direct analysis of gaseous-, liquid- and solid-phase organic compounds, as well as real-world samples. This method has high sensitivity with a limit of detection of 1 picogram for propyphenazone, which allows consuming trace amount of samples. Compared to previous ionization methods, this ion source device is extremely simple, maintain-free, low-cost, user-friendly so that even an ordinary lighter (with n-butane as fuel) can achieve efficient ionization. A new orientation to mass spectrometry ion source exploitation might emerge from such a convenient, easy and inexpensive AFI ion source.

  19. Note: Discharging fused silica test masses with ionized nitrogen

    Science.gov (United States)

    Ugolini, D.; Funk, Q.; Amen, T.

    2011-04-01

    We have developed a technique for discharging fused silica test masses in a gravitational-wave interferometer with nitrogen ionized by an electron beam. The electrons are produced from a heated filament by thermionic emission in a low-pressure region to avoid contamination and burnout. Some electrons then pass through a small aperture and ionize nitrogen in a higher-pressure region, and this ionized gas is pumped across the test mass surface, neutralizing both polarities of charge. The discharge rate varies exponentially with charge density and filament current, quadratically with filament potential, and has an optimal working pressure of ˜8 mT. Adapting the technique to larger test mass chambers is also discussed.

  20. Resonance ionization mass spectroscopy with neptunium and plutonium

    International Nuclear Information System (INIS)

    The resonance ionization mass spectroscopy was one of the methods used for detection of the actinides. The principles of the method are: atoms of the elements to be measured are excited step by step through resonant irradiation with laser light, and are thus ionized. The ions are accelerated by electrical fields and can then be detected. The equipment for this process comprised a pulsed laser system consisting of two copper vapor lasers and three dye lasers, and a linear time-of-flight mass spectrometer with a mass resolution M/ΔM of approx. 1500. Due to a two-step resonant excitation of atomic energy levels and subsequent population of an autoionized state, the three-step ionization method is particularly element-selective. Use of powerful lasers with a high pulse repetition rate yield a high sensitivity and thus allow low detection limits. (orig./BBR)

  1. Acetonitrile Ion Suppression in Atmospheric Pressure Ionization Mass Spectrometry

    Science.gov (United States)

    Colizza, Kevin; Mahoney, Keira E.; Yevdokimov, Alexander V.; Smith, James L.; Oxley, Jimmie C.

    2016-11-01

    Efforts to analyze trace levels of cyclic peroxides by liquid chromatography/mass spectrometry gave evidence that acetonitrile suppressed ion formation. Further investigations extended this discovery to ketones, linear peroxides, esters, and possibly many other types of compounds, including triazole and menadione. Direct ionization suppression caused by acetonitrile was observed for multiple adduct types in both electrospray ionization and atmospheric pressure chemical ionization. The addition of only 2% acetonitrile significantly decreased the sensitivity of analyte response. Efforts to identify the mechanism were made using various nitriles. The ion suppression was reduced by substitution of an acetonitrile hydrogen with an electron-withdrawing group, but was exacerbated by electron-donating or steric groups adjacent to the nitrile. Although current theory does not explain this phenomenon, we propose that polar interactions between the various functionalities and the nitrile may be forming neutral aggregates that manifest as ionization suppression.

  2. Aerosol Analysis via Electrostatic Precipitation-Electrospray Ionization Mass Spectrometry.

    Science.gov (United States)

    He, Siqin; Li, Lin; Duan, Hongxu; Naqwi, Amir; Hogan, Christopher J

    2015-07-01

    Electrospray ionization (ESI) is the preferred mode of ion generation for mass analysis of many organic species, as alternative ionization techniques can lead to appreciable analyte fragmentation. For this reason, ESI is an ideal method for the analysis of species within aerosol particles. However, because of their low concentrations (∼10 μg/m(3)) in most environments, ESI has been applied sparingly in aerosol particle analysis; aerosol mass spectrometers typically employ analyte volatilization followed by electron ionization or chemical ionization, which can lead to a considerable degree of analyte fragmentation. Here, we describe an approach to apply ESI to submicrometer and nanometer scale aerosol particles, which utilizes unipolar ionization to charge particles, electrostatic precipitation to collect particles on the tip of a Tungsten rod, and subsequently, by flowing liquid over the rod, ESI and mass analysis of the species composing collected particles. This technique, which we term electrostatic precipitation-ESI-MS (EP-ESI-MS), is shown to enable analysis of nanogram quantities of collected particles (from aerosol phase concentrations as low as 10(2) ng m(-3)) composed of cesium iodide, levoglucosan, and levoglucosan within a carbon nanoparticle matrix. With EP-ESI-MS, the integrated mass spectrometric signals are found to be a monotonic function of the mass concentration of analyte in the aerosol phase. We additionally show that EP-ESI-MS has a dynamic range of close to 5 orders of magnitude in mass, making it suitable for molecular analysis of aerosol particles in laboratory settings with upstream particle size classification, as well as analysis of PM 2.5 particles in ambient air. PMID:26024017

  3. Progress and application of liquid chromatography-electropray ionization mass spectrometry in forensic DNA analysis%液相电喷雾离子质谱技术在法医DNA中的应用

    Institute of Scientific and Technical Information of China (English)

    许淼; 李淑瑾; 丛斌; 马春玲

    2012-01-01

    生物质谱技术是近年来发展较为迅速的生物分析技术之一,在对大分子生物质量测定中,其以快速、准确、灵敏等优点受到研究者的青睐.其中,液相电喷雾离子电离质谱(LC-ESI-MS)在法医DNA分析中对STR以及SNP遗传标记的检测具有独特的应用价值和广阔的应用前景.本文对ESI-MS的现状和在法医DNA分析中的应用等方面进行了综述,分析了LC-ESI-MS技术在法医学DNA分析中的优缺点,以促进其在国内法医DNA分析中的应用与发展.%Biological mass spectrometry is one of the biological analysis techniques with much more rapid development, which is appreciated in analyzing the biological macromolecules owning to its speediness, accuracy and sensitivity. Biological mass spectrometry technology, especially liquid chromatography-electrospray ionization mass spectrometry ( LC-ESI-MS) , can be used to analyze forensic markers such as short tandem repeats ( STRs) and single nucleotide polymorphisms ( SNPs) with an unique value and broad application prospects. It is stated in this paper the current situation, the application and development and also the advantages and disadvantages of LC-ESI-MS in forensic DNA analysis.

  4. Laser desorption lamp ionization source for ion trap mass spectrometry.

    Science.gov (United States)

    Wu, Qinghao; Zare, Richard N

    2015-01-01

    A two-step laser desorption lamp ionization source coupled to an ion trap mass spectrometer (LDLI-ITMS) has been constructed and characterized. The pulsed infrared (IR) output of an Nd:YAG laser (1064 nm) is directed to a target inside a chamber evacuated to ~15 Pa causing desorption of molecules from the target's surface. The desorbed molecules are ionized by a vacuum ultraviolet (VUV) lamp (filled with xenon, major wavelength at 148 nm). The resulting ions are stored and detected in a three-dimensional quadrupole ion trap modified from a Finnigan Mat LCQ mass spectrometer operated at a pressure of ≥ 0.004 Pa. The limit of detection for desorbed coronene molecules is 1.5 pmol, which is about two orders of magnitude more sensitive than laser desorption laser ionization mass spectrometry using a fluorine excimer laser (157 nm) as the ionization source. The mass spectrum of four standard aromatic compounds (pyrene, coronene, rubrene and 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine (OPC)) shows that parent ions dominate. By increasing the infrared laser power, this instrument is capable of detecting inorganic compounds. PMID:25601688

  5. Biogenic aldehyde determination by reactive paper spray ionization mass spectrometry

    International Nuclear Information System (INIS)

    Highlights: • In-situ derivatization and simultaneous ionization used to detect aldehydes. • Biogenic aliphatic and aromatic aldehydes reacted with 4-aminophenol. • Derivatized products yield structurally characteristic fragment ions. • This measurement demonstrated using a miniaturized portable mass spectrometer. - Abstract: Ionization of aliphatic and aromatic aldehydes is improved by performing simultaneous chemical derivatization using 4-aminophenol to produce charged iminium ions during paper spray ionization. Accelerated reactions occur in the microdroplets generated during the paper spray ionization event for the tested aldehydes (formaldehyde, n-pentanaldehyde, n-nonanaldehyde, n-decanaldehyde, n-dodecanaldehyde, benzaldehyde, m-anisaldehyde, and p-hydroxybenzaldehyde). Tandem mass spectrometric analysis of the iminium ions using collision-induced dissociation demonstrated that straight chain aldehydes give a characteristic fragment at m/z 122 (shown to correspond to protonated 4-(methyleneamino)phenol), while the aromatic aldehyde iminium ions fragment to give a characteristic product ion at m/z 120. These features allow straightforward identification of linear and aromatic aldehydes. Quantitative analysis of n-nonaldehyde using a benchtop mass spectrometer demonstrated a linear response over 3 orders of magnitude from 2.5 ng to 5 μg of aldehyde loaded on the filter paper emitter. The limit of detection was determined to be 2.2 ng for this aldehyde. The method had a precision of 22%, relative standard deviation. The experiment was also implemented using a portable ion trap mass spectrometer

  6. Quantitative matrix-assisted laser desorption/ionization mass spectrometry

    OpenAIRE

    Duncan, Mark W.; Roder, Heinrich; Hunsucker, Stephen W.

    2008-01-01

    This review summarizes the essential characteristics of matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry (TOF MS), especially as they relate to its applications in quantitative analysis. Approaches to quantification by MALDI-TOF MS are presented and published applications are critically reviewed.

  7. Biogenic aldehyde determination by reactive paper spray ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bag, Soumabha; Hendricks, P.I. [Aston Labs, Department of Chemistry, Purdue University, West Lafayette, IN 47907 (United States); Reynolds, J.C. [Centre for Analytical Science, Loughborough University, Loughborough, Leicestershire (United Kingdom); Cooks, R.G., E-mail: cooks@purdue.edu [Aston Labs, Department of Chemistry, Purdue University, West Lafayette, IN 47907 (United States)

    2015-02-20

    Highlights: • In-situ derivatization and simultaneous ionization used to detect aldehydes. • Biogenic aliphatic and aromatic aldehydes reacted with 4-aminophenol. • Derivatized products yield structurally characteristic fragment ions. • This measurement demonstrated using a miniaturized portable mass spectrometer. - Abstract: Ionization of aliphatic and aromatic aldehydes is improved by performing simultaneous chemical derivatization using 4-aminophenol to produce charged iminium ions during paper spray ionization. Accelerated reactions occur in the microdroplets generated during the paper spray ionization event for the tested aldehydes (formaldehyde, n-pentanaldehyde, n-nonanaldehyde, n-decanaldehyde, n-dodecanaldehyde, benzaldehyde, m-anisaldehyde, and p-hydroxybenzaldehyde). Tandem mass spectrometric analysis of the iminium ions using collision-induced dissociation demonstrated that straight chain aldehydes give a characteristic fragment at m/z 122 (shown to correspond to protonated 4-(methyleneamino)phenol), while the aromatic aldehyde iminium ions fragment to give a characteristic product ion at m/z 120. These features allow straightforward identification of linear and aromatic aldehydes. Quantitative analysis of n-nonaldehyde using a benchtop mass spectrometer demonstrated a linear response over 3 orders of magnitude from 2.5 ng to 5 μg of aldehyde loaded on the filter paper emitter. The limit of detection was determined to be 2.2 ng for this aldehyde. The method had a precision of 22%, relative standard deviation. The experiment was also implemented using a portable ion trap mass spectrometer.

  8. Subcellular analysis by laser ablation electrospray ionization mass spectrometry

    Science.gov (United States)

    Vertes, Akos; Stolee, Jessica A; Shrestha, Bindesh

    2014-12-02

    In various embodiments, a method of laser ablation electrospray ionization mass spectrometry (LAESI-MS) may generally comprise micro-dissecting a cell comprising at least one of a cell wall and a cell membrane to expose at least one subcellular component therein, ablating the at least one subcellular component by an infrared laser pulse to form an ablation plume, intercepting the ablation plume by an electrospray plume to form ions, and detecting the ions by mass spectrometry.

  9. Filament power regulator for thermal ionization mass spectrometry

    International Nuclear Information System (INIS)

    A device has been developed that will control the filament temperature in a thermal ionization mass spectrometer. The arrangement is superior to past methods to control this critical parameter. The operating principle lies in the feature of filament power control as contrasted with the formerly used voltage or current controls. Reproducibility and stability of ion beams showed great improvement. The mass spectrometer was developed to analyze for parts-per-billion concentrations of uranium in water samples

  10. Electrospray Ionization Mass Spectrometric Analysis of Highly Reactive Glycosyl Halides

    Directory of Open Access Journals (Sweden)

    Lajos Kovács

    2012-07-01

    Full Text Available Highly reactive glycosyl chlorides and bromides have been analysed by a routine mass spectrometric method using electrospray ionization and lithium salt adduct-forming agents in anhydrous acetonitrile solution, providing salient lithiated molecular ions [M+Li]+, [2M+Li]+ etc. The role of other adduct-forming salts has also been evaluated. The lithium salt method is useful for accurate mass determination of these highly sensitive compounds.

  11. Measurement of boron isotopes by negative thermal ionization mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The isobaric interference for boron isotopic measurement by negative thermal ionization mass spectrometry (NTIMS) has been studied. The result shows that the CNO- is not only from the organic material, but also from nitrate in loading reagent in NTIMS. Monitoring the mass 43 ion intensity and 43/42 ratio of blank are also necessary for the boron isotopic measurement by NTIMS, other than is only boron content.

  12. Positron ionization mass spectrometry: An organic mass spectrometrist's view

    Energy Technology Data Exchange (ETDEWEB)

    Glish, G.L.; Donohue, D.L.; McLuckey, S.A.; Eckenrode, B.A.; Hulett, L.D. Jr.

    1990-01-01

    We are currently engaged in a research program to study the ionization of polyatomic molecules by positrons. We refer to the technique herein as positron ionization mass spectrometry which includes all of the possible ionization mechanisms. In the course of this work we will attempt to characterize each of the important ionization mechanisms. Our ultimate objective is to explore the use of positron ionization mass spectrometry for chemical analysis. Several other groups have also begun to pursue aspects of positron ionization in parallel with our efforts although with somewhat different approaches and, perhaps with slightly different emphases. Recently, for example, Passner et al. have acquired mass spectra in a Penning trap resulting from the ionization of several different polyatomic molecules by near thermal kinetics energy positrons. Our research involves studying the different types of ionizing interactions of positrons with organic molecules, as a function of positron kinetic energy. For ionization of polyatomic molecules by positrons, several possible mechanisms are apparent from lifetime and scattering cross-section data. These mechanisms are discussed.

  13. Matrix-assisted laser desorption ionization and electrospray ionization combined with Fourier transform ion cyclotron resonance mass spectrometry

    OpenAIRE

    Staneke, Paul O.; Nibbering, Nico M. M.

    1997-01-01

    During recent years, matrix-assisted laser desorption ionization (MALDI) and electrospray ionization (ESI) are successfully employed to analyze biomolecules and polymers. In combination with Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry, high mass resolution and mass measurement accuracy can be achieved to enable the determination of molecular weights and structural characterization of biochemical compounds larger than 10 kDa.

  14. Determination of the first ionization potential of actinides by resonance ionization mass spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, S. [Institut fuer Kernchemie Universitaet Mainz, Mainz (Germany); Albus, F. [Institu fuer Physik, Universitaet Mainz, Mainz (Germany); Dibenberger, R.; Erdmann, N.; Funk, H. [Institut fuer Kernchemiess Universitaet Mainz, Mainz (Germany); Hasse, H. [Institut fuer Physik, Universitaet Mainz, Mainz (Germany); Herrmann, G. [Institut fuer Kernchemiess Universitaet Mainz, Mainz (Germany); Huber, G.; Kluge, H.; Nunnemann, M.; Passler, G. [Institut fuer Physik, Universitaet Mainz, Mainz (Germany); Rao, P.M. [Bhabha Atomic Research Centre Bombay (India); Riegel, J.; Trautmann, N. [Institut fuer Kernchemie Universitaet Mainz, Mainz (Germany); Urban, F. [Institut fuer Physik, Universitaet Mainz, Mainz (Germany)

    1995-04-01

    Resonance ionization mass spectroscopy (RIMS) is used for the precise determination of the first ionization potential of transuranium elements. The first ionization potentials (IP) of americium and curium have been measured for the first time to IP{sub {ital Am}}=5.9738(2) and IP{sub {ital Cm}}=5.9913(8) eV, respectively, using only 10{sup 12} atoms of {sup 243}Am and {sup 248}Cm. The same technique was applied to thorium, neptunium, and plutonium yielding IP{sub T{sub H}}=6.3067(2), IP{sub N{sub P}}=6.2655(2), and IP{sub {ital Pu}}=6.0257(8) eV. The good agreement of our results with the literature data proves the precision of the method which was additionally confirmed by the analysis of Rydberg seris of americium measured by RIMS. {copyright}American Institute of Physics 1995

  15. Laser-Induced Ionization Efficiency Enhancement On A Filament For Thermal Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Siegfried, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-14

    The evaluation of trace Uranium and Plutonium isotope ratios for nanogram to femtogram material quantities is a vital tool for nuclear counter-proliferation and safeguard activities. Thermal Ionization Mass Spectrometry (TIMS) is generally accepted as the state of the art technology for highly accurate and ultra-trace measurements of these actinide ratios. However, the very low TIMS ionization yield (typically less than 1%) leaves much room for improvement. Enhanced ionization of Nd and Sm from a TIMS filament was demonstrated using wavelength resonance with a nanosecond (pulse width) laser operating at 10 Hz when light was directed toward the filament.1 For this study, femtosecond and picosecond laser capabilities were to be employed to study the dissociation and ionization mechanisms of actinides/lanthanides and measure the enhanced ionization of the metal of interest. Since the underlying chemistry of the actinide/lanthanide carbides produced and dissociated on a TIMS filament is not well understood, the experimental parameters affecting the photodissociation and photoionization with one and two laser beams were to be investigated.

  16. Development of a Portable Single Photon Ionization-Photoelectron Ionization Time-of-Flight Mass Spectrometer

    Directory of Open Access Journals (Sweden)

    Yunguang Huang

    2015-01-01

    Full Text Available A vacuum ultraviolet lamp based single photon ionization- (SPI- photoelectron ionization (PEI portable reflecting time-of-flight mass spectrometer (TOFMS was designed for online monitoring gas samples. It has a dual mode ionization source: SPI for analyte with ionization energy (IE below 10.6 eV and PEI for IE higher than 10.6 eV. Two kinds of sampling inlets, a capillary inlet and a membrane inlet, are utilized for high concentration and trace volatile organic compounds, respectively. A mass resolution of 1100 at m/z 64 has been obtained with a total size of 40 × 31 × 29 cm, the weight is 27 kg, and the power consumption is only 70 W. A mixture of benzene, toluene, and xylene (BTX, SO2, and discharging products of SF6 were used to test its performance, and the result showed that the limit of quantitation for BTX is as low as 5 ppbv (S/N = 10 : 1 with linear dynamic ranges greater than four orders of magnitude. The portable TOFMS was also evaluated by analyzing volatile organic compounds from wine and decomposition products of SF6 inside of a gas-insulated switchgear.

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

    Science.gov (United States)

    Tran, Bao Quoc; Barton, Christopher; Feng, Jinhua; Sandjong, Aimee; Yoon, Sung Hwan; Awasthi, Shivangi; Liang, Tao; Khan, Mohd M; Kilgour, David P A; Goodlett, David R; Goo, Young Ah

    2016-03-01

    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]. PMID:26793758

  18. 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].

  19. Extractive Electrospray Ionization Mass Spectrometry for Uranium Chemistry Studies

    OpenAIRE

    Chen, Huanwen; Luo, Mingbiao; Xiao, Saijin; OUYANG Yongzhong; Zhou, Yafei; Zhang, Xinglei

    2013-01-01

    Uranium chemistry is of sustainable interest. Breakthroughs in uranium studies make serious impacts in many fields including chemistry, physics, energy and biology, because uranium plays fundamentally important roles in these fields. Substantial progress in uranium studies normally requires development of novel analytical tools. Extractive electrospray ionization mass spectrometry (EESI-MS) is a sensitive technique for trace detection of various analytes in complex matrices without sample pre...

  20. A high efficiency thermal ionization source adapted to mass spectrometers

    International Nuclear Information System (INIS)

    A tungsten crucible thermal ionization source mounted on a quadrupole mass spectrometer is described. The crucible is a disposable rod with a fine hole bored in one end; it is heated by electron bombardment. The schematic design of the assembly, including water cooling, is described and depicted. Historically, the design is derived from that of ion sources used on ion separators at Los Alamos and Dubna, but the crucible is made smaller and simplified. 10 refs., 4 figs

  1. Determination of Epoxiconazole in Wheat and Soil Using Ultra-Performance Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry(UPLC-MS/MS)%超高效液相色谱-串联质谱法(UPLC-MS/MS)快速检测小麦和土壤中氟环唑的残留及消解

    Institute of Scientific and Technical Information of China (English)

    范玉; 田迎迎; 刘新刚; 董丰收; 徐军; 郑永权

    2013-01-01

    In order to know the degradation of epoxiconazole in wheat and soil clearly, a sensitive and effective method for the determination of epoxiconazole in wheat and soil using ultra-high performace liquid chromatographf UPLC-MS/MS) was established. Moreover, the degradation of epoxiconazole in wheat and soil in Shandong, Henan and Beijing Provinces was also investigated. The epoxiconazole residues were analyzed by UPLC-MS/MS under multiple reaction monitoring mode. The average recoveries using this method at three spiking levels(0.05 mg-kg-1, 0.5 mg-kg-1, 1.0 mg-kg-1) were also evaluated. The results indicated that recoveries ranged from 98.8% to 108.1% with variation coefficient (CV) in the range of 2.6%~6.7%(n=5) in soil, from 73.2%~84.4% with CV of 0.9%~4.6% in wheat plant and from 80.7%~82.4% with CV of 2.0%~7.8% in wheat, respectively. Meanwhile, a field experiment was also conducted to reveal the dynamics of epoxiconazole residues in wheat and soil in the three provinces. The results showed that the half life of epoxiconazole was 16.9 days, 21.3 days, 19.7 days in soil and 12.6 days, 9.2 days, 8.1 days in wheat plant in Shandong, Henan and Beijing respectively which showed that epoxiconazole belonged to non-persistent and easily degradable pesticide.%为了解氟环唑在小麦和土壤中的消解动态,建立了超高效液相色谱-串联四级杆质谱(UPLC-MS/MS)快速检测小麦及土壤中氟环唑残留的分析方法,并在山东、河南和北京开展了为期两年的小麦田间试验研究.不同浓度氟环唑(0.05、0.5、1.0 mg· kg-1)的添加回收率试验结果表明:在土壤中平均回收率为98.8%~108.1%,变异系数为2.6%~6.7%;在小麦植株中的平均回收率为73.2%~84.4%,变异系数为0.9%~4.6%;在小麦粒中的平均回收率为80.7%~82.4%,变异系数为2.0%~7.8%.氟环唑在山东、河南和北京三地的小麦和土壤中的消解动态研究结果表明,氟环唑在土壤中的消解半衰期分别为16.9、21.3、19.7 d,在小麦植株上的半衰期分别为12.6、9.2、8.1d,属于易降解农药.

  2. 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.

  3. Continuous wave laser resonance ionization mass spectrometry of technetium

    International Nuclear Information System (INIS)

    The authors have observed two-color, three step resonance ionization of technetium with cw lasers. High power argon-ion lasers were used to pump two tunable, broad-band (≅cm-1) cw dye lasers. The first laser generated ≅400 mW in the spectral region near 420 nm, while the second generated ≅300 mW near 610nm. Technetium samples were prepared by electroplating onto rhenium filaments. Tc atoms were vaporized by resistive heating in the source region of a 12-in., 900 magnetic mass spectrometer. An electron multiplier and counting electronics were used to process the signal. Ionization proceeded through various sublevels of the z6po and e6S states for the sequential 3 photon process. Technetium count rates ≥104 sec -1 were generated for several hours in samples containing ≅1is contained ing of technetium, 10 ng samples gave proportionally smaller signals. No interfering laser-generated ions were detected, although thermal Tc ions were observed. A measurement of ionization efficiency on a traced (95/sup m/Tc) sample indicated that speciation severely limits ionization efficiency. It appears that less than 1 part in 103 of the technetium evaporates in the atomic ground state. This may prove to be a significant limitation to the application of RIMS for the solar neutrino experiment; alternative atomization sources are being explored

  4. Quantification of hydroxyacetone and glycolaldehyde using chemical ionization mass spectrometry

    Directory of Open Access Journals (Sweden)

    K. M. Spencer

    2011-08-01

    Full Text Available Chemical ionization mass spectrometry (CIMS enables online, fast, in situ detection and quantification of hydroxyacetone and glycolaldehyde. Two different CIMS approaches are demonstrated employing the strengths of single quadrupole mass spectrometry and triple quadrupole (tandem mass spectrometry. Both methods are capable of the measurement of hydroxyacetone, an analyte with minimal isobaric interferences. Tandem mass spectrometry provides direct separation of the isobaric compounds glycolaldehyde and acetic acid using distinct, collision-induced dissociation daughter ions. Measurement of hydroxyacetone and glycolaldehyde by these methods was demonstrated during the ARCTAS-CARB 2008 campaign and the BEARPEX 2009 campaign. Enhancement ratios of these compounds in ambient biomass burning plumes are reported for the ARCTAS-CARB campaign. BEARPEX observations are compared to simple photochemical box model predictions of biogenic volatile organic compound oxidation at the site.

  5. Multiphoton ionization mass spectrometry of nitrated polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Tang, Yuanyuan; Imasaka, Tomoko; Yamamoto, Shigekazu; Imasaka, Totaro

    2015-08-01

    In order to suppress the fragmentation and improve the sensitivity for determination of nitrated polycyclic aromatic hydrocarbons (NPAHs), the mechanism of multiphoton ionization was studied for the following representative NPAHs, 9-nitroanthracene, 3-nitrofluoranthene, and 1-nitropyrene. The analytes were extracted from the PM2.5 on the sampling filter ultrasonically, and were measured using gas chromatography/multiphoton ionization/time-of-flight mass spectrometry with a femtosecond tunable laser in the range from 267 to 405 nm. As a result, a molecular ion was observed as the major ion and fragmentation was suppressed at wavelengths longer than 345 nm. Furthermore, the detection limit measured at 345 nm was measured to be the subpicogram level. The organic compounds were extracted from a 2.19 mg sample of particulate matter 2.5 (PM2.5), and the extract was subjected to multiphoton ionization mass spectrometry after gas chromatograph separation. The background signals were drastically suppressed at 345 nm, and the target NPAHs, including 9-nitroanthracene and 1-nitropyrene, were detected, and their concentrations were determined to be 5 and 3 pg/m(3), respectively. PMID:26048831

  6. Data-Independent Microbial Metabolomics with Ambient Ionization Mass Spectrometry

    Science.gov (United States)

    Rath, Christopher M.; Yang, Jane Y.; Alexandrov, Theodore; Dorrestein, Pieter C.

    2013-08-01

    Atmospheric ionization methods are ideally suited for prolonged MS/MS analysis. Data-independent MS/MS is a complementary technique for analysis of biological samples as compared to data-dependent analysis. Here, we pair data-independent MS/MS with the ambient ionization method nanospray desorption electrospray ionization (nanoDESI) for untargeted analysis of bacterial metabolites. Proof-of-principle data and analysis are illustrated by sampling Bacillus subtilis and Pseudomonas aeruginosa directly from Petri dishes. We found that this technique enables facile comparisons between strains via MS and MS/MS plots which can be translated to chemically informative molecular maps through MS/MS networking. The development of novel techniques to characterize microbial metabolites allows rapid and efficient analysis of metabolic exchange factors. This is motivated by our desire to develop novel techniques to explore the role of interspecies interactions in the environment, health, and disease. This is a contribution to honor Professor Catherine C. Fenselau in receiving the prestigious ASMS Award for a Distinguished Contribution in Mass Spectrometry for her pioneering work on microbial mass spectrometry.

  7. Analysis technology of high ionization potential element palladium by thermal ionization mass spectrometry

    International Nuclear Information System (INIS)

    Background: 107Pd is an important long-lived fission product of Palladium isotope which is important in cosmology, nuclear technology and environmental studies. The analysis of Pd by Thermal Ionization Mass Spectrometry (TIMS) is difficult because Pd has high ionization potential (8.33 eV). Purpose: The paper attempts to improve mass efficiency of Palladium in TIMS. Methods: Three loading reagents including TaF5, colloidal graphite and phosphate silica-gel are compared. In the three loading reagents, colloidal graphite and phosphate silica-gel are better than TaF5, their mass efficiency can reach 10-7. Using V-type filament, the most of mass efficiency reaches 4.55×10-7 which is twice as high as that by using single filament. Results: The isotope ratio of 2-μg Pd sample was measured with the loading reagent of phosphate silica-gel, 106Pd/108Pd deviated 0.36% with standard value, RSD was 0.14% (n=10). Conclusion: The experimental results show that the measurement of microgram Palladium sample can obtain good accuracy and precision by using appropriate loading reagents and V-type filament. (authors)

  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. 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

  10. 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.

  11. Determination of sodium tanshinone IIA sulfonate in plasma by liquid chromatography-electrospray ionisation-tandem mass spectrometry.

    Science.gov (United States)

    Hao, Haiping; Wang, Guangji; Cui, Nan; Li, Jing; Ding, Zuoqi

    2007-11-01

    Sodium tanshinone IIA sulfonate (STS) is a water-soluble derivative of tanshinone IIa, an important lipophilic component contained in Salvia miltiorrhizae. A simple, sensitive and robust quantification method for STS based on LC-ESI-MS/MS was developed and validated, and has been successfully applied to the pharmacokinetic study. Liquid-liquid extraction was used for extracting STS from biological samples, with a satisfactory recovery exceeding 75% at all test concentrations. Isocratic mobile phase consisted of 75% acetonitrile and 25% water containing 0.005% ammonia acetate (pH 3). Good retention and baseline separation for STS and the selected internal standard, diclofenac sodium, were obtained on a Shim-pack VP-ODS analytical column under this condition. The method was linear in the concentration range of 1-500 ng/mL. The intra- and inter-day precisions (RSD%) were within 9.0%. The deviation of the assay accuracies was within +/-10.0%. STS was proved to be stable during all sample storing, preparation and analytic procedures. With a lower limit of quantitation at 1 ng/mL, this method has been proved to be sensitive enough for the pharmacokinetic study of STS. The plasma profile of STS followed a single intravenous dosing was well fitted to a three compartmental model. PMID:17630641

  12. Mass spectrometric screening and identification of acidic metabolites in fulvic acid fractions of contaminated groundwater.

    Science.gov (United States)

    Jobelius, Carsten; Frimmel, Fritz H; Zwiener, Christian

    2014-05-01

    The anaerobic microbial degradation of aromatic and heterocyclic compounds is a prevalent process in contaminated groundwater systems. The introduction of functional groups into the contaminant molecules often results in aromatic and heterocyclic and succinic acids. These metabolites can be used as indicators for prevailing degradation processes. Therefore, there is a strong interest in developing analytical methods for screening and identification of these metabolites. In this study, neutral loss scans (NLS) by liquid chromatography-electrospray ionization/tandem mass spectrometry with losses of CO2 (NL ∆m/z = 44) and C2H4(CO2)2 (NL ∆m/z = 116) were applied for the first time successfully to screen selectively for acidic and succinic metabolites of aromatic and heterocyclic contaminants in two fulvic acid fractions from a contaminated site and a downstream region of a tar oil-polluted groundwater. Identification of these preselected signals was performed by high-resolution mass spectrometry with a liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry instrument. High-resolution mass and mass fragmentation data were then compared with a list of known metabolites from a literature search or matched with chemical databases supported with in silico fragmentation. Based on authentic analytical standards, several compounds from NLS were identified (e.g., 4-hydroxy-3-methylbenzoic acid, benzylsuccinic acid, naphthyl-2-methylsuccinic acid, 2-carboxyindane, and 2-carboxybenzothiophene) and tentatively identified (e.g., benzofuranmethylsuccinic acid and dihydrocarboxybenzothiophene) as aromatic, phenolic, heterocyclic, and succinic acids. The acidic metabolites were found exclusively in the contaminated region of the aquifer which indicates active biodegradation processes and no relevant occurrence of acidic metabolites in the downstream region.

  13. Quantifying Uranium Isotope Ratios Using Resonance Ionization Mass Spectrometry: The Influence of Laser Parameters on Relative Ionization Probability

    OpenAIRE

    Isselhardt, Brett Hallen

    2011-01-01

    Resonance Ionization Mass Spectrometry (RIMS) has been developed as a method to measure relative uranium isotope abundances. In this approach, RIMS is used as an element-selective ionization process to provide a distinction between uranium atoms and potential isobars without the aid of chemical purification and separation. We explore the laser parameters critical to the ionization process and their effects on the measured isotope ratio. Specifically, the use of broad bandwidth lasers with aut...

  14. The Effects of Partial Ionization on Prominence Mass Formation

    Science.gov (United States)

    Karpen, J. T.; Olson, K.; DeVore, C. R.; Martinez Gomez, D.; Sokolov, I.

    2015-12-01

    The origin of the prominence mass has been an open question since this cool plasma suspended in the hot corona was first discovered. We have known for a long time that the mass must come from the chromosphere, but it is unclear whether this mass is lifted bodily through magnetic levitation, injected by reconnection-driven upflows, or driven from the chromosphere by evaporation and then condensed. One evaporation-condensation scenario, the thermal nonequilibrium (TNE) model, is the most fully developed, quantitative model for the prominence plasma to date. In the TNE scenario, localized heating concentrated at the coronal loop footpoints produces chromospheric evaporation, filling the flux tube with hot, dense plasma that subsequently collapses radiatively to form cool condensations. Thus far this model has been successful in explaining the key properties of the long, persistent threads and small, highly dynamic, transient blobs in prominences, the damping of large-amplitude field-aligned prominence oscillations, the appearance of horn-shaped features above the cool prominence in EUV images of coronal cavities, and coronal rain in the ambient corona. To date, all studies of TNE have assumed that the plasma is fully ionized, which is appropriate for the hot coronal gas but unrealistic for the cool plasma below ~30,000 K. The energetics, dynamics, and evolutionary time scales of the TNE process are expected to be altered when the effects of ionization and recombination are considered. We have modified ARGOS, our 1D hydrodynamic code with adaptive mesh refinement, to include an equation of state that accounts for the effects of partial ionization of the plasma over a wide range of temperatures and densities. We will discuss the results of these simulations and their comparison with our previous studies of TNE in typical filament-supporting flux tubes. This work was partially supported by NASA's LWS Strategic Capability program.

  15. Capillary electrophoresis - electrospray ionization mass spectrometry in small diameter capillaries

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, J.H.; Goodlett, D.R.; Udseth, H.R.; Smith, R.D.

    1992-06-01

    Methods (such as small inner diameter capillaries) are being explored to increase analyte sensitivity in capillary electrophoresis- electrospray ionization/mass spectroscopy(CE-ESI/MS). Results are reported for melittin in a protein mixture, with 10 to 100 {mu}m ID capillaries; and for a mixture of aprotinin, cytochrome c, myoglobin, and carbonic anhydrase, with 5 to 50 {mu}m ID capillaries. It is shown that an increase in solute sensitivity occurs when small ID capillaries ({lt} 20 {mu}m) are used in CE-ESI/MS for both a peptide and a protein mixture. 3 figs. (DLC)

  16. Monitoring of wine aging process by electrospray ionization mass spectrometry

    Directory of Open Access Journals (Sweden)

    Alexandra Christine Helena Frankland Sawaya

    2011-09-01

    Full Text Available The characterization of wine samples by direct insertion electrospray ionization mass spectrometry (ESI-MS, without pre-treatment or chromatographic separation, in a process denominated fingerprinting, has been applied to several samples of wine produced with grapes of the Pinot noir, Merlot and Cabernet Sauvignon varieties from the state o Rio Grande do Sul, in Brazil. The ESI-MS fingerprints of the samples detected changes which occurred during the aging process in the three grape varieties. Principal Component Analysis (PCA of the negative ion mode fingerprints was used to group the samples, pinpoint the main changes in their composition, and indicate marker ions for each group of samples.

  17. Identification of Fatty Acids, Phospholipids, and Their Oxidation Products Using Matrix-Assisted Laser Desorption Ionization Mass Spectrometry and Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Harmon, Christopher W.; Mang, Stephen A.; Greaves, John; Finlayson-Pitts, Barbara J.

    2010-01-01

    Electrospray ionization mass spectrometry (ESI-MS) and matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) have found increasing application in the analysis of biological samples. Using these techniques to solve problems in analytical chemistry should be an essential component of the training of undergraduate chemists. We…

  18. Isotopic bias effects in resonance ionization mass spectrometry

    International Nuclear Information System (INIS)

    Resonance ionization mass spectrometry (RIMS) is developing into a useful method for isotope ratio measurements with high selectivity and sensitivity of the technique for a large number of elements. The sensitivity of the technique relies on a number of experimental factors. Of primary importance is the proper coupling of the tunable laser output with the atomization source, which is most often a thermal filament. Use of pulsed thermal atomization can also improve efficiency. An increase in temporal efficiency can be achieved by using a continuous wave (CW) laser coupled to a continuous atomization source. CW lasers, in general, therefore must be tightly focused to saturate the ionization step in a resonance ionization process. However, this results in a lowered efficiency due to geometrical factors. The accuracy of isotope ratio measurements is also influenced by the choice of laser system for RIMS. The combination of isotope shifts and the analyte element with the spectral output of the laser will result in wavelength-dependant bias effects which must be controlled to obtain optimum analytical results. This problem has been studied and the results for both pulsed and CW lasers are given. (author)

  19. Exploring the high-mass components of humic acid by laser desorption ionization mass spectrometry.

    Science.gov (United States)

    Chilom, Gabriela; Chilom, Ovidiu; Rice, James A

    2008-05-01

    Leonardite and Elliot soil humic acids have been analyzed by laser desorption ionization mass spectrometry (LDI MS) in the m/z 4000-200,000 range. Positive ion mass spectra for each humic acid obtained under optimum conditions showed a broad high-mass distribution between m/z 20,000 and 80,000. The dependence of the mass distribution on instrumental parameters and solution conditions was used to investigate the nature of the high-mass peaks from humic acid spectra. Our data suggests that macromolecular ions and humic acid aggregates have the same probability of occurrence while cluster ion formation has a low probability of occurrence. PMID:18421699

  20. Desorption and ionization processes in laser mass spectrometry

    International Nuclear Information System (INIS)

    In this thesis results are reported from a study on the desorption- and ionization process initiated by infra-red laser irradiation (LDMS) or ion bombardment (SIMS) of thin organic sample layers. The study is especially focused on the formation of quasimolecular ions under these conditions. Results of these investigations can be used for a better optimization of the LDMS and SIMS techniques in organic mass spectrometry. First, an overview is given of laser desorption mass spectrometry. Next, the coupling of the laser energy into the organic sample layer is investigated. It is concluded that the laser energy is primarily absorbed by the substrate material and not by the organic overlayer. The formation of quasi-molecular ions, either in the gas phase or in the substrate surface is investigated. The final section reports kinetic energy distributions for ions sputtered from organic solids and liquids. (Auth.)

  1. Laser resonant-ionization mass spectrometry of actinides

    International Nuclear Information System (INIS)

    Laser resonant-ionization mass spectrometry has been used to determine small amounts of actinides. The high sensitivity and selectivity of this method has been achieved by three-step photoionization of actinide atoms followed by time-of-flight measurement. The laser system for photoionization consists of a pulsed copper vapour laser of 30 W average power at a pulse repetition rate of 6.5 kHz which is coupled to three dye lasers. The time-of-flight spectrometer has a mass resolution of about 2500. Resonance signals with count rates of several kilohertz were obtained with actinide samples of 1010-1012 atoms yielding a detection limit of 108 atoms in the sample. With some improvements a detection sensitivity of about 106 atoms of plutonium, americium and curium should be reached. (orig.)

  2. Mass spectrometry analysis of polychlorinated biphenyls: chemical ionization and selected ion chemical ionization using methane as a reagent gas

    OpenAIRE

    RAYMOND E. MARCH; MILA D. LAUSEVIC; TATJANA M. VASILJEVIC

    2000-01-01

    In the present paper a quadrupole ion trap mass spectrometer, coupled with a gas chromatograph, was used to compare the electron impact ionization (EI) and chemical ionization (Cl) technique, in terms of their selectivity in polychlorinated biphenyls (PCBs) quantitative analysis. The experiments were carried out with a modified Varian SATURN III quadrupole ion-storage mass spectrometer equipped with Varian waveform generator, coupled with a gas chromatograph with DB-5 capillary column. The di...

  3. Electrospray Ionization Mass Spectrometry of hexanitrohexaazaisowurtzitane (CL-20)

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, James A.; Szecsody, Jim E.; Devary, Brooks J.; Valenzuela, Blandina R.

    2007-09-03

    Hexanitrohexaazaisowurtzitane, (C6H6N12O12, MW 438) {CL-20}, is a high-energy propellent that has been recently developed and successfully tested (Nielsen et al. 1998). CL-20 releases more energy on ignition and is more stable to accidental detonation than currently used energetic materials. It is expected to replace many of the energetic materials currently being used by the Department of Defense (DoD). The EPA method 8330 (EPA 1997) for the analysis of explosives and metabolites in soils calls for the use of UV/Vis detection. High performance liquid chromatography has been used to quantify CL-20 and precursor concentration (Bazaki et al. 1998`) at relatively high concentrations. Fourier transform infrared (FTIR) spectroscopy has been used to identify different crystal forms of CL-20 (4 isomers; Kim et al. 1998). Campbell et al. (1997) utilized particle beam mass spectrometry for the analysis of enzymatic degradation of explosives. Introduction and recent improvements of ionization techniques such as electrospray (ES) have allowed the mass spectrometer to become more widely used in liquid chromatography. Schilling(1996) also examined explosive components and metabolites using electrospray (ES) and atmospheric pressure chemical ionization (APCI) liquid chromatography/mass spectrometry (LC/MS). Schilling’s results showed that compared to thermospray LC/MS, APCI and ES were more sensitive than thermospray by at least an order of magnitude. 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), 10 nitroso-RDX metabolites, and other munitions in ground water have been analyzed using solid phase extraction and isotope dilution liquid chromatography-APCI mass spectrometry (Cassada et al. 1999). The method detection limits indicate that nitramine and nitroaromatic compounds can be routinely determined in ground water samples using electrospray LC/MS with concentration techniques utilizing solid-phase extraction. Miller et al. (1996) studied nitrated explosives with mobile phase

  4. Multistage Reactive Transmission-Mode Desorption Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Peters, Kevin C.; Comi, Troy J.; Perry, Richard H.

    2015-09-01

    Elucidating reaction mechanisms is important for advancing many areas of science such as catalyst development. It is often difficult to probe fast reactions at ambient conditions with high temporal resolution. In addition, systems involving reagents that cross-react require analytical methods that can minimize interaction time and specify their order of introduction into the reacting system. Here, we explore the utility of transmission mode desorption electrospray ionization (TM-DESI) for reaction monitoring by directing a microdroplet spray towards a series of meshes with micrometer-sized openings coated with reagents, an approach we call multistage reactive TM-DESI (TM n -DESI, where n refers to the number of meshes; n = 2 in this report). Various stages of the reaction are initiated at each mesh surface, generating intermediates and products in microdroplet reaction vessels traveling towards the mass spectrometer. Using this method, we investigated the reactivity of iron porphyrin catalytic hydroxylation of propranolol and other substrates. Our experimental results indicate that TM n -DESI provides the ability to spatially separate reagents and control their order of introduction into the reacting system, thereby minimizing unwanted reactions that lead to catalyst deactivation and degradation products. In addition, comparison with DESI-MS analyses (the Zare and Latour laboratories published results suggesting accessible reaction times desorption/ionization per MS scan, increasing the number of analytes and reactions that can be characterized in a single experiment.

  5. Comparative mass spectrometric analyses of Photofrin oligomers by fast atom bombardment mass spectrometry, UV and IR matrix-assisted laser desorption/ionization mass spectrometry, electrospray ionization mass spectrometry and laser desorption/jet-cooling photoionization mass spectrometry.

    Science.gov (United States)

    Siegel, M M; Tabei, K; Tsao, R; Pastel, M J; Pandey, R K; Berkenkamp, S; Hillenkamp, F; de Vries, M S

    1999-06-01

    Photofrin (porfimer sodium) is a porphyrin derivative used in the treatment of a variety of cancers by photodynamic therapy. This oligomer complex and a variety of porphyrin monomers, dimers and trimers were analyzed with five different mass spectral ionization techniques: fast atom bombardment, UV and IR matrix-assisted laser desorption/ionization, electrospray ionization, and laser desorption/jet-cooling photoionization. All five approaches resulted in very similar oligomer distributions with an average oligomer length of 2.7 +/- 0.1 porphyrin units. In addition to the Photofrin analysis, this study provides a side-by-side comparison of the spectra for the five different mass spectrometric techniques.

  6. Chemical ionization mass spectrometer (CIMS for ambient measurements of ammonia

    Directory of Open Access Journals (Sweden)

    D. R. Benson

    2010-03-01

    Full Text Available This study describes a chemical ionization mass spectrometer (CIMS for fast response, in-situ measurements for gas phase ammonia. Protonated ethanol ions were used as the ion-molecule reaction reagent. The CIMS sensitivity was estimated to be between 4–25 Hz/pptv with 30% uncertainty. The instrument background was below 1 ppbv and at lowest was 300 pptv. The uncertainty associated with the instrumental background was less than 30 pptv under the optimized experimental conditions. The time response was less than 30 s, and the detection limit was approximately 60 pptv. This CIMS was used to measure the ambient NH3 in Kent, Ohio, for several weeks throughout three seasons. The measured ammonia mixing ratios were usually at the sub-ppbv level, and higher during the spring (200±120 pptv than in the winter (60±75 pptv and fall (150±80 pptv.

  7. New Types of Ionization Sources for Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    None

    2008-12-01

    The purpose of this Cooperative Research and Development Agreement (CRADA) between UT-Battelle (Contractor) and MDS Sciex (Participant) and ESA, Inc. (Participant) is to research, develop and apply new types of ionization sources and sampling/inlet systems for analytical mass spectrometry making use of the Participants state-of-the-art atmospheric sampling mass spectrometry electrochemical cell technology instrumentation and ancillary equipment. The two overriding goals of this research project are: to understand the relationship among the various instrumental components and operational parameters of the various ion sources and inlet systems under study, the chemical nature of the gases, solvents, and analytes in use, and the nature and abundances of the ions ultimately observed in the mass spectrometer; and to develop new and better analytical and fundamental applications of these ion sources and inlet systems or alternative sources and inlets coupled with mass spectrometry on the basis of the fundamental understanding obtained in Goal 1. The end results of this work are expected to be: (1) an expanded utility for the ion sources and inlet systems under study (such as the analysis of new types of analytes) and the control or alteration of the ionic species observed in the gas-phase; (2) enhanced instrument performance as judged by operational figures-of-merit such as dynamic range, detection limits, susceptibility to matrix signal suppression and sensitivity; and (3) novel applications (such as surface sampling with electrospray) in both applied and fundamental studies. The research projects outlined herein build upon work initiated under the previous CRADA between the Contractor and MDS Sciex on ion sources and inlet systems for mass spectrometry. Specific ion source and inlet systems for exploration of the fundamental properties and practical implementation of these principles are given.

  8. Extractive electrospray ionization mass spectrometry for uranium chemistry studies.

    Science.gov (United States)

    Chen, Huanwen; Luo, Mingbiao; Xiao, Saijin; Ouyang, Yongzhong; Zhou, Yafei; Zhang, Xinglei

    2013-01-01

    Uranium chemistry is of sustainable interest. Breakthroughs in uranium studies make serious impacts in many fields including chemistry, physics, energy and biology, because uranium plays fundamentally important roles in these fields. Substantial progress in uranium studies normally requires development of novel analytical tools. Extractive electrospray ionization mass spectrometry (EESI-MS) is a sensitive technique for trace detection of various analytes in complex matrices without sample pretreatment. EESI-MS shows excellent performance for monitoring uranium species in various samples at trace levels since it tolerates extremely complex matrices. Therefore, EESI-MS is an alternative choice for studying uranium chemistry, especially when it combines ion trap mass spectrometry. In this presentation, three examples of EESI-MS for uranium chemistry studies will be given, illustrating the potential applications of EESI-MS in synthesis chemistry, physical chemistry, and analytical chemistry of uranium. More specifically, case studies on EESI-MS for synthesis and characterization of novel uranium species, and for rapid detection of uranium and its isotope ratios in various samples will be presented. Novel methods based on EESI-MS for screening uranium ores and radioactive iodine-129 will be presented. PMID:24349940

  9. Multistage Reactive Transmission-Mode Desorption Electrospray Ionization Mass Spectrometry.

    Science.gov (United States)

    Peters, Kevin C; Comi, Troy J; Perry, Richard H

    2015-09-01

    Elucidating reaction mechanisms is important for advancing many areas of science such as catalyst development. It is often difficult to probe fast reactions at ambient conditions with high temporal resolution. In addition, systems involving reagents that cross-react require analytical methods that can minimize interaction time and specify their order of introduction into the reacting system. Here, we explore the utility of transmission mode desorption electrospray ionization (TM-DESI) for reaction monitoring by directing a microdroplet spray towards a series of meshes with micrometer-sized openings coated with reagents, an approach we call multistage reactive TM-DESI (TM (n) -DESI, where n refers to the number of meshes; n = 2 in this report). Various stages of the reaction are initiated at each mesh surface, generating intermediates and products in microdroplet reaction vessels traveling towards the mass spectrometer. Using this method, we investigated the reactivity of iron porphyrin catalytic hydroxylation of propranolol and other substrates. Our experimental results indicate that TM (n) -DESI provides the ability to spatially separate reagents and control their order of introduction into the reacting system, thereby minimizing unwanted reactions that lead to catalyst deactivation and degradation products. In addition, comparison with DESI-MS analyses (the Zare and Latour laboratories published results suggesting accessible reaction times <1 ms) of the reduction of dichlorophenolindophenol by L-ascorbic acid suggest that TM (1) -DESI can access reaction times less than 1 ms. Multiple meshes allow sequential stages of desorption/ionization per MS scan, increasing the number of analytes and reactions that can be characterized in a single experiment. PMID:26091888

  10. Potato glycoalkaloids in soil-optimising liquid chromatography-time-of-flight mass spectrometry for quantitative studies.

    Science.gov (United States)

    Jensen, Pia H; Juhler, René K; Nielsen, Nikoline J; Hansen, Thomas H; Strobel, Bjarne W; Jacobsen, Ole S; Nielsen, John; Hansen, Hans Christian B

    2008-02-22

    Potato glycoalkaloids are produced in high amounts in potato fields during the growth season and losses to soil potentially impact shallow groundwater and via tiles to fresh water ecosystems. A quantitative liquid chromatography-electrospray ionization time-of-flight mass spectrometry (LC-ESI-TOF-MS) method for determination and quantification of potato glycoalkaloids and their metabolites in aqueous soil extracts was developed. The LC-ESI-TOF-MS method had linearities up to 2000microg/L for alpha-solanine and alpha-chaconine and up to 760microg/L for solanidine. No matrix effect was observed, and the detection limits found were in the range 2.2-4.7microg/L. The method enabled quantification of the potato glycoalkaloids in environmental samples.

  11. Dehydrodimerization of pterostilbene during electrospray ionization mass spectrometry

    KAUST Repository

    Raji, Misjudeen

    2013-04-30

    RATIONALE Pterostilbene is a member of the hydroxystilbene family of compounds commonly found in plants such as blueberry and grapes. During the analysis of this compound by electrospray ionization mass spectrometry (ESI-MS), an ion was observed that corresponds to the dehydrodimer of pterostilbene in mass-to-charge ratio. Since such unexpected dimerization may lead to decreased monomer signal during quantitative analysis, it was of interest to identify the origin and structure of the observed pterostilbene dimer and examine the experimental conditions that influence its formation. METHODS Liquid Chromatography/Mass Spectrometry (LC/MS), Nuclear Magnetic Resonance (NMR), and High-Field Asymmetric Waveform Ion Mobility Spectrometry (FAIMS) were used to examine the origin of the dimerization products. The structure of the formed pterostilbene dimer was examined by performing MSn analysis on the dimer ion. Effects of solvent composition, analyte concentration, radical scavenger, and other experimental conditions on the dimerization were also studied. RESULTS LC/MS and NMR analyses clearly showed that the starting solution did not contain the pterostilbene dimer. Solvent type and radical scavenger concentration were found to have pronounced effects on the dimer formation. Particularly, presence of acetonitrile or ammonium acetate had favorable effects on the extent of dimerization during ESI-MS analysis whereas hydroquinone and butylated hydroquinone had negative effects. Dimer formation decreased at high flow rates and when fused-silica capillary was used as the spray needle. CONCLUSIONS The data indicate that this dimerization occurs as a result of solution-phase electrochemical reactions taking place during the electrospray process. A possible structure for this dimer was proposed based on the MSn analysis and was similar to that of the enzymatically derived pterostilbene dehydrodimer already reported in the literature. Copyright © 2013 John Wiley & Sons, Ltd

  12. Fast magnetic peak switching for thermal ionization mass spectrometers

    International Nuclear Information System (INIS)

    Common practice in thermal ionization mass spectrometry is to make repeated and rapid comparisons between isotopes of interest by switching the magnetic deflection field sequentially between the values required to deflect each isotope through the collector slit. After each step in the field value (peak switch) it is necessary to pause before logging data, in order to allow the system response to settle to the point where it does not affect the precision of the isotopic ratio determination. The dynamics of the field stabilization system are the principle contributors to this delay period. The system characteristics applicable to a field-controlled magnet system are analyzed in this paer. Possible areas where the step response may be improved by the application of modern control theory are outlined. It is shown that any field-stabilized magnet system can be optimized for step response by the synthesis of a discrete control system. Discrete digital control, i.e. a software implementation, allows system optimization without the necessity for hardware modification, which would be difficult, expensive and possibility in some cases impractical. (orig.)

  13. A Chemical Ionization Mass Spectrometer for ambient measurements of Ammonia

    Directory of Open Access Journals (Sweden)

    D. R. Benson

    2010-08-01

    Full Text Available This study presents a chemical ionization mass spectrometer (CIMS for fast response, in-situ measurements of gas phase ammonia (NH3. The NH3 background level detected with the CIMS ranged between 0.3–1 ppbv, with an uncertainty of 30 pptv under optimized conditions. The instrument sensitivity varied from 4–25 Hz/pptv for >1 MHz of reagent ion signals (protonated ethanol ions, with a 30% uncertainty estimated based on variability in calibration signals. The CIMS detection limit for NH3 was ~60 pptv at a 1 min integration time (3 sigma. The CIMS time response was <30 s. This new NH3-CIMS has been used for ambient measurements in Kent, Ohio, for several weeks throughout three seasons. The measured NH3 mixing ratios were usually at the sub-ppbv level and higher in spring (200 ± 120 pptv than in winter (60 ± 75 pptv and fall (150 ± 80 pptv. High emissions of SO2 from power plants in this region, and thus possible high acidity of aerosol particles, may explain these low NH3 mixing ratios in general.

  14. Quantitative depth profiling by laser-ionization sputtered neutral mass spectrometry

    Science.gov (United States)

    Higashi, Yasuhiro

    1999-01-01

    Depth profiling by laser-ionization sputtered neutral mass spectrometry (SNMS) is reviewed. The matrix effects, including surface and interface effects, in laser-ionization SNMS and secondary ion mass spectrometry (SIMS) are compared with each other and discussed. Laser-ionization SNMS can provide depth profiles with much smaller matrix effects than conventional SIMS. Depth resolution can effectively be improved by using grazing incidence for the primary ion beam with little interfacial effect. The quantification method in laser-ionization SNMS is also mentioned.

  15. A combined desorption ionization by charge exchange (DICE) and desorption electrospray ionization (DESI) source for mass spectrometry.

    Science.gov (United States)

    Chan, Chang-Ching; Bolgar, Mark S; Miller, Scott A; Attygalle, Athula B

    2011-01-01

    A source that couples the desorption ionization by charge exchange (DICE) and desorption electrospray ionization (DESI) techniques together was demonstrated to broaden the range of compounds that can be analyzed in a single mass spectrometric experiment under ambient conditions. A tee union was used to mix the spray reagents into a partially immiscible blend before this mixture was passed through a conventional electrospray (ES) probe capillary. Using this technique, compounds that are ionized more efficiently by the DICE method and those that are ionized better with the DESI procedure could be analyzed simultaneously. For example, hydroquinone, which is not detected when subjected to DESI-MS in the positive-ion generation mode, or the sodium adduct of guaifenesin, which is not detected when examined by DICE-MS, could both be detected in one experiment when the two techniques were combined. The combined technique was able to generate the molecular ion, proton and metal adduct from the same compound. When coupled to a tandem mass spectrometer, the combined source enabled the generation of product ion spectra from the molecular ion and the [M + H](+) or [M + metal](+) ions of the same compound without the need to physically change the source from DICE to DESI. The ability to record CID spectra of both the molecular ion and adduct ions in a single mass spectrometric experiment adds a new dimension to the array of mass spectrometric methods available for structural studies. PMID:21472555

  16. A Combined Desorption Ionization by Charge Exchange (DICE) and Desorption Electrospray Ionization (DESI) Source for Mass Spectrometry

    Science.gov (United States)

    Chan, Chang-Ching; Bolgar, Mark S.; Miller, Scott A.; Attygalle, Athula B.

    2011-01-01

    A source that couples the desorption ionization by charge exchange (DICE) and desorption electrospray ionization (DESI) techniques together was demonstrated to broaden the range of compounds that can be analyzed in a single mass spectrometric experiment under ambient conditions. A tee union was used to mix the spray reagents into a partially immiscible blend before this mixture was passed through a conventional electrospray (ES) probe capillary. Using this technique, compounds that are ionized more efficiently by the DICE method and those that are ionized better with the DESI procedure could be analyzed simultaneously. For example, hydroquinone, which is not detected when subjected to DESI-MS in the positive-ion generation mode, or the sodium adduct of guaifenesin, which is not detected when examined by DICE-MS, could both be detected in one experiment when the two techniques were combined. The combined technique was able to generate the molecular ion, proton and metal adduct from the same compound. When coupled to a tandem mass spectrometer, the combined source enabled the generation of product ion spectra from the molecular ion and the [M + H]+ or [M + metal]+ ions of the same compound without the need to physically change the source from DICE to DESI. The ability to record CID spectra of both the molecular ion and adduct ions in a single mass spectrometric experiment adds a new dimension to the array of mass spectrometric methods available for structural studies.

  17. Hands-on Electrospray Ionization-Mass Spectrometry for Upper-Level Undergraduate and Graduate Students

    Science.gov (United States)

    Stock, Naomi L.; March, Raymond E.

    2014-01-01

    Electrospray ionization-mass spectrometry (ESI-MS) is a powerful technique for the detection, identification, and quantification of organic compounds. As mass spectrometers have become more user-friendly and affordable, many students--often with little experience in mass spectrometry--find themselves needing to incorporate mass spectrometry into…

  18. Mass spectrometry analysis of polychlorinated biphenyls: chemical ionization and selected ion chemical ionization using methane as a reagent gas

    Directory of Open Access Journals (Sweden)

    RAYMOND E. MARCH

    2000-06-01

    Full Text Available In the present paper a quadrupole ion trap mass spectrometer, coupled with a gas chromatograph, was used to compare the electron impact ionization (EI and chemical ionization (Cl technique, in terms of their selectivity in polychlorinated biphenyls (PCBs quantitative analysis. The experiments were carried out with a modified Varian SATURN III quadrupole ion-storage mass spectrometer equipped with Varian waveform generator, coupled with a gas chromatograph with DB-5 capillary column. The disadvantage of using EI in the analysis of PCBs congeners is the extensive fragmentation of the molecular ion. The main fragmentation pattern recorded in the EI mass spectra of PCBs was the loss of a chlorine atom from the molecular ion. Therefore the fragment-ion signal overlapped with the molecular-ion cluster of lower mass congener. The fragmentation reactions of PCBs are suppressed if methane is used as a reagent gas for chemical ionization, but fragment ions are also present in the spectrum as an obstruction for quantitative analysis. The most selective method for PCBs quantitative analysis appears to be Cl with mass-selected C2H5+ ions from methane, which results in a mass spectrum with a negligible amount of fragment ions.

  19. Mass distributions of a macromolecular assembly based on electrospray ionization mass spectrometric masses of the constituent subunits

    Indian Academy of Sciences (India)

    Leonid Hanin; Brian Green; Franck Zal; Serge Vinogradov

    2003-09-01

    Macromolecular assemblies containing multiple protein subunits and having masses in the megadalton (MDa) range are involved in most of the functions of a living cell. Because of variation in the number and masses of subunits, macromolecular assemblies do not have a unique mass, but rather a mass distribution. The giant extracelular erythrocruorins (Ers), ∼ 3.5 MDa, comprized of at least 180 polypeptide chains, are one of the best characterized assemblies. Three-dimensional reconstructions from cryoelectron microscopic images show them to be hexagonal bilayer complexes of 12 subassemblies, each comprised of 12 globin chains, anchored to a subassembly of 36 nonglobin linker chains. We have calculated the most probable mass distributions for Lumbricus and Riftia assemblies and their globin and linker subassemblies, based on the Lumbricus Er stoichiometry and using accurate subunit masses obtained by electrospray ionization mass spectrometry. The expected masses of Lumbricus and Riftia Ers are 3.517 MDa and 3.284 MDa, respectively, with a possible variation of ∼ 9% due to the breadth of the mass distributions. The Lumbricus Er mass is in astonishingly good agreement with the mean of 23 known masses, 3.524 ± 0.481 MDa.

  20. Observation and implications of high mass-to-charge ratio ions from electrospray ionization mass spectrometry.

    Science.gov (United States)

    Winger, B E; Light-Wahl, K J; Ogorzalek Loo, R R; Udseth, H R; Smith, R D

    1993-07-01

    High mass-to-charge ratio ions (> 4000) from electrospray ionization (ESI) have been observed for several proteins, including bovine cytochrome c (M r 12,231) and porcine pepsin (M r 34,584), by using a quadrupole mass spectrometer with an m/z 45,000 range. The ESI mass spectrum for cytochrome c in an aqueous solution gives a charge state distribution that ranges from 12 + to 2 +, with a broad, low-intensity peak in the mass-to-charge ratio region corresponding to the [M + H](+) ion. the negative ion ESI mass spectrum for pepsin in 1% acetic acid solution shows a charge state distribution ranging from 7- to 2-. To observe the [M - H](-) ion, harsher desolvation and interface conditions were required. Also observed was the abundant aggregation of the protens with average charge states substantially lower than observed for their monomeric counterparts. The negative ion ESI mass spectrum for cytochrome c in 1-100 mM NH4OAc solutions showed greater relative abundances for the higher mass-to-charge ratio ions than in acuidic solutions, with an [M - H](-) ion relative abundance approximately 50% that of the most abundant charge state peak. The observation that protein aggregates are formed with charge states comparable to monomeric species (at fower mass-to-charge ratios) suggests that the high mass-to-charge ratio monomers may be formed by the dissociation of aggregate species. The observation of low charge state and aggregate molecular ions concurrently with highly charged species may serve to support a variation of the charged residue model, originally described by Dole and co-workers (Dole, M., et al. J. Chem. Phys. 1968, 49, 2240; Mack, L. L., et al. J. Chem. Phys. 1970, 52, 4977) which involves the Coulombically driven formation of either very highly solvated molecular ions or lower ananometer-diameter droplets. PMID:24227640

  1. Applications of resonance ionization spectroscopy to ultralow-level counting and mass spectroscopy

    International Nuclear Information System (INIS)

    The ability to directly detect a daughter atom, using resonance ionization spectroscopy, in delayed time coincidence with the decay of a parent species promises to drastically reduce the background in low-level counting experiments. Resonance ionization can also be used as an ion source for a mass spectrometer system that is capable of discriminating between isobars

  2. Thermal ionization mass spectrometric study of U-Pu-O system

    International Nuclear Information System (INIS)

    First inference from a thermal ionization mass spectrometric study of samples corresponding to the ternary U-Pu-O system, especially if high surface ionization temperatures are employed, is likely to be at variance with that from equilibrium vaporization thermodynamic studies, that the atomic species U and Pu dominate the vapor phase

  3. Laser vaporization/ionization interface for coupling microscale separation techniques with mass spectrometry

    Science.gov (United States)

    Yeung, Edward S.; Chang, Yu-chen

    1999-06-29

    The present invention provides a laser-induced vaporization and ionization interface for directly coupling microscale separation processes to a mass spectrometer. Vaporization and ionization of the separated analytes are facilitated by the addition of a light-absorbing component to the separation buffer or solvent.

  4. Mass separation of deuterium and helium with conventional quadrupole mass spectrometer by using varied ionization energy

    Science.gov (United States)

    Yu, Yaowei; Hu, Jiansheng; Wan, Zhao; Wu, Jinhua; Wang, Houyin; Cao, Bin

    2016-03-01

    Deuterium pressure in deuterium-helium mixture gas is successfully measured by a common quadrupole mass spectrometer (model: RGA200) with a resolution of ˜0.5 atomic mass unit (AMU), by using varied ionization energy together with new developed software and dedicated calibration for RGA200. The new software is developed by using MATLAB with the new functions: electron energy (EE) scanning, deuterium partial pressure measurement, and automatic data saving. RGA200 with new software is calibrated in pure deuterium and pure helium 1.0 × 10-6-5.0 × 10-2 Pa, and the relation between pressure and ion current of AMU4 under EE = 25 eV and EE = 70 eV is obtained. From the calibration result and RGA200 scanning with varied ionization energy in deuterium and helium mixture gas, both deuterium partial pressures (PD2) and helium partial pressure (PHe) could be obtained. The result shows that deuterium partial pressure could be measured if PD2 > 10-6 Pa (limited by ultimate pressure of calibration vessel), and helium pressure could be measured only if PHe/PD2 > 0.45, and the measurement error is evaluated as 15%. This method is successfully employed in EAST 2015 summer campaign to monitor deuterium outgassing/desorption during helium discharge cleaning.

  5. A Liquid Injection Field Desorption/Ionization-Electrospray Ionization Combination Source for a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer

    Science.gov (United States)

    Linden, H. Bernhard; Gross, Jürgen H.

    2011-12-01

    A new type of combination ion source has been devised. It unites two complementary ionization methods, i.e., liquid injection field desorption/ionization (LIFDI) and electrospray ionization (ESI). This LIFDI-ESI combination ion source has been constructed for a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. The LIFDI-ESI combination ion source can be switched between the LIFDI and ESI modes of operation within 15 min without breaking the vacuum. The source design and its operation are described. LIFDI-FT-ICR spectra of the ionic liquid trihexyl(tetradecyl)-phosphonium tris(pentafluoroethyl)-trifluorophosphate, polyethylene glycol 600, 2,3,4-tridodecyloxy-benzaldehyde, and [60]fullerene are described.

  6. Quantifying Uranium Isotope Ratios Using Resonance Ionization Mass Spectrometry: The Influence of Laser Parameters on Relative Ionization Probability

    Energy Technology Data Exchange (ETDEWEB)

    Isselhardt, Brett H. [Univ. of California, Berkeley, CA (United States)

    2011-09-01

    Resonance Ionization Mass Spectrometry (RIMS) has been developed as a method to measure relative uranium isotope abundances. In this approach, RIMS is used as an element-selective ionization process to provide a distinction between uranium atoms and potential isobars without the aid of chemical purification and separation. We explore the laser parameters critical to the ionization process and their effects on the measured isotope ratio. Specifically, the use of broad bandwidth lasers with automated feedback control of wavelength was applied to the measurement of 235U/238U ratios to decrease laser-induced isotopic fractionation. By broadening the bandwidth of the first laser in a 3-color, 3-photon ionization process from a bandwidth of 1.8 GHz to about 10 GHz, the variation in sequential relative isotope abundance measurements decreased from >10% to less than 0.5%. This procedure was demonstrated for the direct interrogation of uranium oxide targets with essentially no sample preparation. A rate equation model for predicting the relative ionization probability has been developed to study the effect of variation in laser parameters on the measured isotope ratio. This work demonstrates that RIMS can be used for the robust measurement of uranium isotope ratios.

  7. The updated bottom up solution applied to atmospheric pressure photoionization and electrospray ionization mass spectrometry

    Science.gov (United States)

    The Updated Bottom Up Solution (UBUS) was recently applied to atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) of triacylglycerols (TAGs). This report demonstrates that the UBUS applies equally well to atmospheric pressure photoionization (APPI) MS and to electrospray ionizatio...

  8. Determination of plutonium traces isotopic composition by thermal ionization mass spectrometry

    International Nuclear Information System (INIS)

    Plutonium isotopic composition has been determined by thermal ionization mass spectrometry. An ion counting detector has been used. It allows to noticeably reduce the sample quantity to use. The accuracy of the obtained measures are very good

  9. Manganese oxide nanoparticle-assisted laser desorption/ionization mass spectrometry for medical applications

    Directory of Open Access Journals (Sweden)

    Shu Taira, Kenji Kitajima, Hikaru Katayanagi, Eiichiro Ichiishi and Yuko Ichiyanagi

    2009-01-01

    Full Text Available We prepared and characterized manganese oxide magnetic nanoparticles (d =5.6 nm and developed nanoparticle-assited laser desorption/ionization (nano-PALDI mass spectrometry. The nanoparticles had MnO2 and Mn2O3 cores conjugated with hydroxyl and amino groups, and showed paramagnetism at room temperature. The nanoparticles worked as an ionization assisting reagent in mass spectroscopy. The mass spectra showed no background in the low m/z. The nanoparticles could ionize samples of peptide, drug and proteins (approx. 5000 Da without using matrix, i.e., 2,5-dihydroxybenzoic acid (DHB, 4-hydroxy-α-cinnamic acid (CHCA and liquid matrix, as conventional ionization assisting reagents. Post source decay spectra by nano-PALDI mass spectrometry will yield information of the chemical structure of analytes.

  10. Containment of a diffuse ionized mass orbiting around a magnetized central body

    International Nuclear Information System (INIS)

    The containment of a diffused and ionized mass orbiting around a magnetized central body is studied and the condition equation is established. Some qualitative and quantitative applications to the planetary cosmogony problems are developed. (Auth.)

  11. Spatially resolved thermal desorption/ionization coupled with mass spectrometry

    Science.gov (United States)

    Jesse, Stephen; Van Berkel, Gary J; Ovchinnikova, Olga S

    2013-02-26

    A system and method for sub-micron analysis of a chemical composition of a specimen are described. The method includes providing a specimen for evaluation and a thermal desorption probe, thermally desorbing an analyte from a target site of said specimen using the thermally active tip to form a gaseous analyte, ionizing the gaseous analyte to form an ionized analyte, and analyzing a chemical composition of the ionized analyte. The thermally desorbing step can include heating said thermally active tip to above 200.degree. C., and positioning the target site and the thermally active tip such that the heating step forms the gaseous analyte. The thermal desorption probe can include a thermally active tip extending from a cantilever body and an apex of the thermally active tip can have a radius of 250 nm or less.

  12. Instrumental aspects of positive and negative ion chemical ionization mass spectrometry.

    OpenAIRE

    Stafford, G C

    1980-01-01

    Differences in recording positive and negative ion chemical ionization mass spectra on a quadrupole mass spectrometer are discussed. An analog positive and negative ion electron multiplier detector is described which is well suited for a quadrupole instrument. This detector significantly reduces baseline noise in the negative ion mode and improves positive ion high mass sensitivity.

  13. Enhancement of the isotopic abundance sensitivity of mass spectrometry by Doppler-free resonance ionization

    International Nuclear Information System (INIS)

    The use of two-photon Doppler-free excitation in atomic resonance ionization offers the possibility of considerable enhancement of the isotopic abundance sensitivity of conventional mass spectrometry. In some applications of interest, e.g. carbon dating, this technique may provide sensitivity comparable to that presently attained by accelerator-based high energy mass spectrometry. The basic physics underlying the method is discussed and preliminary experimental work on three-photon ionization of atomic carbon is described. (author)

  14. Unusual Fragmentation of Peptide and Protein in Matrix-assisted Laser Desorption/Ionization Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    Mitsuo Takayama

    2001-01-01

    Unusual amine - bond fragmentation on the peptide/protein backbone has been reported using matrix - assisted laser desorption/ionization time - of- flight mass spectrometry (MALDI - TOFMS)The amine - bond cleavage occurred without metastable decay, while the peptide - bond cleavage occurred with metastable decay of peptide ions in a drift region of TOF mass analyzer. It was presumed that the amine - bond cleavage occurred as a non - ergodic process independent of the ionization under MALDI conditions.

  15. High-Speed Tandem Mass Spectrometric in Situ Imaging by Nanospray Desorption Electrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lanekoff, Ingela T.; Burnum-Johnson, Kristin E.; Thomas, Mathew; Short, Joshua TL; Carson, James P.; Cha, Jeeyeon; Dey, Sudhansu K.; Yang, Pengxiang; Prieto Conaway, Maria C.; Laskin, Julia

    2013-10-15

    Nanospray desorption electrospray ionization (nano-DESI) combined with tandem mass spectrometry (MS/MS), high-resolution mass analysis (m/m=17,500 at m/z 200), and rapid spectral acquisition enabled simultaneous imaging and identification of more than 300 molecules from 92 selected m/z windows (± 1 Da) with a spatial resolution of better than 150 um. Uterine sections of implantation sites on day 6 of pregnancy were analyzed in the ambient environment without any sample pre-treatment. MS/MS imaging was performed by scanning the sample under the nano-DESI probe at 10 um/s while acquiring higher-energy collision-induced dissociation (HCD) spectra for a targeted inclusion list of 92 m/z values at a rate of ~6.3 spectra/s. Molecular ions and their corresponding fragments, separated using high-resolution mass analysis, were assigned based on accurate mass measurement. Using this approach, we were able to identify and image both abundant and low-abundance isobaric species within each m/z window. MS/MS analysis enabled efficient separation and identification of isobaric sodium and potassium adducts of phospholipids. Furthermore, we identified several metabolites associated with early pregnancy and obtained the first 2D images of these molecules.

  16. Comparison of the sensitivity of mass spectrometry atmospheric pressure ionization techniques in the analysis of porphyrinoids.

    Science.gov (United States)

    Swider, Paweł; Lewtak, Jan P; Gryko, Daniel T; Danikiewicz, Witold

    2013-10-01

    The porphyrinoids chemistry is greatly dependent on the data obtained in mass spectrometry. For this reason, it is essential to determine the range of applicability of mass spectrometry ionization methods. In this study, the sensitivity of three different atmospheric pressure ionization techniques, electrospray ionization, atmospheric pressure chemical ionization and atmospheric pressure photoionization, was tested for several porphyrinods and their metallocomplexes. Electrospray ionization method was shown to be the best ionization technique because of its high sensitivity for derivatives of cyanocobalamin, free-base corroles and porphyrins. In the case of metallocorroles and metalloporphyrins, atmospheric pressure photoionization with dopant proved to be the most sensitive ionization method. It was also shown that for relatively acidic compounds, particularly for corroles, the negative ion mode provides better sensitivity than the positive ion mode. The results supply a lot of relevant information on the methodology of porphyrinoids analysis carried out by mass spectrometry. The information can be useful in designing future MS or liquid chromatography-MS experiments.

  17. Coupling corona discharge for ambient extractive ionization mass spectrometry.

    Science.gov (United States)

    Hu, Bin; Zhang, Xinglei; Li, Ming; Peng, Xuejiao; Han, Jing; Yang, Shuiping; Ouyang, Yongzhong; Chen, Huanwen

    2011-12-01

    Unlike the extractive electrospray ionization (EESI) technique described elsewhere, a corona discharge instead of electrospray ionization has been utilized to charge a neutral solvent spray under ambient conditions for the generation of highly charged microdroplets, which impact a neutral sample plume for the extractive ionization of the analytes in raw samples without any sample pretreatment. Using the positive ion mode, molecular radical cations were easily generated for the detection of non-polar compounds (e.g., benzene, cyclohexane, etc.), while protonated molecular ions of polar compounds (e.g., acetonitrile, acetic ether) were readily produced for the detection. By dispensing the matrix in a relatively large space, this method tolerates highly complex matrices. For a given sample such as lily fragrances, more compounds were detected by the method established here than the EESI technique. An acceptable relative standard deviation (RSD 8.9%, n = 11) was obtained for the direct measurement of explosives (10 ppb) in waste water samples. The experimental data demonstrate that this method could simultaneously detect both polar and non-polar analytes with high sensitivity, showing promising applications for the rapid detection of a wide variety of compounds present in complex matrices. PMID:21971289

  18. Secondary electrospray ionization ion mobility spectrometry/mass spectrometry of illicit drugs.

    Science.gov (United States)

    Wu, C; Siems, W F; Hill, H H

    2000-01-15

    A secondary electrospray ionization (SESI) method was developed as a nonradioactive ionization source for ion mobility spectrometry (IMS). This SESI method relied on the gas-phase interaction between charged particles created by electrospray ionization (ESI) and neutral gaseous sample molecules. Mass spectrometry (MS) was used as the detection method after ion mobility separation for ion identification. Preliminary investigations focussed on understanding the ionization process of SESI. The performance of ESI-IMS and SESI-IMS for illicit drug detection was evaluated by determining the analytical figures of merit. In general, SESI had a higher ionization efficiency for small volatile molecules compared with the electrospray method. The potential of developing a universal interface for both GC- and LC-MS with an addition stage of mobility separation was demonstrated.

  19. Analysis of solvent dyes in refined petroleum products by electrospray ionization mass spectrometry

    Science.gov (United States)

    Rostad, C.E.

    2010-01-01

    Solvent dyes are used to color refined petroleum products to enable differentiation between gasoline, diesel, and jet fuels. Analysis for these dyes in the hydrocarbon product is difficult due to their very low concentrations in such a complex matrix. Flow injection analysis/electrospray ionization/mass spectrometry in both negative and positive mode was used to optimize ionization of ten typical solvent dyes. Samples of hydrocarbon product were analyzed under similar conditions. Positive electrospray ionization produced very complex spectra, which were not suitably specific for targeting only the dyes. Negative electrospray ionization produced simple spectra because aliphatic and aromatic moieties were not ionized. This enabled screening for a target dye in samples of hydrocarbon product from a spill.

  20. Chemical Aspects of the Extractive Methods of Ambient Ionization Mass Spectrometry

    Science.gov (United States)

    Badu-Tawiah, Abraham K.; Eberlin, Livia S.; Ouyang, Zheng; Cooks, R. Graham

    2013-04-01

    Ambient ionization techniques allow complex chemical samples to be analyzed in their native state with minimal sample preparation. This brings the obvious advantages of simplicity, speed, and versatility to mass spectrometry: Desorption electrospray ionization (DESI), for example, is used in chemical imaging for tumor margin diagnosis. This review on the extractive methods of ambient ionization focuses on chemical aspects, mechanistic considerations, and the accelerated chemical reactions occurring in charged liquid droplets generated in the spray process. DESI uses high-velocity solvent droplets to extract analytes from surfaces. Nano-DESI employs liquid microjunctions for analyte dissolution, whereas paper-spray ionization uses DC potentials applied to wet porous material such as paper or biological tissue to field emit charged analyte-containing solvent droplets. These methods also operate in a reactive mode in which added reagents allow derivatization during ionization. The accelerated reaction rates seen in charged microdroplets are useful in small-scale rapid chemical synthesis.

  1. Ambient desorption/ionization mass spectrometry using a liquid sampling-atmospheric glow discharge (LS-APGD) ionization source.

    Science.gov (United States)

    Marcus, R Kenneth; Burdette, Carolyn Q; Manard, Benjamin T; Zhang, Lynn X

    2013-10-01

    A novel approach to ambient desorption/ionization mass spectrometry (ADI-MS) is described, based on a recently developed liquid sampling-atmospheric pressure glow discharge (LS-APGD) ionization source. The device is essentially unmodified relative to its implementation in elemental mass spectrometry, where the operational space is characterized by low operation power (LS-APGD source is mounted onto the source interface of a Thermo Finnigan LCQ Advantage Max quadrupole ion trap mass spectrometer without modifications to the instrument faceplate or ion optics. Described here is the initial evaluation of the roles of source geometry and working parameters, including electrolytic solution composition and plasma current, on the response of caffeine residues, with preliminary limits of detection based on the relative standard deviation of the spectral background suggested to be on the 10-pg level. Demonstrative spectra are presented for green tea extracts and raw leaves, coffee beans, a dried (raw) tobacco leaf, an analgesic tablet, and paper currency. Versatility is further revealed through the determination of components in common cigarette smoke. In each case, the spectra are characterized by (M + H)(+) species of the expected constituents. The capacity for a single source to perform both in solution and particulate elemental analysis (as shown previously) and ADI of molecular species is unique in the realm of mass spectrometry.

  2. Ambient mass spectrometry imaging: plasma assisted laser desorption ionization mass spectrometry imaging and its applications.

    Science.gov (United States)

    Feng, Baosheng; Zhang, Jialing; Chang, Cuilan; Li, Liping; Li, Min; Xiong, Xingchuang; Guo, Chengan; Tang, Fei; Bai, Yu; Liu, Huwei

    2014-05-01

    Mass spectrometry imaging (MSI) has been widely used in many research areas for the advantages of providing informative molecular distribution with high specificity. Among the recent progress, ambient MSI has attracted increasing interests owing to its characteristics of ambient, in situ, and nonpretreatment analysis. Here, we are presenting the ambient MSI for traditional Chinese medicines (TCMs) and authentication of work of art and documents using plasma assisted laser desorption ionization mass spectrometry (PALDI-MS). Compared with current ambient MSI methods, an excellent average resolution of 60 μm × 60 μm pixel size was achieved using this system. The feasibility of PALDI-based MSI was confirmed by seal imaging, and its authentication applications were demonstrated by imaging of printed Chinese characters. Imaging of the Radix Scutellariae slice showed that the two active components, baicalein and wogonin, mainly were distributed in the epidermis of the root, which proposed an approach for distinguishing TCMs' origins and the distribution of active components of TCMs and exploring the environmental effects of plant growth. PALDI-MS imaging provides a strong complement for the MSI strategy with the enhanced spatial resolution, which is promising in many research fields, such as artwork identification, TCMs' and botanic research, pharmaceutical applications, etc. PMID:24670045

  3. Analysis of pesticides by gas chromatography/multiphoton ionization/mass spectrometry using a femtosecond laser

    International Nuclear Information System (INIS)

    Highlights: → Gas chromatography/multiphoton ionization/time-of-flight mass spectrometry was utilized for analysis. → A standard mixture sample containing 49 pesticides and 4 real samples were measured. → Third-harmonic emission of a Ti:sapphire laser (100 fs) was employed as an ionization source. → Most of the pesticides were softly ionized by the femtosecond laser. → Three pesticides were found, although some of them were not detected by GC/EI/MS-MS. - Abstract: Gas chromatography/multiphoton ionization/time-of-flight mass spectrometry (GC/MPI/TOFMS) was utilized for analysis of a standard mixture sample containing 49 pesticides and 4 real samples using the third-harmonic emission (267 nm) of a femtosecond Ti:sapphire laser (100 fs) as the ionization source. A sample of a standard mixture of n-alkane was also measured for calibration of the retention time indices of the pesticides. Two photons are required for the excitation of n-alkane due to an absorption band located in the far ultraviolet region (140 nm). The n-alkane molecule in the excited state was subsequently ionized either directly or by absorbing another photon because of a high ionization potential. Due to a large excess of energy, the molecular ion was decomposed and formed many fragment ions. Compared to n-alkanes, most of the pesticides were softly ionized by the femtosecond laser; one photon was used for excitation and another was used for the subsequent ionization. The pesticides with no conjugated double bond had a lower ionization efficiency. The present analytical instrument was applied to several samples prepared from a variety of vegetables and a single fruit after pretreatment with solid-phase extraction. Three pesticides were found in these samples, although some of them were not detected by conventional GC/EI/MS-MS due to insufficient sensitivity and selectivity.

  4. 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.

  5. Comparison of Three Plasma Sources for Ambient Desorption/Ionization Mass Spectrometry

    Science.gov (United States)

    McKay, Kirsty; Salter, Tara L.; Bowfield, Andrew; Walsh, James L.; Gilmore, Ian S.; Bradley, James W.

    2014-09-01

    Plasma-based desorption/ionization sources are an important ionization technique for ambient surface analysis mass spectrometry. In this paper, we compare and contrast three competing plasma based desorption/ionization sources: a radio-frequency (rf) plasma needle, a dielectric barrier plasma jet, and a low-temperature plasma probe. The ambient composition of the three sources and their effectiveness at analyzing a range of pharmaceuticals and polymers were assessed. Results show that the background mass spectrum of each source was dominated by air species, with the rf needle producing a richer ion spectrum consisting mainly of ionized water clusters. It was also seen that each source produced different ion fragments of the analytes under investigation: this is thought to be due to different substrate heating, different ion transport mechanisms, and different electric field orientations. The rf needle was found to fragment the analytes least and as a result it was able to detect larger polymer ions than the other sources.

  6. Field ionization mass spectrometry (FIMS) applied to tracer studies and isotope dilution analysis

    International Nuclear Information System (INIS)

    The nonfragmenting nature of field ionization mass spectrometry makes it a preferred technique for the isotopic analysis of multilabeled organic compounds. The possibility of field ionization of nonvolatile thermolabile materials significantly extends the potential uses of this technique beyond those of conventional ionization methods. Multilabeled tracers may be studied in biological systems with a sensitivity comparable to that of radioactive tracers. Isotope dilution analysis may be performed reliably by this technique down to picogram levels. These techniques will be illustrated by a number of current studies using multilabeled metabolites and drugs. The scope and limitations of the methodology are discussed

  7. Applications of resonance ionization spectroscopy to ultralow-level counting and mass spectroscopy

    International Nuclear Information System (INIS)

    In this paper it is shown that the ability to directly detect a daughter atom, using resonance ionization spectroscopy, in delayed time coincidence with the decay of a parent species promises to drastically reduce the background in low-level counting experiments. In addition, resonance ionization can also be used as an ion source for a mass spectrometer system that is capable of discriminating between isobars

  8. The Application of Resonance-Enhanced Multiphoton Ionization Technique in Gas Chromatography Mass Spectrometry

    OpenAIRE

    2014-01-01

    Gas chromatography resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (GC/REMPI-TOFMS) using a nanosecond laser has been applied to analyze the 16 polycyclic aromatic hydrocarbons (PAHs). The excited-state lifetime, absorption characters, and energy of electronic states of the 16 PAHs were investigated to optimize the ionization yield. A river water sample pretreated by means of solid phase extraction was analyzed to evaluate the performance of the analytical instrumen...

  9. Drug Detection and Quantification Directly from Tissue using Novel Ionization Methods for Mass Spectrometry

    OpenAIRE

    Wang, Beixi; Dearring, Chenelle L.; Wager-Miller, James; Mackie, Ken; Trimpin, Sarah

    2015-01-01

    Solvent assisted ionization inlet (SAII) and matrix assisted ionization vacuum (MAIV) were used to rapidly quantify an antipsychotic drug, clozapine, directly from surfaces with minimal sample preparation. This simple surface analysis method based on SAII- and MAIV-mass spectrometry (MS) was developed to allow detection of endogenous lipids, metabolites, and clozapine directly from mouse brain tissue sections. Rapid surface assessment was achieved by SAII with the assistance of heat on the ma...

  10. Characterizing Bacterial Volatiles using Secondary Electrospray Ionization Mass Spectrometry (SESI-MS)

    OpenAIRE

    Bean, Heather D.; Zhu, Jiangjiang; Hill, Jane E.

    2011-01-01

    Secondary electrospray ionization mass spectrometry (SESI-MS) is a method developed for the rapid detection of volatile compounds, without the need for sample pretreatment. The method was first described by Fenn and colleagues1 and has been applied to the detection of illicit drugs2 and explosives3-4, the characterization of skin volatiles5, and the analysis of breath6-7. SESI ionization occurs by proton transfer reactions between the electrospray solution and the volatile analyte, and is the...

  11. Electrospray ionization combined with ion trap mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Van Berkel, G.J.; Glish, G.L.; McLuckey, S.A. (Oak Ridge National Laboratory, TN (USA))

    1990-07-01

    Ions from a variety of molecules, formed via electrospray, have been injected into and analyzed with a quadrupole ion trap mass spectrometer. Examples are shown in which one or more stages of mass spectrometry (e.g., mass spectrometry/mass spectrometry) have been performed on both multiply charged anions and cations. Compounds for which data are described include the disodium salt of 2-hydroxynapthalene-3,6-disulfonic acid, Direct Red 81, bradykinin, melittin, cytochrome c, myoglobin, and bovine albumin. For some compounds, notable the sulfonates, evidence is presented for the injection of highly solvated ions that desolvate within the ion trap. The cations derived from the peptides, on the other hand, appear to be essentially desolvated prior to injection into the ion trap.

  12. Are molecular outflows around high-mass stars driven by ionization feedback?

    CERN Document Server

    Peters, Thomas; Mac Low, Mordecai-Mark; Klessen, Ralf S; Banerjee, Robi

    2012-01-01

    The formation of massive stars exceeding 10 solar masses usually results in large-scale molecular outflows. Numerical simulations, including ionization, of the formation of such stars show evidence for ionization-driven molecular outflows. We here examine whether the outflows seen in these models reproduce the observations. We compute synthetic ALMA and CARMA maps of CO emission lines of the outflows, and compare their signatures to existing single-dish and interferometric data. We find that the ionization-driven models can only reproduce weak outflows around high-mass star-forming regions. We argue that expanding H II regions probably do not represent the dominant mechanism for driving observed outflows. We suggest instead that observed outflows are driven by the collective action of the outflows from the many lower-mass stars that inevitably form around young massive stars in a cluster.

  13. Electrospray-assisted laser desorption/ionization mass spectrometry for direct ambient analysis of solids.

    Science.gov (United States)

    Shiea, Jentaie; Huang, Min-Zon; Hsu, Hsiu-Jung; Lee, Chi-Yang; Yuan, Cheng-Hui; Beech, Iwona; Sunner, Jan

    2005-01-01

    A new method of electrospray-assisted laser desorption/ionization (ELDI) mass spectrometry, which combines laser desorption with post-ionization by electrospray, was applied to rapid analysis of solid materials under ambient conditions. Analytes were desorbed from solid metallic and insulating substrata using a pulsed nitrogen laser. Post-ionization produced high-quality mass spectra characteristic of electrospray, including protein multiple charging. For the first time, mass spectra of intact proteins were obtained using laser desorption without adding a matrix. Bovine cytochrome c and an illicit drug containing methaqualone were chosen in this study to demonstrate the applicability of ELDI to the analysis of proteins and synthetic organic compounds. PMID:16299699

  14. Surface-assisted laser desorption ionization mass spectrometry techniques for application in forensics.

    Science.gov (United States)

    Guinan, Taryn; Kirkbride, Paul; Pigou, Paul E; Ronci, Maurizio; Kobus, Hilton; Voelcker, Nicolas H

    2015-01-01

    Matrix-assisted laser desorption ionization (MALDI) mass spectrometry (MS) is an excellent analytical technique for the rapid and sensitive analysis of macromolecules (>700 Da), such as peptides, proteins, nucleic acids, and synthetic polymers. However, the detection of smaller organic molecules with masses below 700 Da using MALDI-MS is challenging due to the appearance of matrix adducts and matrix fragment peaks in the same spectral range. Recently, nanostructured substrates have been developed that facilitate matrix-free laser desorption ionization (LDI), contributing to an emerging analytical paradigm referred to as surface-assisted laser desorption ionization (SALDI) MS. Since SALDI enables the detection of small organic molecules, it is rapidly growing in popularity, including in the field of forensics. At the same time, SALDI also holds significant potential as a high throughput analytical tool in roadside, work place and athlete drug testing. In this review, we discuss recent advances in SALDI techniques such as desorption ionization on porous silicon (DIOS), nano-initiator mass spectrometry (NIMS) and nano assisted laser desorption ionization (NALDI™) and compare their strengths and weaknesses with particular focus on forensic applications. These include the detection of illicit drug molecules and their metabolites in biological matrices and small molecule detection from forensic samples including banknotes and fingerprints. Finally, the review highlights recent advances in mass spectrometry imaging (MSI) using SALDI techniques.

  15. Analysis of isorhamnetin-3-O-neohesperidoside in rat plasma by liquid chromatography/electrospray ionization tandem mass spectrometry and its application to pharmacokinetic studies%高效液相质谱联用法分析大鼠血浆中异鼠李素-3-O-新橙皮糖苷的浓度及其药代动力学研究

    Institute of Scientific and Technical Information of China (English)

    刘史佳; 陈佩东; 戴国梁; 居文政; 谢丽艳; 徐洁; 周玲; 丁安伟; 余伯阳

    2013-01-01

    目的:建立LC-MS/MS方法测定异鼠李素-3-O-新橙皮糖苷的浓度并研究其在大鼠体内的药代动力学.方法:8只大鼠分别尾静脉注射异鼠李素-3-O-新橙皮糖苷5 mg·kg-1.建立并确证高灵敏度的液质联用法分析大鼠血浆中异鼠李素-3-O-新橙皮糖苷的浓度,采用芦丁作为内标.采用甲醇蛋白沉淀法提取血浆中的异鼠李素-3-O-新橙皮糖苷和芦丁.然后用10 mmol·L-1的乙酸铵/甲醇(20∶80,V/V)的流动相在C1色谱柱(150 mm×2.1mm,I.D.,5μm)上进行洗脱并采用多反应检测的方式进行质谱分析.结果:异鼠李素-3-O-新橙皮糖苷的在大鼠血浆中的线性范围为0.01-10μg·mL-1.其定量下限为0.01 μg·mL-1.结论:该方法可以用于测定大鼠血浆中异鼠李素-3-0-新橙皮糖苷的浓度.

  16. Atmospheric pressure ionization-tandem mass spectrometry of the phenicol drug family.

    Science.gov (United States)

    Alechaga, Élida; Moyano, Encarnación; Galceran, M Teresa

    2013-11-01

    In this work, the mass spectrometry behaviour of the veterinary drug family of phenicols, including chloramphenicol (CAP) and its related compounds thiamphenicol (TAP), florfenicol (FF) and FF amine (FFA), was studied. Several atmospheric pressure ionization sources, electrospray (ESI), atmospheric pressure chemical ionization and atmospheric pressure photoionization were compared. In all atmospheric pressure ionization sources, CAP, TAP and FF were ionized in both positive and negative modes; while for the metabolite FFA, only positive ionization was possible. In general, in positive mode, [M + H](+) dominated the mass spectrum for FFA, while the other compounds, CAP, TAP and FF, with lower proton affinity showed intense adducts with species present in the mobile phase. In negative mode, ESI and atmospheric pressure photoionization showed the deprotonated molecule [M-H](-), while atmospheric pressure chemical ionization provided the radical molecular ion by electron capture. All these ions were characterized by tandem mass spectrometry using the combined information obtained by multistage mass spectrometry and high-resolution mass spectrometry in a quadrupole-Orbitrap instrument. In general, the fragmentation occurred via cyclization and losses or fragmentation of the N-(alkyl)acetamide group, and common fragmentation pathways were established for this family of compounds. A new chemical structure for the product ion at m/z 257 for CAP, on the basis of the MS(3) and MS(4) spectra is proposed. Thermally assisted ESI and selected reaction monitoring are proposed for the determination of these compounds by ultra high-performance liquid chromatography coupled to tandem mass spectrometry, achieving instrumental detection limits down to 0.1 pg.

  17. Characterization of the chemical composition of a block copolymer by liquid chromatography/mass spectrometry using atmospheric pressure chemical ionization and electrospray ionization

    NARCIS (Netherlands)

    Leeuwen, van Suze M.; Tan, BoonHua; Grijpma, Dirk W.; Feijen, J.; Karst, Uwe

    2007-01-01

    Liquid chromatography/mass spectrometry (LC/MS) with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) in the positive and negative ion modes was used for the characterization of a block copolymer consisting of methoxy poly(ethylene oxide) (mPEO), an -caprolactone (CL

  18. Characterization of the chemical composition of a block copolymer by liquid chromatography/mass spectrometry using atmospheric pressure chemical ionization and electrospray ionization

    NARCIS (Netherlands)

    van Leeuwen, Suze M.; Tan, BoonHua; Grijpma, Dirk W.; Fejen, Jan; Karst, Uwe

    2007-01-01

    Liquid chromatography/mass spectrometry (LC/MS) with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) in the positive and negative ion modes was used for the characterization of a block copolymer consisting of methoxy poly(ethylene oxide) (mPEO), an epsilon-caprolact

  19. Direct protein detection from biological media through electrospray-assisted laser desorption ionization/mass spectrometry.

    Science.gov (United States)

    Huang, Min-Zong; Hsu, Hsiu-Jung; Lee, Jen-Yih; Jeng, Jingyueh; Shiea, Jentaie

    2006-05-01

    We report here using a novel technology-electrospray-assisted laser desorption ionization (ELDI)/mass spectrometry-for the rapid and sensitive detection of the major proteins that exist in dried biological fluids (e.g., blood, tears, saliva, serum), bacterial cultures, and tissues (e.g., porcine liver and heart) under ambient conditions. This technique required essentially no sample pretreatment. The proteins in the samples were desorbed using a pulsed nitrogen laser without the assistance of an organic matrix. The desorbed protein molecules were then post-ionized through their fusion into the charged solvent droplets produced from the electrospray of an acidic methanol solution; electrospray ionization (ESI) proceeded from the newly formed droplets to generate the ESI-like protein ions. This new ionization approach combines some of the features of electrospray ionization with those of matrix-assisted laser desorption ionization (MALDI), that is, sampling of a solid surface with spatial resolution, generating ESI-like mass spectra of the desorbed proteins, and operating under ambient conditions. PMID:16674100

  20. Ambient diode laser desorption dielectric barrier discharge ionization mass spectrometry of nonvolatile chemicals.

    Science.gov (United States)

    Gilbert-López, Bienvenida; Schilling, Michael; Ahlmann, Norman; Michels, Antje; Hayen, Heiko; Molina-Díaz, Antonio; García-Reyes, Juan F; Franzke, Joachim

    2013-03-19

    In this work, the combined use of desorption by a continuous wave near-infrared diode laser and ionization by a dielectric barrier discharge-based probe (laser desorption dielectric barrier discharge ionization mass spectrometry (LD-DBDI-MS)) is presented as an ambient ionization method for the mass spectrometric detection of nonvolatile chemicals on surfaces. A separation of desorption and ionization processes could be verified. The use of the diode laser is motivated by its low cost, ease of use, and small size. To achieve an efficient desorption, the glass substrates are coated at the back side with a black point (target point, where the sample is deposited) in order to absorb the energy offered by the diode laser radiation. Subsequent ionization is accomplished by a helium plasmajet generated in the dielectric barrier discharge source. Examples on the application of this approach are shown in both positive and negative ionization modes. A wide variety of multiclass species with low vapor pressure were tested including pesticides, pharmaceuticals and explosives (reserpine, roxithromycin, propazine, prochloraz, spinosad, ampicillin, dicloxacillin, enrofloxacin, tetracycline, oxytetracycline, erythromycin, spinosad, cyclo-1,3,5,7-tetramethylene tetranitrate (HMX), and cyclo-1,3,5-trimethylene trinitramine (RDX)). A comparative evaluation revealed that the use of the laser is advantageous, compared to just heating the substrate surface. PMID:23419061

  1. Multi photon ionization mass spectrometry of carbamate pesticides, herbicides and fungicides

    International Nuclear Information System (INIS)

    Pesticides and herbicides are useful for a wide range of applications today. The determination of these substances either in the pure form or in complex matrices is of high analytical interest. Especially since these substances can by found in every day products. The combination of multi photon ionization (MUPI) and time of flight laser mass spectrometry may be a powerful tool for achieving fast well interpretable mass spectra for analytical purposes. In this paper we will discuss the mass spectra of several pesticides and herbicides accessed by MUPI-time-of-flight mass spectrometry. The influence of the laser pulse duration on the mass spectra are discussed

  2. Laser desorption/ionization mass spectrometry on nanostructured semiconductor substrates: DIOS(TM) and QuickMass(TM)

    Science.gov (United States)

    Law, K. P.

    2010-02-01

    In the era of systems biology, new analytical platforms are under demand. Desorption/ionization on silicon mass spectrometry (DIOS-MS) is a promising high throughput laser mass spectrometry approach that has attracted a lot of attention, and has been commercialized. Another substrate material manufactured by physical method has also been made commercially available under the trade name of QuickMass(TM). These two commercial substrates, DIOS(TM) and QuickMass(TM), were investigated independently from the manufacturers and were characterized by a number of advanced surface techniques. This work determined (1) the correlation between the substrate physicochemical properties and their LDI activity, (2) the feasibility of metabolic profiling from complex biological matrices and (3) the laser desorption/ionization mechanism. The DIOS(TM) substrate was characterized with a thick nano-sized porous layer, a high surface concentration of fluorocarbon and silicon oxides and super-hydrophobicity. In contrast, the QuickMass(TM) substrate consisted of a non-porous germanium thin-film. The relatively high ionization efficiency obtained from the DIOS(TM) substrate was contributed to the fluorosilane manufacturing processes and its porous morphology. Despite the QuickMass(TM) substrate being less effective, it was noted that the use of germanium affords a self-cleaning mechanism and suppresses background interference of mass spectra. The suitability of DIOS(TM) substrates for metabolic profiling of complex biological matrices was demonstrated. DIOS mass spectra of human blood plasma, human urine and animal liver tissue extracts were produced. Suitable extraction methods were found to be important, but relatively simplified approaches were sufficient. Further investigations of the DIOS desorption/ionization mechanism were carried out. The previously proposed sub-surface state reaction could be a molten-solid interfacial state reaction of the substrate and this had a significant

  3. Determination of Hexachlorocyclohexane by Gas Chromatography Combined with Femtosecond Laser Ionization Mass Spectrometry

    Science.gov (United States)

    Yang, Xixiang; Imasaka, Tomoko; Li, Adan; Imasaka, Totaro

    2016-09-01

    Structural isomers and enantiomers of hexachlorocyclohexane (HCH) were separated using a chiral column by gas chromatography and quantitatively determined by multiphoton ionization mass spectrometry using an ultraviolet femtosecond laser (200 and 267 nm) as the ionization source. The order of elution of the enantiomers (i.e., (+)-α-HCH and (-)-α-HCH) was predicted from stabilization energies calculated for the complexes using permethylated γ-cyclodextrin as the stationary phase of the column, and the results were compared with the experimental data. The molecular ions observed for HCH were weak, even though they can be ionized through a process of resonance enhanced two-photon ionization at 200 nm. This unfavorable result can be attributed to the dissociation of the molecular ion, as predicted from quantum chemical calculations.

  4. The Application of Resonance-Enhanced Multiphoton Ionization Technique in Gas Chromatography Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Adan Li

    2014-01-01

    Full Text Available Gas chromatography resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (GC/REMPI-TOFMS using a nanosecond laser has been applied to analyze the 16 polycyclic aromatic hydrocarbons (PAHs. The excited-state lifetime, absorption characters, and energy of electronic states of the 16 PAHs were investigated to optimize the ionization yield. A river water sample pretreated by means of solid phase extraction was analyzed to evaluate the performance of the analytical instrument. The results suggested that REMPI is superior to electron impact ionization method for soft ionization and suppresses the background signal due to aliphatic hydrocarbons. Thus, GC/REMPI-TOFMS is a more reliable method for the determination of PAHs present in the environment.

  5. Experimental Concept for a Precision Measurement of Nuclear Recoil Ionization Yields for Low Mass WIMP Searches

    Science.gov (United States)

    Saab, T.; Figueroa-Feliciano, E.

    2016-07-01

    Understanding the response of dark matter detectors at the lowest recoil energies is important for correctly interpreting data from current experiments or predicting the sensitivity of future experiments to low mass weakly interacting massive particles. In particular, the ionization yield is essential for determining the correct recoil energy of candidate nuclear recoil events; however, few measurements in cryogenic crystals exist below 1 keV. Using the voltage-assisted calorimetric ionization detection technique with a mono-energetic neutron source, we show that it is possible to determine the ionization yield in cryogenic crystals down to an energy to 100 eV. This measurement will also determine the statistics of ionization production at these low energies.

  6. Development and Applications of Liquid Sample Desorption Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Zheng, Qiuling; Chen, Hao

    2016-06-01

    Desorption electrospray ionization mass spectrometry (DESI-MS) is a recent advance in the field of analytical chemistry. This review surveys the development of liquid sample DESI-MS (LS-DESI-MS), a variant form of DESI-MS that focuses on fast analysis of liquid samples, and its novel analy-tical applications in bioanalysis, proteomics, and reaction kinetics. Due to the capability of directly ionizing liquid samples, liquid sample DESI (LS-DESI) has been successfully used to couple MS with various analytical techniques, such as microfluidics, microextraction, electrochemistry, and chromatography. This review also covers these hyphenated techniques. In addition, several closely related ionization methods, including transmission mode DESI, thermally assisted DESI, and continuous flow–extractive DESI, are briefly discussed. The capabilities of LS-DESI extend and/or complement the utilities of traditional DESI and electrospray ionization and will find extensive and valuable analytical application in the future.

  7. Ambient Femtosecond Laser Vaporization and Nanosecond Laser Desorption Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Flanigan, Paul; Levis, Robert

    2014-06-01

    Recent investigations of ambient laser-based transfer of molecules into the gas phase for subsequent mass spectral analysis have undergone a renaissance resulting from the separation of vaporization and ionization events. Here, we seek to provide a snapshot of recent femtosecond (fs) duration laser vaporization and nanosecond (ns) duration laser desorption electrospray ionization mass spectrometry experiments. The former employs pulse durations of electrospray ionization, femtosecond laser vaporization provides a universal, rapid mass spectral analysis method requiring no sample workup. Remarkably, laser pulses with intensities exceeding 1013 W cm-2 desorb intact macromolecules, such as proteins, and even preserve the condensed phase of folded or unfolded protein structures according to the mass spectral charge state distribution, as demonstrated for cytochrome c and lysozyme. Because of the ability to vaporize and ionize multiple components from complex mixtures for subsequent analysis, near perfect classification of explosive formulations, plant tissue phenotypes, and even the identity of the manufacturer of smokeless powders can be determined by multivariate statistics. We also review the more mature field of nanosecond laser desorption for ambient mass spectrometry, covering the wide range of systems analyzed, the need for resonant absorption, and the spatial imaging of complex systems like tissue samples.

  8. Atmospheric pressure chemical ionization Fourier transform ion cyclotron resonance mass spectrometry for complex thiophenic mixture analysis

    KAUST Repository

    Hourani, Nadim

    2013-10-01

    Rationale Polycyclic aromatic sulfur heterocycles (PASHs) are detrimental species for refining processes in petroleum industry. Current mass spectrometric Methods that determine their composition are often preceded by derivatization and dopant addition approaches. Different ionization Methods have different impact on the molecular assignment of complex PASHs. The analysis of such species under atmospheric pressure chemical ionization (APCI) is still considered limited due to uncontrolled ion generation with low- and high-mass PASHs. Methods The ionization behavior of a model mixture of five selected PASH standards was investigated using an APCI source with nitrogen as the reagent gas. A complex thiophenic fraction was separated from a vacuum gas oil (VGO) and injected using the same method. The samples were analyzed using Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS). RESULTS PASH model analytes were successfully ionized and mainly [M + H]+ ions were produced. The same ionization pattern was observed for the real thiophenic sample. It was found that S1 class species were the major sulfur-containing species found in the VGO sample. These species indicated the presence of alkylated benzothiophenic (BT), dibenzothiophenic (DBT) and benzonaphthothiophenic (BNT) series that were detected by APCI-FTICR MS. CONCLUSIONS This study provides an established APCI-FTICR MS method for the analysis of complex PASHs. PASHs were detected without using any derivatization and without fragmentation. The method can be used for the analysis of S-containing crude oil samples. © 2013 John Wiley & Sons, Ltd.

  9. Plasma ionization under simulated ambient Mars conditions for quantification of methane by mass spectrometry.

    Science.gov (United States)

    Taghioskoui, Mazdak; Zaghloul, Mona

    2016-04-01

    Ambient ionization techniques enable ion production in the native sample environment for mass spectrometry, without a need for sample preparation or separation. These techniques provide superior advantages over conventional ionization methods and are well developed and investigated for various analytical applications. However, employing ambient ionization techniques for in situ extra-terrestrial chemical analysis requires these techniques to be designed and developed according to the ambient conditions of extra-terrestrial environments, which substantially differ from the ambient conditions of Earth. Here, we report a plasma ionization source produced under simulated ambient Mars conditions for mass spectrometry. The plasma ionization source was coupled to a quadrupole mass spectrometer, and quantitative and qualitative analyses of trace amounts of methane, as an analyte of interest in Mars discovery missions, were demonstrated. The miniature plasma source was operational at a net power as low as ∼1.7 W in the pressure range of 4-16 Torr. A detection limit as low as ∼0.15 ppm (v/v) at 16 Torr for methane was demonstrated. PMID:26947458

  10. Deblurring molecular images using desorption electrospray ionization mass spectrometry

    Science.gov (United States)

    Parry, R. Mitchell; Galhena, Asiri S.; Fernandez, Facundo M.; Wang, May D.

    2016-01-01

    Traditional imaging techniques for studying the spatial distribution of biological molecules such as proteins, metabolites, and lipids, require the a priori selection of a handful of target molecules. Imaging mass spectrometry provides a means to analyze thousands of molecules at a time within a tissue sample, adding spatial detail to proteomic, metabolomic, and lipidomic studies. Compared to traditional microscopic images, mass spectrometric images have reduced spatial resolution and require a destructive acquisition process. In order to increase spatial detail, we propose a constrained acquisition path and signal degradation model enabling the use of a general image deblurring algorithm. Our analysis shows the potential of this approach and supports prior observations that the effect of the sprayer focuses on a central region much smaller than the extent of the spray. PMID:19963935

  11. Atmospheric pressure chemical ionization studies of non-polar isomeric hydrocarbons using ion mobility spectrometry and mass spectrometry with different ionization techniques

    Science.gov (United States)

    Borsdorf, H.; Nazarov, E. G.; Eiceman, G. A.

    2002-01-01

    The ionization pathways were determined for sets of isomeric non-polar hydrocarbons (structural isomers, cis/trans isomers) using ion mobility spectrometry and mass spectrometry with different techniques of atmospheric pressure chemical ionization to assess the influence of structural features on ion formation. Depending on the structural features, different ions were observed using mass spectrometry. Unsaturated hydrocarbons formed mostly [M - 1]+ and [(M - 1)2H]+ ions while mainly [M - 3]+ and [(M - 3)H2O]+ ions were found for saturated cis/trans isomers using photoionization and 63Ni ionization. These ionization methods and corona discharge ionization were used for ion mobility measurements of these compounds. Different ions were detected for compounds with different structural features. 63Ni ionization and photoionization provide comparable ions for every set of isomers. The product ions formed can be clearly attributed to the structures identified. However, differences in relative abundance of product ions were found. Although corona discharge ionization permits the most sensitive detection of non-polar hydrocarbons, the spectra detected are complex and differ from those obtained with 63Ni ionization and photoionization. c. 2002 American Society for Mass Spectrometry.

  12. ARE MOLECULAR OUTFLOWS AROUND HIGH-MASS STARS DRIVEN BY IONIZATION FEEDBACK?

    Energy Technology Data Exchange (ETDEWEB)

    Peters, Thomas; Klessen, Ralf S. [Institut fuer Theoretische Astrophysik, Universitaet Heidelberg, Zentrum fuer Astronomie, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany); Klaassen, Pamela D. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Mac Low, Mordecai-Mark [Department of Astrophysics, American Museum of Natural History, 79th Street at Central Park West, New York, NY 10024-5192 (United States); Banerjee, Robi, E-mail: tpeters@physik.uzh.ch [Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg (Germany)

    2012-11-20

    The formation of massive stars exceeding 10 M {sub Sun} usually results in large-scale molecular outflows. Numerical simulations, including ionization, of the formation of such stars show evidence for ionization-driven molecular outflows. Here we examine whether the outflows seen in these models reproduce the observations. We compute synthetic ALMA and CARMA maps of CO emission lines of the outflows, and compare their signatures to existing single-dish and interferometric data. We find that the ionization-driven models can only reproduce weak outflows around high-mass star-forming regions. We argue that expanding H II regions probably do not represent the dominant mechanism for driving observed outflows. We suggest instead that observed outflows are driven by the collective action of the outflows from the many lower-mass stars that inevitably form around young massive stars in a cluster.

  13. Pharmaceutical Analysis by Solid-Substrate Electrospray Ionization Mass Spectrometry with Wooden Tips

    Science.gov (United States)

    Yang, Yunyun; Deng, Jiewei; Yao, Zhong-Ping

    2014-01-01

    Electrospray ionization (ESI) using wooden tips as solid substrates allows direct ionization of various samples and their simple and efficient analyses by mass spectrometry (MS). In this study, wooden-tip ESI-MS was used for pharmaceutical analysis. A wide variety of active components present in pharmaceuticals with forms of tablets, capsules, granules, dry suspensions, suspensions, drops, and oral liquids, etc., were all successfully ionized directly for mass spectrometric analysis. Trace degradation products were also sensitively detected using wooden-tip ESI-MS. This strategy was extended to construct chemical fingerprints of herbal products containing complex and unknown components, and the fingerprints provided valuable information for their quality assessment and origin tracing. Our experimental data demonstrated that wooden-tip ESI-MS is a useful tool for rapid pharmaceutical analysis, with high sensitivity and wide applicability, showing promising perspectives for quality assessment and control, authentication, and origin tracing of pharmaceuticals.

  14. Resonance-Enhanced Multiphoton Ionization Mass Spectrometry (REMPI-MS): Applications for Process Analysis

    Science.gov (United States)

    Streibel, Thorsten; Zimmermann, Ralf

    2014-06-01

    Process analysis is an emerging discipline in analytical sciences that poses special requirements on analytical techniques, especially when conducted in an online manner. Mass spectrometric methods seem exceedingly suitable for this task, particularly if a soft ionization method is applied. Resonance-enhanced multiphoton ionization (REMPI) in combination with time-of-flight mass spectrometry (TOFMS) provides a selective and sensitive means for monitoring (poly)aromatic compounds in process flows. The properties of REMPI and various variations of the ionization process are presented. The potential of REMPI for process analysis is highlighted with several examples, and drawbacks of the method are also noted. Applications of REMPI-TOFMS for the detection and monitoring of aromatic species in a large variety of combustion processes comprising flames, vehicle exhaust, and incinerators are discussed. New trends in technical development and combination with other analytical methods are brought forward.

  15. Direct Analysis of Oil Additives by High-Field Asymmetric Waveform Ion Mobility Spectrometry-Mass Spectrometry Combined with Electrospray Ionization and Desorption Electrospray Ionization.

    Science.gov (United States)

    Da Costa, Caitlyn; Turner, Matthew; Reynolds, James C; Whitmarsh, Samuel; Lynch, Tom; Creaser, Colin S

    2016-02-16

    The analysis of corrosion inhibitors in the presence and absence of an oil matrix is reported using electrospray ionization (ESI) and desorption electrospray ionization (DESI), hyphenated with miniaturized high-field asymmetric waveform ion mobility spectrometry (FAIMS) and mass spectrometry (MS). The target analytes were successfully ionized in solution by ESI and directly from steel surfaces using DESI ambient ionization at levels ≥0.0004% w/w (4 ppm) in oil. Differences in the mass spectral profiles observed for the additive/oil mixture are attributed to differences between the ESI and DESI ionization processes. The use of FAIMS improved selectivity for ESI generated analyte ions through reduction in the chemical noise resulting from the oil matrix. DESI enabled the direct, rapid, native state interrogation of oil samples on steel surfaces without sample pretreatment, and the hyphenation of DESI with the miniaturized FAIMS enhanced the relative analyte responses of the surface-active corrosion inhibitors. PMID:26780580

  16. Deconvolution of Soft Ionization Mass Spectra of Chlorinated Paraffins To Resolve Congener Groups.

    Science.gov (United States)

    Yuan, Bo; Alsberg, Tomas; Bogdal, Christian; MacLeod, Matthew; Berger, Urs; Gao, Wei; Wang, Yawei; de Wit, Cynthia A

    2016-09-20

    We describe and illustrate a three-step data-processing approach that enables individual congener groups of chlorinated paraffins (CPs) to be resolved in mass spectra obtained from either of two soft ionization methods: electron capture negative ionization mass spectrometry (ECNI-MS) or atmospheric pressure chemical ionization mass spectrometry (APCI-MS). In the first step, general fragmentation pathways of CPs are deduced from analysis of mass spectra of individual CP congeners. In the second step, all possible fragment ions in the general fragmentation pathways of CPs with 10 to 20 carbon atoms are enumerated and compared to mass spectra of CP mixture standards, and a deconvolution algorithm is applied to identify fragment ions that are actually observed. In the third step, isotope permutations of the observed fragment ions are calculated and used to identify isobaric overlaps, so that mass intensities of individual CP congener groups can be deconvolved from the unresolved isobaric ion signal intensities in mass spectra. For a specific instrument, the three steps only need to be done once to enable deconvolution of CPs in unknown samples. This approach enables congener group-level resolution of CP mixtures in environmental samples, and it opens up the possibility for quantification of congener groups. PMID:27531279

  17. Optimizing sequence coverage for a moderate mass protein in nano-electrospray ionization quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Matsuda, Ryan; Kolli, Venkata; Woods, Megan; Dodds, Eric D; Hage, David S

    2016-09-15

    Sample pretreatment was optimized to obtain high sequence coverage for human serum albumin (HSA, 66.5 kDa) when using nano-electrospray ionization quadrupole time-of-flight mass spectrometry (nESI-Q-TOF-MS). Use of the final method with trypsin, Lys-C, and Glu-C digests gave a combined coverage of 98.8%. The addition of peptide fractionation resulted in 99.7% coverage. These results were comparable to those obtained previously with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The sample pretreatment/nESI-Q-TOF-MS method was also used with collision-induced dissociation to analyze HSA digests and to identify peptides that could be employed as internal mass calibrants in future studies of modifications to HSA.

  18. Optimizing sequence coverage for a moderate mass protein in nano-electrospray ionization quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Matsuda, Ryan; Kolli, Venkata; Woods, Megan; Dodds, Eric D; Hage, David S

    2016-09-15

    Sample pretreatment was optimized to obtain high sequence coverage for human serum albumin (HSA, 66.5 kDa) when using nano-electrospray ionization quadrupole time-of-flight mass spectrometry (nESI-Q-TOF-MS). Use of the final method with trypsin, Lys-C, and Glu-C digests gave a combined coverage of 98.8%. The addition of peptide fractionation resulted in 99.7% coverage. These results were comparable to those obtained previously with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The sample pretreatment/nESI-Q-TOF-MS method was also used with collision-induced dissociation to analyze HSA digests and to identify peptides that could be employed as internal mass calibrants in future studies of modifications to HSA. PMID:27320213

  19. Ultrasensitive detection of actinides and technetium by laser resonance ionization mass spectrometry

    International Nuclear Information System (INIS)

    The application of laser resonance ionization mass spectrometry for the detection of extremely small numbers of atoms has been explored in the very recent years. High sensitivity and unambiguity in element and isotope identification can be achieved by three-step photoionization of the elements in the atomic state followed by time-of-flight mass analysis. The laser system for photoionization consists of three dye lasers which are pumped simultaneously by a copper vapor laser. For mass determination a time-of-flight spectrometer with a mass resolution better than 1500 is used. By ionization via autoionizing states and by saturation in each excitation step a detection limit of about 107 atoms of actinides or of technetium in the sample has been obtained

  20. Plume collimation for laser ablation electrospray ionization mass spectrometry

    Science.gov (United States)

    Vertes, Akos; Stolee, Jessica A.

    2014-09-09

    In various embodiments, a device may generally comprise a capillary having a first end and a second end; a laser to emit energy at a sample in the capillary to ablate the sample and generate an ablation plume in the capillary; an electrospray apparatus to generate an electrospray plume to intercept the ablation plume to produce ions; and a mass spectrometer having an ion transfer inlet to capture the ions. The ablation plume may comprise a collimated ablation plume. The device may comprise a flow cytometer. Methods of making and using the same are also described.

  1. Plume collimation for laser ablation electrospray ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Vertes, Akos; Stolee, Jessica A.

    2016-06-07

    In various embodiments, a device may generally comprise a capillary having a first end and a second end; a laser to emit energy at a sample in the capillary to ablate the sample and generate an ablation plume in the capillary; an electrospray apparatus to generate an electrospray plume to intercept the ablation plume to produce ions; and a mass spectrometer having an ion transfer inlet to capture the ions. The ablation plume may comprise a collimated ablation plume. The device may comprise a flow cytometer. Methods of making and using the same are also described.

  2. Identification of tetraacylglycerols in lesquerella oil by electrospray ionization mass spectrometry of the lithium adducts

    Science.gov (United States)

    Tetraacylglycerol (an acylglycerol estolide) contains an acyl chain attached to the hydroxyl group of another acyl chain attached to the glycerol backbone. Lequerolic acid (Ls, OH1420:111) is the main fatty acid in lequerella oil and can be used in industry. We have used electrospray ionization mass...

  3. Identification of Bacteria Using Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry

    Science.gov (United States)

    Kedney, Mollie G.; Strunk, Kevin B.; Giaquinto, Lisa M.; Wagner, Jennifer A.; Pollack, Sidney; Patton, Walter A.

    2007-01-01

    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS or simply MALDI) has become ubiquitous in the identification and analysis of biomacromolecules. As a technique that allows for the molecular weight determination of otherwise nonvolatile molecules, MALDI has had a profound impact in the molecular…

  4. Concise Synthesis of Photocleavable Molecular Tag for Laser Desorption Ionization Mass Spectrometry via Fries Reaction

    OpenAIRE

    Gathirwa, Jeremiah W.; Maki, Toshihide

    2013-01-01

    A new synthetic route for the photocleavable molecular tag for laser desorption ionization mass spectrometry (LDI-MS) was achieved using Fries reaction of 2,6-dimethylphenyl ester as its key reaction. Zirconium chloride was found as uniquely efficient adjuvant to promote the reaction. The molecular tag was obtained in 5 steps without chromatographic purification.

  5. Analysis of the Aconitine Alkaloids in Chuanwu by Electrospray Ionization/Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    Ai Min SUN; Hui LI; Zhi Ming HUANG; P.P.H.BUT; Xue Qin DING

    2004-01-01

    An electrospray ionization / tandem mass spectrometric (ESI/MS/MS) method was developed for the simultaneous identification and analysis of three aconitine alkaloids [ mesacontine (MA), hypaconitine (HA), and aconitine (A)] as intact molecules at low nanogram level in Chinese traditional medicine Chuanwu decoction as well as in human whole blood extract without chromatographic separation.

  6. Examination and Manipulation of Protein Surface Charge in Solution with Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Gross, Deborah S.; Van Ryswyk, Hal

    2014-01-01

    Electrospray ionization mass spectrometry (ESI-MS) is a powerful tool for examining the charge of proteins in solution. The charge can be manipulated through choice of solvent and pH. Furthermore, solution-accessible, protonated lysine side chains can be specifically tagged with 18-crown-6 ether to form noncovalent adducts. Chemical derivatization…

  7. Imaging of plant materials using indirect desorption electrospray ionization mass spectrometry

    DEFF Research Database (Denmark)

    Janfelt, Christian

    2015-01-01

    Indirect desorption electrospray ionization mass spectrometry (DESI-MS) imaging is a method for imaging distributions of metabolites in plant materials, in particular leaves and petals. The challenge in direct imaging of such plant materials with DESI-MS is particularly the protective layer of cu...

  8. Characterization of typical chemical background interferences in atmospheric pressure ionization liquid chromatography-mass spectrometry

    NARCIS (Netherlands)

    Guo, Xinghua; Bruins, Andries P.; Covey, Thomas R.

    2006-01-01

    The structures and origins of typical chemical background noise ions in positive atmospheric pressure ionization liquid chromatography/mass spectrometry (API LC/MS) are investigated and summarized in this study. This was done by classifying chemical background ions using precursor and product ion sc

  9. Miniaturizing sample spots for matrix-assisted laser desorption/ionization mass spectrometry

    OpenAIRE

    Tu, Tingting; Gross, Michael L.

    2009-01-01

    The trend of miniaturization in bioanalytical chemistry is shifting from technical development to practical application. In matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), progress in miniaturizing sample spots has been driven by the needs to increase sensitivity and speed, to interface with other analytical microtechnologies, and to develop miniaturized instrumentation.

  10. A Combined Laser Ablation-Resonance Ionization Mass Spectrometer for Planetary Surface Geochronology

    Science.gov (United States)

    Cardell, G.; Taylor, M. E.; Stewart, B. W.; Capo, R. C.; Crown, D. A.

    2002-01-01

    Progress in the development of an instrument for direct geochronologic measurements on rocks in situ will be described. The instrument integrates laser ablation sampling, resonance ionization, and mass spectrometry to directly measure concentrations of the Rb-Sr isotope system. Additional information is contained in the original extended abstract.

  11. Investigation of the interaction between HIV-1 DNA and cyclic peptides by electrospray ionization mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    Yi Quan Liu; Hui Hui Li; Yun Hua Ye; Gu Yuan

    2009-01-01

    The interaction between HIV-I DNA and five cyclic peptides (CPI-CP5) was investigated using electrospray ionization mass spectrometry (ESI-MS). It revealed that CPI [c(Ala-Tyr-Leu-Ala-Gly)] and CP4 [c(Pro-D-Tyr-Leu-D-Ala-Gly)] have the higher binding affinity with the duplex DNA among the five cyclic peptides.

  12. Real-Time Flavor Release from French Fries Using Atmospheric Pressure Chemical Ionization-Mass Spectrometry

    NARCIS (Netherlands)

    Loon, W.A.M.; Linssen, J.P.H.; Boelrijk, A.E.M.; Burgering, M.J.M.; Voragen, A.G.J.

    2005-01-01

    Flavor release from French fries was measured with atmospheric pressure chemical ionization-mass spectrometry (APCI-MS) using both assessors (in vivo) and a mouth model system (in vitro). Several volatiles measured with APCI were identified with MS-MS. The effect of frying time, salt addition, and a

  13. Feasibility of desorption electrospray ionization mass spectrometry for rapid screening of anabolic steroid esters in hair

    NARCIS (Netherlands)

    Nielen, M.W.F.; Nijrolder, A.W.J.M.; Hooijerink, H.; Stolker, A.A.M.

    2011-01-01

    Hormone and veterinary drug screening and forensics can benefit from the recent developments in desorption electrospray ionization (DESI) mass spectrometry (MS). In this work the feasibility of DESI application for the rapid screening of intact esters of anabolic steroids in bovine hair has been stu

  14. Desorption electrospray ionization mass spectrometry in the analysis of chemical food contaminants in food

    NARCIS (Netherlands)

    Nielen, M.W.F.; Hooijerink, H.; Zomer, P.; Mol, J.G.J.

    2011-01-01

    Since its introduction, desorption electrospray ionization (DESI) mass spectrometry (MS) has been mainly applied in pharmaceutical and forensic analysis. We expect that DESI will find its way in many different fields, including food analysis. In this review, we summarize DESI developments aimed at c

  15. Identification of the Species of Origin for Meat Products by Rapid Evaporative Ionization Mass Spectrometry.

    Science.gov (United States)

    Balog, Julia; Perenyi, Dora; Guallar-Hoyas, Cristina; Egri, Attila; Pringle, Steven D; Stead, Sara; Chevallier, Olivier P; Elliott, Chris T; Takats, Zoltan

    2016-06-15

    Increasingly abundant food fraud cases have brought food authenticity and safety into major focus. This study presents a fast and effective way to identify meat products using rapid evaporative ionization mass spectrometry (REIMS). The experimental setup was demonstrated to be able to record a mass spectrometric profile of meat specimens in a time frame of food safety applications providing a reliable and simple method for the rapid characterization of food products. PMID:27167240

  16. Rapid high mass resolution mass spectrometry using matrix-assisted ionization.

    Science.gov (United States)

    Trimpin, Sarah; Thawoos, Shameemah; Foley, Casey D; Woodall, Daniel W; Li, Jing; Inutan, Ellen D; Stemmer, Paul M

    2016-07-15

    Matrix-assisted ionization (MAI) is demonstrated to be a robust and sensitive analytical method capable of analyzing proteins such as cholera toxin B-subunit and pertussis toxin mutant from conditions containing relatively high amounts of inorganic salts, buffers, and preservatives without the need for prior sample clean-up or concentration. By circumventing some of the sample preparation steps, MAI simplifies and accelerates the analytical workflow for biological samples in complex media. The benefits of multiply charged ions characteristic of electrospray ionization (ESI) and the robustness of matrix-assisted laser desorption/ionization (MALDI) can be obtained from a single method, making it well suited for analysis of proteins and other biomolecules at ultra-high resolution as demonstrated on an Orbitrap Fusion where protein subunits were resolved for which MALDI-time-of-flight failed. MAI results are compared with those obtained with ESI, MALDI, and laserspray ionization methods and fundamental commonalities discussed. PMID:26835606

  17. Resonance Ionization Mass Spectrometry (RIMS) with Pulsed and CW-Lasers on Plutonium

    Science.gov (United States)

    Kunz, P.; Huber, G.; Passler, G.; Trautmann, N.; Wendt, K.

    2005-04-01

    The detection of long-lived plutonium isotopes in ultra-trace amounts by resonance ionization mass spectrometry (RIMS) is a well-established routine method. Detection limits of 106 to 107 atoms and precise measurements of the isotopic composition have been achieved. In this work multi-step resonance ionization of plutonium atoms has been performed with tunable lasers having very different output intensities and spectral properties. In order to compare different ways for the resonance ionization of plutonium broadband pulsed dye and titanium:sapphire lasers as well as narrow-band cw-diode and titanium:sapphire lasers have been applied for a number of efficient excitation schemes. It has been shown, that for identical excitation schemes the optical isotope selectivity can be improved by using cw-lasers (bandwidths lasers (bandwidths > 2 GHz). Pulsed and cw-laser systems have been used simultaneously for resonance ionization enabling direct comparisons of pulsed and continuous ionization processes. So far, a three-step, three-color laser excitation scheme has been proven to be most practical in terms of efficiency, selectivity and laser wavelengths. Alternatively a newly discovered three-step, two-color excitation scheme which includes a strong two-photon transition from an excited state into a high-lying autoionizing state yields similar ionization efficiencies. This two-photon transition was characterized with respect to saturation behavior and line width.

  18. Resonance Ionization Mass Spectrometry (RIMS) with Pulsed and CW-Lasers on Plutonium

    International Nuclear Information System (INIS)

    The detection of long-lived plutonium isotopes in ultra-trace amounts by resonance ionization mass spectrometry (RIMS) is a well-established routine method. Detection limits of 106 to 107 atoms and precise measurements of the isotopic composition have been achieved. In this work multi-step resonance ionization of plutonium atoms has been performed with tunable lasers having very different output intensities and spectral properties. In order to compare different ways for the resonance ionization of plutonium broadband pulsed dye and titanium:sapphire lasers as well as narrow-band cw-diode and titanium:sapphire lasers have been applied for a number of efficient excitation schemes. It has been shown, that for identical excitation schemes the optical isotope selectivity can be improved by using cw-lasers (bandwidths 2 GHz). Pulsed and cw-laser systems have been used simultaneously for resonance ionization enabling direct comparisons of pulsed and continuous ionization processes. So far, a three-step, three-color laser excitation scheme has been proven to be most practical in terms of efficiency, selectivity and laser wavelengths. Alternatively a newly discovered three-step, two-color excitation scheme which includes a strong two-photon transition from an excited state into a high-lying autoionizing state yields similar ionization efficiencies. This two-photon transition was characterized with respect to saturation behavior and line width.

  19. A novel sample preparation method of matrix-assisted laser desorption/ionization time of flight mass spectrometry for polystyrene

    Institute of Scientific and Technical Information of China (English)

    Shu Zhang; Zhen Wen Zhao; Lei Xiong; Bin Xin; Wei Hua Hu; Shao Xiang Xiong

    2007-01-01

    A novel sample preparation method of matrix-assisted laser desorption/ionization mass spectrometry for polystyrene was reported.Compared to the conventional dried-droplet method, the efficiency of ionization and signal intensity of mass spectra were improved.The mechanism was also analyzed.

  20. [Identification of high-lying odd energy levels of uranium by resonant ionization mass spectrometry].

    Science.gov (United States)

    Du, H; Shi, G; Huang, M; Jin, C

    2000-06-01

    Single-colour and two-colour multiphoton resonant ionization spectra of uranium atom were studied extensively with a Nd:YAG laser-pumped dye laser atomic beam apparatus time-of-flight mass spectrometer in our laboratory. The energy locations of high-lying odd-parity levels in the region 33,003-34,264 cm-1, measured by a two-colour three-step ionization technique, were reported here. The angular momentum quantum number J was uniquely assigned for these levels by using angular momentum selection rules. PMID:12958925

  1. Observation of autoionizing states of beryllium by resonance ionization mass spectrometry

    International Nuclear Information System (INIS)

    We have made the first observations of the Be 2p21S state, and of high-lying members of the Rydberg series 2pnd 1P0 (n less than or equal to 16), by resonance ionization mass spectrometry (RIMS). The energy of the 1S state agrees well with theoretical predictions, if corrections are made for intershell electron correlations. These results show that precision specroscopy can be performed by RIMS with samples of a few hundred atoms, and that direct multiphoton excitation of autoionizing states may be a useful new addition to the existing catalogue of resonance ionization schemes

  2. Mass spectrometric characterization of a pyrolytic radical source using femtosecond ionization

    Energy Technology Data Exchange (ETDEWEB)

    Frey, H.M.; Beaud, P.; Mischler, B.; Radi, P.P.; Tzannis, A.P.; Gerber, T. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Radicals play, as reactive species, an important role in the chemistry of combustion. In contrast to atmospheric flames where spectra are congested due to high vibrational and rotational excitation, experiments in the cold environment of a molecular beam (MB) yield clean spectra that can be easily attributed to one species by Resonantly Enhanced Multi Photon Ionization (REMP). A pyrolytic radical source has been set up. To characterize the efficiency of the source `soft` ionization with femto second pulses is applied which results in less fragmentation, simplifying the interpretation of the mass spectrum. (author) figs., tabs., refs.

  3. In-Line Reactions and Ionizations of Vaporized Diphenylchloroarsine and Diphenylcyanoarsine in Atmospheric Pressure Chemical Ionization Mass Spectrometry

    Science.gov (United States)

    Okumura, Akihiko; Takada, Yasuaki; Watanabe, Susumu; Hashimoto, Hiroaki; Ezawa, Naoya; Seto, Yasuo; Takayama, Yasuo; Sekioka, Ryoji; Yamaguchi, Shintaro; Kishi, Shintaro; Satoh, Takafumi; Kondo, Tomohide; Nagashima, Hisayuki; Nagoya, Tomoki

    2016-07-01

    We propose detecting a fragment ion (Ph2As+) using counter-flow introduction atmospheric pressure chemical ionization ion trap mass spectrometry for sensitive air monitoring of chemical warfare vomiting agents diphenylchloroarsine (DA) and diphenylcyanoarsine (DC). The liquid sample containing of DA, DC, and bis(diphenylarsine)oxide (BDPAO) was heated in a dry air line, and the generated vapor was mixed into the humidified air flowing through the sampling line of a mass spectrometer. Humidity effect on the air monitoring was investigated by varying the humidity of the analyzed air sample. Evidence of the in-line conversion of DA and DC to diphenylarsine hydroxide (DPAH) and then BDPAO was obtained by comparing the chronograms of various ions from the beginning of heating. Multiple-stage mass spectrometry revealed that the protonated molecule (MH+) of DA, DC, DPAH, and BDPAO could produce Ph2As+ through their in-source fragmentation. Among the signals of the ions that were investigated, the Ph2As+ signal was the most intense and increased to reach a plateau with the increased air humidity, whereas the MH+ signal of DA decreased. It was suggested that DA and DC were converted in-line into BDPAO, which was a major source of Ph2As+.

  4. Matrix-assisted ionization vacuum for high-resolution Fourier transform ion cyclotron resonance mass spectrometers.

    Science.gov (United States)

    Wang, Beixi; Tisdale, Evgenia; Trimpin, Sarah; Wilkins, Charles L

    2014-07-15

    Matrix-assisted ionization vacuum (MAIV) produces charge states similar to electrospray ionization (ESI) from the solid state without requiring high voltage or added heat. MAIV differs from matrix-assisted laser desorption/ionization (MALDI) in that no laser is needed and abundant multiply charged ions are produced from molecules having multiple basic sites such as proteins. Here we introduce simple modifications to the commercial vacuum MALDI and ESI sources of a 9.4 T Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometer to perform MAIV from both intermediate and atmospheric pressure. The multiply charged ions are shown for the proteins bovine insulin, ubiquitin, and lysozyme using 3-nitrobenzonitrile as matrix. These are the first examples of MAIV operating at pressures as low as 10(-6) mbar in an FT-ICR mass spectrometer source, and the expected mass resolving power of 100000 to 400000 is achieved. Identical protein charge states are observed with and without laser ablation indicating minimal, if any, role of photochemical ionization for the compounds studied.

  5. 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.

  6. Laser resonance ionization mass spectrometry as a sensitive analytical method for actinides and technetium

    International Nuclear Information System (INIS)

    Laser resonance ionization mass spectrometry has been investigated as a method for the determination of trace amounts of actinides and technetium. A high sensitivity and selectivity have been achieved by three-step photoionization of the elements in the atomic state followed by time-of-flight measurement for mass analysis. The system for photoionization consists of three dye lasers which are pumped simultaneously by a copper vapour laser of 30 W average power at a pulse repetition rate of 6.5 KHz. The time-of-flight spectrometer has a mass resolution better than 2500. By ionization via autoionization states and by saturation in each excitation step a detection limit of less than 108 atoms of actinides or of technetium in the sample can be reached. (author)

  7. High-resolution field desorption/ionization fourier transform ion cyclotron resonance mass analysis of nonpolar molecules.

    Science.gov (United States)

    Schaub, Tanner M; Hendrickson, Christopher L; Qian, Kuangnan; Quinn, John P; Marshall, Alan G

    2003-05-01

    We report the first field desorption ionization broadband high-resolution (m/Deltam(50%) approximately 65 000) mass spectra. We have interfaced a field ionization/field desorption source to a home-built 9.4-T FT-ICR mass spectrometer. The instrumental configuration employs convenient sample introduction (in-source liquid injection) and external ion accumulation. We demonstrate the utility of this configuration by generating high-resolution positive-ion mass spectra of C(60) and a midboiling crude oil distillate. The latter contains species not accessible by common soft-ionization methods, for example, low-voltage electron ionization, electrospray ionization, and matrix-assisted laser desorption/ionization. The present work demonstrates significant advantages of FI/FD FT-ICR MS for analysis of nonpolar molecules in complex mixtures.

  8. Ambient Mass Spectrometry Imaging with Picosecond Infrared Laser Ablation Electrospray Ionization (PIR-LAESI).

    Science.gov (United States)

    Zou, Jing; Talbot, Francis; Tata, Alessandra; Ermini, Leonardo; Franjic, Kresimir; Ventura, Manuela; Zheng, Jinzi; Ginsberg, Howard; Post, Martin; Ifa, Demian R; Jaffray, David; Miller, R J Dwayne; Zarrine-Afsar, Arash

    2015-12-15

    A picosecond infrared laser (PIRL) is capable of cutting through biological tissues in the absence of significant thermal damage. As such, PIRL is a standalone surgical scalpel with the added bonus of minimal postoperative scar tissue formation. In this work, a tandem of PIRL ablation with electrospray ionization (PIR-LAESI) mass spectrometry is demonstrated and characterized for tissue molecular imaging, with a limit of detection in the range of 100 nM for reserpine or better than 5 nM for verapamil in aqueous solution. We characterized PIRL crater size using agar films containing Rhodamine. PIR-LAESI offers a 20-30 μm vertical resolution (∼3 μm removal per pulse) and a lateral resolution of ∼100 μm. We were able to detect 25 fmol of Rhodamine in agar ablation experiments. PIR-LAESI was used to map the distribution of endogenous methoxykaempferol glucoronide in zebra plant (Aphelandra squarrosa) leaves producing a localization map that is corroborated by the literature. PIR-LAESI was further used to image the distribution inside mouse kidneys of gadoteridol, an exogenous magnetic resonance contrast agent intravenously injected. Parallel mass spectrometry imaging (MSI) using desorption electrospray ionization (DESI) and matrix assisted laser desorption ionization (MALDI) were performed to corroborate PIR-LAESI images of the exogenous agent. We further show that PIR-LAESI is capable of desorption ionization of proteins as well as phospholipids. This comparative study illustrates that PIR-LAESI is an ion source for ambient mass spectrometry applications. As such, a future PIRL scalpel combined with secondary ionization such as ESI and mass spectrometry has the potential to provide molecular feedback to guide PIRL surgery.

  9. Non-traditional applications of laser desorption/ionization mass spectrometry

    Science.gov (United States)

    McAlpin, Casey R.

    Seven studies were carried out using laser desorption/ionization mass spectrometry (LDI MS) to develop enhanced methodologies for a variety of analyte systems by investigating analyte chemistries, ionization processes, and elimination of spectral interferences. Applications of LDI and matrix assisted laser/desorption/ionization (MALDI) have been previously limited by poorly understood ionization phenomena, and spectral interferences from matrices. Matrix assisted laser desorption ionization MS is well suited to the analysis of proteins. However, the proteins associated with bacteriophages often form complexes which are too massive for detection with a standard MALDI mass spectrometer. As such, methodologies for pretreatment of these samples are discussed in detail in the first chapter. Pretreatment of bacteriophage samples with reducing agents disrupted disulfide linkages and allowed enhanced detection of bacteriophage proteins. The second chapter focuses on the use of MALDI MS for lipid compounds whose molecular mass is significantly less than the proteins for which MALDI is most often applied. The use of MALDI MS for lipid analysis presented unique challenges such as matrix interference and differential ionization efficiencies. It was observed that optimization of the matrix system, and addition of cationization reagents mitigated these challenges and resulted in an enhanced methodology for MALDI MS of lipids. One of the challenges commonly encountered in efforts to expand MALDI MS applications is as previously mentioned interferences introduced by organic matrix molecules. The third chapter focuses on the development of a novel inorganic matrix replacement system called metal oxide laser ionization mass spectrometry (MOLI MS). In contrast to other matrix replacements, considerable effort was devoted to elucidating the ionization mechanism. It was shown that chemisorption of analytes to the metal oxide surface produced acidic adsorbed species which then

  10. Quantitative analysis of abused drugs in physiological fluids by gas chromatography/chemical ionization mass spectrometry

    International Nuclear Information System (INIS)

    Methods have been developed for quantitative analysis of commonly abused drugs in physiological fluids using gas chromatography/chemical ionization mass spectrometry. The methods are being evaluated in volunteer analytical and toxicological laboratories, and analytical manuals describing the methods are being prepared. The specific drug and metabolites included in this program are: Δ9-tetrahydrocannabinol, methadone, phencyclidine, methaqualone, morphine, amphetamine, methamphetamine, mescaline, 2,5-dimethoxy-4-methyl amphetamine, cocaine, benzoylecgonine, diazepam, and N-desmethyldiazepam. The current analytical methods utilize relatively conventional instrumentation and procedures, and are capable of measuring drug concentrations as low as 1 ng/ml. Various newer techniques such as sample clean-up by high performance liquid chromatography, separation by glass capillary chromatography, and ionization by negative ion chemical ionization are being investigated with respect to their potential for achieving higher sensitivity and specificity, as well as their ability to facilitate simultaneous analysis of more than one drug and metabolite. (Auth.)

  11. 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.

  12. Electrospray ionization mass spectral characteristics and fragmentation mechanisms of Angiotensin II and its analogues

    Science.gov (United States)

    Li, Huihui; Yuan, Gu

    2006-05-01

    The characteristic fragmentation pathways of Angiotensin II and eight analogues were investigated by electrospray ionization tandem mass spectrometry. The main fragmentations involve the cleavages of the CCO and CONH bonds with the loss of water, ammonia or carbon monoxide and rearrangements involving hydrogen atoms, and the MS/MS spectra give significant sequence information of these octapeptides. In addition, the two members of the analogues with the same mass and different elemental composition can be distinguished by the MS/MS spectra of [M + H]+ and fragment ions. These results show that ESI tandem mass spectrometry is an excellent tool for the structural identification of Angiotensin II and its analogues.

  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. 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.

  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. omniSpect: an open MATLAB-based tool for visualization and analysis of matrix-assisted laser desorption/ionization and desorption electrospray ionization mass spectrometry images.

    Science.gov (United States)

    Parry, R Mitchell; Galhena, Asiri S; Gamage, Chaminda M; Bennett, Rachel V; Wang, May D; Fernández, Facundo M

    2013-04-01

    We present omniSpect, an open source web- and MATLAB-based software tool for both desorption electrospray ionization (DESI) and matrix-assisted laser desorption ionization (MALDI) mass spectrometry imaging (MSI) that performs computationally intensive functions on a remote server. These functions include converting data from a variety of file formats into a common format easily manipulated in MATLAB, transforming time-series mass spectra into mass spectrometry images based on a probe spatial raster path, and multivariate analysis. OmniSpect provides an extensible suite of tools to meet the computational requirements needed for visualizing open and proprietary format MSI data.

  19. OmniSpect: An Open MATLAB-Based Tool for Visualization and Analysis of Matrix-Assisted Laser Desorption/Ionization and Desorption Electrospray Ionization Mass Spectrometry Images

    Science.gov (United States)

    Parry, R. Mitchell; Galhena, Asiri S.; Gamage, Chaminda M.; Bennett, Rachel V.; Wang, May D.; Fernández, Facundo M.

    2013-04-01

    We present omniSpect, an open source web- and MATLAB-based software tool for both desorption electrospray ionization (DESI) and matrix-assisted laser desorption ionization (MALDI) mass spectrometry imaging (MSI) that performs computationally intensive functions on a remote server. These functions include converting data from a variety of file formats into a common format easily manipulated in MATLAB, transforming time-series mass spectra into mass spectrometry images based on a probe spatial raster path, and multivariate analysis. OmniSpect provides an extensible suite of tools to meet the computational requirements needed for visualizing open and proprietary format MSI data. [Figure not available: see fulltext.

  20. Cold-spray ionization mass spectrometry: applications in structural coordination chemistry.

    Science.gov (United States)

    Yamaguchi, Kentaro

    2013-01-01

    Electrospray ionization (ESI)-mass spectrometry (MS) is generally used for the characterization of labile supramolecules in which non-covalent bonding interactions are predominant. However, molecular ions are not detected in many cases because of their instability, and even if such ions are detected, thermal decomposition generates fragment ions that also appear in the mass spectrum. Cold-spray ionization (CSI) is designed for the MS detection of labile organic species. It is used to analyze the structures of biomolecular complexes and labile organic species in solution. The method, a variant of ESI-MS, operates at low temperature, allowing simple and precise characterization of labile non-covalent complexes that are difficult or impossible to observe by conventional MS techniques. The CSI method is particularly suitable for elucidating the structures of labile organometallic compounds in solution as it offers a means to investigate the dynamic behavior of unstable molecules and/or labile clusters in solution. Various labile organic compounds are analyzed by using the CSI method in the field of organic chemistry. CSI-MS is also used to investigate the behavior of aggregated steroid compounds, namely, bisguanidinobenzene-benzoic acid complexes, in solution. This method is a powerful tool for analyzing the equilibria of multiply linked self-assembling catenanes in solution. Its application to unstable and complex supramolecules will be shown. We have developed an effective ionization method that uses metal-complex-based ionization probes containing 2,6-bis(oxazolinyl) pyridine (pybox) ligands. Using this method, we were able to detect multiply charged ions of target molecules. This method was proven to effectively ionize large complex molecules, including biomolecules and various supramolecules, as well as carbon clusters, such as fullerenes. Moreover, isotope-labeled pybox-La complexes were used to clearly detect isotopic labeling shifts. Their applications to

  1. Development of Soft Ionization for Particulate Organic Detection with the Aerodyne Aerosol Mass Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Trimborn, A; Williams, L R; Jayne, J T; Worsnop, D R

    2008-06-19

    During this DOE SBIR Phase II project, we have successfully developed several soft ionization techniques, i.e., ionization schemes which involve less fragmentation of the ions, for use with the Aerodyne time-of-flight aerosol mass spectrometer (ToF-AMS). Vacuum ultraviolet single photon ionization was demonstrated in the laboratory and deployed in field campaigns. Vacuum ultraviolet single photon ionization allows better identification of organic species in aerosol particles as shown in laboratory experiments on single component particles, and in field measurements on complex multi-component particles. Dissociative electron attachment with lower energy electrons (less than 30 eV) was demonstrated in the measurement of particulate organics in chamber experiments in Switzerland, and is now a routine approach with AMS systems configured for bipolar, negative ion detection. This technique is particularly powerful for detection of acidic and other highly oxygenated secondary organic aerosol (SOA) chemical functionality. Low energy electron ionization (10 to 12 eV) is also a softer ionization approach routinely available to AMS users. Finally, Lithium ion attachment has been shown to be sensitive to more alkyl-like chemical functionality in SOA. Results from Mexico City are particularly exciting in observing changes in SOA molecular composition under different photochemical/meteorological conditions. More recent results detecting biomass burns at the Montana fire lab have demonstrated quantitative and selective detection of levoglucosan. These soft ionization techniques provide the ToF-AMS with better capability for identifying organic species in ambient atmospheric aerosol particles. This, in turn, will allow more detailed study of the sources, transformations and fate of organic-containing aerosol.

  2. Gas chromatography interfaced with atmospheric pressure ionization-quadrupole time-of-flight-mass spectrometry by low-temperature plasma ionization

    DEFF Research Database (Denmark)

    Norgaard, Asger W.; Kofoed-Sorensen, Vivi; Svensmark, Bo;

    2013-01-01

    A low temperature plasma (LTP) ionization interface between a gas chromatograph (GC) and an atmospheric pressure inlet mass spectrometer, was constructed. This enabled time-of-flight mass spectrometric detection of GC-eluting compounds. The performance of the setup was evaluated by injection...

  3. Resonance ionization mass spectrometric analysis of thorium by external laser cavity enhancement techniques

    International Nuclear Information System (INIS)

    Over the last several years, extensive effort has been directed towards the demonstration of Resonance Ionization Mass Spectrometry (RIMS) as a generally-applicable isotopic analysis technique. The major problems in this task have been to achieve a high overall ionization efficiency as well as good sample utilization. Several aspects of these problems are apparent in the choice of the excitation and ionization sources for the selective RIMS process. Pulsed lasers have typically had low repetition rates, poor spectral and temporal behavior, and short pulse durations. These characteristics have limited the general utility of pulsed lasers because of the low duty cycle (low efficiency), pulse pile-up detection difficulties (limited dynamic range), and relatively poor stability (poor precision). In contrast, cw lasers offer 100% effective duty cycles, well-controlled laser profiles (spectrally, spatially and temporally), and excellent power stability. The main feature limiting the utility of cw lasers has been power. While sufficient intensity is available to saturate the resonant transition, efficient promotion of excited atoms to the ionization continuum is difficult. This last aspect is where the authors efforts have centered. Presently, they are pursuing an external cavity technique which will generate overall ionization efficiencies of tens of percent, as well as increase the available spectral range. Experimental aspects and process to date on thorium will be discussed in detail

  4. Improved Polymerase Chain Reaction-restriction Fragment Length Polymorphism Genotyping of Toxic Pufferfish by Liquid Chromatography/Mass Spectrometry.

    Science.gov (United States)

    Miyaguchi, Hajime

    2016-09-20

    An improved version of a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method for genotyping toxic pufferfish species by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) is described. DNA extraction is carried out using a silica membrane-based DNA extraction kit. After the PCR amplification using a detergent-free PCR buffer, restriction enzymes are added to the solution without purifying the reaction solution. A reverse-phase silica monolith column and a Fourier transform high resolution mass spectrometer having a modified Kingdon trap analyzer are employed for separation and detection, respectively. The mobile phase, consisting of 400 mM 1,1,1,3,3,3-hexafluoro-2-propanol, 15 mM triethylamine (pH 7.9) and methanol, is delivered at a flow rate of 0.4 ml/min. The cycle time for LC/ESI-MS analysis is 8 min including equilibration of the column. Deconvolution software having an isotope distribution model of the oligonucleotide is used to calculate the corresponding monoisotopic mass from the mass spectrum. For analysis of oligonucleotides (range 26-79 nucleotides), mass accuracy was 0.62 ± 0.74 ppm (n = 280) and excellent accuracy and precision were sustained for 180 hr without use of a lock mass standard.

  5. Improved Polymerase Chain Reaction-restriction Fragment Length Polymorphism Genotyping of Toxic Pufferfish by Liquid Chromatography/Mass Spectrometry.

    Science.gov (United States)

    Miyaguchi, Hajime

    2016-01-01

    An improved version of a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method for genotyping toxic pufferfish species by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) is described. DNA extraction is carried out using a silica membrane-based DNA extraction kit. After the PCR amplification using a detergent-free PCR buffer, restriction enzymes are added to the solution without purifying the reaction solution. A reverse-phase silica monolith column and a Fourier transform high resolution mass spectrometer having a modified Kingdon trap analyzer are employed for separation and detection, respectively. The mobile phase, consisting of 400 mM 1,1,1,3,3,3-hexafluoro-2-propanol, 15 mM triethylamine (pH 7.9) and methanol, is delivered at a flow rate of 0.4 ml/min. The cycle time for LC/ESI-MS analysis is 8 min including equilibration of the column. Deconvolution software having an isotope distribution model of the oligonucleotide is used to calculate the corresponding monoisotopic mass from the mass spectrum. For analysis of oligonucleotides (range 26-79 nucleotides), mass accuracy was 0.62 ± 0.74 ppm (n = 280) and excellent accuracy and precision were sustained for 180 hr without use of a lock mass standard. PMID:27684516

  6. [Real-time analysis of polyvinyl chloride thermal decomposition/combustion products with single photon ionization/photoelectron ionization online mass spectrometer].

    Science.gov (United States)

    Chen, Wen-Dong; Hou, Ke-Yong; Chen, Ping; Li, Fang-Long; Zhao, Wu-Duo; Cui, Hua-Peng; Hua, Lei; Xie, Yuan-Yuan; Li, Hai-Yang

    2013-01-01

    With the features of a broad range of ionizable compounds, reduced fragments and simple mass spectrum, a homemade magnetic field enhanced photoelectron ionization (MEPEI) source combined with single photon ionization (SPI) for time-of-flight mass spectrometer was built and applied to analyze thermal decomposition/combustion products of polyvinyl chloride (PVC). The combined ion source can be switched very fast between SPI mode and SPI-MEPEI mode for detecting different targeted compounds, and only adjusting the voltage of the electrode in the ionization region to trigger the switch. Among the PVC thermal decomposition/combustion products, HCl and CO2, which ionization energies (12.74 eV, 13.77 eV respectively) were higher than the energy of photon (10.60 eV), were ionized by MEPEI, while alkenes, dichloroethylene, benzene and its homologs, monochlorobenzene, styrene, indane, naphthalene and its homologs were ionized by SPI and MEPEI simultaneously. Spectra of interested products as a function of temperatures indicated that products are formed via two main mechanisms: (1) dechlorination and intramolecular cyclization can lead to the formation of HCl, benzene and naphthalene at 250-370 degrees C; (2) intermolecular crosslinking leads to the formation of alkyl aromatics such as toluene and xylene/ethylbenzene at 380-510 degrees C. The experimental results show that the combined ion source of SPI/ SPI-MEPEI for TOF-MS has broad application prospects in the online analysis field.

  7. Staying Alive: Measuring Intact Viable Microbes with Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Forsberg, Erica; Fang, Mingliang; Siuzdak, Gary

    2016-07-01

    Mass spectrometry has traditionally been the technology of choice for small molecule analysis, making significant inroads into metabolism, clinical diagnostics, and pharmacodynamics since the 1960s. In the mid-1980s, with the discovery of electrospray ionization (ESI) for biomolecule analysis, a new door opened for applications beyond small molecules. Initially, proteins were widely examined, followed by oligonucleotides and other nonvolatile molecules. Then in 1991, three intriguing studies reported using mass spectrometry to examine noncovalent protein complexes, results that have been expanded on for the last 25 years. Those experiments also raised the questions: How soft is ESI, and can it be used to examine even more complex interactions? Our lab addressed these questions with the analyses of viruses, which were initially tested for viability following electrospray ionization and their passage through a quadrupole mass analyzer by placing them on an active medium that would allow them to propagate. This observation has been replicated on multiple different systems, including experiments on an even bigger microbe, a spore. The question of analysis was also addressed in the early 2000s with charge detection mass spectrometry. This unique technology could simultaneously measure mass-to-charge and charge, allowing for the direct determination of the mass of a virus. More recent experiments on spores and enveloped viruses have given us insight into the range of mass spectrometry's capabilities (reaching 100 trillion Da), beginning to answer fundamental questions regarding the complexity of these organisms beyond proteins and genes, and how small molecules are integral to these supramolecular living structures.

  8. Super-atmospheric pressure ionization mass spectrometry and its application to ultrafast online protein digestion analysis.

    Science.gov (United States)

    Chen, Lee Chuin; Ninomiya, Satoshi; Hiraoka, Kenzo

    2016-06-01

    Ion source pressure plays a significant role in the process of ionization and the subsequent ion transmission inside a mass spectrometer. Pressurizing the ion source to a gas pressure greater than atmospheric pressure is a relatively new approach that aims to further improve the performance of atmospheric pressure ionization sources. For example, under a super-atmospheric pressure environment, a stable electrospray can be sustained for liquid with high surface tension such as pure water, because of the suppression of electric discharge. Even for nano-electrospray ionization (nano-ESI), which is known to work with aqueous solution, its stability and sensitivity can also be enhanced, particularly in the negative mode when the ion source is pressurized. A brief review on the development of super-atmospheric pressure ion sources, including high-pressure electrospray, field desorption and superheated ESI, and the strategies to interface these ion sources to a mass spectrometer will be given. Using a recent ESI prototype with an operating temperature at 220 °C under 27 atm, we also demonstrate that it is possible to achieve an online Asp-specific protein digestion analysis in which the whole processes of digestion, ionization and MS acquisition could be completed on the order of a few seconds. This method is fast, and the reaction can even be monitored on a near-real-time basis. Copyright © 2016 John Wiley & Sons, Ltd.

  9. Electrospray-assisted laser desorption/ionization and tandem mass spectrometry of peptides and proteins.

    Science.gov (United States)

    Peng, Ivory X; Shiea, Jentaie; Ogorzalek Loo, Rachel R; Loo, Joseph A

    2007-01-01

    We have constructed an electrospray-assisted laser desorption/ionization (ELDI) source which utilizes a nitrogen laser pulse to desorb intact molecules from matrix-containing sample solution droplets, followed by electrospray ionization (ESI) post-ionization. The ELDI source is coupled to a quadrupole ion trap mass spectrometer and allows sampling under ambient conditions. Preliminary data showed that ELDI produces ESI-like multiply charged peptides and proteins up to 29 kDa carbonic anhydrase and 66 kDa bovine albumin from single-protein solutions, as well as from complex digest mixtures. The generated multiply charged polypeptides enable efficient tandem mass spectrometric (MS/MS)-based peptide sequencing. ELDI-MS/MS of protein digests and small intact proteins was performed both by collisionally activated dissociation (CAD) and by nozzle-skimmer dissociation (NSD). ELDI-MS/MS may be a useful tool for protein sequencing analysis and top-down proteomics study, and may complement matrix-assisted laser desorption/ionization (MALDI)-based measurements. PMID:17639579

  10. Rotation planar chromatography coupled on-line with atmospheric pressure chemical ionization mass spectrometry.

    Science.gov (United States)

    Van Berkel, Gary J; Llave, Jonathan J; De Apadoca, Marilyn F; Ford, Michael J

    2004-01-15

    The coupling of a rotation planar preparative thin-layer chromatography system on-line with mass spectrometry is demonstrated using a simple plumbing scheme and a self-aspirating heated nebulizer probe of a corona discharge atmospheric pressure chemical ionization source. The self-aspiration of the heated nebulizer delivers approximately 20 microL/min of the 3.0 mL/min eluate stream to the mass spectrometer, eliminating the need for an external pump in the system. The viability of the coupling is demonstrated with a three-dye mixture composed of fat red 7B, solvent green 3, and solvent blue 35 separated and eluted from a silica gel-coated rotor using toluene. The real-time characterization of the dyes eluting from the rotor is illustrated in positive ion full-scan mode. Other self-aspirating ion source systems including atmospheric pressure photoionization, electrospray ionization, and inductively coupled plasma ionization, for example, might be configured and used in a similar manner coupled to the chromatograph to expand the types of analytes that could be ionized, detected, and characterized effectively.

  11. Efficient laser desorption ionization mass spectrometry of polycyclic aromatic hydrocarbons using excitation energy transfer from anthracene

    International Nuclear Information System (INIS)

    Highlights: ► Femtomolar detection of PAHs such as perylene and benzopyrene was achieved. ► Photoexcited anthracene molecules transferred their energy to PAHs. ► Electronically excited PAHs were then excited to be ions. ► Two-photon ionization process was necessary to complete the ionization process. ► The number of defect sites could be reduced by the annealing procedure. - Abstract: Polycyclic aromatic hydrocarbons (PAHs), such as perylene and benzopyrene, doped at amounts on the order of femtomol (∼10−15 mol) in anthracene crystals could be detected by laser desorption ionization mass spectrometry. Sensitivity was roughly 103 times higher than that of LDI method in our experimental conditions. It was revealed from the excitation power dependence of the peak intensity of PAHs on the mass spectra that two-photon excitation in one UV pulse was necessary to complete the ionization process. It was also clarified that the number of defect sites that trap excitons generated in anthracene crystals could be reduced by the annealing procedure, by which an efficient energy transfer between anthracene and PAHs became possible

  12. Interfacing Capillary-Based Separations to Mass Spectrometry Using Desorption Electro-spray Ionization

    International Nuclear Information System (INIS)

    The powerful hybrid analysis method of capillary-based separations followed by mass spectrometric analysis gives substantial chemical identity and structural information. It is usually carried out using electro-spray ionization. However, the salts and detergents used in the mobile phase for electrokinetic separations suppress ionization efficiencies and contaminate the inlet of the mass spectrometer. This report describes a new method that uses desorption electro-spray ionization (DESI) to overcome these limitations. Effluent from capillary Columns is deposited on a rotating Teflon disk that is covered with paper. As the surface rotates, the temporal separation of the eluting analytes (i.e., the electro-pherogram) is spatially encoded on the surface. Then, using DESI, surface-deposited analytes are preferentially ionized, reducing the effects of ion suppression and inlet contamination on signal. With the use of this novel approach, two capillary-based separations were performed; a mixture of the rhodamine dyes at milligram/milliliter levels in a 10 mM sodium borate solution was separated by capillary electrophoresis, and a mixture of three cardiac drugs at milligram/milliliter levels in a 12.5 mM sodium borate and 12.5 mM sodium dodecyl sulfate solution was separated by micellar electrokinetic chromatography. In both experiments, the negative effects of detergents and salts on the MS analyses were minimized. (authors)

  13. Super-atmospheric pressure ionization mass spectrometry and its application to ultrafast online protein digestion analysis.

    Science.gov (United States)

    Chen, Lee Chuin; Ninomiya, Satoshi; Hiraoka, Kenzo

    2016-06-01

    Ion source pressure plays a significant role in the process of ionization and the subsequent ion transmission inside a mass spectrometer. Pressurizing the ion source to a gas pressure greater than atmospheric pressure is a relatively new approach that aims to further improve the performance of atmospheric pressure ionization sources. For example, under a super-atmospheric pressure environment, a stable electrospray can be sustained for liquid with high surface tension such as pure water, because of the suppression of electric discharge. Even for nano-electrospray ionization (nano-ESI), which is known to work with aqueous solution, its stability and sensitivity can also be enhanced, particularly in the negative mode when the ion source is pressurized. A brief review on the development of super-atmospheric pressure ion sources, including high-pressure electrospray, field desorption and superheated ESI, and the strategies to interface these ion sources to a mass spectrometer will be given. Using a recent ESI prototype with an operating temperature at 220 °C under 27 atm, we also demonstrate that it is possible to achieve an online Asp-specific protein digestion analysis in which the whole processes of digestion, ionization and MS acquisition could be completed on the order of a few seconds. This method is fast, and the reaction can even be monitored on a near-real-time basis. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27270863

  14. [Development of a membrane inlet-single photon ionization/chemical ionization-mass spectrometer for online analysis of VOCs in water].

    Science.gov (United States)

    Hua, Lei; Wu, Qing-Hao; Hou, Ke-Yong; Cui, Hua-Peng; Chen, Ping; Zhao, Wu-Duo; Xie, Yuan-Yuan; Li, Hai-Yang

    2011-12-01

    A home-made membrane inlet- single photon ionization/chemical ionization- time-of-flight mass spectrometer has been described. A vacuum ultraviolet (VUV) lamp with photon energy of 10.6 eV was used as the light source for single photon ionization (SPI). Chemical ionization (CI) was achieved through ion-molecule reactions with O2- reactant ions generated by photoelectron ionization. The two ionization modes could be rapidly switched by adjusting electric field in the ionization region within 2 s. Membrane inlet system used for rapid enrichment of volatile organic compounds (VOCs) in water was constructed by using a polydimethylsiloxane (PDMS) membrane with a thickness of 50 microm. A purge gas was added to accelerate desorption of analytes from the membrane surface. The purge gas could also help to prevent the pump oil back-streaming into the ionization region from the analyzer chamber and improve the signal to noise ratio (S/N). Achieved detection limits were 2 microg x L(-1) for methyl tert-butyl ether (MTBE) in SPI mode and 1 microg x L(-1) for chloroform in SPI-CI mode within 10 s analysis time, respectively. The instrument has been successfully applied to the rapid analysis of MTBE in simulated underground water nearby petrol station and VOCs in disinfected drinking water. The results indicate that the instrument has a great application prospect for online analysis of VOCs in water.

  15. Overview literature on matrix assisted laser desorption ionization mass spectroscopy (MALDI MS): basics and its applications in characterizing polymeric materials

    Indian Academy of Sciences (India)

    R N Jagtap; A H Ambre

    2005-10-01

    Matrix assisted laser desorption ionization mass spectroscopy (MALDI MS) is a technique which allows the measurement of molecular mass > 200,000 Daltons by ionization and vapourization without degradation. This technique is useful for the mass analysis of synthetic polymers, which have very low volatility. The basic principles of and its applications for polymer characterization have been discussed in this paper. In addition, the possibilities of combining MALDI MS with chromatographic and other analytical techniques have also been discussed.

  16. Food quality and authenticity screening via easy ambient sonic-spray ionization mass spectrometry.

    Science.gov (United States)

    Porcari, Andreia M; Fernandes, Gabriel D; Barrera-Arellano, Daniel; Eberlin, Marcos N; Alberici, Rosana M

    2016-02-21

    This review is the first to summarize a decade of studies testing the use of easy ambient sonic-spray ionization mass spectrometry (EASI-MS) and its several sister techniques, Venturi (V-EASI), thermal imprinting (TI-EASI) and Spartan (S-EASI) mass spectrometry in food quality control and authentication. Since minimal or no sample preparation is required, such ambient desorption/ionization techniques have been shown to provide direct, fast and selective fingerprinting characterization at the molecular level based on the pools of the most typical components. They have also been found to be applicable on intact, undisturbed samples or on simple solvent extracts. Fundamentals of EASI-MS and its sister techniques, including mechanisms, devices, parameters and strategies, as well as the many applications reported for food analysis, are summarized and discussed. PMID:26820190

  17. Food quality and authenticity screening via easy ambient sonic-spray ionization mass spectrometry.

    Science.gov (United States)

    Porcari, Andreia M; Fernandes, Gabriel D; Barrera-Arellano, Daniel; Eberlin, Marcos N; Alberici, Rosana M

    2016-02-21

    This review is the first to summarize a decade of studies testing the use of easy ambient sonic-spray ionization mass spectrometry (EASI-MS) and its several sister techniques, Venturi (V-EASI), thermal imprinting (TI-EASI) and Spartan (S-EASI) mass spectrometry in food quality control and authentication. Since minimal or no sample preparation is required, such ambient desorption/ionization techniques have been shown to provide direct, fast and selective fingerprinting characterization at the molecular level based on the pools of the most typical components. They have also been found to be applicable on intact, undisturbed samples or on simple solvent extracts. Fundamentals of EASI-MS and its sister techniques, including mechanisms, devices, parameters and strategies, as well as the many applications reported for food analysis, are summarized and discussed.

  18. 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.

  19. Effect of dimethylamine on the gas phase sulfuric acid concentration measured by Chemical Ionization Mass Spectrometry

    OpenAIRE

    L. Rondo; Flagan, R. C.

    2016-01-01

    Sulfuric acid is widely recognized as a very important substance driving atmospheric aerosol nucleation. Based on quantum chemical calculations it has been suggested that the quantitative detection of gas phase sulfuric acid (H_2SO_4) by use of Chemical Ionization Mass Spectrometry (CIMS) could be biased in the presence of gas phase amines such as dimethylamine (DMA). An experiment (CLOUD7 campaign) was set up at the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber to investigate the quantita...

  20. Cold-spray Ionization Mass Spectrometry for Characterization of Biomolecules in Solution

    Institute of Scientific and Technical Information of China (English)

    Kentaro YAMAGUCHI; Shigeru SAKAMOTO

    2003-01-01

    @@ A direct solution analysis method, coldspray ionization (CSI) mass spectrometry (MS)[1], a variant of electrospray (ESI) MS operating at low temperature (ca. - 80 ~ 10℃), allows facile and precise characterization of labile organic species, especially those in which non-covalent bonding interactions are prominent. We have applies this method to investigations of the solution structures of many labile organic species, including unstable reagents and reaction intermediates, asymmetric catalysts, supramolecules, and even primary biomolecules.

  1. Study of molecular complexation of glycyrrhizic acid with chloramphenicol by electrospray ionization mass spectrometry

    OpenAIRE

    Vetrova, Elena V.; Lekar, Anna V.; Filonova, Olga V.; Borisenko, Sergey N.; Maksimenko, Elena V.; Borisenko, Nikolay I.

    2015-01-01

    Context: Glycyrrhizic acid (GA) is a triterpene glycoside representing the main active component of licorice root extract obtained from plants of the Glycyrrhiza glabra L. and widely used as a complex-forming agent for the synthesis of new transport forms of the well-known drugs. Aims: For the first time, the complexation of GA with chloramphenicol antibiotic (ChlA) was investigated by electrospray ionization mass spectrometry (ESI MS). Subjects and Methods: ESI MS was utilized in order to de...

  2. Determination of triacetone triperoxide using ultraviolet femtosecond multiphoton ionization time-of-flight mass spectrometry

    International Nuclear Information System (INIS)

    Highlights: • A UV ultrashort laser pulse was useful for ionization of triacetone triperoxide. • A molecular ion was strongly enhanced in multiphoton ionization mass spectrometry. • Triacetone triperoxide in the human blood was measured without any interferences. • An organic compound of phorone was formed in the human blood from acetone. - Abstract: Triacetone triperoxide (TATP), an explosive compound, was measured using gas chromatography combined with multiphoton ionization time-of-flight mass spectrometry (GC/MPI-TOFMS). By decreasing the pulse width of a femtosecond laser from 80 to 35 fs, a molecular ion was drastically enhanced and was measured as one of the major ions in the mass spectrum. The detection limits obtained using the molecular (M·+) and fragment (C2H3O+) ions were similar or slightly superior to those obtained using conventional mass spectrometry based on electron and chemical ionization. In order to improve the reliability, an isotope of TATP, i.e., TATP-d18, was synthesized and used as an internal standard in the trace analysis of TATP in a sample of human blood. TATP could be identified in a two-dimensional display, even though numerous interfering compounds were present in the sample. Acetone, which is frequently used as a solvent in sampling TATP, produced a chemical species with a retention time nearly identical to that of TATP and provided a C2H3O+ fragment ion that was employed for measuring a chromatogram of TATP in conventional MS. This compound, the structure of which was assigned as phorone, was clearly differentiated from TATP based on a molecular ion observable in MPI-TOFMS

  3. Matrix-assisted laser desorption/ionization mass spectrometry of immobilized duplex DNA probes.

    OpenAIRE

    Tang, K; Fu, D.; Kötter, S; Cotter, R J; Cantor, C R; Köster, H

    1995-01-01

    Matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry was used to analyze short DNA duplex probes with one strand immobilized on solid supports (straptavidin-coated magnetic beads or controlled pore glass beads). Only the non-immobilized strand could be detected. Partial denaturation was found when the duplex probes were mixed with 3-hydroxypicolinic acid, ammonium citrate matrix. The strategy has several applications, such as fast DNA sequence analysis an...

  4. Real-time monitoring of volatile organic compounds using chemical ionization mass spectrometry

    Science.gov (United States)

    Mowry, Curtis Dale; Thornberg, Steven Michael

    1999-01-01

    A system for on-line quantitative monitoring of volatile organic compounds (VOCs) includes pressure reduction means for carrying a gaseous sample from a first location to a measuring input location maintained at a low pressure, the system utilizing active feedback to keep both the vapor flow and pressure to a chemical ionization mode mass spectrometer constant. A multiple input manifold for VOC and gas distribution permits a combination of calibration gases or samples to be applied to the spectrometer.

  5. MALDI mass spectrometry imaging of N-glycans on tibial cartilage and subchondral bone proteins in knee osteoarthritis.

    Science.gov (United States)

    Briggs, Matthew T; Kuliwaba, Julia S; Muratovic, Dzenita; Everest-Dass, Arun V; Packer, Nicolle H; Findlay, David M; Hoffmann, Peter

    2016-06-01

    Magnetic resonance imaging (MRI) is a non-invasive technique routinely used to investigate pathological changes in knee osteoarthritis (OA) patients. MRI uniquely reveals zones of the most severe change in the subchondral bone (SCB) in OA, called bone marrow lesions (BMLs). BMLs have diagnostic and prognostic significance in OA, but MRI does not provide a molecular understanding of BMLs. Multiple N-glycan structures have been observed to play a pivotal role in the OA disease process. We applied matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) of N-glycans to formalin-fixed paraffin-embedded (FFPE) SCB tissue sections from patients with knee OA, and liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) was conducted on consecutive sections to structurally characterize and correlate with the N-glycans seen by MALDI-MSI. The application of this novel MALDI-MSI protocol has enabled the first steps to spatially investigate the N-glycome in the SCB of knee OA patients. PMID:26992165

  6. Identification of Microalgae by Laser Desorption/Ionization Mass Spectrometry Coupled with Multiple Nanomatrices.

    Science.gov (United States)

    Peng, Lung-Hsiang; Unnikrishnan, Binesh; Shih, Chi-Yu; Hsiung, Tung-Ming; Chang, Jeng; Hsu, Pang-Hung; Chiu, Tai-Chia; Huang, Chih-Ching

    2016-04-01

    In this study, we demonstrate a simple method to identify microalgae by surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) using three different substrates: HgSe, HgTe, and HgTeSe nanostructures. The fragmentation/ionization processes of complex molecules in algae varied according to the heat absorption and transfer efficiency of the nanostructured matrices (NMs). Therefore, the mass spectra obtained for microalgae showed different patterns of m/z values for different NMs. The spectra contained both significant and nonsignificant peaks. Constructing a Venn diagram with the significant peaks obtained for algae when using HgSe, HgTe, and HgTeSe NMs in m/z ratio range 100-1000, a unique relationship among the three sets of values was obtained. This unique relationship of sets is different for each species of microalgae. Therefore, by observing the particular relationship of sets, we successfully identified different algae such as Isochrysis galbana, Emiliania huxleyi, Thalassiosira weissflogii, Nannochloris sp., Skeletonema cf. costatum, and Tetraselmis chui. This simple and cost-effective SALDI-MS analysis method coupled with multi-nanomaterials as substrates may be extended to identify other microalgae and microorganisms in real samples. Graphical Abstract Identification of microalgae by surface-assisted laser desorption/ionization mass spectrometry coupled with three different mercury-based nanosubstrates. PMID:26842733

  7. Laser desorption/ionization mass spectrometry of lipids using etched silver substrates.

    Science.gov (United States)

    Schnapp, Andreas; Niehoff, Ann-Christin; Koch, Annika; Dreisewerd, Klaus

    2016-07-15

    Silver-assisted laser desorption/ionization mass spectrometry can be used for the analysis of small molecules. For example, adduct formation with silver cations enables the molecular analysis of long-chain hydrocarbons, which are difficult to ionize via conventional matrix-assisted laser desorption ionization (MALDI). Here we used highly porous silver foils, produced by etching with nitric acid, as sample substrates for LDI mass spectrometry. As model system for the analysis of complex lipid mixtures, cuticular extracts of fruit flies (Drosophila melanogaster) and worker bees (Apis mellifera) were investigated. The mass spectra obtained by spotting extract onto the etched silver substrates demonstrate the sensitive detection of numerous lipid classes such as long-chain saturated and unsaturated hydrocarbons, fatty acyl alcohols, wax esters, and triacylglycerols. MS imaging of cuticular surfaces with a lateral resolution of a few tens of micrometers became possible after blotting, i.e., after transferring lipids by physical contact with the substrate. The examples of pheromone-producing male hindwings of the squinting bush brown butterfly (Bicyclus anynana) and a fingermark are shown. Because the substrates are also easy to produce, they provide a viable alternative to colloidal silver nanoparticles and other so far described silver substrates. PMID:26827933

  8. Imaging of Proteins in Tissue Samples Using Nanospray Desorption Electrospray Ionization Mass Spectrometry.

    Science.gov (United States)

    Hsu, Cheng-Chih; Chou, Pi-Tai; Zare, Richard N

    2015-11-17

    Chemical maps of tissue samples provide important information on biological processes therein. Recently, advances in tissue imaging have been achieved using ambient ionization techniques, such as desorption electrospray ionization mass spectrometry (DESI-MS), but such techniques have been almost exclusively confined to the mapping of lipids and metabolites. We report here the use of nanospray desorption electrospray ionization (nanoDESI) that allows us to image proteins in tissue samples in a label-free manner at atmospheric pressure with only minimum sample preparation. Multiply charged proteins with masses up to 15 kDa were successfully detected by nanoDESI using an LTQ Orbitrap mass spectrometer. In an adult mice brain section, expression of proteins including ubiquitin, β-thymosin, myelin basic protein, and hemoglobin were spatially mapped and characterized. We also determined the location of methylation on myelin basic protein. This imaging modality was further implemented to MYC-induced lymphomas. We observed an array of truncated proteins in the region where normal thymus cells were infiltrated by tumor cells, in contrast to healthy tissue.

  9. Super-atmospheric pressure ionization mass spectrometry and its application to ultrafast online protein digestion analysis.

    Science.gov (United States)

    Chen, L C; Ninomiya, S; Hiraoka, K

    2016-06-01

    Pressure is a key parameter for an ionization source. In this Special Feature article, Lee Chuin Chen and colleagues review super-atmospheric pressure ionization MS with electrospray, corona-discharge-based chemical ionization, and field desorption. They routinely run their mass spectrometer with ion source pressures ranging from several to several tens of atmospheres. A number of strategies have been used to preserve the high vacuum of the instrument while working with a high-pressure (HP) ion source. A recent prototype uses a booster pump with variable pumping speed added to the first pumping stage of the mass spectrometer to regulate a constant vacuum pressure. Further, a new HP-ESI source allowing rapid (a few seconds) online protein digestion MS is also reported. Dr. Lee Chuin Chen is Associate Professor in the Department of Interdisciplinary Research at the University of Yamanashi (Yamanashi, Japan). His main research interest is the development of novel mass spectrometric methods for in-situ medical diagnosis. PMID:27270871

  10. Fast detection of narcotics by single photon ionization mass spectrometry and laser ion mobility spectrometry

    Science.gov (United States)

    Laudien, Robert; Schultze, Rainer; Wieser, Jochen

    2010-10-01

    In this contribution two analytical devices for the fast detection of security-relevant substances like narcotics and explosives are presented. One system is based on an ion trap mass spectrometer (ITMS) with single photon ionization (SPI). This soft ionization technique, unlike electron impact ionization (EI), reduces unwanted fragment ions in the mass spectra allowing the clear determination of characteristic (usually molecular) ions. Their enrichment in the ion trap and identification by tandem MS investigations (MS/MS) enables the detection of the target substances in complex matrices at low concentrations without time-consuming sample preparation. For SPI an electron beam pumped excimer light source of own fabrication (E-Lux) is used. The SPI-ITMS system was characterized by the analytical study of different drugs like cannabis, heroin, cocaine, amphetamines, and some precursors. Additionally, it was successfully tested on-site in a closed illegal drug laboratory, where low quantities of MDMA could be directly detected in samples from floors, walls and lab equipments. The second analytical system is based on an ion mobility (IM) spectrometer with resonant multiphoton ionization (REMPI). With the frequency quadrupled Nd:YAG laser (266 nm), used for ionization, a selective and sensitive detection of aromatic compounds is possible. By application of suited aromatic dopants, in addition, also non-aromatic polar compounds are accessible by ion molecule reactions like proton transfer or complex formation. Selected drug precursors could be successfully detected with this device as well, qualifying it to a lower-priced alternative or useful supplement of the SPI-ITMS system for security analysis.

  11. Determination of Phytochelatins in Rice by Stable Isotope Labeling Coupled with Liquid Chromatography-Mass Spectrometry.

    Science.gov (United States)

    Liu, Ping; Cai, Wen-Jing; Yu, Lei; Yuan, Bi-Feng; Feng, Yu-Qi

    2015-07-01

    A highly sensitive method was developed for the detection of phytochelatins (PCs) in rice by stable isotope labeling coupled with liquid chromatography-electrospray ionization-tandem mass spectrometry (IL-LC-ESI-MS/MS) analysis. A pair of isotope-labeling reagents [ω-bromoacetonylquinolinium bromide (BQB) and BQB-d(7)] were used to label PCs in plant sample and standard PCs, respectively, and then combined prior to LC/MS analysis. The heavy labeled standards were used as the internal standards for quantitation to minimize the matrix and ion suppression effects in MS analysis. In addition, the ionization efficiency of PCs was greatly enhanced through the introduction of a permanent charged moiety of quaternary ammonium of BQB into PCs. The detection sensitivities of PCs upon BQB labeling improved by 14-750-fold, and therefore, PCs can be quantitated using only 5 mg of plant tissue. Furthermore, under cadmium (Cd) stress, we found that the contents of PCs in rice dramatically increased with the increased concentrations and treatment time of Cd. It was worth noting that PC5 was first identified and quantitated in rice tissues under Cd stress in the current study. Taken together, this IL-LC-ESI-MS/MS method demonstrated to be a promising strategy in detection of PCs in plants with high sensitivity and reliability.

  12. Broad spectrum drug screening using electron-ionization gas chromatography-mass spectrometry (EI-GCMS).

    Science.gov (United States)

    Stone, Judy

    2010-01-01

    A liquid-liquid extraction (LLE) of drugs and internal standard (promazine) is performed by mixing urine at basic pH with 1-chlorobutane. There are no hydrolysis or derivatization steps. After centrifugation the organic (upper) layer is transferred to another tube and evaporated. The dried extract is reconstituted with ethyl acetate and 1 microL is injected onto the GCMS. Drugs are volatilized in the GC inlet and separated on a capillary column. In the EI source drugs become positively charged and fragment. Mass analysis of ionized fragments occurs with a single quadrupole. The resulting full scan mass spectra are automatically searched against three libraries. PMID:20077071

  13. The Need for Speed in Matrix-Assisted Laser Desorption/Ionization Imaging Mass Spectrometry

    Science.gov (United States)

    Prentice, Boone M.; Caprioli, Richard M.

    2016-01-01

    Imaging mass spectrometry (IMS) has emerged as a powerful analytical tool enabling the direct molecular mapping of many types of tissue. Specifically, matrix-assisted laser desorption/ ionization (MALDI) represents one of the most broadly applicable IMS technologies. In recent years, advances in solid state laser technology, mass spectrometry instrumentation, computer technology, and experimental methodology have produced IMS systems capable of unprecedented data acquisition speeds (>50 pixels/second). In applications of this technology, throughput is an important consideration when designing an IMS experiment. As IMS becomes more widely adopted, continual improvements in experimental setups will be important to address biologically and clinically relevant time scales.

  14. Novel Rearrangement of Small Peptides in Electrospray Ionization Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    CHEN,Yi(陈益); WANG,Jin(王津); LIU,Xiao-Hong(刘晓红); SUN,Ming(孙命); CHEN,Jing(陈晶); JIANG,Yang(江洋); ZHAO,Yu-Fen(赵玉芬)

    2004-01-01

    Electrospray ionization mass spectrometry (ESI-MS) is a powerful method for sequencing peptides.A novel fragmentation pattern with the loss of a neutral fragment of 45 Da was observed with the dipeptides,tripeptides,tetrapeptides and pentapeptides containing phenylalanine or histidine residues.A novel rearrangement reaction with the extrusion of a formamide piece was studied and the rearrangement mechanism was proposed and confirmed by deuterium labeling experiments with ESI-MSn and high-resolution mass spectrometry.These findings are potentially helpful in identifying the specific sequence pattern in the peptide sequencing.

  15. Standard test method for uranium and plutonium concentrations and isotopic abundances by thermal ionization mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the determination of the concentration and isotopic composition of uranium and plutonium in solutions. The purified uranium or plutonium from samples ranging from nuclear materials to environmental or bioassay matrices is loaded onto a mass spectrometric filament. The isotopic ratio is determined by thermal ionization mass spectrometry, the concentration is determined by isotope dilution. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish safety and health practices and determine the applicability of regulatory limitations prior to use.

  16. Critical comparison of mass analyzers for forensic hair analysis by ambient ionizations mass spectrometry

    NARCIS (Netherlands)

    Duvivier, W.F.; Beek, van T.A.; Nielen, M.W.F.

    2016-01-01

    Rationale
    Recently, several direct and/or ambient mass spectrometry (MS) approaches have been suggested for drugs of abuse imaging in hair. The use of mass spectrometers with insufficient selectivity could result in false-positive measurements due to isobaric interferences. Different mass analyz

  17. Simultaneous Determination of Fifteen Constituents of Jitai Tablet Using Ultra High-Performance Liquid Chromatography Coupled with Triple Quadrupole Electrospray Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Shuping Wang

    2014-01-01

    Full Text Available An ultra-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS method was developed for simultaneous determination of fifteen constituents in Jitai tablet (JTT, a complex Traditional Chinese Medicine prescription (TCMP used in treating opiate addiction. Benefitting from a small particle size (1.8 µm C18 column, accelerated analysis with satisfactory resolution, sensitivity and selectivity were achieved in a single run within 7 min with linear gradient elution of acetonitrile-0.1% (v/v formic acid in water. The analytical signal was obtained by multiple reaction monitoring transitions via electrospray ionization source operating in both positive and negative ionization mode. The approach was validated for linearity, sensitivity, precision, repeatability, stability and recovery. All analytes showed good linearity over a wide concentration range (r > 0.99. The method limits ranged from 0.03 ng/mL to 19.35 ng/mL which are sensitive enough for quality control studies. The developed method was successfully applied to the simultaneous determination of fifteen constituents in JTT. In conclusion, our experimental results demonstrate that UHPLC-ESI-MS/MS is a useful approach for the overall quality assessment of complex TCMPs.

  18. 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.

  19. 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

  20. Ionization Suppression and Recovery in Direct Biofluid Analysis Using Paper Spray Mass Spectrometry

    Science.gov (United States)

    Vega, Carolina; Spence, Corina; Zhang, Chengsen; Bills, Brandon J.; Manicke, Nicholas E.

    2016-04-01

    Paper spray mass spectrometry is a method for the direct analysis of biofluid samples in which extraction of analytes from dried biofluid spots and electrospray ionization occur from the paper on which the dried sample is stored. We examined matrix effects in the analysis of small molecule drugs from urine, plasma, and whole blood. The general method was to spike stable isotope labeled analogs of each analyte into the spray solvent, while the analyte itself was in the dried biofluid. Intensity of the labeled analog is proportional to ionization efficiency, whereas the ratio of the analyte intensity to the labeled analog in the spray solvent is proportional to recovery. Ion suppression and recovery were found to be compound- and matrix-dependent. Highest levels of ion suppression were obtained for poor ionizers (e.g., analytes lacking basic aliphatic amine groups) in urine and approached -90%. Ion suppression was much lower or even absent for good ionizers (analytes with aliphatic amines) in dried blood spots. Recovery was generally highest in urine and lowest in blood. We also examined the effect of two experimental parameters on ion suppression and recovery: the spray solvent and the sample position (how far away from the paper tip the dried sample was spotted). Finally, the change in ion suppression and analyte elution as a function of time was examined by carrying out a paper spray analysis of dried plasma spots for 5 min by continually replenishing the spray solvent.

  1. 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.

  2. A huge reservoir of ionized gas around the Milky Way: Accounting for the Missing Mass?

    CERN Document Server

    Gupta, A; Krongold, Y; Nicastro, F; Galeazzi, M

    2012-01-01

    Most of the baryons from galaxies have been "missing" and several studies have attempted to map the circumgalactic medium (CGM) of galaxies in their quest. Recent studies with the Hubble Space Telescope have shown that many galaxies contain a large reservoir of ionized gas with temperatures of about 10^5 K. Here we report on X-ray observations made with the Chandra X-ray Observatory probing an even hotter phase of the CGM of our Milky Way at about 10^6 K. We show that this phase of the CGM is massive, extending over a large region around the Milky Way, with a radius of over 100 kpc. The mass content of this phase is over ten billion solar masses, many times more than that in cooler gas phases and comparable to the total baryonic mass in the disk of the Galaxy. The missing mass of the Galaxy appears to be in this warm-hot gas phase.

  3. Detection and identification of immobilized low-volatility organophosphates by desorption ionization mass spectrometry

    Science.gov (United States)

    Hagan, Nathan A.; Cornish, Timothy J.; Pilato, Robert S.; van Houten, Kelly A.; Antoine, Miquel D.; Lippa, Timothy P.; Becknell, Alan F.; Demirev, Plamen A.

    2008-12-01

    Two desorption ionization mass spectrometry (MS) techniques - ultraviolet laser desorption/ionization (LDI) and desorption electrospray ionization (DESI) - have been used to detect and identify low-volatility organophosphates when deposited on surfaces or loaded into the pore volume of porous inorganic or polymeric organic powders. The insecticides malathion and dicrotophos were chosen for this study as simulants of low vapor pressure chemical warfare agents which are inherently difficult to detect directly by traditional methods. Both liquid and powdered forms of either insecticide were readily detected by LDI or DESI MS. LDI MS was performed on a miniaturized home-built time-of-flight (TOF) mass spectrometer and a commercial TOF/TOF instrument. For DESI MS, a home-built ion source was interfaced to a commercial quadrupole ion trap. In LDI, intact molecular ion signatures could be acquired by using an appropriate cationizing agent and powder additive in positive ion mode. Tandem MS was used to confirm the identity of each analyte based on the observed characteristic fragmentation pattern. In DESI, less than 100 pg of the liquid insecticides spotted on clean surfaces were detected, while detection limits for the powder-loaded preparations were lower than 1 [mu]g. The effects of sample surface, salt additives, nanoparticle admixtures, and analyte solubility on the LDI and DESI MS sensitivity have been investigated as well.

  4. Chemical characterization of synthetic cannabinoids by electrospray ionization FT-ICR mass spectrometry.

    Science.gov (United States)

    Kill, Jade B; Oliveira, Izabela F; Tose, Lilian V; Costa, Helber B; Kuster, Ricardo M; Machado, Leandro F; Correia, Radigya M; Rodrigues, Rayza R T; Vasconcellos, Géssica A; Vaz, Boniek G; Romão, Wanderson

    2016-09-01

    The synthetic cannabinoids (SCs) represent the most recent advent of the new psychotropic substances (NPS) and has become popularly known to mitigate the effects of the Δ(9)-THC. The SCs are dissolved in organic solvents and sprayed in a dry herbal blend. However, little information is reported on active ingredients of SCs as well as the excipients or diluents added to the herbal blend. In this work, the direct infusion electrospray ionization Fourier transform ion cyclotron mass spectrometry technique (ESI-FT-ICR MS) was applied to explore the chemical composition of nine samples of herbal extract blends, where a total of 11 SCs (UR-144, JWH-073, XLR-11, JWH-250, JWH-122, AM-2201, AKB48, JWH-210, JWH-081, MAM-2201 and 5F-AKB48) were identified in the positive ionization mode, ESI(+), and other 44 chemical species (saturated and unsaturated fatty acids, sugars, flavonoids, etc.) were detected in the negative ionization mode, ESI(-). Additionally, CID experiments were performed, and fragmentation pathways were proposed to identify the connectivity of SCs. Thus, the direct infusion ESI-FT-ICR MS technique is a powerful tool in forensic chemistry that enables the rapid and unequivocal way for the determination of molecular formula, the degree of unsaturation (DBE-double bond equivalent) and exact mass (<1ppm) of a total of 55 chemical species without the prior separation step. PMID:27471991

  5. Air flow assisted ionization for remote sampling of ambient mass spectrometry and its application.

    Science.gov (United States)

    He, Jiuming; Tang, Fei; Luo, Zhigang; Chen, Yi; Xu, Jing; Zhang, Ruiping; Wang, Xiaohao; Abliz, Zeper

    2011-04-15

    Ambient ionization methods are an important research area in mass spectrometry (MS) analysis. Under ambient conditions, the gas flow and atmospheric pressure significantly affect the transfer and focusing of ions. The design and implementation of air flow assisted ionization (AFAI) as a novel and effective, remote sampling method for ambient mass spectrometry are described herein. AFAI benefits from a high extracting air flow rate. A systematic investigation of the extracting air flow in the AFAI system has been carried out, and it has been demonstrated not only that it plays a role in the effective capture and remote transport of charged droplets, but also that it promotes desolvation and ion formation, and even prevents ion fragmentation during the ionization process. Moreover, the sensitivity of remote sampling ambient MS analysis was improved significantly by the AFAI method. Highly polar and nonpolar molecules, including dyes, pharmaceutical samples, explosives, drugs of abuse, protein and volatile compounds, have been successfully analyzed using AFAI-MS. The successful application of the technique to residue detection on fingers, large object analysis and remote monitoring in real time indicates its potential for the analysis of a variety of samples, especially large objects. The ability to couple this technique with most commercially available MS instruments with an API interface further enhances its broad applicability.

  6. Study of Electrochemical Reactions Using Nanospray Desorption Electrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Pengyuan; Lanekoff, Ingela T.; Laskin, Julia; Dewald, Howard D.; Chen, Hao

    2012-07-03

    The combination of electrochemistry (EC) and mass spectrometry (MS) is a powerful analytical tool for studying mechanisms of redox reactions, identification of products and intermediates, and online derivatization/recognition of analytes. This work reports a new coupling interface for EC/MS by employing nanospray desorption electrospray ionization (nano-DESI), a recently developed ambient ionization method. We demonstrate online coupling of nano-DESI-MS with a traditional electrochemical flow cell, in which the electrolyzed solution emanating from the cell is ionized by nano-DESI for MS analysis. Furthermore, we show first coupling of nano-DESI-MS with an interdigitated array (IDA) electrode enabling chemical analysis of electrolyzed samples directly from electrode surfaces. Because of its inherent sensitivity, nano-DESI enables chemical analysis of small volumes and concentrations of sample solution. Specifically, good-quality signal of dopamine and its oxidized form, dopamine ortho-quinone, was obtained using 10 μL of 1 μM solution of dopamine on the IDA. Oxidation of dopamine, reduction of benzodiazepines, and electrochemical derivatization of thiol groups were used to demonstrate the performance of the technique. Our results show the potential of nano-DESI as a novel interface for electrochemical mass spectrometry research.

  7. Nanostructured silicon surface modifications for as a selective matrix-free laser desorption/ionization mass spectrometry.

    Science.gov (United States)

    Tsao, C W; Lin, C H; Cheng, Y C; Chien, C C; Chang, C C; Chen, W Y

    2012-06-01

    Matrix-assisted laser desorption/ionization mass spectrometry is an established soft ionization method that is widely applied to analyze biomolecules. The UV-absorbing organic matrix is essential for biomolecule ionization; however, it also creates matrix background interference, which results in problematic analyses of biomolecules of less than 700 Da. Therefore, this study investigates hydrophilic, hydrophobic cationic, anionic and immobilized metal ion surface chemical modifications to advance nanostructured silicon mass spectrometry performance (nSi-MS). This investigation provides information required for a possible novel mass spectroscopy that combines surface-enhanced and nanostructured silicon surface-assisted laser desorption/ionization mass spectrometry for the selective detection of specific compounds of a mixture. PMID:22531330

  8. In-Situ Organic Compound Analysis of the Meteorite Surface by Desorption Electrospray Ionization Coupled with an Orbitrap Mass Spectrometer

    Science.gov (United States)

    Naraoka, H.; Hashiguchi, M.

    2016-08-01

    It-situ analysis of organic compounds on the meteorite surface was performed by desorption electrospray ionization coupled with high resolution mass spectrometry. Indigenous peaks of meteorite origin were discriminated from the background.

  9. An algorithmic approach to automated high-throughput identification of disulfide connectivity in proteins using tandem mass spectrometry.

    Science.gov (United States)

    Lee, Timothy; Singh, Rahul; Yen, Ten-Yang; Macher, Bruce

    2007-01-01

    Knowledge of the pattern of disulfide linkages in a protein leads to a better understanding of its tertiary structure and biological function. At the state-of-the-art, liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) can produce spectra of the peptides in a protein that are putatively joined by a disulfide bond. In this setting, efficient algorithms are required for matching the theoretical mass spaces of all possible bonded peptide fragments to the experimentally derived spectra to determine the number and location of the disulfide bonds. The algorithmic solution must also account for issues associated with interpreting experimental data from mass spectrometry, such as noise, isotopic variation, neutral loss, and charge state uncertainty. In this paper, we propose a algorithmic approach to high-throughput disulfide bond identification using data from mass spectrometry, that addresses all the aforementioned issues in a unified framework. The complexity of the proposed solution is of the order of the input spectra. The efficacy and efficiency of the method was validated using experimental data derived from proteins with with diverse disulfide linkage patterns.

  10. Direct analysis of samples by mass spectrometry: From elements to bio-molecules using laser ablation inductively couple plasma mass spectrometry and laser desorption/ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Perdian, David C. [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Mass spectrometric methods that are able to analyze solid samples or biological materials with little or no sample preparation are invaluable to science as well as society. Fundamental research that has discovered experimental and instrumental parameters that inhibit fractionation effects that occur during the quantification of elemental species in solid samples by laser ablation inductively coupled plasma mass spectrometry is described. Research that determines the effectiveness of novel laser desorption/ionization mass spectrometric methods for the molecular analysis of biological tissues at atmospheric pressure and at high spatial resolution is also described. A spatial resolution is achieved that is able to analyze samples at the single cell level.

  11. Ultrasensitive resonance ionization mass spectrometer for evaluating krypton contamination in xenon dark matter detectors

    International Nuclear Information System (INIS)

    An ultrasensitive resonance ionization mass spectrometer that can be applied to evaluate krypton (Kr) contamination in xenon (Xe) dark matter detectors has been developed for measuring Kr at the parts-per-trillion (ppt) or sub-ppt level in Xe. The gas sample is introduced without any condensation into a time-of-flight mass spectrometer through a pulsed supersonic valve. Using a nanosecond pulsed laser at 212.6 nm, 84Kr atoms in the sample are resonantly ionized along with other Kr isotopes. 84Kr ions are then mass separated and detected by the mass spectrometer in order to measure the Kr impurity concentration. With our current setup, approximately 0.4 ppt of Kr impurities contained in pure argon (Ar) gas are detectable with a measurement time of 1000 s. Although Kr detection sensitivity in Xe is expected to be approximately half of that in Ar, our spectrometer can evaluate Kr contamination in Xe to the sub-ppt level

  12. Laser-Ionization TOF Mass Spectrometer Characterization of Benzene Destruction in Atmospheric Pressure Pulsed Discharge

    Institute of Scientific and Technical Information of China (English)

    LIU Jiahong; XIAO Qingmei; WANG Liping; YAO Zhi; DING Hongbin

    2009-01-01

    Benzene is.a major industrial air pollutant and can cause serious human health disorders. In this paper an investigation on benzene destruction, in an atmospheric-pressure fast-flow pulsed DC-discharge by means of laser ionization combined with time-of-flight (TOF) mass spectrometry, is reported. Most by-products including transient reactive species from the benzene discharge were characterized by molecular beam sampling combined with TOF mass spectrometry.It is showed that, with a gas mixture of 0.5% C6H6 in Ar, benzene can be effectively destroyed by discharge plasma. The intermediate species consisted of small fragments of CNHm (n=3~5,m =1~11), cycle-chain species of CNHm (n=6~9, m = 7~10) and polycyclic species CNHm (n ≥9,m = 8~12). The alternation of mass peaks (intensity) with even/odd electrons was observed in the measured mass spectra. The results indicated that the alternation is mainly due to the different ionization potentials of the open shell and close shell species. Based on the examination of the features of the species' composition, the primary reaction pathways are proposed and discussed.

  13. Trace analysis of actinides in the environment using resonance ionization mass spectrometry

    International Nuclear Information System (INIS)

    In this work the resonant ionization of neutral atoms using laser radiation was applied and optimized for ultra-trace analysis of the actinides thorium, uranium, neptunium and plutonium. The sensitive detection of these actinides is a challange for the monitoring and quantification of radioactive releases from nuclear facilities. Using resonance ionization spectroscopy combined with a newly developed quadrupole-mass-spectrometer, numerous energy levels in the atomic structure of these actinides could be identified. With this knowledge efficient excitation schemes for the mentioned actinides could be identified and characterised. The applied in-source-ionization ensures for a high detection efficiency due to the good overlap of laser radiation with the atomic beam and allows therefore for a low sample consumption which is required for the analysis of radio nuclides. The selective excitation processes in the resonant ionization method supresses unwanted contaminations and was optimized for analytical detection of ultra-trace amounts in environmental samples as well as for determination of isotopic compositions. The efficient in-source-ionization combined with high power pulsed laser radiation allows for detections efficiency up to 1%. For plutonium detection limits in the range of 104-105 atoms could be demonstrated for synthetic samples as well as for first environmental samples. The usage of narrow bandwidth continuous wave lasers in combination with a transversal overlap of the laser radiation and the free propagating atomic beam enable for resolving individual isotopic shifts of the resonant transitions. This results in a high selectivity against dominant neighboring isotopes but with a significant loss in detection efficiency. For the ultra-trace isotope 236U a detection limit down to 10-9 for the isotope ratio N (236U)/N (238U) could be determined.

  14. The Ionization of Accretion Flows in High Mass Star Formation: W51e2

    CERN Document Server

    Keto, Eric

    2008-01-01

    Previous observations show that the hypercompact HII region W51e2 is surrounded by a massive molecular accretion flow centered on the HII region. New observations of the H53alpha radio recombination line made with the VLA at 0.45 arc second angular resolution show a velocity gradient in the ionized gas within the HII region of > 500 kms-1 pc-1 comparable to the velocity gradient seen in the molecular accretion flow. New CO line observations made with the SMA at arc second angular resolution detect a molecular bipolar outflow immediately around the W51e2 HII region and extending along the axis of rotation of the molecular flow. These observations are consistent with an evolutionary phase for high mass star formation in which a newly formed massive star first begins to ionize its surroundings including its own accretion flow.

  15. Applications of electrospray laser desorption ionization mass spectrometry for document examination.

    Science.gov (United States)

    Cheng, Sy-Chyi; Lin, Yu-Shan; Huang, Ming-Zong; Shiea, Jentaie

    2010-01-01

    We have employed electrospray laser desorption ionization mass spectrometry (ELDI-MS) to rapidly characterize certain classes of compounds--the inks within the characters made by inks and inkjet printer on regular paper and the chemical compounds within thermal papers. This ELDI-MS approach allowed the ink and paper samples to be distinguished in terms of their chemical compositions. Sample pretreatment was unnecessary and the documents were practically undamaged after examination. The ink chemicals on the documents were desorbed through laser irradiation (sampling spot area: <100 microm(2)); the desorbed molecules then entered an electrospray plume--prepared from an acidic methanol/water solution (50%)--where they became ionized through fusion or ion-molecule reactions with the charged solvent species and droplets in the plume.

  16. Compound coverage enhancement of electrospray ionization mass spectrometry through the addition of a homemade needle.

    Science.gov (United States)

    Xiao, Shun; Qian, Shuai; Wang, Yi; Zhang, Yufeng; Cheng, Yiyu

    2013-03-21

    The response of many previously low-detectable or undetectable compounds in electrospray ionization mass spectrometry (ESI-MS) has been enhanced by the addition of a simple, homemade needle into the traditional ESI interface. The needle located between the ESI emitter and the ion sweep cone (inlet of the detector) would ionize those neutral gaseous compounds, formed during electrospray, by a corona discharge process. The mobile phases, ESI parameters and positions of the needle were investigated and optimized. Several groups of compounds and herbal extracts were tested using the homemade set-up. Both the results of the flow injection and the hyphenated MS analyses showed significant enhancement effects of our homemade needle. The advantages of the proposed method include low cost, simplicity and practicality. PMID:23364279

  17. Selective isotope determination of lanthanum by diode-laser-initiated resonance-ionization mass spectrometry

    International Nuclear Information System (INIS)

    A diode-laser step has been incorporated into a resonance-ionization mass spectrometry optical excitation process to enhance the isotopic selectivity of the technique. Lanthanum isotope ratio enhancements as high as 103 were achieved by use of a single-frequency cw diode laser tuned to excite the first step of a three-step excitation--ionization optical process; the subsequent steps were excited by use of a pulsed dye laser. Applying the same optical technique, we measured atomic hyperfine constants for the high-lying even-parity 4D5/2 state of lanthanum at 30 354 cm--1. The general utility of this spectral approach is discussed

  18. A high repetition rate solid state laser system for resonance ionization mass spectrometry of actinides

    International Nuclear Information System (INIS)

    A new, high repetition rate solid state laser system consisting of three Titanium-Sapphire (Ti:Sa) lasers pumped by one Nd:YAG laser has been set up for resonance ionization mass spectrometry for routine trace analysis of actinides. Each Ti:Sa laser produces up to 4 W of laser light with a bandwidth of 2-6 GHz continuously tuneable in a range from 725 to 900 nm. Using a three step ionization scheme with λ1=420.76 nm, λ2=847.28 nm and λ3239Pu, the overall detection efficiency of the setup has been measured to be ε=8.0x10-6. Thus a detection limit of 1x107 atoms of 239Pu is derived and opens up the way to use a reliable and easy to handle laser system for routine applications of RIMS

  19. Detection of plutonium isotopes at lowest quantities using in-source resonance ionization mass spectrometry.

    Science.gov (United States)

    Raeder, S; Hakimi, A; Stöbener, N; Trautmann, N; Wendt, K

    2012-11-01

    The in-source resonance ionization mass spectrometry technique was applied for quantification of ultratrace amounts of plutonium isotopes as a proof of principle study. In addition to an overall detection limit of 10(4) to 10(5) atoms, this method enables the unambiguous identification and individual quantification of the plutonium isotopes (238)Pu and (241)Pu which are of relevance for dating of radiogenic samples. Due to the element-selective ionization process, these isotopes can be measured even under a high surplus of isobaric contaminations from (238)U or (241)Am, which considerably simplifies chemical preparation. The technique was developed, tested, and characterized on a variety of synthetic and calibration samples and is presently applied to analyze environmental samples.

  20. Quantum dots assisted laser desorption/ionization mass spectrometric detection of carbohydrates: qualitative and quantitative analysis.

    Science.gov (United States)

    Bibi, Aisha; Ju, Huangxian

    2016-04-01

    A quantum dots (QDs) assisted laser desorption/ionization mass spectrometric (QDA-LDI-MS) strategy was proposed for qualitative and quantitative analysis of a series of carbohydrates. The adsorption of carbohydrates on the modified surface of different QDs as the matrices depended mainly on the formation of hydrogen bonding, which led to higher MS intensity than those with conventional organic matrix. The effects of QDs concentration and sample preparation method were explored for improving the selective ionization process and the detection sensitivity. The proposed approach offered a new dimension to the application of QDs as matrices for MALDI-MS research of carbohydrates. It could be used for quantitative measurement of glucose concentration in human serum with good performance. The QDs served as a matrix showed the advantages of low background, higher sensitivity, convenient sample preparation and excellent stability under vacuum. The QDs assisted LDI-MS approach has promising application to the analysis of carbohydrates in complex biological samples.

  1. Shotgun Approach for Quantitative Imaging of Phospholipids Using Nanospray Desorption Electrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lanekoff, Ingela T.; Thomas, Mathew; Laskin, Julia

    2014-02-04

    Mass spectrometry imaging (MSI) has been extensively used for determining spatial distributions of molecules in biological samples, and there is increasing interest in using MSI for quantification. Nanospray desorption electrospray ionization, or nano-DESI, is an ambient MSI technique where a solvent is used for localized extraction of molecules followed by nanoelectrospray ionization. Doping the nano-DESI solvent with carefully selected standards enables online quantification during MSI experiments. In this proof-of-principle study, we demonstrate this quantification approach can be extended to provide shotgun-like quantification of phospholipids in thin brain tissue sections. Specifically, two phosphatidylcholine (PC) standards were added to the nano-DESI solvent for simultaneous imaging and quantification of 22 PC species observed in nano-DESI MSI. Furthermore, by combining the quantitative data obtained in the individual pixels, we demonstrate quantification of these PC species in seven different regions of a rat brain tissue section.

  2. Time Resolved Studies of Interfacial Reactions of Ozone with Pulmonary Phospholipid Surfactants Using Field Induced Droplet Ionization Mass Spectrometry

    OpenAIRE

    Kim, Hugh I.; Kim, Hyungjun; Shin, Young Shik; Beegle, Luther W.; Goddard, William A.; Heath, James R.; Kanik, Isik; Beauchamp, J. L.

    2010-01-01

    Field induced droplet ionization mass spectrometry (FIDI-MS) comprises a soft ionization method to sample ions from the surface of microliter droplets. A pulsed electric field stretches neutral droplets until they develop dual Taylor cones, emitting streams of positively and negatively charged submicrometer droplets in opposite directions, with the desired polarity being directed into a mass spectrometer for analysis. This methodology is employed to study the heterogeneous ozonolysis of 1-pal...

  3. Thin-Layer Chromatography/Desorption Electrospray Ionization Mass Spectrometry: Investigation of Goldenseal Alkaloids

    Energy Technology Data Exchange (ETDEWEB)

    Van Berkel, Gary J [ORNL; Tomkins, Bruce A [ORNL; Kertesz, Vilmos [ORNL

    2007-01-01

    Desorption electrospray ionization mass spectrometry was investigated as a means to qualitatively identify and to quantify analytes directly from developed normal-phase thin layer chromatography plates. The atmospheric sampling capillary of a commercial ion trap mass spectrometer was extended to permit sampling and ionization of analytes in bands separated on intact TLC plates (up to 10 cm x 10 cm). A surface positioning software package and the appropriate hardware enabled computer-controlled surface scanning along the length of development lanes or at fixed RF value across the plates versus the stationary desorption electrospray emitter. Goldenseal (Hydrastis canadensis) and related alkaloids and commercial dietary supplements were used as standards and samples. Alkaloid standards and samples were spotted and separated on aluminum- or glass-backed plates using established literature methods. The mass spectral signal levels as a function of desorption spray solvent were investigated with acetonitrile proving superior to methanol. The detection levels (ca. 5 ng each or 14 -28 pmol) in mass spectral full scan mode were determined statistically from the calibration curves (2.5 - 100 pmol) for the standards berberine, palmatine and hydrastinine spotted as a mixture and separated on the plates. Qualitative screening of the major alkaloids present in six different over-the-counter "goldenseal" dietary supplements was accomplished by obtaining full scan mass spectra during surface scans along the development lane in the direction of increasing RF value. In one sample, alkaloids were detected that strongly suggested the presence of at least one additional herb undeclared on the product label. These same data indicated the misidentification of one of the alkaloids in the TLC literature. Quantities of the alkaloids present in two of the samples determined using the mass spectral data were in reasonable agreement with the label values indicating the quantitative ability of

  4. Secondary ionization of chemical warfare agent simulants: atmospheric pressure ion mobility time-of-flight mass spectrometry.

    Science.gov (United States)

    Steiner, Wes E; Clowers, Brian H; Haigh, Paul E; Hill, Herbert H

    2003-11-15

    For the first time, the use of a traditional ionization source for ion mobility spectrometry (radioactive nickel ((63)Ni) beta emission ionization) and three alternative ionization sources (electrospray ionization (ESI), secondary electrospray ionization (SESI), and electrical discharge (corona) ionization (CI)) were employed with an atmospheric pressure ion mobility orthogonal reflector time-of-flight mass spectrometer (IM(tof)MS) to detect chemical warfare agent (CWA) simulants from both aqueous- and gas-phase samples. For liquid-phase samples, ESI was used as the sample introduction and ionization method. For the secondary ionization (SESI, CI, and traditional (63)Ni ionization) of vapor-phase samples, two modes of sample volatilization (heated capillary and thermal desorption chamber) were investigated. Simulant reference materials, which closely mimic the characteristic chemical structures of CWA as defined and described by Schedule 1, 2, or 3 of the Chemical Warfare Convention treaty verification, were used in this study. A mixture of four G/V-type nerve simulants (dimethyl methylphosphonate, pinacolyl methylphosphonate, diethyl phosphoramidate, and 2-(butylamino)ethanethiol) and one S-type vesicant simulant (2-chloroethyl ethyl sulfide) were found in each case (sample ionization and introduction methods) to be clearly resolved using the IM(tof)MS method. In many cases, reduced mobility constants (K(o)) were determined for the first time. Ion mobility drift times, flight times, relative signal intensities, and fragmentation product signatures for each of the CWA simulants are reported for each of the methods investigated. PMID:14615983

  5. Profiling and identification of the absorbed constituents and metabolites of schisandra lignans by ultra-performance liquid chromatography coupled to mass spectrometry.

    Science.gov (United States)

    Sun, Hui; Wu, Fangfang; Zhang, Aihua; Wei, Wenfeng; Han, Ying; Wang, Xijun

    2013-11-01

    Schisandra chinensis Baill grows wild in Russia, China, Korea and Japan, and its fruit has been found to be effective in amnesia and insomnia. It is enriched in schisandra lignans (SL) that are major components responsible for therapeutic action. However, there are no reports on the biotransformation analysis of SL. An ultra-performance liquid chromatography/electrospray-ionization high-definition mass spectrometry (UPLC-Q-TOF-HDMS) method was developed to investigate the metabolism of SL in vivo. MS was performed on a Waters Micromass high-definition system with an electrospray ionization source in positive ion mode and automated MetaboLynx software analysis with excellent MS accuracy and enhanced MS data acquisition. An improved mass defect filter (MDF) method employing both drug and core structure filter templates was applied to the processing of UPLC-Q-TOF-HDMS data for the detection and structural characterization of metabolites. In this study, 30 metabolites were detected and identified in vivo, and demethylation and hydroxylation were confirmed as the primacy metabolic pathway for SL in rat plasma. In conclusion, the presently developed methodology was suitable for biotransformation research of SL and will find wide use in metabolic studies for other herbal medicines.

  6. Hyphenation of two simultaneously employed soft photo ionization mass spectrometers with thermal analysis of biomass and biochar

    International Nuclear Information System (INIS)

    Highlights: ► First simultaneous hyphenation of two time-of-flight mass spectrometers with different soft photo ionization techniques (SPI and REMPI) to Thermal Analysis using a newly developed prototype for EGA is presented. ► Resonance enhanced multi-photon ionization (REMPI) enables sensitive and selective analysis of aromatic species. ► Single photon ionization (SPI) using VUV light supplied by an innovative electron-beam pumped excimer light source (EBEL) comprehensively ionizes (nearly) all organic molecules. ► The resulting mass spectra show distinct patterns for the evolved gases of the miscellaneous biomasses and chars thereof. ► The potential for detailed kinetic studies is apparent on account of the complex pyrolysis gas compositions. - Abstract: Evolved gas analysis (EGA) is a powerful and complementary tool for Thermal Analysis. In this context, two time-of-flight mass spectrometers with different soft photo-ionization techniques are simultaneously hyphenated to a thermo balance and applied in form of a newly developed prototype for EGA of pyrolysis gases from biomass and biochar. Resonance enhanced multi-photon ionization (REMPI) is applied for selective analysis of aromatic species. Furthermore, single photon ionization (SPI) using VUV light supplied by an electron-beam pumped excimer light source (EBEL) was used to comprehensively ionize (nearly) all organic molecules. The soft ionization capability of photo-ionization techniques allows direct and on-line analysis of the evolved pyrolysis gases. Characteristic mass spectra with specific patterns could be obtained for the miscellaneous biomass feeds used. Temperature profiles of the biochars reveal a desorption step, followed by pyrolysis as observed for the biomasses. Furthermore, the potential for kinetic studies is apparent for this instrumental setup.

  7. Imaging of Lipids and Metabolites Using Nanospray Desorption Electrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lanekoff, Ingela; Laskin, Julia

    2015-01-17

    In recent years, mass spectroscopy imaging (MSI) has emerged as a foundational technique in metabolomics and drug screening providing deeper understanding of complex mechanistic pathways within biochemical systems and biological organisms. We have been invited to contribute a chapter to a new Springer series volume, entitled “Mass Spectrometry Imaging of Small Molecules”. The volume is planned for the highly successful lab protocol series Methods in Molecular Biology, published by Humana Press, USA. The volume is aimed to equip readers with step-by-step mass spectrometric imaging protocols and bring rapidly maturing methods of MS imaging to life science researchers. The chapter will provide a detailed protocol of ambient MSI by use of nanospray desorption electrospray ionization.

  8. Real-time monitoring of volatile organic compounds using chemical ionization mass spectroscopy: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Thornberg, S.M.; Mowry, C.D.; Keenan, M.R.; Bender, S.F.A. [Sandia National Labs., Albuquerque, NM (United States). Gas Analysis Lab.; Owen, T. [Intel Corp., Rio Rancho, NM (United States)

    1997-04-01

    Volatile organic compound (VOC) emission to the atmosphere is of great concern to semiconductor manufacturing industries, research laboratories, the public, and regulatory agencies. Some industries are seeking ways to reduce emissions by reducing VOCs at the point of use (or generation). This paper discusses the requirements, design, calibration, and use of a sampling inlet/quadrupole mass spectrometer system for monitoring VOCs in a semiconductor manufacturing production line. The system uses chemical ionization to monitor compounds typically found in the lithography processes used to manufacture semiconductor devices (e.g., acetone, photoresist). The system was designed to be transportable from tool to tool in the production line and to give the operator real-time feedback so the process(es) can be adjusted to minimize VOC emissions. Detection limits ranging from the high ppb range for acetone to the low ppm range fore other lithography chemicals were achieved using chemical ionization mass spectroscopy at a data acquisition rate of approximately 1 mass spectral scan (30 to 200 daltons) per second. A demonstration of exhaust VOC monitoring was performed at a working semiconductor fabrication facility during actual wafer processing.

  9. Real-time monitoring of enzymatic DNA hydrolysis by electrospray ionization mass spectrometry.

    Science.gov (United States)

    van den Heuvel, Robert H H; Gato, Sara; Versluis, Cees; Gerbaux, Pascal; Kleanthous, Colin; Heck, Albert J R

    2005-01-01

    A fast and direct method for the monitoring of enzymatic DNA hydrolysis was developed using electrospray ionization mass spectrometry. We incorporated the use of a robotic chip-based electrospray ionization source for increased reproducibility and throughput. The mass spectrometry method allows the detection of DNA fragments and intact non-covalent protein-DNA complexes in a single experiment. We used the method to monitor in real-time single-stranded (ss) DNA hydrolysis by colicin E9 DNase and to characterize transient non-covalent E9 DNase-DNA complexes present during the hydrolysis reaction. The mass spectra showed that E9 DNase interacts with ssDNA in the absence of a divalent metal ion, but is strictly dependent on Ni2+ or Co2+ for ssDNA hydrolysis. We demonstrated that the sequence selectivity of E9 DNase is dependent on the ratio protein:ssDNA or the ssDNA concentration and that only 3'-hydroxy and 5'-phosphate termini are produced. It was also shown that the homologous E7 DNase is reactive with Zn2+ as transition metal ion and that this DNase displays a different sequence selectivity. The method described is of general use to analyze the reactivity and specificity of nucleases. PMID:15956101

  10. Determination of triacetone triperoxide using ultraviolet femtosecond multiphoton ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Ezoe, Ryota; Imasaka, Tomoko; Imasaka, Totaro

    2015-01-01

    Triacetone triperoxide (TATP), an explosive compound, was measured using gas chromatography combined with multiphoton ionization time-of-flight mass spectrometry (GC/MPI-TOFMS). By decreasing the pulse width of a femtosecond laser from 80 to 35 fs, a molecular ion was drastically enhanced and was measured as one of the major ions in the mass spectrum. The detection limits obtained using the molecular (M(+)) and fragment (C2H3O(+)) ions were similar or slightly superior to those obtained using conventional mass spectrometry based on electron and chemical ionization. In order to improve the reliability, an isotope of TATP, i.e., TATP-d18, was synthesized and used as an internal standard in the trace analysis of TATP in a sample of human blood. TATP could be identified in a two-dimensional display, even though numerous interfering compounds were present in the sample. Acetone, which is frequently used as a solvent in sampling TATP, produced a chemical species with a retention time nearly identical to that of TATP and provided a C2H3O(+) fragment ion that was employed for measuring a chromatogram of TATP in conventional MS. This compound, the structure of which was assigned as phorone, was clearly differentiated from TATP based on a molecular ion observable in MPI-TOFMS. PMID:25467497

  11. 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

  12. GoAmazon 2014/15 Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Smith, JN [Univ. of California, Irvine, CA (United States)

    2016-04-01

    The Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS) deployment to the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility T3 site in Manacapuru, Brazil, was motivated by two main scientific objectives of the Green Ocean Amazon (GoAmazon) 2014/15 field campaign. 1) Study the interactions between anthropogenic and biogenic emissions by determining important molecular species in ambient nanoparticles. To address this, TDCIMS data will be combined with coincident measurements such as gas-phase sulfuric acid to determine the contribution of sulfuric acid condensation to nucleation and growth. We can then compare that result to TDCIMS-derived nanoparticle composition to determine the fraction of growth that can be attributed to the uptake of organic compounds. The molecular composition of sampled particles will also be used to attribute specific chemical species and mechanisms to growth, such as the condensation of low-volatility species or the oligomerization of α-dicarbonyl compounds. 2) Determine the source of new ambient nanoparticles in the Amazon. The hypothesis prior to measurements was that potassium salts formed from the evaporation of primary particles emitted by fungal spores can provide a unique and important pathway for new particle production in the Amazon basin. To explore this hypothesis, the TDCIMS recorded the mass spectra of sampled ambient particles using a protonated water cluster Chemical Ionization Mass Spectrometer (CIMS). Laboratory tests performed using potassium salts show that the TDCIMS can detect potassium with high sensitivity with this technique.

  13. Electroless plating of silver nanoparticles on porous silicon for laser desorption/ionization mass spectrometry

    Science.gov (United States)

    Yan, Hong; Xu, Ning; Huang, Wen-Yi; Han, Huan-Mei; Xiao, Shou-Jun

    2009-03-01

    An improved DIOS (desorption ionization on porous silicon) method for laser desorption/ionization mass spectrometry (LDI MS) by electroless plating of silver nanoparticles (AgNPs) on porous silicon (PSi) was developed. By addition of 4-aminothiophenol (4-ATP) into the AgNO3 plating solution, the plating speed can be slowed down and simultaneously 4-ATP self-assembled monolayers (SAMs) on AgNPs (4-ATP/AgNPs) were formed. Both AgNPs and 4-ATP/AgNPs coated PSi substrates present much higher stability, sensitivity and reproducibility for LDI MS than the un-treated porous silicon ones. Their shelf life in air was tested for several weeks to a month and their mass spectra still displayed the same high quality and sensitivity as the freshly prepared ones. And more 4-ATP SAMs partly play a role of matrix to increase the ionization efficiency. A small organic molecule of tetrapyridinporphyrin (TPyP), oligomers of polyethylene glycol (PEG 400 and 2300), and a peptide of oxytocin were used as examples to demonstrate the feasibility of the silver-plated PSi as a matrix-free-like method for LDI MS. This approach can obtain limits of detection to femtomoles for TPyP, subpicomoles for oxytocin, and picomoles for PEG 400 and 2300, comparable to the traditional matrix method and much better than the DIOS method. It simplifies the sample preparation as a matrix-free-like method without addition of matrix molecules and homogenizes the sample spread over the spot for better and more even mass signals.

  14. Activation energies for gas-phase dissociations of multiply charged ions from electrospay ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Busman, M.; Rockwood, A.L.; Smith, R.D. [Pacific Northwest Lab., Richland, WA (United States)

    1992-03-19

    The reactions of multiply protonated melittin molecular ions of various charge states produced from an electrospray ionization source have been studied. The flow of ions entrained in gas through a heated metal capillary inlet serves as a reaction vessel for gas-phase measurements of molecular ion reaction rates using mass spectrometry. Activation energies for the unimolecular dissociation reactions are calculated from the temperature dependence of the reaction kinetics. The differences in activation energies for the reactions of the different charge states are attributed to the destabilizing effect of Coulombic repulsion for high charged ions. 18 refs., 3 figs., 1 tab.

  15. Analysis of sexual assault evidence by desorption electrospray ionization mass spectrometry.

    Science.gov (United States)

    Mirabelli, Mario F; Chramow, Alexander; Cabral, Elaine C; Ifa, Demian R

    2013-07-01

    Desorption electrospray ionization mass spectrometry (DESI-MS) is employed in the forensic analysis of chemical components present in condoms and imaging of latent fingerprints as circumstantial evidence of sexual assault. Polymers such as nonoxynol-9, polyethylene glycol, and polydimethylsiloxane, as well as small molecules additives such as N-methylmorpholine, N-octylamine, N,N-dibutyl formamide, and isonox 132, commonly used in lubricated condom formulations, were successfully characterized by DESI. The results suggest that DESI-MS is useful for identification of this type of evidence, and it has advantages over conventional extractive techniques, in terms of speed of analysis and ease of use. PMID:23832933

  16. Gas-phase Smiles Rearrangement of Sulfonylurea Herbicides in Electrospray Ionization Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    张佳; 柴云峰; 王伟; 尚伟; 潘远江

    2012-01-01

    In the negative ion mode of electrospray ionization tandem mass spectrometry (ES1-MS/MS) of four sulfonyl- urea herbicides, Smiles rearrangements were observed in rimsulfuron and nicosulfuron. In the case of rimsulfuron, two competitive gas-phase Smiles rearrangements initiated by nitrogen anion and oxygen anion respectively were witnessed. The ion-neutral complex was proposed as the reactive intermediate in the course of this unimoleeular dissociation reaction of the oxygen attack Smiles rearrangement route. The density functional theory (DFT) was carried out to elucidate the mechanism as well as to show the possible transition states and the intermediates.

  17. Cosmetic Analysis Using Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging (MALDI-MSI

    Directory of Open Access Journals (Sweden)

    Rodrigo Ramos Catharino

    2013-03-01

    Full Text Available A new “omic” platform—Cosmetomics—that proves to be extremely simple and effective in terms of sample preparation and readiness for data acquisition/interpretation is presented. This novel approach employing Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging (MALDI-MSI for cosmetic analysis has proven to readily identify and quantify compounds of interest. It also allows full control of all the production phases, as well as of the final product, by integration of both analytical and statistical data. This work has focused on products of daily use, namely nail polish, lipsticks and eyeliners of multiple brands sold in the worldwide market.

  18. Study of multi-photon ionization mass spectra of triethylamine at the laser of 266 nm

    International Nuclear Information System (INIS)

    Using the four-harmonic YAG laser as excitation source, studying on the process of resonance-enhanced two-photon ionization of triethylamine, the time-of-flight mass spectra of triethylamine is obtained. Parent ion and fragment ion reach as much as 29 kinds. Analyzing the abnormal variation of (C2H5)2N+ CH2(86+) show that when the signal ions' intensity are very strong, the 25-times instantaneous deceleration effort of 25 kinds of ions before 86+ are stronger than 3-times deceleration effort of 3 kinds of ions after 86+. (authors)

  19. High-resolution, three-step resonance ionization mass spectrometry of gadolinium

    Science.gov (United States)

    Blaum, K.; Bushaw, B. A.; Nörtershäuser, W.; Wendt, K.

    2001-08-01

    High-resolution resonance ionization mass spectrometry has been used to measure triple-resonance autoionization (AI) spectra of gadolinium. Al resonances as narrow as 10 MHz have been observed and isotope shifts and hyperfine structure have been measured in selected AI states. The strongest AI state observed at 49663.576 cm-1 with a photoionization cross section of >3.6×10-15 cm2 was found to have an overall detection efficiency of >3×10-5, allowing application to a number of ultratrace determination problems. Analytical measurements with a diode-laser-based system have been successfully performed on bio-medical tissue samples.

  20. High-resolution, three-step resonance ionization mass spectrometry of gadolinium

    International Nuclear Information System (INIS)

    High-resolution resonance ionization mass spectrometry has been used to measure triple-resonance autoionization (AI) spectra of gadolinium. Al resonances as narrow as 10 MHz have been observed and isotope shifts and hyperfine structure have been measured in selected AI states. The strongest AI state observed at 49663.576 cm-1 with a photoionization cross section of >3.6x10-15 cm2 was found to have an overall detection efficiency of >3x10-5, allowing application to a number of ultratrace determination problems. Analytical measurements with a diode-laser-based system have been successfully performed on bio-medical tissue samples

  1. Merits of online electrochemistry liquid sample desorption electrospray ionization mass spectrometry (EC/LS DESI MS).

    Science.gov (United States)

    Looi, Wen Donq; Brown, Blake; Chamand, Laura; Brajter-Toth, Anna

    2016-03-01

    A new online electrochemistry/liquid sample desorption electrospray ionization mass spectrometry (EC/LS DESI MS) system with a simple electrochemical thin-layer flow-through cell was developed and tested using N,N-dimethyl-p-phenylenediamine (DMPA) as a model probe. Although oxidation of DMPA is observed as a result of ionization of LS in positive ion mode LS DESI, application of voltage to the online electrochemical (EC) cell in EC/LS DESI MS increases yields of oxidation products. An advantage of LS DESI MS is its sensitivity in aqueous electrolyte solutions, which improves efficiency of electrochemical reactions in EC/LS DESI MS. In highly conductive low pH aqueous buffer solutions, oxidation efficiency is close to 100%. EC/ESI MS typically requires mixed aqueous/organic solvents and low electrolyte concentrations for efficient ionization in MS, limiting efficiency of electrochemistry online with MS. Independently, the results verify higher electrochemical oxidation efficiency during positive mode ESI than during LS DESI.

  2. A comparison of alternating current and direct current electrospray ionization for mass spectrometry.

    Science.gov (United States)

    Sarver, Scott A; Chetwani, Nishant; Dovichi, Norman J; Go, David B; Gartner, Carlos A

    2014-04-01

    A series of studies comparing the performance of alternating current electrospray ionization (AC ESI) mass spectrometry (MS) and direct current electrospray ionization (DC ESI) MS have been conducted, exploring the absolute signal intensity and signal-to-background ratios produced by both methods using caffeine and a model peptide as targets. Because the high-voltage AC signal was more susceptible to generating gas discharges, the operating voltage range of AC ESI was significantly smaller than that for DC ESI, such that the absolute signal intensities produced by DC ESI at peak voltages were one to two orders of magnitude greater than those for AC ESI. Using an electronegative nebulizing gas, sulfur hexafluoride (SF6), instead of nitrogen (N2) increased the operating range of AC ESI by ~50%, but did not appreciably improve signal intensities. While DC ESI generated far greater signal intensities, both ionization methods produced comparable signal-to-background noise, with AC ESI spectra appearing qualitatively cleaner. A quantitative calibration analysis was performed for two analytes, caffeine and the peptide MRFA. AC ESI utilizing SF6 outperforms all other techniques for the detection of MRFA, producing chromatographic limits of detection nearly one order of magnitude lower than that of DC ESI utilizing N2, and one-half that of DC ESI utilizing SF6. However, DC ESI outperforms AC ESI for the analysis of caffeine, indicating that improvements in spectral quality may benefit certain compounds or classes of compounds, on an individual basis. PMID:24464359

  3. Merits of online electrochemistry liquid sample desorption electrospray ionization mass spectrometry (EC/LS DESI MS).

    Science.gov (United States)

    Looi, Wen Donq; Brown, Blake; Chamand, Laura; Brajter-Toth, Anna

    2016-03-01

    A new online electrochemistry/liquid sample desorption electrospray ionization mass spectrometry (EC/LS DESI MS) system with a simple electrochemical thin-layer flow-through cell was developed and tested using N,N-dimethyl-p-phenylenediamine (DMPA) as a model probe. Although oxidation of DMPA is observed as a result of ionization of LS in positive ion mode LS DESI, application of voltage to the online electrochemical (EC) cell in EC/LS DESI MS increases yields of oxidation products. An advantage of LS DESI MS is its sensitivity in aqueous electrolyte solutions, which improves efficiency of electrochemical reactions in EC/LS DESI MS. In highly conductive low pH aqueous buffer solutions, oxidation efficiency is close to 100%. EC/ESI MS typically requires mixed aqueous/organic solvents and low electrolyte concentrations for efficient ionization in MS, limiting efficiency of electrochemistry online with MS. Independently, the results verify higher electrochemical oxidation efficiency during positive mode ESI than during LS DESI. PMID:26886744

  4. Computational Prediction of Electron Ionization Mass Spectra to Assist in GC/MS Compound Identification.

    Science.gov (United States)

    Allen, Felicity; Pon, Allison; Greiner, Russ; Wishart, David

    2016-08-01

    We describe a tool, competitive fragmentation modeling for electron ionization (CFM-EI) that, given a chemical structure (e.g., in SMILES or InChI format), computationally predicts an electron ionization mass spectrum (EI-MS) (i.e., the type of mass spectrum commonly generated by gas chromatography mass spectrometry). The predicted spectra produced by this tool can be used for putative compound identification, complementing measured spectra in reference databases by expanding the range of compounds able to be considered when availability of measured spectra is limited. The tool extends CFM-ESI, a recently developed method for computational prediction of electrospray tandem mass spectra (ESI-MS/MS), but unlike CFM-ESI, CFM-EI can handle odd-electron ions and isotopes and incorporates an artificial neural network. Tests on EI-MS data from the NIST database demonstrate that CFM-EI is able to model fragmentation likelihoods in low-resolution EI-MS data, producing predicted spectra whose dot product scores are significantly better than full enumeration "bar-code" spectra. CFM-EI also outperformed previously reported results for MetFrag, MOLGEN-MS, and Mass Frontier on one compound identification task. It also outperformed MetFrag in a range of other compound identification tasks involving a much larger data set, containing both derivatized and nonderivatized compounds. While replicate EI-MS measurements of chemical standards are still a more accurate point of comparison, CFM-EI's predictions provide a much-needed alternative when no reference standard is available for measurement. CFM-EI is available at https://sourceforge.net/projects/cfm-id/ for download and http://cfmid.wishartlab.com as a web service. PMID:27381172

  5. Atmospheric pressure chemical ionization of fluorinated phenols in atmospheric pressure chemical ionization mass spectrometry, tandem mass spectrometry, and ion mobility spectrometry

    Science.gov (United States)

    Eiceman, G. A.; Bergloff, J. F.; Rodriguez, J. E.; Munro, W.; Karpas, Z.

    1999-01-01

    Atmospheric pressure chemical ionization (APCI)-mass spectrometry (MS) for fluorinated phenols (C6H5-xFxOH Where x = 0-5) in nitrogen with Cl- as the reagent ion yielded product ions of M Cl- through ion associations or (M-H)- through proton abstractions. Proton abstraction was controllable by potentials on the orifice and first lens, suggesting that some proton abstraction occurs through collision induced dissociation (CID) in the interface region. This was proven using CID of adduct ions (M Cl-) with Q2 studies where adduct ions were dissociated to Cl- or proton abstracted to (M-H)-. The extent of proton abstraction depended upon ion energy and structure in order of calculated acidities: pentafluorophenol > tetrafluorophenol > trifluorophenol > difluorophenol. Little or no proton abstraction occurred for fluorophenol, phenol, or benzyl alcohol analogs. Ion mobility spectrometry was used to determine if proton abstraction reactions passed through an adduct intermediate with thermalized ions and mobility spectra for all chemicals were obtained from 25 to 200 degrees C. Proton abstraction from M Cl- was not observed at any temperature for phenol, monofluorophenol, or difluorophenol. Mobility spectra for trifluorophenol revealed the kinetic transformations to (M-H)- either from M Cl- or from M2 Cl- directly. Proton abstraction was the predominant reaction for tetra- and penta-fluorophenols. Consequently, the evidence suggests that proton abstraction occurs from an adduct ion where the reaction barrier is reduced with increasing acidity of the O-H bond in C6H5-xFxOH.

  6. Investigation of structure, dynamics and function of metalloproteins with electrospray ionization mass spectrometry.

    Science.gov (United States)

    Kaltashov, Igor A; Zhang, Mingxuan; Eyles, Stephen J; Abzalimov, Rinat R

    2006-10-01

    Electrospray ionization mass spectrometry (ESI MS) has emerged recently as a powerful tool for analyzing many structural and behavioral aspects of metalloproteins in great detail. In this review we discuss recent developments in the field, placing particular emphasis on the unique features of ESI MS that lend themselves to metalloprotein characterization at a variety of levels. Direct mass measurement enables the determination of protein-metal ion binding stoichiometry in solution and metalloprotein higher order structure in the case of multi-subunit proteins. MS techniques have been developed for determining the locations of metal-binding centers, metal oxidation states and reaction intermediates of metal-containing enzymes. Other ESI MS techniques are also discussed, such as protein ion charge state distributions and hydrogen/deuterium exchange studies, which can be used to measure metal binding affinities and to shed light on vital dynamic aspects of the functional properties of metalloproteins endowed by metal binding.

  7. Fast Screening of Chicken Egg Lysozyme in White Wine Products by Extractive Electrospray Ionization Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhi-quan; JIANG Jie; LI Ming; ZHAO Zhan-feng; FU Jun

    2012-01-01

    Fast detection of trace lysozyme,one of the most important food allergens in white wine samples,was achieved by extractive electrospray ionization mass spectrometry without sample pretreatment in this study.The multiply-charged ions of m/z 1587 were chosen for the quantitative detection of lysozyme in white wine,showing linear dynamic signal responses in a range of 5-75 μg/mL with a linearity coefficient of 0.999 and an acceptable relative standard deviation(RSD)of 8.0%-15.0% for directly measuring lysozyme in the complex food samples.The limit of detection for lysozyme in white wine sample was calculated to be 5 μg/mL,which was lower than the amounts that can provoke allergic reactions(oral test with 3 mg or labial test with 1 mg/mL).A single sample analysis was completed within 1 min.The data demonstrate that extractive electrospray ionization mass spectrometry is a useful tool for fast screening lysozyme in the complex matrix,showing promising application in the rapid detection of food allergen.

  8. Molecular Ionization-Desorption Analysis Source (MIDAS) for Mass Spectrometry: Thin-Layer Chromatography

    Science.gov (United States)

    Winter, Gregory T.; Wilhide, Joshua A.; LaCourse, William R.

    2016-02-01

    Molecular ionization-desorption analysis source (MIDAS), which is a desorption atmospheric pressure chemical ionization (DAPCI) type source, for mass spectrometry has been developed as a multi-functional platform for the direct sampling of surfaces. In this article, its utility for the analysis of thin-layer chromatography (TLC) plates is highlighted. Amino acids, which are difficult to visualize without staining reagents or charring, were detected and identified directly from a TLC plate. To demonstrate the full potential of MIDAS, all active ingredients from an analgesic tablet, separated on a TLC plate, were successfully detected using both positive and negative ion modes. The identity of each of the compounds was confirmed from their mass spectra and compared against standards. Post separation, the chemical signal (blue permanent marker) as reference marks placed at the origin and solvent front were used to calculate retention factor (Rf) values from the resulting ion chromatogram. The quantitative capabilities of the device were exhibited by scanning caffeine spots on a TLC plate of increasing sample amount. A linear curve based on peak are, R2 = 0.994, was generated for seven spots ranging from 50 to 1000 ng of caffeine per spot.

  9. Real Time Monitoring of Containerless Microreactions in Acoustically Levitated Droplets via Ambient Ionization Mass Spectrometry.

    Science.gov (United States)

    Crawford, Elizabeth A; Esen, Cemal; Volmer, Dietrich A

    2016-09-01

    Direct in-droplet (in stillo) microreaction monitoring using acoustically levitated micro droplets has been achieved by combining acoustic (ultrasonic) levitation for the first time with real time ambient tandem mass spectrometry (MS/MS). The acoustic levitation and inherent mixing of microliter volumes of reactants (3 μL droplets), yielding total reaction volumes of 6 μL, supported monitoring the acid-catalyzed degradation reaction of erythromycin A. This reaction was chosen to demonstrate the proof-of-principle of directly monitoring in stillo microreactions via hyphenated acoustic levitation and ambient ionization mass spectrometry. The microreactions took place completely in stillo over 30, 60, and 120 s within the containerless stable central pressure node of an acoustic levitator, thus readily promoting reaction miniaturization. For the evaluation of the miniaturized in stillo reactions, the degradation reactions were also carried out in vials (in vitro) with a total reaction volume of 400 μL. The reacted in vitro mixtures (6 μL total) were similarly introduced into the acoustic levitator prior to ambient ionization MS/MS analysis. The in stillo miniaturized reactions provided immediate real-time snap-shots of the degradation process for more accurate reaction monitoring and used a fraction of the reactants, while the larger scale in vitro reactions only yielded general reaction information. PMID:27505037

  10. 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

  11. Interlayer spray ionization mass spectrometry for the simple direct analysis of low amounts of sample.

    Science.gov (United States)

    Chen, Jin; Tang, Fei; Guo, Cheng'an; Huo, Xinming; Zhang, Sichun; Wang, Xiaohao

    2016-07-01

    Interlayer spray is proposed as a convenient ionization source for direct analysis by mass spectrometry. Two slices of non-absorbent substrate hold the liquid sample to form a sandwich structure. By applying a high voltage to the sample, spray is generated at the tip of the substrate. The sampling procedure can be operated easily in an open condition and the spray is processed in a semi-enclosed condition, which leads to a relatively stable process. An ultralow amount (target are maintained. Less influence from the substrate is achieved compared with the spray methods based on porous absorbent materials, which results in a sensitivity enhancement of large molecule samples. It is demonstrated that the interlayer spray is applicable for the analysis of various compounds, including therapeutic drugs, peptides, and proteins. Good linearity can be obtained at a concentration as low as 50 ng/mL in the quantitative analysis for imatinib. We also show the ability to identify the chemical residuals on surfaces with high sensitivity by the "wipe-spray" method, which is useful for the fast screening of illicit substances. Interlayer spray working with mass spectrometry provides a promising method for direct analysis in an ambient environment. Graphical Abstract The schematic of the interlayer spray ionization source. PMID:27173393

  12. Drug detection and quantification directly from tissue using novel ionization methods for mass spectrometry.

    Science.gov (United States)

    Wang, Beixi; Dearring, Chenelle L; Wager-Miller, James; Mackie, Ken; Trimpin, Sarah

    2015-01-01

    Solvent assisted ionization inlet (SAII) and matrix assisted ionization vacuum (MAIV) were used to quantify rapidly an antipsychotic drug, clozapine, directly from surfaces with minimal sample preparation. This simple surface analysis method based on SAII- and MAIV-mass spectrometry (MS) was developed to allow the detection of endogenous lipids, metabolites, and clozapine directly from sections of mouse brain tissue. A rapid surface assessment was achieved by SAII with the assistance of heat applied to the mass spectrometer inlet. MAIV provided an improved reproducibility without the need of a heated inlet. In addition, isotope dilution and standard addition were used without sample clean-up, and the results correlate well with liquid chromatography tandem MS using sample work-up. Using the simple surface methods, standard solutions containing clozapine and a deuterated internal standard (clozapine-d8) at different concentration ratios were used in the extraction and quantification of clozapine from brain tissue sections of a drug-treated mouse using different tissue thicknesses. The amount of clozapine extracted by these surface methods was independent of tissue thickness. PMID:26307700

  13. Chemical derivatization for electrospray ionization mass spectrometry. 1. Alkyl halides, alcohols, phenols, thiols, and amines

    Energy Technology Data Exchange (ETDEWEB)

    Quirke, J.M.E.; Adams, C.L.; Van Berkel, G.J. (Oak Ridge National Lab., TN (United States))

    1994-04-15

    Derivatization strategies and specific derivatization reactions for conversion of simple alkyl halides, alcohols, phenols, thiols, and amines to ionic or solution-ionizable derivatives, that is [open quotes]electrospray active[close quotes] (ES-active) forms of the analyte, are presented. Use of these reactions allows detection of analytes among those listed that are not normally amenable to analysis by electrospray ionization mass spectrometry (ES-MS). In addition, these reactions provide for analysis specificity and flexibility through functional group specific derivatization and through the formation of derivatives that can be detected in positive ion or in negative ion mode. For a few of the functional groups, amphoteric derivatives are formed that can be analyzed in either positive or negative ion modes. General synthetic strategies for transformation of members of these five compound classes to ES-active species are presented along with illustrative examples of suitable derivatives. Selected derivatives were prepared using model compounds and the ES mass spectra obtained for these derivatives are discussed. The analytical utility of derivatization for ES-MS analysis is illustrated in three experiments: (1) specific detection of the major secondary alcohol in oil of peppermint, (2) selective detection of phenols within a synthetic mixture of phenols, and (3) identification of the medicinal amines within a commercially available cold medication as primary, secondary or tertiary. 65 refs., 3 figs., 3 tabs.

  14. Isobutane Made Practical as a Reagent Gas for Chemical Ionization Mass Spectrometry

    Science.gov (United States)

    Newsome, G. Asher; Steinkamp, F. Lucus; Giordano, Braden C.

    2016-08-01

    As a reagent gas for positive- and negative-mode chemical ionization mass spectrometry (CI-MS), isobutane (i-C4H10) produces superior analyte signal abundance to methane. Isobutane has never been widely adopted for CI-MS because it fouls the ion source more rapidly and produces positive CI spectra that are more strongly dependent on reagent gas pressure compared with methane. Isobutane was diluted to various concentrations in argon for use as a reagent gas with an unmodified commercial gas chromatograph-mass spectrometer. Analyte spectra were directly compared using methane, isobutane, and isobutane/argon mixtures. A mixture of 10% i-C4H10 in argon produced twice the positive-mode analyte signal of methane, equal to pure isobutane, and reduced spectral dependence on reagent gas pressure. Electron capture negative chemical ionization using 1% i-C4H10 in argon tripled analyte signal compared with methane and was reproducible, unlike pure isobutane. The operative lifetime of the ion source using isobutane/argon mixtures was extended exponentially compared with pure isobutane, producing stable and reproducible CI signal throughout. By diluting the reagent gas in an inert buffer gas, isobutane CI-MS experiments were made as practical to use as methane CI-MS experiments but with superior analytical performance.

  15. Assessment of resonance ionization mass spectrometry for analytical chemistry and spectroscopy

    International Nuclear Information System (INIS)

    Resonance ionization mass spectrometry (RIMS) is a natural outgrowth of RIS. The result of an RIS process is an ion pair. The electron can be used to detect the process, and single atom detection has been demonstrated by this method. The cation resulting from the RIS process actually carries more easily accessible and useful information (i.e. the mass of the ion). RIMS is useful in mass analysis. The development of RIMS has proceeded along several different directions, using CW or pulsed lasers, narrow or wide band laser energies, different kinds of sample generation, and different kinds of mass separations. RIMS in various forms can be used to obtain either element or isotope selectivity. Even though the RIMS technique has developed along several lines, several things are common to all approaches. Ultimately RIMS requires gaseous, free, atoms. RIMS makes use of the photoionization of these atoms by absorption of photons through allowed transitions involving real energy levels. The ion once formed is detected by standard mass spectrometric techniques

  16. Desorption Electrospray Ionization (DESI) Mass Spectrometric Imaging of the Distribution of Rohitukine in the Seedling of Dysoxylum binectariferum Hook. F.

    Science.gov (United States)

    Mohana Kumara, Patel; Srimany, Amitava; Arunan, Suganya; Ravikanth, Gudasalamani; Uma Shaanker, Ramanan; Pradeep, Thalappil

    2016-01-01

    Ambient ionization mass spectrometric imaging of all parts of the seedling of Dysoxylum binectariferum Hook. f (Meliaceae) was performed to reconstruct the molecular distribution of rohitukine (Rh) and related compounds. The species accumulates Rh, a prominent chromone alkaloid, in its seeds, fruits, and stem bark. Rh possesses anti-inflammatory, anti-cancer, and immuno-modulatory properties. Desorption electrospray ionization mass spectrometry imaging (DESI MSI) and electrospray ionization (ESI) tandem mass spectrometry (MS/MS) analysis detected Rh as well as its glycosylated, acetylated, oxidized, and methoxylated analogues. Rh was predominantly distributed in the main roots, collar region of the stem, and young leaves. In the stem and roots, Rh was primarily restricted to the cortex region. The identities of the metabolites were assigned based on both the fragmentation patterns and exact mass analyses. We discuss these results, with specific reference to the possible pathways of Rh biosynthesis and translocation during seedling development in D. binectariferum. PMID:27362422

  17. Desorption Electrospray Ionization (DESI Mass Spectrometric Imaging of the Distribution of Rohitukine in the Seedling of Dysoxylum binectariferum Hook. F.

    Directory of Open Access Journals (Sweden)

    Patel Mohana Kumara

    Full Text Available Ambient ionization mass spectrometric imaging of all parts of the seedling of Dysoxylum binectariferum Hook. f (Meliaceae was performed to reconstruct the molecular distribution of rohitukine (Rh and related compounds. The species accumulates Rh, a prominent chromone alkaloid, in its seeds, fruits, and stem bark. Rh possesses anti-inflammatory, anti-cancer, and immuno-modulatory properties. Desorption electrospray ionization mass spectrometry imaging (DESI MSI and electrospray ionization (ESI tandem mass spectrometry (MS/MS analysis detected Rh as well as its glycosylated, acetylated, oxidized, and methoxylated analogues. Rh was predominantly distributed in the main roots, collar region of the stem, and young leaves. In the stem and roots, Rh was primarily restricted to the cortex region. The identities of the metabolites were assigned based on both the fragmentation patterns and exact mass analyses. We discuss these results, with specific reference to the possible pathways of Rh biosynthesis and translocation during seedling development in D. binectariferum.

  18. EUV ionization of pure He nanodroplets: Mass-correlated photoelectron imaging, Penning ionization and electron energy-loss spectra

    CERN Document Server

    Buchta, D; Brauer, N B; Drabbels, M; O'Keeffe, P; Devetta, M; Di Fraia, M; Callegari, C; Richter, R; Coreno, M; Prince, K C; Stienkemeier, F; Moshammer, R; Mudrich, M

    2013-01-01

    The ionization dynamics of pure He nanodroplets irradiated by EUV radiation is studied using Velocity-Map Imaging PhotoElectron-PhotoIon COincidence (VMI-PEPICO) spectroscopy. We present photoelectron energy spectra and angular distributions measured in coincidence with the most abundant ions He+, He2+, and He3+. Surprisingly, below the autoionization threshold of He droplets we find indications for multiple excitation and subsequent ionization of the droplets by a Penning-like process. At high photon energies we evidence inelastic collisions of photoelectrons with the surrounding He atoms in the droplets.

  19. Calibration of matrix-assisted laser desorption/ionization time-of-flight peptide mass fingerprinting spectra

    DEFF Research Database (Denmark)

    Hjernø, Karin; Højrup, Peter

    2007-01-01

    This chapter describes a number of aspects important for calibration of matrix-assisted laser desorption/ionization time-of-flight spectra prior to peptide mass fingerprinting searches. Both multipoint internal calibration and mass defect-based calibration is illustrated. The chapter describes ho...

  20. 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.

  1. Atmospheric-Pressure Chemical Ionization Tandem Mass Spectrometry (APGC/MS/MS) an Alternative to High-Resolution Mass Spectrometry (HRGC/HRMS) for the Determination of Dioxins

    NARCIS (Netherlands)

    Bavel, Van Bert; Geng, Dawei; Cherta, Laura; Nácher-Mestre, Jaime; Portolés, Tania; Ábalos, Manuela; Sauló, Jordi; Abad, Esteban; Dunstan, Jody; Jones, Rhys; Kotz, Alexander; Winterhalter, Helmut; Malisch, Rainer; Traag, Wim; Hagberg, Jessika; Ericson Jogsten, Ingrid; Beltran, Joaquim; Hernández, Félix

    2015-01-01

    The use of a new atmospheric-pressure chemical ionization source for gas chromatography (APGC) coupled with a tandem quadrupole mass spectrometry (MS/MS) system, as an alternative to high-resolution mass spectrometry (HRMS), for the determination of PCDDs/PCDFs is described. The potential of usin

  2. Signal and Charge Enhancement for Protein Analysis by Liquid Chromatography-Mass Spectrometry with Desorption Electrospray Ionization

    OpenAIRE

    Liu, Yan; Miao, Zhixin; Lakshmanan, Rajeswari; Ogorzalek Loo, Rachel R.; Loo, Joseph A.; Chen, Hao

    2012-01-01

    We recently reported the use of desorption electrospray ionization (DESI) as a novel interface to couple high-performance liquid chromatography (HPLC) with mass spectrometry (MS) (Chem. Commun. 2011, 47, 4171). One of the benefits of such an interface is that post-column derivatization of separated analytes can be integrated with ionization via a “reactive” DESI approach in which a derivatizing reagent is doped into the spray solvent. The reactive DESI interface allows analyte desorption/ioni...

  3. Clustering, methodology, and mechanistic insights into acetate chemical ionization using high-resolution time-of-flight mass spectrometry

    Science.gov (United States)

    Brophy, Patrick; Farmer, Delphine K.

    2016-08-01

    We present a comprehensive characterization of cluster control and transmission through the Tofwerk atmospheric pressure interface installed on various chemical ionization time-of-flight mass spectrometers using authentic standards. This characterization of the atmospheric pressure interface allows for a detailed investigation of the acetate chemical ionization mechanisms and the impact of controlling these mechanisms on sensitivity, selectivity, and mass spectral ambiguity with the aim of non-targeted analysis. Chemical ionization with acetate reagent ions is controlled by a distribution of reagent ion-neutral clusters that vary with relative humidity and the concentration of the acetic anhydride precursor. Deprotonated carboxylic acids are primarily detected only if sufficient declustering is employed inside the atmospheric pressure interface. The configuration of a high-resolution time-of-flight chemical ionization mass spectrometer (HR-TOF-CIMS) using an acetate chemical ionization source for non-targeted analysis is discussed. Recent approaches and studies characterizing acetate chemical ionization as it applies to the HR-TOF-CIMS are evaluated in light of the work presented herein.

  4. Direct analysis of Stevia leaves for diterpene glycosides by desorption electrospray ionization mass spectrometry.

    Science.gov (United States)

    Jackson, Ayanna U; Tata, Alessandra; Wu, Chunping; Perry, Richard H; Haas, George; West, Leslie; Cooks, R Graham

    2009-05-01

    The analysis of Stevia leaves has been demonstrated without any sample preparation using desorption electrospray ionization (DESI) mass spectrometry. Direct rapid analysis was achieved using minimal amounts of sample ( approximately 0.15 cm x 0.15 cm leaf fragment). Characteristic constituents of the Stevia plant are observed in both the positive and negative ion modes including a series of diterpene 'sweet' glycosides. The presence of the glycosides was confirmed via tandem mass spectrometry analysis using collision-induced dissociation and further supported by exact mass measurements using an LTQ-Orbitrap. The analysis of both untreated and hexane-extracted dry leaves proved that DESI can be successfully used to analyze untreated leaf fragments as identical profiles were obtained from both types of samples. Characterization and semi-quantitative determination of the glycosides was achieved based on the glycoside profile within the full mass spectrum. In addition, the presence of characteristic glycosides in an all-natural commercial Stevia dietary supplement was confirmed. This study provides an example of the application of DESI to direct screening of plant materials, in this case diterpene glycosides. PMID:19381377

  5. 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

  6. Thermal mass loss of protoplanetary cores with hydrogen-dominated atmospheres: The influences of ionization and orbital distance

    CERN Document Server

    Erkaev, N V; Odert, P; Kislyakova, K G; Johnstone, C P; Güdel, M; Khodachenko, M L

    2016-01-01

    We investigate the loss rates of the hydrogen atmospheres of terrestrial planets with a range of masses and orbital distances by assuming a 100 times stronger soft X-ray and extreme ultraviolet (XUV) flux. We apply a 1D upper atmosphere radiation absorption and hydrodynamic escape model that takes into account ionization, dissociation and recombination to calculate hydrogen mass loss rates. We study the effect of the ionization, dissociation and recombination on the thermal mass loss rates of hydrogen-dominated super-Earths and compare the results with those obtained by the energy-limited escape formula which is widely used for mass loss evolution studies. Our results indicate that the energy-limited formula can to a great extent over- or underestimate the hydrogen mass loss rates by amounts that depend on the stellar XUV flux and planetary parameters such as mass, size, effective temperature, and XUV absorption radii.

  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. Enhanced capabilities for imaging gangliosides in murine brain with matrix-assisted laser desorption/ionization and desorption electrospray ionization mass spectrometry coupled to ion mobility separation.

    Science.gov (United States)

    Škrášková, Karolina; Claude, Emmanuelle; Jones, Emrys A; Towers, Mark; Ellis, Shane R; Heeren, Ron M A

    2016-07-15

    The increased interest in lipidomics calls for improved yet simplified methods of lipid analysis. Over the past two decades, mass spectrometry imaging (MSI) has been established as a powerful technique for the analysis of molecular distribution of a variety of compounds across tissue surfaces. Matrix-assisted laser desorption/ionization (MALDI) MSI is widely used to study the spatial distribution of common lipids. However, a thorough sample preparation and necessity of vacuum for efficient ionization might hamper its use for high-throughput lipid analysis. Desorption electrospray ionization (DESI) is a relatively young MS technique. In DESI, ionization of molecules occurs under ambient conditions, which alleviates sample preparation. Moreover, DESI does not require the application of an external matrix, making the detection of low mass species more feasible due to the lack of chemical matrix background. However, irrespective of the ionization method, the final information obtained during an MSI experiment is very complex and its analysis becomes challenging. It was shown that coupling MSI to ion mobility separation (IMS) simplifies imaging data interpretation. Here we employed DESI and MALDI MSI for a lipidomic analysis of the murine brain using the same IMS-enabled instrument. We report for the first time on the DESI IMS-MSI of multiply sialylated ganglioside species, as well as their acetylated versions, which we detected directly from the murine brain tissue. We show that poly-sialylated gangliosides can be imaged as multiply charged ions using DESI, while they are clearly separated from the rest of the lipid classes based on their charge state using ion mobility. This represents a major improvement in MSI of intact fragile lipid species. We additionally show that complementary lipid information is reached under particular conditions when DESI is compared to MALDI MSI.

  9. Enhanced capabilities for imaging gangliosides in murine brain with matrix-assisted laser desorption/ionization and desorption electrospray ionization mass spectrometry coupled to ion mobility separation.

    Science.gov (United States)

    Škrášková, Karolina; Claude, Emmanuelle; Jones, Emrys A; Towers, Mark; Ellis, Shane R; Heeren, Ron M A

    2016-07-15

    The increased interest in lipidomics calls for improved yet simplified methods of lipid analysis. Over the past two decades, mass spectrometry imaging (MSI) has been established as a powerful technique for the analysis of molecular distribution of a variety of compounds across tissue surfaces. Matrix-assisted laser desorption/ionization (MALDI) MSI is widely used to study the spatial distribution of common lipids. However, a thorough sample preparation and necessity of vacuum for efficient ionization might hamper its use for high-throughput lipid analysis. Desorption electrospray ionization (DESI) is a relatively young MS technique. In DESI, ionization of molecules occurs under ambient conditions, which alleviates sample preparation. Moreover, DESI does not require the application of an external matrix, making the detection of low mass species more feasible due to the lack of chemical matrix background. However, irrespective of the ionization method, the final information obtained during an MSI experiment is very complex and its analysis becomes challenging. It was shown that coupling MSI to ion mobility separation (IMS) simplifies imaging data interpretation. Here we employed DESI and MALDI MSI for a lipidomic analysis of the murine brain using the same IMS-enabled instrument. We report for the first time on the DESI IMS-MSI of multiply sialylated ganglioside species, as well as their acetylated versions, which we detected directly from the murine brain tissue. We show that poly-sialylated gangliosides can be imaged as multiply charged ions using DESI, while they are clearly separated from the rest of the lipid classes based on their charge state using ion mobility. This represents a major improvement in MSI of intact fragile lipid species. We additionally show that complementary lipid information is reached under particular conditions when DESI is compared to MALDI MSI. PMID:26922843

  10. Determination of ribavirin in human serum using liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    van der Lijke, Henk; Alffenaar, Jan-Willem C; Kok, Wim Th; Greijdanus, Ben; Uges, Donald R A

    2012-01-15

    A method has been developed for the determination of ribavirin in human serum for therapeutic drug monitoring purposes, using liquid chromatography electrospray ionization mass spectrometry. Separation was obtained with a mobile phase gradient starting and ending in 100% aqueous conditions using a Waters Atlantis® T3 column (100×2mm, 3μm). The entire sample preparation consisted of dilution, followed by ultrafiltration. From the clear ultrafiltrate 5μL was injected on the LC-MS/MS system. The calibration curves were linear in the range of 0.2-10mg/L with within-run and between-run precisions (CVs) in the range of 0-10%. The method was validated with respect to specificity, selectivity, linearity, accuracy, precision, recovery and stability and meets the requirements of the FDA. The method was extensively tested for matrix effects by determining the variation of the slopes of calibration curves in different sources of serum and plasma. This method is suitable for the determination of ribavirin in human serum for therapeutic drug monitoring. PMID:22265514

  11. [Determination of 25 quinolones in cosmetics by liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Lin, Li; Zhang, Yi; Tu, Xiaoke; Xie, Liqi; Yue, Zhenfeng; Kang, Haining; Wu, Weidong; Luo, Yao

    2015-03-01

    An analytical method was developed for the simultaneous determination of 25 quinolones, including danofloxacin mesylate, enrofloxacin, flumequine, oxloinic acid, ciprofloxacin, sarafloxacin, nalidixic acid, norfloxacin, and ofloxacin etc in cosmetics using direct extraction and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Cosmetic sample was extracted by acidified acetonitrile, defatted by n-hexane and separated on Poroshell EC-C18 column with gradient elution program using acetonitrile and water (both containing 0. 1% formic acid) as the mobile phases and analyzed by LC-ESI-MS/MS under the positive mode using multiple reaction monitoring (MRM). The interference of matrix was reduced by the matrix-matched calibration standard curve. The method showed good linearities over the range of 1-200 mg/kg for the 25 quinolones with good linear correlation coefficients (r ≥ 0.999). The method detection limit of the 25 quinolones was 1.0 mg/kg, and the recoveries of all analytes in lotion, milky and cream cosmetics matrices ranged from 87.4% to 105% at the spiked levels of 1, 5 and 10 mg/kg with the relative standard deviations (RSD) of 4.54%-19.7% (n = 6). The results indicated that this method is simple, fast and credible, and suitable for the simultaneous determination of the quinolones in the above three types of cosmetics.

  12. Synthesis and Electrospray Ionization Mass Spectra of N-(1,3,2-Dioxaphosphorinan-2-ylmethyl)thiophosphoramidates

    Institute of Scientific and Technical Information of China (English)

    MIAO,Zhi-Wei; FU,Cui-Rong; WANG,Bin; CUI,Zhan-Wei; ZHANG,Jian-Feng; CHEN,Ru-Yu

    2007-01-01

    N-(1,3,2-Dioxaphosphorinan-2-ylmethyl) thiophosphoramidates were synthesized and determined by NMR spectra and positive ion electrospray ionization mass spectrometry (ESI-MS) in conjunction with tandem mass spectrometry (MS/MS). The fragmentation pathways were investigated. The results show that these characteristic ions in ESI mass spectra are useful in the structural determination of N-(1,3,2-dioxaphosphorinan-2-ylmethyl)thiophosphoramidates.

  13. Investigation of the Reactivity of Oligodeoxynucleotides with Glyoxal and KMnO4 Chemical Probes by Electrospray Ionization Mass Spectrometry

    OpenAIRE

    Parr, Carol; Pierce, Sarah E.; Smith, Suncerae I.; Brodbelt, Jennifer S.

    2011-01-01

    The reactions of two well-known chemical probes, glyoxal and potassium permanganate (KMnO4), with oligodeoxynucleotides were monitored by electrospray ionization (ESI) mass spectrometry to evaluate the influence of the sequence of DNA, its secondary structure, and interactions with associated ligands on the reactivity of the two probes. Glyoxal, a guanine-reactive probe, incorporated a mass shift of 58 Da, and potassium permanganate (KMnO4) is a thymine-reactive probe that resulted in a mass ...

  14. Cobalt coated substrate for matrix-free analysis of small molecules by laser desorption/ionization mass spectrometry

    International Nuclear Information System (INIS)

    Small molecule analysis is one of the most challenging issues in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. We have developed a cobalt coated substrate as a target for matrix-free analysis of small molecules in laser desorption/ionization mass spectrometry. Cobalt coating of 60-70 nm thickness has been characterized by scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, and laser induced breakdown spectroscopy. This target facilitates hundreds of samples to be spotted and analyzed without mixing any matrices, in a very short time. This can save a lot of time and money and can be a very practical approach for the analysis of small molecules by laser desorption/ionization mass spectrometry.

  15. Critical factors determining the quantification capability of matrix-assisted laser desorption/ionization- time-of-flight mass spectrometry.

    Science.gov (United States)

    Wang, Chia-Chen; Lai, Yin-Hung; Ou, Yu-Meng; Chang, Huan-Tsung; Wang, Yi-Sheng

    2016-10-28

    Quantitative analysis with mass spectrometry (MS) is important but challenging. Matrix-assisted laser desorption/ionization (MALDI) coupled with time-of-flight (TOF) MS offers superior sensitivity, resolution and speed, but such techniques have numerous disadvantages that hinder quantitative analyses. This review summarizes essential obstacles to analyte quantification with MALDI-TOF MS, including the complex ionization mechanism of MALDI, sensitive characteristics of the applied electric fields and the mass-dependent detection efficiency of ion detectors. General quantitative ionization and desorption interpretations of ion production are described. Important instrument parameters and available methods of MALDI-TOF MS used for quantitative analysis are also reviewed.This article is part of the themed issue 'Quantitative mass spectrometry'. PMID:27644968

  16. A time-of-flight mass spectrometer with laser ionization for sensitive product molecule detection for heterogeneous model reactions

    International Nuclear Information System (INIS)

    Investigations of model catalysts are very often performed in ultra-high vacuum for ensuring very well-defined systems. Usually, product molecule detection is performed by electron impact (EI) ionization in a quadrupole mass spectrometer. While this method offers the possibilities of continuous measurements and high sensitivity, it features the drawback that a mass scan has to be performed to detect the masses of all reaction products. In addition, the discrimination between isobars is difficult to achieve because of the unselective properties of EI ionization. In this work we present a time-of-flight MS in combination with laser ionization. Due to the setup, this system allows for a very sensitive detection of isobaric species. In this poster the detection principle is illustrated and first proof-of-principle measurements are shown.

  17. Search for efficient laser resonance ionization schemes of tantalum using a newly developed time-of-flight mass-spectrometer in KISS

    Science.gov (United States)

    Mukai, M.; Hirayama, Y.; Ishiyama, H.; Jung, H. S.; Miyatake, H.; Oyaizu, M.; Watanabe, Y. X.; Kimura, S.; Ozawa, A.; Jeong, S. C.; Sonoda, T.

    2016-06-01

    The technique of laser resonance ionization is employed for an element-selective ionization of multi-nucleon transfer reaction products which are stopped and neutralized in a gas cell filled with argon gas at 50 kPa. We have been searching for efficient laser ionization schemes for refractory elements of Z = 73-78 using a time-of-flight mass-spectrometer (TOF-MS) chamber. To evaluate the isotope shift and ionization efficiency for each candidate of the ionization scheme, isotope separation using the TOF-MS was devised. The TOF-MS was designed to separate the isotopes using two-stage linear acceleration with a mass resolving power M / ΔM of >350. A mass resolving power of 250 was experimentally confirmed by measuring the TOF of laser-ionized tantalum (Z = 73) ions with mass number 181. We searched for a laser resonance ionization scheme of tantalum using the TOF-MS.

  18. Sensitivity effects in Uk'37 paleotemperature estimation by chemical ionization mass spectrometry.

    Science.gov (United States)

    Chaler, R; Grimalt, J O; Pelejero, C; Calvo, E

    2000-12-15

    Analysis of C37 alkenone mixtures by gas chromatography (GC) with flame ionization detection (FID) and GC coupled to mass spectrometry (GC/MS) in the chemical ionization mode (CI) shows that the later is useful for paleotemperature estimation when ammonia is used as reagent gas. Conversely, the use of isobutane gives rise to Uk'37 readings that are dependent on the amount of C37 alkenones introduced in the system, being unreliable for paleoclimatic studies. However, ammonia CI GC/MS may produce Uk'37 measurements that deviate from those obtained by GC-FID, the method calibrated for temperature estimation from algal cultures and marine sedimentary data. The differences result from changes in relative sensitivity between the di- and triunsaturated alkenones and depend on the instrument used and operational conditions. This problem is solved in the present study by determination of the response factor linear equations for each alkenone and their average relative sensitivity (R) using mixtures of known composition. These parameters allow the transformation of the GC/MS readings into the GC-FID equivalents using the following equation: UG = R x UM/(1 - UM(1 - R)). Examples of the suitability of this approach are given. PMID:11140754

  19. Quantum dots assisted laser desorption/ionization mass spectrometric detection of carbohydrates: qualitative and quantitative analysis.

    Science.gov (United States)

    Bibi, Aisha; Ju, Huangxian

    2016-04-01

    A quantum dots (QDs) assisted laser desorption/ionization mass spectrometric (QDA-LDI-MS) strategy was proposed for qualitative and quantitative analysis of a series of carbohydrates. The adsorption of carbohydrates on the modified surface of different QDs as the matrices depended mainly on the formation of hydrogen bonding, which led to higher MS intensity than those with conventional organic matrix. The effects of QDs concentration and sample preparation method were explored for improving the selective ionization process and the detection sensitivity. The proposed approach offered a new dimension to the application of QDs as matrices for MALDI-MS research of carbohydrates. It could be used for quantitative measurement of glucose concentration in human serum with good performance. The QDs served as a matrix showed the advantages of low background, higher sensitivity, convenient sample preparation and excellent stability under vacuum. The QDs assisted LDI-MS approach has promising application to the analysis of carbohydrates in complex biological samples. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27041659

  20. Secondary ozonides of endo-cyclic alkenes analyzed by atmospheric sampling Townsend discharge ionization mass spectrometry

    Science.gov (United States)

    Nøjgaard, J. K.; Nørgaard, A. W.; Wolkoff, P.

    2007-05-01

    Secondary ozonides (SOZ) of cyclohexene, 1-methylcyclohexene, 4-isopropyl-1-methylcyclohexene and d-limonene were cryo-synthesized by ozonolysis in pentane and purified on a silica gel column. The mass spectra obtained by atmospheric sampling Townsend discharge ionization (ASTDI) and collision activated dissociation (CAD) of the protonized SOZ showed characteristic losses evident of the ozonide structure. Oxygen was eliminated as, e.g., O and O2, and loss of (HCHO + HCHO) or (O + CO2) corresponded to the SOZ base-peak for the substituted cyclohexenes by ASTDI-MS. The CAD spectra of the protonized species by use of methane as chemical ionization gas, showed consecutive losses of three oxygen atoms. Elimination of hydroxy-methyl hydroperoxide (HMHP) was particular important for the protonized SOZ, unlike consecutive loss of (HCHO + HCHO) or (O + CO2). In addition, the spectra of d-limonene were characterized by an unique loss of H2O2. These losses appear to be useful for identification of SOZ in gas-phase ozonolysis mixtures of endo-cyclic alkenes, which makes ASTDI an alternative to other on-line techniques for analysis of SOZ in ozonolysis mixtures.

  1. Study of Ozone-Initiated Limonene Reaction Products by Low Temperature Plasma Ionization Mass Spectrometry

    Science.gov (United States)

    Nørgaard, Asger W.; Vibenholt, Anni; Benassi, Mario; Clausen, Per Axel; Wolkoff, Peder

    2013-07-01

    Limonene and its ozone-initiated reaction products were investigated in situ by low temperature plasma (LTP) ionization quadrupole time-of-flight (QTOF) mass spectrometry. Helium was used as discharge gas and the protruding plasma generated ~850 ppb ozone in front of the glass tube by reaction with the ambient oxygen. Limonene applied to filter paper was placed in front of the LTP afterglow and the MS inlet. Instantly, a wide range of reaction products appeared, ranging from m/ z 139 to ca. 1000 in the positive mode and m/ z 115 to ca. 600 in the negative mode. Key monomeric oxidation products including levulinic acid, 4-acetyl-1-methylcyclohexene, limonene oxide, 3-isopropenyl-6-oxo-heptanal, and the secondary ozonide of limonene could be identified by collision-induced dissociation. Oligomeric products ranged from the nonoxidized dimer of limonene (C20H30) and up to the hexamer with 10 oxygen atoms (C60H90O10). The use of LTP for in situ ozonolysis and ionization represents a new and versatile approach for the assessment of ozone-initiated terpene chemistry.

  2. Detection of histamine in beer by nano extractive electrospray ionization mass spectrometry.

    Science.gov (United States)

    Cai, Jiuxiao; Li, Ming; Xiong, Xingchuang; Fang, Xiang; Xu, Ruifeng

    2014-01-01

    In this study, rapid quantitative detection of histamine in beer was achieved by using nano extractive electrospray ionization mass spectrometry (nano EESI-MS) coupling with standard addition method. Based on the MS(2) experiment, histamine concentrations in three beer samples were determined to be 1.10 ± 0.12 µg/ml, 0.81 ± 0.09 µg/ml and 0.79 ± 0.09 µg/ml. The limit of detection for this method was calculated to be 0.02 µg/ml. These results show that this novel method can be used for direct, rapid and sensitive detection of histamine in beer without any tedious sample pretreatment.

  3. Large Scale Nanoparticle Screening for Small Molecule Analysis in Laser Desorption Ionization Mass Spectrometry.

    Science.gov (United States)

    Yagnik, Gargey B; Hansen, Rebecca L; Korte, Andrew R; Reichert, Malinda D; Vela, Javier; Lee, Young Jin

    2016-09-20

    Nanoparticles (NPs) have been suggested as efficient matrixes for small molecule profiling and imaging by laser-desorption ionization mass spectrometry (LDI-MS), but so far there has been no systematic study comparing different NPs in the analysis of various classes of small molecules. Here, we present a large scale screening of 13 NPs for the analysis of two dozen small metabolite molecules. Many NPs showed much higher LDI efficiency than organic matrixes in positive mode and some NPs showed comparable efficiencies for selected analytes in negative mode. Our results suggest that a thermally driven desorption process is a key factor for metal oxide NPs, but chemical interactions are also very important, especially for other NPs. The screening results provide a useful guideline for the selection of NPs in the LDI-MS analysis of small molecules. PMID:27573492

  4. New methods and instrumentation for the characterization of biopolymers using electrospray ionization-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.D.; Udseth, H.R.; Rockwood, A.L.; Winger, B.E.; Hofstadler, S.A.; Goodlett, D.R.; Light-Wahl, K.J.

    1992-09-01

    The technique of electrospray ionization (ESI) has significantly extended the ability to characterize large molecules by mass spectrometry. Proteins to at least 200,000 D can be transferred intact to the gas phase and molecular weights determined with precisions as high as 0.001% if individual charge states can be resolved. The ESI-MS can also serve as a near ideal interface and detector for capillary column separations providing a basis for highly efficient sample utilization. Using capillary electrophoresis (CE)-MS, injection quantities in the 10[sup [minus]18] mole range can be detected for smaller polypeptides using selected ion monitoring, and separation efficiencies as high as 5[center dot]10[sup 5] theoretical plates have been realized. We have recently shown that the use of small 5 [mu]m i.d. capillaries allows CE-MS with scanning detection for proteins for injection of 600 attomoles.

  5. New methods and instrumentation for the characterization of biopolymers using electrospray ionization-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.D.; Udseth, H.R.; Rockwood, A.L.; Winger, B.E.; Hofstadler, S.A.; Goodlett, D.R.; Light-Wahl, K.J.

    1992-09-01

    The technique of electrospray ionization (ESI) has significantly extended the ability to characterize large molecules by mass spectrometry. Proteins to at least 200,000 D can be transferred intact to the gas phase and molecular weights determined with precisions as high as 0.001% if individual charge states can be resolved. The ESI-MS can also serve as a near ideal interface and detector for capillary column separations providing a basis for highly efficient sample utilization. Using capillary electrophoresis (CE)-MS, injection quantities in the 10{sup {minus}18} mole range can be detected for smaller polypeptides using selected ion monitoring, and separation efficiencies as high as 5{center_dot}10{sup 5} theoretical plates have been realized. We have recently shown that the use of small 5 {mu}m i.d. capillaries allows CE-MS with scanning detection for proteins for injection of 600 attomoles.

  6. Screening Anti-Cancer Drugs against Tubulin using Catch-and-Release Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Rezaei Darestani, Reza; Winter, Philip; Kitova, Elena N.; Tuszynski, Jack A.; Klassen, John S.

    2016-05-01

    Tubulin, which is the building block of microtubules, plays an important role in cell division. This critical role makes tubulin an attractive target for the development of chemotherapeutic drugs to treat cancer. Currently, there is no general binding assay for tubulin-drug interactions. The present work describes the application of the catch-and-release electrospray ionization mass spectrometry (CaR-ESI-MS) assay to investigate the binding of colchicinoid drugs to αβ-tubulin dimers extracted from porcine brain. Proof-of-concept experiments using positive (ligands with known affinities) and negative (non-binders) controls were performed to establish the reliability of the assay. The assay was then used to screen a library of seven colchicinoid analogues to test their binding to tubulin and to rank their affinities.

  7. Characterization of mustard seeds and paste by DART ionization with time-of-flight mass spectrometry.

    Science.gov (United States)

    Prchalová, Jana; Kovařík, František; Ševčík, Rudolf; Čížková, Helena; Rajchl, Aleš

    2014-09-01

    Direct analysis in real time (DART) is a novel technique with great potential for rapid screening analysis. The DART ionization method coupled with high-resolution time-of-flight mass spectrometry (TOF-MS) has been used for characterization of mustard seeds and table mustard. The possibility to use DART to analyse glucosinolates was confirmed on determination of sinalbin (4-hydroxybenzyl glucosinolate). The DART-TOF-MS method was optimized and validated. A set of samples of mustard seeds and mustard products was analyzed. High-performance liquid chromatography and DART-TOF-MS were used to determine glucosinolates in mustard seeds and compared. The correlation equation between these methods was DART = 0.797*HPLC + 6.987, R(2)  = 0.972. The DART technique seems to be a suitable method for evaluation of the quality of mustard seeds and mustard products. PMID:25230177

  8. Multiphoton Ionization Time-of-Flight Mass Spectrometry for the Detection of Bioactive Lignan.

    Science.gov (United States)

    Uchimura, Tomohiro; Tokumoto, Goro; Batnyam, Onon; Chou, Chih-Wei; Fujita, Satoshi

    2016-01-01

    Multiphoton ionization time-of-flight mass spectrometry (MPI-TOFMS) combined with a pulsed laser for sample vaporization was developed for the detection of a low-volatile compound in a solution. A solution containing Taiwanin A ((3E,4E)-3,4-bis(1,3-benzodioxol-5-ylmethylene)dihydro-2(3H)-furanone), which is a lignan that has an anticancer effect, was employed in the present study. Consequently, Taiwanin A could be detected by irradiating a laser pulse for vaporization to an inlet nozzle, rather than by heating. Therefore, the present method could be effective for detecting compounds with lower volatilities in a liquid sample. PMID:26860576

  9. Separation Techniques for Uranium and Plutonium at Trace Levels for the Thermal Ionization Mass Spectrometric Determination

    Energy Technology Data Exchange (ETDEWEB)

    Suh, M. Y.; Han, S. H.; Kim, J. G.; Park, Y. J.; Kim, W. H

    2005-12-15

    This report describes the state of the art and the progress of the chemical separation and purification techniques required for the thermal ionization mass spectrometric determination of uranium and plutonium in environmental samples at trace or ultratrace levels. Various techniques, such as precipitation, solvent extraction, extraction chromatography, and ion exchange chromatography, for separation of uranium and plutonium were evaluated. Sample preparation methods and dissolution techniques for environmental samples were also discussed. Especially, both extraction chromatographic and anion exchange chromatographic procedures for uranium and plutonium in environmental samples, such as soil, sediment, plant, seawater, urine, and bone ash were reviewed in detail in order to propose some suitable methods for the separation and purification of uranium and plutonium from the safeguards environmental or swipe samples. A survey of the IAEA strengthened safeguards system, the clean room facility of IAEA's NWAL(Network of Analytical Laboratories), and the analytical techniques for safeguards environmental samples was also discussed here.

  10. Direct Measurement of Atmospheric Ammonia from an Airborne Miniature Chemical Ionization Mass Spectrometer (miniCIMS)

    Science.gov (United States)

    Casados, K.; Schill, S.; Freeman, S.; Zoerb, M.; Bertram, T. H.; Lefer, B. L.

    2015-12-01

    Ammonia is emitted into the atmosphere from a variety of sources such as trees, ocean, diary fields, biomass burning, and fuel emissions. Previous studies have investigated the environmental impacts of atmospheric ammonia which can include chemical reactivity, nucleation of fine particulate matter 2.5 (PM 2.5 ), and implications for human health, but its chemical nature and relatively short lifetime make direct measurement of atmospheric ammonia difficult. During the 2015 NASA Student Airborne Research Program (SARP) an airborne miniature Chemical Ionization Mass Spectrometer (miniCIMS) was deployed on the NASA DC-8 flying laboratory in the Southern California region. The spatial and temporal variability of measured atmospheric ammonia concentrations will be discussed.

  11. Analysis of uncertainties in isotopic assay of UO2 pellets using thermal ionization mass spectrometer

    International Nuclear Information System (INIS)

    Control Laboratory being a centralized analytical facility of NFC is responsible for isotopic assay of UO2 pellets by Thermal ionization mass spectrometry (TIMS). TIMS is a precise and accurate technique for the determination of isotopic ratios. The present work involves the evaluation of uncertainty components affecting the measurement results. Qualitative and Quantitative Uncertainty factors have been evaluated. Qualitative factors mentioned are mostly related to technical competency of operators involved in the analysis; while quantitative factors have been evaluated. The isotope reference material selected as check standard is SRM U-005 Uranium Isotopic Standard with 235U (at%): 0.4833 ± 0.0005 and the Natural isotopic composition of 235U sample has been selected for analysis to calculate uncertainty sources effecting the obtained isotopic ratios

  12. Analytical developments in thermal ionization mass spectrometry for the isotopic analysis of very small amounts

    International Nuclear Information System (INIS)

    In the framework of the French transmutation project of nuclear wastes, experiments consisted in the irradiation in a fast neutron reactor of few milligrams of isotopically enriched powders. Hence, the isotopic analysis of very small amount of irradiation products is one of the main issues. The aim of this study was to achieve analytical developments in thermal ionization mass spectrometry in order to accurately analyze these samples. Several axes were studied including the new total evaporation method, deposition techniques, electron multiplier potentialities and comparison between different isotope measurement techniques. Results showed that it was possible to drastically decrease the amounts needed for analysis, especially with Eu and Nd, while maintaining an uncertainty level in agreement with the project requirements. (author)

  13. Reconstruction and feature selection for desorption electrospray ionization mass spectroscopy imagery

    Science.gov (United States)

    Gao, Yi; Zhu, Liangjia; Norton, Isaiah; Agar, Nathalie Y. R.; Tannenbaum, Allen

    2014-03-01

    Desorption electrospray ionization mass spectrometry (DESI-MS) provides a highly sensitive imaging technique for differentiating normal and cancerous tissue at the molecular level. This can be very useful, especially under intra-operative conditions where the surgeon has to make crucial decision about the tumor boundary. In such situations, the time it takes for imaging and data analysis becomes a critical factor. Therefore, in this work we utilize compressive sensing to perform the sparse sampling of the tissue, which halves the scanning time. Furthermore, sparse feature selection is performed, which not only reduces the dimension of data from about 104 to less than 50, and thus significantly shortens the analysis time. This procedure also identifies biochemically important molecules for further pathological analysis. The methods are validated on brain and breast tumor data sets.

  14. Infrared matrix-assisted laser desorption electrospray ionization mass spectrometry imaging analysis of biospecimens.

    Science.gov (United States)

    Bokhart, M T; Muddiman, D C

    2016-09-21

    Infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) mass spectrometry imaging (MSI) is a technique well suited for analysis of biological specimens. This tutorial review focuses on recent advancements and applications of IR-MALDESI MSI to better understand key biological questions. Through optimization of user-defined source parameters, comprehensive and quantitative MSI data can be obtained for a variety of analytes. The effect of an ice matrix layer is well defined in the context of desorption dynamics and resulting ion abundance. Optimized parameters and careful control of conditions affords quantitative MSI data which provides valuable information for targeted, label-free drug distribution studies and untargeted metabolomic datasets. Challenges and limitations of MSI using IR-MALDESI are addressed in the context of the bioimaging field. PMID:27484166

  15. Ultrasensitive Nanoelectrospray Ionization-Mass Spectrometry using Poly(dimethylsiloxane) Microchips with Monolithically Integrated Emitters

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xuefei; Kelly, Ryan T.; Tang, Keqi; Smith, Richard D.

    2010-09-01

    Poly(dimethylsiloxane) (PDMS) is the most widely used substrate for microfluidic devices as it enables facile fabrication and has other distinctive properties. However, for applications involving highly sensitive nanoelectrospray ionization mass spectrometry (nanoESI-MS) detection, the use of PDMS microdevices has been hindered by the leaching of uncross-linked oligomers and other contaminants from the substrate that yields a large background of chemical noise in the mass spectra. A more general challenge is that microfluidic devices containing integrated electrospray emitters are frequently unable to operate stably in the nanoflow regime where the best sensitivity is achieved. In this report, we extracted the contaminants from PDMS substrates using a series of solvents, eliminating the background observed when untreated PDMS microchips are used for nanoESI-MS. Optimization of the integrated emitter geometry enabled stable operation at flow rates as low as 10 nL/min. Peptide concentrations of 1 nM were readily detected, representing ~170 zmol of consumed analyte, and an extrapolated detection limit of ~40 zmol; these are the lowest mass and concentration detection limits reported to date for a microchip having an integrated electrospray emitter.

  16. Desorption electrospray ionization mass spectrometry: direct toxicological screening and analysis of illicit Ecstasy tablets.

    Science.gov (United States)

    Leuthold, Luc Alexis; Mandscheff, Jean-François; Fathi, Marc; Giroud, Christian; Augsburger, Marc; Varesio, Emmanuel; Hopfgartner, Gérard

    2006-01-01

    Desorption electrospray ionization mass spectrometry (DESI-MS) was used as a simple and rapid way to analyze drug tablets and powders without sample preparation. Experiments were performed with a home-made DESI source coupled to a triple-quadrupole linear-ion trap (QqQ(LIT)) mass spectrometer. Twenty-one commercial drugs as well as some illicit Ecstasy tablets and powders were analyzed. MS spectra almost exclusively showed the protonated or deprotonated ion of the drug after directing the pneumatically assisted electrospray onto the tablet's surface. With some tablets, inhomogeneity of the surface resulted in different spectra depending on the spot analyzed, thus showing that DESI could be used for imaging. Directly triggered MS/MS spectra were used for confirmatory analysis, with analysis times often below 10 s per tablet. For illicit Ecstasy tablets, DESI-MS, GC/MS and LC/MS analyses provided similar qualitative results for the main analytes. With MS/MS spectra library comparison or exact mass measurements, this technique could become very powerful for the rapid analysis of unknown tablets and shows the great potential of desorption techniques as an alternative to solution-based analysis. PMID:16331738

  17. Controlled-Resonant Surface Tapping-Mode Scanning Probe Electrospray Ionization Mass Spectrometry Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, Matthias [ORNL; Ovchinnikova, Olga S [ORNL; Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

    2014-01-01

    This paper reports on the advancement of a controlled-resonance surface tapping-mode single capillary liquid junction extraction/ESI emitter for mass spectrometry imaging. The basic instrumental setup and the general operation of the system were discussed and optimized performance metrics were presented. The ability to spot sample, lane scan and chemically image in an automated and controlled fashion were demonstrated. Rapid, automated spot sampling was demonstrated for a variety of compound types including the cationic dye basic blue 7, the oligosaccharide cellopentaose, and the protein equine heart cytochrome c. The system was used for lane scanning and chemical imaging of the cationic dye crystal violet in inked lines on glass and for lipid distributions in mouse brain thin tissue sections. Imaging of the lipids in mouse brain tissue under optimized conditions provided a spatial resolution of approximately 35 m based on the ability to distinguish between features observed both in the optical and mass spectral chemical images. The sampling spatial resolution of this system was comparable to the best resolution that has been reported for other types of atmospheric pressure liquid extraction-based surface sampling/ionization techniques used for mass spectrometry imaging.

  18. In situ analysis of corrosion inhibitors using a portable mass spectrometer with paper spray ionization

    KAUST Repository

    Jjunju, Fred P M

    2013-01-01

    Paper spray (PS) ambient ionization is implemented using a portable mass spectrometer and applied to the detection of alkyl quaternary ammonium salts in a complex oil matrix. These salts are commonly used as active components in the formulation of corrosion inhibitors. They were identified in oil and confirmed by their fragmentation patterns recorded using tandem mass spectrometry (MS/MS). The cations of alkyl and benzyl-substituted quaternary ammonium salts showed characteristic neutral losses of CnH2n (n carbon number of the longest chain) and C7H8, respectively. Individual quaternary ammonium compounds were detected at low concentrations (<1 ng μL-1) and over a dynamic range of ∼5 pg μL-1 to 500 pg μL-1 (ppb). Direct detection of these compounds in complex oil samples without prior sample preparation or pre-concentration was also demonstrated using a home-built miniature mass spectrometer at levels below 1 ng μL-1.© 2013 The Royal Society of Chemistry.

  19. In situ analysis of corrosion inhibitors using a portable mass spectrometer with paper spray ionization.

    Science.gov (United States)

    Jjunju, Fred P M; Li, Anyin; Badu-Tawiah, Abraham; Wei, Pu; Li, Linfan; Ouyang, Zheng; Roqan, Iman S; Cooks, R Graham

    2013-07-01

    Paper spray (PS) ambient ionization is implemented using a portable mass spectrometer and applied to the detection of alkyl quaternary ammonium salts in a complex oil matrix. These salts are commonly used as active components in the formulation of corrosion inhibitors. They were identified in oil and confirmed by their fragmentation patterns recorded using tandem mass spectrometry (MS/MS). The cations of alkyl and benzyl-substituted quaternary ammonium salts showed characteristic neutral losses of CnH2n (n carbon number of the longest chain) and C7H8, respectively. Individual quaternary ammonium compounds were detected at low concentrations (<1 ng μL(-1)) and over a dynamic range of ∼5 pg μL(-1) to 500 pg μL(-1) (ppb). Direct detection of these compounds in complex oil samples without prior sample preparation or pre-concentration was also demonstrated using a home-built miniature mass spectrometer at levels below 1 ng μL(-1).

  20. Chemical ionization mass spectrometry using carbon nanotube field emission electron sources.

    Science.gov (United States)

    Radauscher, Erich J; Keil, Adam D; Wells, Mitch; Amsden, Jason J; Piascik, Jeffrey R; Parker, Charles B; Stoner, Brian R; Glass, Jeffrey T

    2015-11-01

    A novel chemical ionization (CI) source has been developed based on a carbon nanotube (CNT) field emission electron source. The CNT-based electron source was evaluated and compared with a standard filament thermionic electron source in a commercial explosives trace detection desktop mass spectrometer. This work demonstrates the first reported use of a CNT-based ion source capable of collecting CI mass spectra. Both positive and negative modes were investigated. Spectra were collected for a standard mass spectrometer calibration compound, perfluorotributylamine (PFTBA), as well as trace explosives including trinitrotoluene (TNT), Research Department explosive (RDX), and pentaerythritol tetranitrate (PETN). The electrical characteristics, lifetime at operating pressure, and power requirements of the CNT-based electron source are reported. The CNT field emission electron sources demonstrated an average lifetime of 320 h when operated in constant emission mode under elevated CI pressures. The ability of the CNT field emission source to cycle on and off can provide enhanced lifetime and reduced power consumption without sacrificing performance and detection capabilities. Graphical Abstract ᅟ. PMID:26133527