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Sample records for ultraperformance liquid chromatography

  1. Fingerprint analysis of Resina Draconis by ultra-performance liquid chromatography

    OpenAIRE

    Xue, Yudi; Zhu, Lin; Yi, Tao

    2017-01-01

    Background Resina Draconis, a bright red resin derived from Dracaena cochinchinensis, is a traditional medicine used in China. To improve its quality control approach, an ultra-performance liquid chromatography (UPLC) fingerprint method was developed for rapidly evaluating the quality of Resina Draconis. Methods The precision, repeatability and stability of the proposed UPLC method were validated in the study. Twelve batches of Resina Draconis samples from various sources were analyzed by the...

  2. Quantification of VX Nerve Agent in Various Food Matrices by Solid-Phase Extraction Ultra-Performance Liquid ChromatographyTime-of-Flight Mass Spectrometry

    Science.gov (United States)

    2016-04-01

    QUANTIFICATION OF VX NERVE AGENT IN VARIOUS FOOD MATRICES BY SOLID - PHASE EXTRACTION ULTRA-PERFORMANCE...TITLE AND SUBTITLE Quantification of VX Nerve Agent in Various Food Matrices by Solid - Phase Extraction Ultra-Performance Liquid Chromatography...QUANTIFICATION OF VX NERVE AGENT IN VARIOUS FOOD MATRICES BY SOLID - PHASE EXTRACTION ULTRA-PERFORMANCE LIQUID CHROMATOGRAPHY–TIME-OF-FLIGHT MASS

  3. Fast and Simple Forensic Red Pen Ink Analysis Using Ultra-Performance Liquid Chromatography (UPLC)

    International Nuclear Information System (INIS)

    Lee, L.C.; Ying, S.L.; Wan Nur Syazwani Wan Mohamad Fuad; Ab Aziz Ishak; Khairul Osman

    2016-01-01

    Ultra-performance liquid chromatography (UPLC) is more effective than high performance liquid chromatography in terms of analysis speed and sensitivity. This paper presents a feasibility study on forensic red pen inks analysis using UPLC. A total of 12 varieties of red ball point pen inks were purchased from selected stationary shop. For each variety, four different individual pens were sampled to provide intra-variability within a particular variety of pen. The proposed approach is very simple that it only involved limited analysis step and chemicals. A total of 144 chromatograms were obtained from red ink entries extracted with 1.5 mL 80 % (v/v) acetonitrile. Peaks originated from pen inks were determined by comparing the chromatograms of both blank paper and blank solvent against that of ink samples. Subsequently, one-way ANOVA was conducted to discriminate all 66 possible pairs for red pen inks. Results showed that the proposed approach giving discriminating power of 95.45 %. The outcome of the study indicates that UPLC could be a fast and simple approach to red ball point pen inks analysis. (author)

  4. Integration of electrochemistry with ultra-performance liquid chromatography/mass spectrometry.

    Science.gov (United States)

    Cai, Yi; Zheng, Qiuling; Liu, Yong; Helmy, Roy; Loo, Joseph A; Chen, Hao

    2015-01-01

    This study presents the development of ultra-performance liquid chromatography (UPLC) mass spectrometry (MS) combined with electrochemistry (EC) for the first time and its application for the structural analysis of proteins/peptides that contain disulfide bonds. In our approach, a protein/peptide mixture sample undergoes a fast UPLC separation and subsequent electrochemical reduction in an electrochemical flow cell followed by online MS and tandem mass spectrometry (MS/MS) analyses. The electrochemical cell is coupled to the mass spectrometer using our recently developed desorption electrospray ionization (DESI) interface. Using this UPLC/EC/DESI-MS method, peptides that contain disulfide bonds can be differentiated from those without disulfide bonds, as the former are electroactive and reducible. MS/MS analysis of the disulfide-reduced peptide ions provides increased information on the sequence and disulfide-linkage pattern. In a reactive DESI- MS detection experiment in which a supercharging reagent was used to dope the DESI spray solvent, increased charging was obtained for the UPLC-separated proteins. Strikingly, upon online electrolytic reduction, supercharged proteins (e.g., α-lactalbumin) showed even higher charging, which will be useful in top- down protein structure MS analysis as increased charges are known to promote protein ion dissociation. Also, the separation speed and sensitivity are enhanced by approximately 1(~)2 orders of magnitude by using UPLC for the liquid chromatography (LC)/EC/MS platform, in comparison to the previously used high- performance liquid chromatography (HPLC). This UPLC/EC/DESI-MS method combines the power of fast UPLC separation, fast electrochemical conversion, and online MS structural analysis for a potentially valuable tool for proteomics research and bioanalysis.

  5. Simultaneous determination of ascorbic acid and caffeine in commercial soft drinks using reversed-phase ultraperformance liquid chromatography.

    Science.gov (United States)

    Turak, Fatma; Güzel, Remziye; Dinç, Erdal

    2017-04-01

    A new reversed-phase ultraperformance liquid chromatography method with a photodiode array detector was developed for the quantification of ascorbic acid (AA) and caffeine (CAF) in 11 different commercial drinks consisting of one energy drink and 10 ice tea drinks. Separation of the analyzed AA and CAF with an internal standard, caffeic acid, was performed on a Waters BEH C 18 column (100 mm × 2.1 mm, 1.7 μm i.d.), using a mobile phase consisting of acetonitrile and 0.2M H 3 PO 4 (11:89, v/v) with a flow rate of 0.25 mL/min and an injection volume of 1.0 μL. Calibration graphs for AA and CAF were computed from the peak area ratio of AA/internal standard and CAF/internal standard detected at 244.0 nm and 273.6 nm, respectively. The developed reversed-phase ultraperformance liquid chromatography method was validated by analyzing standard addition samples. The proposed reversed-phase ultraperformance liquid chromatography method gave us successful results for the quantitative analysis of commercial drinks containing AA and CAF substances. Copyright © 2016. Published by Elsevier B.V.

  6. Simultaneous determination of ascorbic acid and caffeine in commercial soft drinks using reversed-phase ultraperformance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Fatma Turak

    2017-04-01

    Full Text Available A new reversed-phase ultraperformance liquid chromatography method with a photodiode array detector was developed for the quantification of ascorbic acid (AA and caffeine (CAF in 11 different commercial drinks consisting of one energy drink and 10 ice tea drinks. Separation of the analyzed AA and CAF with an internal standard, caffeic acid, was performed on a Waters BEH C18 column (100 mm × 2.1 mm, 1.7 μm i.d., using a mobile phase consisting of acetonitrile and 0.2M H3PO4 (11:89, v/v with a flow rate of 0.25 mL/min and an injection volume of 1.0 μL. Calibration graphs for AA and CAF were computed from the peak area ratio of AA/internal standard and CAF/internal standard detected at 244.0 nm and 273.6 nm, respectively. The developed reversed-phase ultraperformance liquid chromatography method was validated by analyzing standard addition samples. The proposed reversed-phase ultraperformance liquid chromatography method gave us successful results for the quantitative analysis of commercial drinks containing AA and CAF substances.

  7. Rapid Quantitation of Furanocoumarins and Flavonoids in Grapefruit Juice using Ultra-Performance Liquid Chromatography.

    Science.gov (United States)

    Vandermolen, Karen M; Cech, Nadja B; Paine, Mary F; Oberlies, Nicholas H

    2013-01-01

    Grapefruit juice can increase or decrease the systemic exposure of myriad oral medications, leading to untoward effects or reduced efficacy. Furanocoumarins in grapefruit juice have been established as inhibitors of cytochrome P450 3A (CYP3A)-mediated metabolism and P-glycoprotein (P-gp)-mediated efflux, while flavonoids have been implicated as inhibitors of organic anion transporting polypeptide (OATP)-mediated absorptive uptake in the intestine. The potential for drug interactions with a food product necessitates an understanding of the expected concentrations of a suite of structurally diverse and potentially bioactive compounds. Develop methods for the rapid quantitation of two furanocoumarins (bergamottin and 6',7'-dihydroxybergamottin) and four flavonoids (naringin, naringenin, narirutin and hesperidin) in five grapefruit juice products using ultra-performance liquid chromatography (UPLC). Grapefruit juice products were extracted with ethyl acetate; the concentrated extract was analysed by UPLC using acetonitrile:water gradients and a C18 -column. Analytes were detected using a photodiode array detector, set at 250 nm (furanocoumarins) and 310 nm (flavonoids). Intraday and interday precision and accuracy and limits of detection and quantitation were determined. Rapid (0.999. Considerable between-juice variation in the concentrations of these compounds was observed, and the quantities measured were in agreement with the concentrations published in HPLC studies. These analytical methods provide an expedient means to quantitate key furanocoumarins and flavonoids in grapefruit juice and other foods used in dietary substance-drug interaction studies. Copyright © 2013 John Wiley & Sons, Ltd.

  8. Multiclass analysis of antibiotic residues in honey by ultraperformance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Vidal, Jose Luis Martínez; Aguilera-Luiz, María Del Mar; Romero-González, Roberto; Frenich, Antonia Garrido

    2009-03-11

    A method has been developed and validated for the simultaneous analysis of different veterinary drug residues (macrolides, tetracyclines, quinolones, and sulfonamides) in honey. Honey samples were dissolved with Na(2)EDTA, and veterinary residues were extracted from the supernatant by solid-phase extraction (SPE), using OASIS HLB cartridges. The separation and determination was carried out by ultraperformance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS), using an electrospay ionization source (ESI) in positive mode. Data acquisition under MS/MS was achieved by applying multiple reaction monitoring (MRM) of two ion transitions per compound to provide a high degree of sensitivity and specificity. The method was validated, and mean recoveries were evaluated at three concentration levels (10, 50, and 100 microg/kg), ranging from 70 to 120% except for doxycycline, erythromycin, and tylmicosin with recovery higher than 50% at the three levels assayed. Relative standard deviations (RSDs) of the recoveries were less than 20% within the intraday precision and less than 25% within the interday precision. The limits of quantification (LOQs) were always lower than 4 microg/kg. The developed procedure was applied to 16 honey samples, and erythromycin, sarafloxacin, and tylosin were found in a few samples.

  9. Simultaneous Determination of 25 Common Pharmaceuticals in Whole Blood Using Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry

    DEFF Research Database (Denmark)

    Nielsen, Marie Katrine Klose; Johansen, Sys Stybe

    2012-01-01

    An ultra-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the quantification of 25 common pharmaceuticals in whole blood. The selected pharmaceuticals represent the most frequently detected drugs in our forensic laboratory with basic properties....../kg depending on the analyte. A good linear behavior was achieved for all analytes in the range from LOQ to 1.0 or 2.0 mg/kg blood. The absolute recoveries were between 55-87% for all compounds except norfluoxetine (44%). The method showed acceptable precision and accuracy for almost all analytes. Only unstable...

  10. Qualitative and quantitative characterization of secondary metabolites and carbohydrates in Bai-Hu-Tang using ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry and ultraperformance liquid chromatography coupled with photodiode array detector.

    Science.gov (United States)

    Zhong, Wei-Fang; Tong, Wing-Sum; Zhou, Shan-Shan; Yip, Ka-Man; Li, Song-Lin; Zhao, Zhong-Zhen; Xu, Jun; Chen, Hu-Biao

    2017-10-01

    Bai-Hu-Tang (BHT), a classic traditional Chinese medicine (TCM) formula used for clearing heat and promoting body fluid, consists of four traditional Chinese medicines, i.e., Gypsum Fibrosum (Shigao), Anemarrhenae Rhizoma (Zhimu), Glycyrrhizae Radix et Rhizoma Praeparata cum Melle (Zhigancao), and nonglutinous rice (Jingmi). The chemical composition of BHT still remains largely elusive thus far. To qualitatively and quantitatively characterize secondary metabolites and carbohydrates in BHT, here a combination of analytical approaches using ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry and ultraperformance liquid chromatography coupled with photodiode array detector was developed and validated. A total of 42 secondary metabolites in BHT were tentatively or definitely identified, of which 10 major chemicals were quantified by the extracting ion mode of quadrupole time-of-flight mass spectrometry. Meanwhile, polysaccharides, oligosaccharides, and monosaccharides in BHT were also characterized via sample pretreatment followed by sugar composition analysis. The quantitative results indicated that the determined chemicals accounted for 35.76% of the total extract of BHT, which demonstrated that the study could be instrumental in chemical dissection and quality control of BHT. The research deliverables not only laid the root for further chemical and biological evaluation of BHT, but also provided a comprehensive analytical strategy for chemical characterization of secondary metabolites and carbohydrates in traditional Chinese medicine formulas. Copyright © 2017. Published by Elsevier B.V.

  11. Qualitative and quantitative characterization of secondary metabolites and carbohydrates in Bai-Hu-Tang using ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry and ultraperformance liquid chromatography coupled with photodiode array detector

    Directory of Open Access Journals (Sweden)

    Wei-Fang Zhong

    2017-10-01

    Full Text Available Bai-Hu-Tang (BHT, a classic traditional Chinese medicine (TCM formula used for clearing heat and promoting body fluid, consists of four traditional Chinese medicines, i.e., Gypsum Fibrosum (Shigao, Anemarrhenae Rhizoma (Zhimu, Glycyrrhizae Radix et Rhizoma Praeparata cum Melle (Zhigancao, and nonglutinous rice (Jingmi. The chemical composition of BHT still remains largely elusive thus far. To qualitatively and quantitatively characterize secondary metabolites and carbohydrates in BHT, here a combination of analytical approaches using ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry and ultraperformance liquid chromatography coupled with photodiode array detector was developed and validated. A total of 42 secondary metabolites in BHT were tentatively or definitely identified, of which 10 major chemicals were quantified by the extracting ion mode of quadrupole time-of-flight mass spectrometry. Meanwhile, polysaccharides, oligosaccharides, and monosaccharides in BHT were also characterized via sample pretreatment followed by sugar composition analysis. The quantitative results indicated that the determined chemicals accounted for 35.76% of the total extract of BHT, which demonstrated that the study could be instrumental in chemical dissection and quality control of BHT. The research deliverables not only laid the root for further chemical and biological evaluation of BHT, but also provided a comprehensive analytical strategy for chemical characterization of secondary metabolites and carbohydrates in traditional Chinese medicine formulas.

  12. Development of a broad toxicological screening technique for urine using ultra-performance liquid chromatography and time-of-flight mass spectrometry

    DEFF Research Database (Denmark)

    Lee, Hon Kit; Ho, Chung Shun; Iu, Yan Ping Heidi

    2009-01-01

    Withdrawal of the support for the REMEDi HS drug profiling system has necessitated its replacement within our laboratories with an alternative broad toxicological screening technique. To this end, a novel method, based on ultra-performance liquid chromatography (UPLC) and time-of-flight (TOF) mass...

  13. New ultra-performance liquid chromatography-tandem mass spectrometry method for the determination of irbesartan in human plasma

    Directory of Open Access Journals (Sweden)

    Tanveer A. Wani

    2015-09-01

    Full Text Available With the objective of reducing analysis time and maintaining good efficiency, there has been substantial focus on high-speed chromatographic separations and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS is a preeminent analytical tool for rapid biomedical analysis. In this study a simple, rapid, sensitive, and specific ultra-performance liquid chromatography-MS/MS method was developed and validated for quantification of the angiotensin II receptor antagonist, irbesartan (IRB, in human plasma. After a simple protein precipitation using methanol and acetonitrile, IRB and internal standard (IS telmisartan were separated on Acquity UPLC BEH C18 column (50 mm × 2.1 mm, i.d. 1.7 μm, Waters, Milford, MA, USA using a mobile phase consisted of acetonitrile: methanol: 10 mM ammonium acetate (70: 15: 15 v/v/v with a flow rate of 0.4 mL/min and detected MS/MS in negative ion mode. The ion transitions recorded in multiple reaction monitoring mode were m/z 427.2→193.08 for IRB and m/z 513.2→469.3 for IS. The assay exhibited a linear dynamic range of 2–500 ng/mL for IRB in human plasma with good correlation coefficient of (0.995 and with a lower limit of quantitation of 2 ng/mL. The intra- and interassay precisions were satisfactory; the relative standard deviations did not exceed 9.91%. The proposed UPLC-MS/MS method is simple, rapid, and highly sensitive, and hence it could be reliable for pharmacokinetic and toxicokinetic study in both animals and humans.

  14. Validation of a confirmatory method for the determination of melamine in egg by gas chromatography-mass spectrometry and ultra-performance liquid chromatography-tandem mass spectrometry

    International Nuclear Information System (INIS)

    Xia Xi; Ding Shuangyang; Li Xiaowei; Gong Xiao; Zhang Suxia; Jiang Haiyang; Li Jiancheng; Shen Jianzhong

    2009-01-01

    A sensitive and reliable method was developed and validated for detection and confirmation of melamine in egg based on gas chromatography-mass spectrometry (GC-MS) and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Trichloroacetic acid solution was used for sample extraction and precipitation of proteins. The aqueous extracts were subjected to solid-phase extraction by mixed-mode reversed-phase/strong cation-exchange cartridges. Using ultra-performance liquid chromatography and electrospray ionization in the positive ion mode, melamine was determined by LC-MS/MS, which was completed in 5 min for each injection. For the GC-MS analysis, extracted melamine was derivatized with N,O-bis(trimethylsilyl)trifluoracetamide prior to selected ion monitoring detection in electron impact mode. The average recovery of melamine from fortified samples ranged from 85.2% to 103.2%, with coefficients of variation lower than 12%. The limit of detection obtained by GC-MS and UPLC-MS/MS was 10 and 5 μg kg -1 , respectively. This validated method was successfully applied to the determination of melamine in real samples from market.

  15. Determination of seven sunscreen agents and two ultraviolet stabilizers in skin care products using ultra-performance liquid chromatography.

    Science.gov (United States)

    Gowell, Aimee; Habel, John; Weiss, Caryn; Parkanzky, Paul

    2015-01-01

    Ultraviolet radiation (UVR) is a well-known environmental carcinogen. Protection against UVR exposure has resulted in an increasing number of sunscreen agents being incorporated into a greater variety of cosmetic formulations including moisturizing lotions, color cosmetics, and skin care creams. Meanwhile, global regulation of sun care products is changing. New guidelines for sunscreen efficacy have resulted in a shift in product formulation that requires sunscreen products to provide broad spectrum UV protection. Since not all sunscreen ingredients protect against both UVA and UVB radiation, most sun care products require a combination of sunscreen agents. This article describes a new method for simultaneous separation and quantitation of seven organic sunscreens and two UV stabilizers using ultra-performance liquid chromatography. This method is capable of resolving all nine analytes, and has been validated for selectivity, precision, and accuracy. Because of the use of core-shell column technology, the separation is also achieved at back pressures compatible with conventional high-performance liquid chromatography instrumentation.

  16. [Rapid determination of theophylline, theobromine and caffeine in dietary supplements containing guarana by ultra-performance liquid chromatography].

    Science.gov (United States)

    Hasegawa, Takashi; Takahashi, Kazunaga; Saijo, Masaaki; Ishii, Toshiyasu; Nagata, Tomoko

    2009-12-01

    A rapid and simple method for determination of theophylline, theobromine and caffeine in dietary supplements containing guarana by ultra-performance liquid chromatography (UPLC) has been developed. Theophylline, theobromine and caffeine were extracted from finely powdered samples with water in a boiling water bath for 20 min, then the extracts were filtered and the filtrates were subjected to UPLC. Liquid samples were diluted with water and filteres, and the filtrates were subjected to UPLC. UPLC separation was performed on an AQUITY UPLC BEH C18 column (2.1 mm i.d.x50 mm, 1.7 microm, Waters) with 10 mmol/L ammonium acetate buffer (pH 4.0)-acetonitrile gradient and eluates were monitored at 275 nm. The recoveries of theophylline (spiked at 200 microg/g [tablet] and 50 microg/mL [liquid]), theobromine (spiked at 200 microg/g [tablet] and 50 microg/mL [liquid]) and caffeine (spiked at 1,000 microg/g [tablet] and 250 microg/mL [liquid]) were 97.6-98.7%, 97.3-99.7%, 97.1-105.4%, respectively. The quantitation limits of theophylline, theobromine and caffeine were 10 microg/g (seed, seed powder, tablet and capsule) and 2.0 microg/mL (liquid) each. When this analytical method was applied to commercial dietary supplements, theophylline, theobromine and caffeine were found at concentrations of 4.45 mg/tablet, 5.48 mg/tablet, 139 mg/tablet, respectively. Taking 4 tablets of this product according to the directions on the package could be dangerous to consumers because of possible overdosing of these ingredients.

  17. Liquid chromatography and ultra-performance liquid chromatography-mass spectrometry fingerprinting of human urine: sample stability under different handling and storage conditions for metabonomics studies.

    Science.gov (United States)

    Gika, Helen G; Theodoridis, Georgios A; Wilson, Ian D

    2008-05-02

    Typically following collection biological samples are kept in a freezer for periods ranging from a few days to several months before analysis. Experience has shown that in LC-MS-based metabonomics research the best analytical practice is to store samples as these are collected, complete the sample set and analyse it in a single run. However, this approach is prudent only if the samples stored in the refrigerator or in the freezer are stable. Another important issue is the stability of the samples following the freeze-thaw process. To investigate these matters urine samples were collected from 6 male volunteers and analysed by LC-MS and ultra-performance liquid chromatography (UPLC)-MS [in both positive and negative electrospray ionization (ESI)] on the day of collection or at intervals of up to 6 months storage at -20 degrees C and -80 degrees C. Other sets of these samples underwent a series of up to nine freeze-thaw cycles. The stability of samples kept at 4 degrees C in an autosampler for up to 6 days was also assessed, with clear differences appearing after 48h. Data was analysed using multivariate statistical analysis (principal component analysis). The results show that sample storage at both -20 and -80 degrees C appeared to ensure sample stability. Similarly up to nine freeze thaw cycles were without any apparent effect on the profile.

  18. Quantitative analysis of multiple fatty acid ethanolamides using ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Lin, Lin; Yang, Haifeng; Jones, Peter J H

    2012-12-01

    Fatty acid ethanolamides (FAE) represent a group of lipid signaling molecules associated with many physiological and pharmacological actions; however, low FAE tissue levels pose challenges in terms of analytical characterization. The objective was to develop a competent ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for analysis of multiple FAE in animal and human tissue samples. Analytes were extracted using lipid-phase and solid-phase extraction procedures. Chromatographic separation was achieved using a gradient elution in 8 min. FAE were quantified by MS/MS in positive electrospray ionization mode. Linearity was shown in lower and higher FAE concentration ranges, with a limit of quantification (LOQ) ≤0.2 ng/ml for FAE including alpha-linolenoylethanolamide (ALEA), arachidonoylethanolamide (AEA), docosahexaenoylethanolamide (DHEA), linoleoylethanolamide (LEA), oleoylethanolamide (OEA) and palmitoylethanolamide (PEA). Accuracy was shown to be between 92.4% and 108.8%, and precision was <10% for all FAE species. In sum, this sensitive and reproducible method can be used to simultaneously determine multiple FAE at low concentrations in order to facilitate further study of the role of FAE on physiological state. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Simultaneous determination of three pesticides and their metabolites in unprocessed foods using ultraperformance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Rong, Lili; Wu, Xiaohu; Xu, Jun; Dong, Fengshou; Liu, Xingang; Pan, Xinglu; Du, Pengqiang; Wei, Dongmei; Zheng, Yongquan

    2018-02-01

    We have developed a rapid, multi-compound analytical method for measuring residues of the pesticides thiamethoxam and its metabolite, clothianidin; fipronil and its three metabolites, fipronil sulfone, fipronil sulfide, and fipronil desulfinyl; and pyraclostrobin in unprocessed foods (rice, corn, cucumbers, tomatoes, apples, and bananas) by ultra-performance liquid chromatography coupled to tandem mass spectrometry. Acetonitrile was used as the extraction solvent, and an octadecylsilane-dispersive SPE was used to clean up the analytes, which were then separated through a UPLC HSS T3 column connected to a tandem mass spectrometer via an electrospray ionisation source. The linearity of this method for the target analytes was excellent (R 2  ≥0.990) in the concentration range of 5-1000 μg kg -1 . The average recoveries of the seven compounds at concentrations of 10, 100, and 1000 μg kg -1 from six spiked matrix samples ranged from 73.6 to 110.6%, all with RSD values of ≤19.7%. The limit of quantification was 10 μg kg -1 . The method validated the effectiveness of the method for routine monitoring the residue of these pesticides and their metabolites in foods.

  20. Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry Measurement of Caffeine in Caffeine-Laced Pants and in Urine and Skin of a Pants User

    OpenAIRE

    Pellegrini, Manuela; Orsi, Daniela De; Guarino, Carmine; Rotolo, Maria; Giovannandrea, Rita di; Pacifici, Roberta; Pichini, Simona

    2014-01-01

    A fast and sensitive ultra-performance liquid chromatography tandem mass spectrometry method was developed for the measurement of caffeine in caffeine-laced pants and in urine and skin of a pants user. The substance and its internal standard (N-ethylnorcotinine) were separated by reversed phase chromatography with 5 mM ammonium formate pH 3.0 and 0.3% formic acid in acetonitrile mobile phase (83:17 v/v) by isocratic elution and detected by tandem mass spectrometry operated in multiple reacti...

  1. Plasma metabonomics study of the patients with acute anterior uveitis based on ultra-performance liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Guo, Junguo; Yan, Tingqin; Bi, Hongsheng; Xie, Xiaofeng; Wang, Xingrong; Guo, Dadong; Jiang, Haiqiang

    2014-06-01

    The identification of the biomarkers of patients with acute anterior uveitis (AAU) may allow for a less invasive and more accurate diagnosis, as well as serving as a predictor in AAU progression and treatment response. The aim of this study was to identify the potential biomarkers and the metabolic pathways from plasma in patients with AAU. Both plasma metabolic biomarkers and metabolic pathways in the AAU patients versus healthy volunteers were investigated using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) and a metabonomics approach. The principal component analysis (PCA) was used to separate AAU patients from healthy volunteers as well as to identify the different biomarkers between the two groups. Metabolic compounds were matched to the KEGG, METLIN, and HMDB databases, and metabolic pathways associated with AAU were identified. The PCA for UPLC-MS data shows that the metabolites in AAU patients were significantly different from those of healthy volunteers. Of the 4,396 total features detected by UPLC-MS, 102 features were significantly different between AAU patients and healthy volunteers according to the variable importance plot (VIP) values (greater than two) of partial least squares discriminate analysis (PLS-DA). Thirty-three metabolic compounds were identified and were considered as potential biomarkers. Meanwhile, ten metabolic pathways were found that were related to the AAU according to the identified biomarkers. These data suggest that metabolomics study can identify potential metabolites that differ between AAU patients and healthy volunteers. Based on the PCA, PLS-DA, several potential metabolic biomarkers and pathways in AAU patients were found and identified. In addition, the UPLC-MS technique combined with metabonomics could be a suitable systematic biology tool in research in clinical problems in ophthalmology, and can provide further insight into the pathophysiology of AAU.

  2. Measurement of total and free docetaxel concentration in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Rigo-Bonnin, Raül; Cobo-Sacristán, Sara; Gonzalo-Diego, Núria; Colom, Helena; Muñoz-Sánchez, Carmen; Urruticoechea, Ander; Falo, Catalina; Alía, Pedro

    2016-01-05

    Docetaxel is a semi-synthetic taxane with cytotoxic anti-neoplastic activity and, currently used as anticancer agent in several types of cancer. Docetaxel is highly bound to plasma proteins, and this significantly determines its clearance and activity. Therefore, measurement of free docetaxel in plasma is pharmacologically important when pharmacokinetics is investigated. We developed and validated chromatographic methods by ultra-performance liquid chromatography-tandem mass spectrometry to measure total and free docetaxel concentration in human plasma. The final validated methods involved liquid-liquid extraction followed by dryness under nitrogen evaporation. To measure free docetaxel concentration, sample preparation was preceded by ultrafiltration. Chromatographic separation was achieved using an Acquity(®) UPLC(®) BEH™ (2.1×100 mm id, 1.7 μm) reverse-phase C18 column at a flow rate of 0.4 mL/min, using isocratic elution mode containing ammonium acetate/formic acid in water/methanol (30:70 v/v) as mobile phase. Docetaxel and its internal standard (paclitaxel) were detected by electrospray ionization mass spectrometry in positive ion multiple reaction monitoring mode using mass-to-charge (m/z) transitions of 808.3→527.0 (quantifier) and 808.3→509.0 (qualifier); and 854.3→569.0 (quantifier) and 854,3→509,0 (qualifier), respectively. The run time per sample was 3.5 min. The limits of quantification were 1,95 and 0.42 μg/L and linearity was observed between 1.95 and 1000 and 0.42-100 μg/L for total and free docetaxel, respectively. Coefficients of variation and absolute relative biases were less than 13.8% and 10.0%. Recovery values were greater than 79.4%. Evaluation of the matrix effect showed ion suppression and no carry-over was observed. The validated methods could be useful for both therapeutic drug monitoring and pharmacokinetic studies. They could be applied to daily clinical laboratory practice to measure the concentration of total and free

  3. Determination of 2-alkylcyclobutanones by combining precolumn derivatization with 1-naphthalenyl hydrazine and ultra-performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Meng, Xiangpeng; Tong, Tong; Wang, Lianrong; Liu, Hanxia; Chan, Wan

    2016-05-01

    2-Alkylcyclobutanones (2-ACBs) are uniquely formed when triglycerides-containing food products are exposed to ionizing radiation. Thus, 2-ACBs have been used as marker molecules to identify irradiated food. Most methods to determine 2-ACBs involve mass spectrometric detection after chromatographic separation. The spectrofluorometer is rarely used to determine 2-ACBs because these molecules do not fluoresce. In this study, we developed an ultra-performance liquid chromatography (UPLC) method to determine 2-ACBs. 2-ACBs were converted into fluorophores after reacting with 1-naphthalenyl hydrazine to facilitate their sensitive and selective detection using a fluorescence detector (FLD). Analysis of 2-ACBs using our developed UPLC-FLD method allows sensitive determination of 2-ACBs at a detection limit of 2 ng 2-ACBs per g of fat (30 pg/injection), which is significantly lower than that of existing analytical methods. After validation for trueness and precision, the method was applied to γ-irradiated chicken samples to determine their 2-ACB content. Comparative studies employing liquid chromatography-tandem mass spectrometric method revealed no systematic difference between the two methods, thereby demonstrating that the proposed UPLC-FLD method can be suitably used to determine 2-ACBs in irradiated foodstuffs. Graphical Abstract Determination of radiation-induced food-borne 2-dodecylcyclobutanone and 2-tetradecylcyclobutanone by combining 1-naphthalenyl hydrazine derivatization and ultra-performance liquid chromatography with fluorescence detection.

  4. Profiling ABA metabolites in Nicotiana tabacum L. leaves by ultra-performance liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Turecková, Veronika; Novák, Ondrej; Strnad, Miroslav

    2009-11-15

    We have developed a simple method for extracting and purifying (+)-abscisic acid (ABA) and eight ABA metabolites--phaseic acid (PA), dihydrophaseic acid (DPA), neophaseic acid (neoPA), ABA-glucose ester (ABAGE), 7'-hydroxy-ABA (7'-OH-ABA), 9'-hydroxy-ABA (9'-OH-ABA), ABAaldehyde, and ABAalcohol--before analysis by a novel technique for these substances, ultra-performance liquid chromatography-electrospray ionisation tandem mass spectrometry (UPLC-ESI-MS/MS). The procedure includes addition of deuterium-labelled standards, extraction with methanol-water-acetic acid (10:89:1, v/v), simple purification by Oasis((R)) HLB cartridges, rapid chromatographic separation by UPLC, and sensitive, accurate quantification by MS/MS in multiple reaction monitoring modes. The detection limits of the technique ranged between 0.1 and 1 pmol for ABAGE and ABA acids in negative ion mode, and 0.01-0.50 pmol for ABAGE, ABAaldehyde, ABAalcohol and the methylated acids in positive ion mode. The fast liquid chromatographic separation and analysis of ABA and its eight measured derivatives by UPLC-ESI-MS/MS provide rapid, accurate and robust quantification of most of the substances, and the low detection limits allow small amounts of tissue (1-5mg) to be used in quantitative analysis. To demonstrate the potential of the technique, we isolated ABA and its metabolites from control and water-stressed tobacco leaf tissues then analysed them by UPLC-ESI-MS/MS. Only ABA, PA, DPA, neoPA, and ABAGE were detected in the samples. PA was the most abundant analyte (ca. 1000 pmol/g f.w.) in both the control and water-stressed tissues, followed by ABAGE and DPA, which were both present at levels ca. 5-fold lower. ABA levels were at least 100-fold lower than PA concentrations, but they increased following the water stress treatment, while ABAGE, PA, and DPA levels decreased. Overall, the technique offers substantial improvements over previously described methods, enabling the detailed, direct study of

  5. Characterization of ornidazole metabolites in human bile after intraveneous doses by ultraperformance liquid chromatography/quadrupole time-of-flight mass spectrometry

    Directory of Open Access Journals (Sweden)

    Jiangbo Du

    2012-04-01

    Full Text Available Ultraperformance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS was used to characterize ornidazole metabolites in human bile after intravenous doses. A liquid chromatography tandem mass spectrometry (LC–MS/MS assay was developed for the determination of the bile level of ornidazole. Bile samples, collected from four patients with T-tube drainage after biliary tract surgery, were prepared by protein precipitation with acetonitrile before analysis. A total of 12 metabolites, including 10 novel metabolites, were detected and characterized. The metabolites of ornidazole in human bile were the products of hydrochloride (HCl elimination, oxidative dechlorination, hydroxylation, sulfation, diastereoisomeric glucuronation, and substitution of NO2 or Cl atom by cysteine or N-acetylcysteine, and oxidative dechlorination followed by further carboxylation. The bile levels of ornidazole at 12 h after multiple intravenous infusions were well above its minimal inhibitory concentration for common strains of anaerobic bacteria.

  6. Simultaneous determination of 2 aconitum alkaloids and 12 ginsenosides in Shenfu injection by ultraperformance liquid chromatography coupled with a photodiode array detector with few markers to determine multicomponents

    Directory of Open Access Journals (Sweden)

    Ai-Hua Ge

    2015-06-01

    Full Text Available A method with few markers to determine multicomponents was established and validated to evaluate the quality of Shenfu injection by ultraperformance liquid chromatography coupled with a photodiode array detector. The separations were performed on an ACQUITY UPLC BEH C18 (2.1 × 50 mm2, 1.7 μm column. Methanol and 0.1% formic acid aqueous solution were used as the mobile phase. The flow rate was 0.3 mL/min. 2 aconitum alkaloids and 12 ginsenosides could be perfectly separated within 15 minutes. Ginsenoside Rg1 and benzoylmesaconine, the easily available active components, were employed as the maker components to calculate the relative correction factors of other components in Shenfu injection, Panax ginseng and Aconitum carmichaeli. The external standard method was also established to validate the feasibility of the method with few markers to determine multicomponents. Parameter p and the principal component analysis method were employed to investigate the disparities among batches for the effective quality control of Shenfu injection. The results demonstrated that the ultraperformance liquid chromatography coupled with a photodiode array detector method with few markers to determine multicomponents could be used as a powerful tool for the quality evaluation of traditional Chinese medicines and their preparations.

  7. Confirmation of congenital adrenal hyperplasia by adrenal steroid profiling of filter paper dried blood samples using ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Rossi, Claudia; Calton, Lisa; Brown, Heather A; Gillingwater, Scott; Wallace, A Michael; Petrucci, Francesca; Ciavardelli, Domenico; Urbani, Andrea; Sacchetta, Paolo; Morris, Michael

    2011-04-01

    The specificity of screening for congenital adrenal hyperplasia by direct measurement of 17-hydroxyprogesterone in filter paper dried blood spot samples by immunoassay is low and has a high false-positive rate. In order to reduce the false-positive rate of this test, we developed a rapid, robust, specific confirmatory procedure in which cortisol, 4-androstene-3,17-dione and 17-hydroxyprogesterone were measured simultaneously by ultra-performance liquid chromatography-tandem mass spectrometry. After extraction, samples were analysed by ultra-performance liquid chromatography-tandem mass spectrometry and 17-hydroxyprogesterone was quantified accurately. Other steroids were determined using stable deuterated internal standards. In total, 25 patient blood spot samples and 92 control samples were analysed. The assay was linear for 17-hydroxyprogesterone, with a coefficient of determination >0.997 and imprecision ≤ 6.5%. An upper limit of normal for 17-hydroxyprogester-one of 4.45 nmol/L was established by analysing a cohort of samples from unaffected newborns. In addition, a cut-off of 3.5 for the peak areas ratio (17-hydroxyprogesterone+4-androstene-3,17-dione)/cortisol, allows confirmation of the affected steroidogenic enzyme. A high throughput method for the detection of steroids related to congenital adrenal hyperplasia has been developed, allowing the false-positive rate associated with screening for 17-hydroxyprogesterone by immunoassay to be determined.

  8. Ultra-performance liquid chromatography-tandem mass spectrometry method for the determination of febuxostat in dog plasma and its application to a pharmacokinetic study.

    Science.gov (United States)

    Zhang, Tianhong; Sun, Yuanpeng; Zhang, Peng; Gao, Jingmei; Wang, Shanshan; He, Zhonggui

    2013-02-01

    A rapid, sensitive and selective ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the determination of febuxostat in dog plasma. Using paclitaxel as an internal standard (IS), a simple liquid-liquid extraction method with ethyl acetate was adopted for plasma sample pretreatment. Separation was carried out on an Acquity UPLC BEH C(18) column with a mobile phase consisting of acetonitrile and water (containing 0.2% formic acid). The assay was linear in the concentration ranged from 5 to 5000 ng/mL with a lower limit of quantification of 5 ng/mL for febuxostat. The single run analysis was as short as 2.0 min. Finally, the developed method was successfully applied to the pharmacokinetic study of febuxostat tablets following oral administration at a single dose of 40 mg in beagle dogs. Copyright © 2012 John Wiley & Sons, Ltd.

  9. Profiling the indole alkaloids in yohimbe bark with ultra-performance liquid chromatography coupled with ion mobility quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Sun, Jianghao; Baker, Andrew; Chen, Pei

    2011-09-30

    An ultra-performance liquid chromatography/ion mobility quadrupole time-of-flight mass spectrometry (UPLC/IM-QTOF-MS) method was developed for profiling the indole alkaloids in yohimbe bark. Many indole alkaloids with the yohimbine or ajmalicine core structure, plus methylated, oxidized and reduced species, were characterized. Common fragments and mass differences are described. It was shown that the use of IMS could provide another molecular descriptor, i.e. molecular shape by rotationally averaged collision cross-section; this is of great value for identification of constituents when reference materials are usually not available. Using the combination of high resolution (~40000) accurate mass measurement with time-aligned parallel (TAP) fragmentation, MS(E) (where E represents collision energy), ion mobility mass spectrometry (IMS) and UPLC chromatography, a total 55 indole alkaloids were characterized and a few new indole alkaloids are reported for the first time. Published in 2011 by John Wiley & Sons, Ltd.

  10. Kinetic study for a stress testing of L,L-ethylenedicysteine by ultra-performance liquid chromatography/tandem mass spectrometry analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sun Xiaotao [Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875 (China); Qiao Jinping, E-mail: Qiaojp920@gmail.co [Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875 (China); Zhu Lin; Qiao Hongwen [Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875 (China); Zhong Jianguo [National Institute for the Control of Pharmaceutical and Biological Products, Beijing 100050 (China)

    2010-12-15

    This study proposed a stress testing to study oxidative stability and estimate the potential shelf-life of L,L-ethylenedicysteine (L,L-EC) under normal storage temperature condition (20-25 {sup o}C). L,L-EC was detected as a function of time at four different temperatures by ultra-performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS). The degradation of L,L-EC followed the first order kinetics, and the temperature-dependent kinetics was well described by the linear Arrhenius equation. The activation energy (E{sub a}) was calculated, and the shelf-life at 25 and 4 {sup o}C was predicted. The results are useful for the proper storage and quality evaluation of L,L-EC.

  11. Analysis of defense signals in Arabidopsis thaliana leaves by ultra-performance liquid chromatography/tandem mass spectrometry: jasmonates, salicylic acid, abscisic acid.

    Science.gov (United States)

    Stingl, Nadja; Krischke, Markus; Fekete, Agnes; Mueller, Martin J

    2013-01-01

    Defense signaling compounds and phytohormones play an essential role in the regulation of plant responses to various environmental abiotic and biotic stresses. Among the most severe stresses are herbivory, pathogen infection, and drought stress. The major hormones involved in the regulation of these responses are 12-oxo-phytodienoic acid (OPDA), the pro-hormone jasmonic acid (JA) and its biologically active isoleucine conjugate (JA-Ile), salicylic acid (SA), and abscisic acid (ABA). These signaling compounds are present and biologically active at very low concentrations from ng/g to μg/g dry weight. Accurate and sensitive quantification of these signals has made a significant contribution to the understanding of plant stress responses. Ultra-performance liquid chromatography (UPLC) coupled with a tandem quadrupole mass spectrometer (MS/MS) has become an essential technique for the analysis and quantification of these compounds.

  12. Kinetic study for a stress testing of L,L-ethylenedicysteine by ultra-performance liquid chromatography/tandem mass spectrometry analysis

    International Nuclear Information System (INIS)

    Sun Xiaotao; Qiao Jinping; Zhu Lin; Qiao Hongwen; Zhong Jianguo

    2010-01-01

    This study proposed a stress testing to study oxidative stability and estimate the potential shelf-life of L,L-ethylenedicysteine (L,L-EC) under normal storage temperature condition (20-25 o C). L,L-EC was detected as a function of time at four different temperatures by ultra-performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS). The degradation of L,L-EC followed the first order kinetics, and the temperature-dependent kinetics was well described by the linear Arrhenius equation. The activation energy (E a ) was calculated, and the shelf-life at 25 and 4 o C was predicted. The results are useful for the proper storage and quality evaluation of L,L-EC.

  13. Rapid determination of 9 aromatic amines in mainstream cigarette smoke by modified dispersive liquid liquid microextraction and ultraperformance convergence chromatography tandem mass spectrometry.

    Science.gov (United States)

    Deng, Huimin; Yang, Fei; Li, Zhonghao; Bian, Zhaoyang; Fan, Ziyan; Wang, Ying; Liu, Shanshan; Tang, Gangling

    2017-07-21

    Aromatic amines in mainstream cigarette smoke have long been monitored due to their carcinogenic toxicity. In this work, a reliable and rapid method was developed for the simultaneous determination of 9 aromatic amines in mainstream cigarette smoke by modified dispersive liquid liquid microextraction (DLLME) and ultraperformance convergence chromatography tandem mass spectrometry (UPC 2 -MS/MS). Briefly, the particulate phase of the cigarette smoke was captured by a Cambridge filter pad, and diluted hydrogen chloride aqueous solution is employed to extract the aromatic amines under mechanical shaking. After alkalization with sodium hydroxide solution, small amount of toluene was introduced to further extract and enrich aromatic amines by modified DLLME under vortexing. After centrifugation, toluene phase was purified by a universal QuEChERS cleanup kit and was finally analyzed by UPC 2 -MS/MS. Attributing to the superior performance of UPC 2 -MS/MS, this novel approach allowed the separation and determination of 9 aromatic amines within 5.0min with satisfactory resolution and sensitivity. The proposed method was finally validated using Kentucky reference cigarette 3R4F, and emission levels of targeted aromatic amines determined were comparable to previously reported methods At three different spiked levels, the recoveries of most analytes were ranged from 74.01% to 120.50% with relative standard deviation (RSD) less than 12%, except that the recovery of p-toluidine at low spiked level and 3-aminobiphenyl at medium spiked level was 62.77% and 69.37% respectively. Thus, this work provides a novel alternative method for the simultaneous analysis of 9 aromatic amines in mainstream cigarette smoke. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Optimization of ultra-performance liquid chromatography (UPLC) with fluorescence detector (FLD) method for the quantitative determination of selected neurotransmitters in rat brain.

    Science.gov (United States)

    Stragierowicz, Joanna; Daragó, Adam; Brzeźnicki, Sławomir; Kilanowicz, Anna

    2017-07-26

    Glutamate (Glu) and γ-aminobutyric acid (GABA) are the main neurotransmitters in the central nervous system for excitatory and inhibitory processes, respectively. Monitoring these neurotransmitters is an essential tool in establishing pathological functions, among others in terms of occupational exposure to toxic substances. We present modification of the HPLC (high-performance liquid chromatography) to the UPLC (ultra-performance liquid chromatography) method for the simultaneous determination of glutamate and γ-aminobutyric acid in a single injection. The isocratic separation of these neurotransmitter derivatives was performed on Waters Acquity BEH (ethylene bridged hybrid) C18 column with particle size of 1.7 μm at 35°C using a mobile phase consisting of 0.1 M acetate buffer (pH 6.0) and methanol (60:40, v/v) at a flow rate of 0.3 ml/min. The analytes were detected with the fluorescence detector (FLD) using derivatization with o-phthaldialdehyde (OPA), resulting in excitation at 340 nm and emission at 455 nm. Several validation parameters including linearity (0.999), accuracy (101.1%), intra-day precision (1.52-1.84%), inter-day precision (2.47-3.12%), limit of detection (5-30 ng/ml) and quantification (100 ng/ml) were examined. The developed method was also used for the determination of these neurotransmitters in homogenates of selected rat brain structures. The presented UPLC-FLD is characterized by shorter separation time (3.5 min), which is an adaptation of the similar HPLC methods and is an alternative for more expensive references techniques such as liquid chromatography coupled with tandem mass-spectrometry (LC-MS/MS) methods. Med Pr 2017;68(5):583-591. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  15. Fenofibrate Metabolism in the Cynomolgus Monkey using Ultraperformance Liquid Chromatography-Quadrupole Time-of-Flight Mass Spectrometry-Based MetabolomicsS⃞

    Science.gov (United States)

    Liu, Aiming; Patterson, Andrew D.; Yang, Zongtao; Zhang, Xinying; Liu, Wei; Qiu, Fayang; Sun, He; Krausz, Kristopher W.; Idle, Jeffrey R.; Gonzalez, Frank J.; Dai, Renke

    2009-01-01

    Fenofibrate, widely used for the treatment of dyslipidemia, activates the nuclear receptor, peroxisome proliferator-activated receptor α. However, liver toxicity, including liver cancer, occurs in rodents treated with fibrate drugs. Marked species differences occur in response to fibrate drugs, especially between rodents and humans, the latter of which are resistant to fibrate-induced cancer. Fenofibrate metabolism, which also shows species differences, has not been fully determined in humans and surrogate primates. In the present study, the metabolism of fenofibrate was investigated in cynomolgus monkeys by ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOFMS)-based metabolomics. Urine samples were collected before and after oral doses of fenofibrate. The samples were analyzed in both positive-ion and negative-ion modes by UPLC-QTOFMS, and after data deconvolution, the resulting data matrices were subjected to multivariate data analysis. Pattern recognition was performed on the retention time, mass/charge ratio, and other metabolite-related variables. Synthesized or purchased authentic compounds were used for metabolite identification and structure elucidation by liquid chromatographytandem mass spectrometry. Several metabolites were identified, including fenofibric acid, reduced fenofibric acid, fenofibric acid ester glucuronide, reduced fenofibric acid ester glucuronide, and compound X. Another two metabolites (compound B and compound AR), not previously reported in other species, were characterized in cynomolgus monkeys. More importantly, previously unknown metabolites, fenofibric acid taurine conjugate and reduced fenofibric acid taurine conjugate were identified, revealing a previously unrecognized conjugation pathway for fenofibrate. PMID:19251819

  16. Development and validation of an ultra-performance liquid chromatography quadrupole time of flight mass spectrometry method for rapid quantification of free amino acids in human urine.

    Science.gov (United States)

    Joyce, Richard; Kuziene, Viktorija; Zou, Xin; Wang, Xueting; Pullen, Frank; Loo, Ruey Leng

    2016-01-01

    An ultra-performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-qTOF-MS) method using hydrophilic interaction liquid chromatography was developed and validated for simultaneous quantification of 18 free amino acids in urine with a total acquisition time including the column re-equilibration of less than 18 min per sample. This method involves simple sample preparation steps which consisted of 15 times dilution with acetonitrile to give a final composition of 25 % aqueous and 75 % acetonitrile without the need of any derivatization. The dynamic range for our calibration curve is approximately two orders of magnitude (120-fold from the lowest calibration curve point) with good linearity (r (2) ≥ 0.995 for all amino acids). Good separation of all amino acids as well as good intra- and inter-day accuracy (amino acids in the prepared urine samples was found to be stable for 72 h at 4 °C, after one freeze thaw cycle and for up to 4 weeks at -80 °C. We have applied this method to quantify the content of 18 free amino acids in 646 urine samples from a dietary intervention study. We were able to quantify all 18 free amino acids in these urine samples, if they were present at a level above the LOD. We found our method to be reproducible (accuracy and precision were typically <10 % for QCL, QCM and QCH) and the relatively high sample throughput nature of this method potentially makes it a suitable alternative for the analysis of urine samples in clinical setting.

  17. A validated method for simultaneous screening and quantification of twenty-three benzodiazepines and metabolites plus zopiclone and zaleplone in whole blood by liquid-liquid extraction and ultra-performance liquid chromatography- tandem mass spectrometry

    DEFF Research Database (Denmark)

    Simonsen, Kirsten Wiese; Hermansson, Sigurd; Steentoft, Anni

    2010-01-01

    , oxazepam, temazepam, triazolam, zaleplon, and zopiclone. Whole blood from drug-free volunteers was used for all experiments. Blood samples (0.200 g) were extracted with ethyl acetate at pH 9. Target drugs were quantified using a Waters ACQUITY UPLC system coupled to a Waters Quattro Premier XE triple......An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) method for detection of 23 benzodiazepines and related compounds in whole blood was developed and validated. The method is used for screening and quantitation of benzodiazepines in whole blood received from autopsy...... quadrupole in positive electrospray ionization, multiple reaction monitoring mode. The use of deuterated internal standards for most compounds verified that the accuracy of the method was not influenced by matrix effects. Extraction recoveries were 73-108% for all analytes. Lower limits of quantification...

  18. Metabolism of Genipin in Rat and Identification of Metabolites by Using Ultraperformance Liquid Chromatography/Quadrupole Time-of-Flight Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Yue Ding

    2013-01-01

    Full Text Available The in vivo and in vitro metabolism of genipin was systematically investigated in the present study. Urine, plasma, feces, and bile were collected from rats after oral administration of genipin at a dose of 50 mg/kg body weight. A rapid and sensitive method using ultraperformance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-Q/TOF MS was developed for analysis of metabolic profile of genipin in rat biological samples (urine, plasma, feces, and bile. A total of ten metabolites were detected and identified by comparing their fragmentation patterns with that of genipin using MetaboLynx software tools. On the basis of the chromatographic peak area, the sulfated and glucuronidated conjugates of genipin were identified as major metabolites. And the existence of major metabolites G1 and G2 was confirmed by the in vitro enzymatic study further. Then, metabolite G1 was isolated from rat bile by semipreparative HPLC. Its structure was unambiguously identified as genipin-1-o-glucuronic acid by comparison of its UV, IR, ESI-MS, 1H-NMR, and 13C-NMR spectra with conference. In general, genipin was a very active compound that would transform immediately, and the parent form of genipin could not be observed in rats biological samples. The biotransformation pathways of genipin involved demethylated, ring-opened, cysteine-conjugated, hydroformylated, glucuronidated, and sulfated transformations.

  19. Sensitive analysis of steroid estrogens and bisphenol a in small volumes of water using isotope-dilution ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Chang, Hong; Shen, Xiaoyan; Shao, Bing; Wu, Fengchang

    2018-04-01

    An isotope-dilution ultra-performance liquid chromatography-electrospray tandem mass spectrometry method combined with dansylation was established to sensitively quantify four steroid estrogens (estrone, 17α-estradiol, 17β-estradiol and 17α-ethynylestradiol) and bisphenol A in sewage influent and effluent. A simple hexane extraction was performed from a small volume (10 mL), followed by dansyl chloride derivatization and purification with a silica cartridge. The method effectively reduced the matrix effects in sample extract and permitted the selective and sensitive determination of target compounds from complicated matrices. The detection limits of the method for steroid estrogens were 0.20-0.90 ng L -1 in influent and 0.10-0.20 ng L -1 in effluent samples. For bisphenol A, the limits detection of the method were 20 and 0.80 for influent and effluent samples, respectively. Recoveries of 85%-96% were observed in all matrices. The method was applied to analyze residual estrogens and bisphenol A in sewage influent and effluent samples from Beijing, China. The concentrations of bisphenol A (636-1200 ng L -1 ) were up to 250 times higher than those of steroid estrogens. Estrone was the dominant estrogen in influent and effluent samples, while similar concentrations of 17α-estradiol and 17β-estradiol were detected in all samples. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Early Metabolome Profiling and Prognostic Value in Paraquat-Poisoned Patients: Based on Ultraperformance Liquid Chromatography Coupled To Quadrupole Time-of-Flight Mass Spectrometry.

    Science.gov (United States)

    Hu, Lufeng; Hong, Guangliang; Tang, Yahui; Wang, Xianqin; Wen, Congcong; Lin, Feiyan; Lu, Zhongqiu

    2017-12-18

    Paraquat (PQ) has caused countless deaths throughout the world. There remains no effective treatment for PQ poisoning. Here we study the blood metabolome of PQ-poisoned patients using ultraperformance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS). Patients were divided into groups according to blood PQ concentration. Healthy subjects served as controls. Metabolic features were statistically analyzed using multivariate pattern-recognition techniques to identify the most important metabolites. Selected metabolites were further compared with a series of clinical indexes to assess the prognostic value. PQ-poisoned patients showed substantial differences compared with healthy subjects. Based on variable of importance in the project (VIP) values and statistical analysis, 17 metabolites were selected and identified. These metabolites well-classified low PQ-poisoned patients, high PQ-poisoned patients, and healthy subjects, which was better than that of a complete blood count (CBC). Among the 17 metabolites, 20:3/18:1-PC (PC), LPA (0:0/16:0) (LPA), 19-oxo-deoxycorticosterone (19-oxo-DOC), and eicosapentaenoic acid (EPA) had prognostic value. In particular, EPA was the most sensitive one. Besides, the levels of EPA was correlated with LPA and 19-oxo-DOC. If EPA was excessively consumed, then prognosis was poor. In conclusion, the serum metabolome is substantially perturbed by PQ poisoning. EPA is the most important biomarker in early PQ poisoning.

  1. Multi-ingredients determination and fingerprint analysis of leaves from Ilex latifolia using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Fan, Chunlin; Deng, Jiewei; Yang, Yunyun; Liu, Junshan; Wang, Ying; Zhang, Xiaoqi; Fai, Kuokchiu; Zhang, Qingwen; Ye, Wencai

    2013-10-01

    An ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) method integrating multi-ingredients determination and fingerprint analysis has been established for quality assessment and control of leaves from Ilex latifolia. The method possesses the advantages of speediness, efficiency, accuracy, and allows the multi-ingredients determination and fingerprint analysis in one chromatographic run within 13min. Multi-ingredients determination was performed based on the extracted ion chromatograms of the exact pseudo-molecular ions (with a 0.01Da window), and fingerprint analysis was performed based on the base peak chromatograms, obtained by negative-ion electrospray ionization QTOF-MS. The method validation results demonstrated our developed method possessing desirable specificity, linearity, precision and accuracy. The method was utilized to analyze 22 I. latifolia samples from different origins. The quality assessment was achieved by using both similarity analysis (SA) and principal component analysis (PCA), and the results from SA were consistent with those from PCA. Our experimental results demonstrate that the strategy integrated multi-ingredients determination and fingerprint analysis using UPLC-QTOF-MS technique is a useful approach for rapid pharmaceutical analysis, with promising prospects for the differentiation of origin, the determination of authenticity, and the overall quality assessment of herbal medicines. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Simultaneous determination of ethyl carbamate and urea in Korean rice wine by ultra-performance liquid chromatography coupled with mass spectrometric detection.

    Science.gov (United States)

    Lee, Gyeong-Hweon; Bang, Dae-Young; Lim, Jung-Hoon; Yoon, Seok-Min; Yea, Myeong-Jai; Chi, Young-Min

    2017-10-15

    In this study, a rapid method for simultaneous detection of ethyl carbamate (EC) and urea in Korean rice wine was developed. To achieve quantitative analysis of EC and urea, the conditions for Ultra-performance liquid chromatography (UPLC) separation and atmospheric-pressure chemical ionization tandem mass spectrometry (APCI-MS/MS) detection were first optimized. Under the established conditions, the detection limit, relative standard deviation and linear range were 2.83μg/L, 3.75-5.96%, and 0.01-10.0mg/L, respectively, for urea; the corresponding values were 0.17μg/L, 1.06-4.01%, and 1.0-50.0μg/L, respectively, for EC. The correlation between the contents of EC and its precursor urea was determined under specific pH (3.5 and 4.5) and temperature (4, 25, and 50°C) conditions using the developed method. As a result, EC content was increased with greater temperature and lower pH. In Korean rice wine, urea was detected 0.19-1.37mg/L and EC was detected 2.0-7.7μg/L. The method developed in this study, which has the advantages of simplified sample preparation, low detection limits, and good selectivity, was successfully applied for the rapid analysis of EC and urea. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Determination of sildenafil mixed into herbal honey mixture by ultra-performance liquid chromatography-quadrupole time of flight mass spectrometry

    Directory of Open Access Journals (Sweden)

    Neira Mustabasic

    2017-01-01

    Full Text Available There has been a number of reports of natural products contaminated with illegal adulterants that threaten consumer health because of their adverse pharmacological effects worldwide. In this study, a multi-residual ultra-performance liquid chromatography method with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS was applied for the identification of sildenafil added into a herbal honey mixture used as an immune system booster. Electrospray ionization (ESI source was applied and operated in the positive ion mode. The mobile phase consisted of 0.1% formic acid aqueous solution/acetonitrile (70:30, v/v using the isocratic gradient elution system at a detection wavelength of 290 nm. The compound of sildenafil added into traditional herbal mixed honey was identified according to the spectrum, chromatographic behavior, and mass spectral data were identified by comparison with the reference substance. The method is selective, sensitive and can be used to detect the sildenafil illegally added into traditional herbal medicinal preparations.

  4. Hydrophilic interaction ultra-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry for highly rapid and sensitive analysis of underivatized amino acids in functional foods.

    Science.gov (United States)

    Zhou, Guisheng; Pang, Hanqing; Tang, Yuping; Yao, Xin; Mo, Xuan; Zhu, Shaoqing; Guo, Sheng; Qian, Dawei; Qian, Yefei; Su, Shulan; Zhang, Li; Jin, Chun; Qin, Yong; Duan, Jin-ao

    2013-05-01

    This work presented a new analytical methodology based on hydrophilic interaction ultra-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry in multiple-reaction monitoring mode for analysis of 24 underivatized free amino acids (FAAs) in functional foods. The proposed method was first reported and validated by assessing the matrix effects, linearity, limit of detections and limit of quantifications, precision, repeatability, stability and recovery of all target compounds, and it was used to determine the nutritional substances of FAAs in ginkgo seeds and further elucidate the nutritional value of this functional food. The result showed that ginkgo seed turned out to be a good source of FAAs with high levels of several essential FAAs and to have a good nutritional value. Furthermore, the principal component analysis was performed to classify the ginkgo seed samples on the basis of 24 FAAs. As a result, the samples could be mainly clustered into three groups, which were similar to areas classification. Overall, the presented method would be useful for the investigation of amino acids in edible plants and agricultural products.

  5. Determination of multicomponent contents in Calculus bovis by ultra-performance liquid chromatography-evaporative light scattering detection and its application for quality control.

    Science.gov (United States)

    Kong, Weijun; Jin, Cheng; Xiao, Xiaohe; Zhao, Yanling; Liu, Wei; Li, Zulun; Zhang, Ping

    2010-06-01

    A fast ultra-performance liquid chromatography-evaporative light scattering detection (UPLC-ELSD) method was established for simultaneous quantification of seven components in natural Calculus bovis (C. bovis) and its substitutes or spurious breeds. On a Waters Acquity UPLC BEH C(18) column, seven analytes were efficiently separated using 0.2% aqueous formic acid-acetonitrile as the mobile phase in a gradient program. The evaporator tube temperature of ELSD was set at 100 degrees C with the nebulizing gas flow-rate of 1.9 L/min. The results showed that this established UPLC-ELSD method was validated to be sensitive, precise and accurate with the LODs of seven analytes at 2-11 ng, and the overall intra-day and inter-day variations less than 3.0%. The recovery of the method was in the range of 97.8-101.6%, with RSD less than 3.0%. Further results of PCA on the contents of seven investigated analytes suggested that compounds of cholic acid, deoxycholic acid and chenodeoxycholic acid or cholesterol should be added as chemical markers to UPLC analysis of C. bovis samples for quality control and to discriminate natural C. bovis sample and its substitutes or some spurious breeds, then normalize the use of natural C. bovis and ensure its clinical efficacy.

  6. Ultra-performance liquid chromatography-tandem mass spectrometry-based multiplex enzyme assay for six enzymes associated with hereditary hemolytic anemia.

    Science.gov (United States)

    Park, Chul Min; Lee, Kyunghoon; Jun, Sun-Hee; Song, Sang Hoon; Song, Junghan

    2017-08-15

    Deficiencies in erythrocyte metabolic enzymes are associated with hereditary hemolytic anemia. Here, we report the development of a novel multiplex enzyme assay for six major enzymes, namely glucose-6-phosphate dehydrogenase, pyruvate kinase, pyrimidine 5'-nucleotidase, hexokinase, triosephosphate isomerase, and adenosine deaminase, deficiencies in which are implicated in erythrocyte enzymopathies. To overcome the drawbacks of traditional spectrophotometric enzyme assays, the present assay was based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The products of the six enzymes were directly measured by using ion pairing UPLC-MS/MS, and the precision, linearity, ion suppression, optimal sample amounts, and incubation times were evaluated. Eighty-three normal individuals and 13 patients with suspected enzymopathy were analyzed. The UPLC running time was within 5min. No ion suppression was observed at the retention time for the products or internal standards. We selected an optimal dilution factor and incubation time for each enzyme system. The intra- and inter-assay imprecision values (CVs) were 2.5-12.1% and 2.9-14.3%, respectively. The linearity of each system was good, with R 2 values >0.97. Patient samples showed consistently lower enzyme activities than those from normal individuals. The present ion paring UPLC-MS/MS assay enables facile and reproducible multiplex evaluation of the activity of enzymes implicated in enzymopathy-associated hemolytic anemia. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. [Simultaneous determination of 33 primary aromatic amines of free state in fine pigments by ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry].

    Science.gov (United States)

    Man, Zhengyin; Wang, Quanlin; Li, Hesheng; Zhang, Aizhi

    2014-12-01

    A comprehensive analytical method based on ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-MS/MS) has been developed for the simultaneous determination of 33 primary aromatic amines (PAAs) in fine pigments such as gouache paint, oil painting pigment and acrylic paint. The primary aromatic amines in samples were extracted with acetonitrile. Then the extract was concentrated by centrifugation and nitrogen blow, finally diluted to 2 mL with methanol-water (1:9, v/v) and filtered through 0. 22 im membrane before UPLC-MS/MS analysis. The analytes were separated on a BEH Phenyl column (100 mm x 2. 1 mm, 1. 7 1µm) with 0. 07% (v/v) formic acid in methanol-water as mobile phases in gradient elution. The PAAs were detected by UPLC-MS/MS under multiple reaction monitoring (MRM) mode and quantified by the internal standard method. The separation conditions, fragment voltages and collision energies were optimized. The impacts of extraction times, extraction solvents and concentration methods on recoveries were studied. The limits of detection and limits of quantitation for the 33 primary aromatic amines were 5-50 µg/kg and 15-150 µg/kg respectively. The mean recoveries of three different dye products at three spiked levels were 70. 1% - 115. 8%. The relative standard deviations were 2. 1% - 15%. The expenmental results indicated that the method is simple, rapid, sensitive, accurate and can meet the requirements for the determination.

  8. Multiresidue pesticide analysis of tuber and root commodities by QuEchERS extraction and ultra-performance liquid chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Garrido Frenich, Antonia; Martín Fernández, María del Mar; Díaz Moreno, Laura; Martínez Vidal, Jose Lúis; López-Gutiérrez, Noelia

    2012-01-01

    A simple, rapid, and reliable multiresidue method to determine 84 pesticides in potato and carrot samples by ultra-performance liquid chromatography coupled to MS/MS has been developed and fully validated for routine analysis according to ISO/IEC 17025:2005. The method makes use of a buffered Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) sample preparation procedure based on a single extraction with acidified acetonitrile, followed by partitioning with salts. Chromatographic conditions were optimized in order to achieve a rapid separation in the multiple reaction monitoring mode. Performance characteristics of the method, including an estimation of measurement uncertainty using validation data, are reported for both matrixes. Calibration curves were linear from 0.010 to 0.150 mg/kg for most compounds. The LOD and LOQ were 0.006 and 0.010 mg/kg, respectively, except for fluorocloridone, fluquinconazol, and hexitiazox, which were 0.030 and 0.050 mg/kg, respectively. Recoveries obtained were in the range 70-116%, with intraday precision values < or = 20% RSD and interday precision values < or = 25% RSD at two different concentration levels. The overall uncertainty of the method was estimated at two concentrations as being lower than 34% in all cases. The method has been applied to the analysis of 70 vegetable samples, and imidacloprid and linuron were the pesticides most frequently found in potato and carrot commodities, respectively.

  9. High-sensitivity direct analysis of aflatoxins in peanuts and cereal matrices by ultra-performance liquid chromatography with fluorescence detection involving a large volume flow cell.

    Science.gov (United States)

    Oulkar, Dasharath; Goon, Arnab; Dhanshetty, Manisha; Khan, Zareen; Satav, Sagar; Banerjee, Kaushik

    2018-04-03

    This paper reports a sensitive and cost effective method of analysis for aflatoxins B1, B2, G1 and G2. The sample preparation method was primarily optimised in peanuts, followed by its validation in a range of peanut-processed products and cereal (rice, corn, millets) matrices. Peanut slurry [12.5 g peanut + 12.5 mL water] was extracted with methanol: water (8:2, 100 mL), cleaned through an immunoaffinity column and thereafter measured directly by ultra-performance liquid chromatography-fluorescence (UPLC-FLD) detection, within a chromatographic runtime of 5 minutes. The use of a large volume flow cell in the FLD nullified the requirement of any post-column derivatisation and provided the lowest ever reported limits of quantification of 0.025 for B1 and G1 and 0.01 μg/kg for B2 and G2. The single laboratory validation of the method provided acceptable selectivity, linearity, recovery and precision for reliable quantifications in all the test matrices as well as demonstrated compliance with the EC 401/2006 guidelines for analytical quality control of aflatoxins in foodstuffs.

  10. A novel strategy for target profiling analysis of bioactive phenylethanoid glycosides in Plantago medicinal plants using ultra-performance liquid chromatography coupled with tandem quadrupole mass spectrometry.

    Science.gov (United States)

    Qi, Meng; Xiong, Aizhen; Geng, Fang; Yang, Li; Wang, Zhengtao

    2012-06-01

    Phenylethanoid glycosides are a group of phenolic compounds with diverse biological activities such as hypotensive, diuretic, and hypoglycemic effects. In this study, a target profiling analysis approach using ultra-performance liquid chromatography coupled with tandem quadrupole mass spectrometry (MS) was established on the basis of parent ion scanning for m/z 161, the characteristic product ion for phenylethanoid glycosides. It was successfully employed to discriminate the chemical composition of phenylethanoid glycosides between Plantaginis Herba and Plantaginis Semen, two medicinal parts of Plantago plants, which are widely used as herbal medicine in China. Totally, 34 phenylethanoid glycosides were characterized and tentatively identified by their retention times, MS, and tandem quadrupole MS (MS/MS) data. Combined with chemometrics analysis of principal component analysis and orthogonal projection to latent structural discriminate analysis, eight of them, especially acteoside and plantamajoside, were picked out and contributed to the chemical distinction between Plantaginis Herba and Plantaginis Semen, which might be responsible for the differences in diuretic and hypotensive effects between the two medicinal parts. This new approach for target profiling provides not only a novel idea for specific analysis of active chemical constituents in the same type, but also a promising and reference method for quality evaluation of traditional Chinese medicines. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Rapid Identification of Steroidal Saponins in Trillium tschonoskii Maxim by Ultraperformance Liquid Chromatography Coupled to Electrospray Ionisation Quadrupole Time-of-Flight Tandem Mass Spectrometry.

    Science.gov (United States)

    Gao, Xin; Sun, Wenjun; Fu, Qiang; Niu, Xiaofeng

    2015-01-01

    Steroidal saponins in Trillium tschonoskii Maxim have many biological activities, including immunological regulation and anti-tumour. Comprehensive ingredient identification is critical for understanding its pharmacological mechanism and establishing quality control protocols. However, it is a challenging problem because of the complexity of steroidal saponins. To develop a UPLC-MS method for identifying and characterising steroidal saponins in the root and rhizome of T. tschonoskii. Methanolic extracts of T. tschonoskii were analysed by using ultraperformance liquid chromatography coupled to electrospray ionisation quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI/QTOF/MS). The UPLC experiments were performed by means of a reversed-phase C18 -column and a binary mobile phase system consisting of water and acetonitrile with formic acid under gradient elution conditions. For the UPLC-MS measurements, positive and negative ion modes were used in order to obtain better tandem mass spectra and high-resolution mass spectra. Based on retention times, accurate mass and mass spectrometric fragmentation, a total of 31 saponins distributed over eight steroidal aglycone skeletons were identified or tentatively elucidated from T. tschonoskii. The UPLC-ESI/QTOF/MS method has proven to be a powerful tool for rapid identification of steroidal saponins in T. tschonoskii without tedious and time-consuming isolation of pure constituents. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Determination of ametoctradin residue in fruits and vegetables by modified quick, easy, cheap, effective, rugged, and safe method using ultra-performance liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Hu, Mingfeng; Liu, Xingang; Dong, Fengshou; Xu, Jun; Li, Shasha; Xu, Hanqing; Zheng, Yongquan

    2015-05-15

    A rapid, effective and sensitive method to quantitatively determine ametoctradin residue in apple, cucumber, cabbage, tomato and grape was developed and validated using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The target compound was determined in less than 5.0 min using an electrospray ionisation source in positive mode (ESI+). The limit of detection was below 0.043 μg kg(-1), whereas the limits of quantification did not exceed 0.135 μg kg(-1) in all five matrices. The method showed excellent linearity (R(2)>0.9969) for the target compound. Recovery studies were performed in all matrices at three spiked levels (1, 10 and 100 μg L(-1)). The mean recoveries from five matrices ranged from 81.81% to 100.1%, with intra-day relative standard deviations (RSDr) in the range of 0.65-7.88% for the test compound. This method will be useful for the quick and routine detection of ametoctradin residues in potato, grape, cucumber, apple and tomato. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Metabolite profiling of a diverse collection of wheat lines using ultraperformance liquid chromatography coupled with time-of-flight mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Shawna B Matthews

    Full Text Available Genetic differences among major types of wheat are well characterized; however, little is known about how these distinctions affect the small molecule profile of the wheat seed. Ethanol/water (65% v/v extracts of seed from 45 wheat lines representing 3 genetically distinct classes, tetraploid durum (Triticum turgidum subspecies durum (DW and hexaploid hard and soft bread wheat (T. aestivum subspecies aestivum (BW were subjected to ultraperformance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC-TOF-MS. Discriminant analyses distinguished DW from BW with 100% accuracy due to differences in expression of nonpolar and polar ions, with differences attributed to sterol lipids/fatty acids and phospholipids/glycerolipids, respectively. Hard versus soft BW was distinguished with 100% accuracy by polar ions, with differences attributed to heterocyclic amines and polyketides versus phospholipid ions, respectively. This work provides a foundation for identification of metabolite profiles associated with desirable agronomic and human health traits and for assessing how environmental factors impact these characteristics.

  14. Trace residue analysis of dicyandiamide, cyromazine, and melamine in animal tissue foods by ultra-performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Xusheng Ge

    2016-07-01

    Full Text Available An effective sample preparation procedure using an accelerated solvent extraction (ASE procedure, followed by cleaning with melamine molecularly imprinted polymers solid-phase extraction (MISPE was developed. A novel and highly sensitive ASE–MISPE–ultra-performance liquid chromatography (UPLC method was developed for effective separation and simultaneous determination of dicyandiamide (DCD, cyromazine (CYR, and melamine (MEL in complex animal tissue foods. Under optimized conditions, good linearity was achieved with a correlation coefficient (r of 0.9999 in the range of at least two orders of magnitude. The limit of quantification of the method was 1.7 μg/kg, 5.0 μg/kg, and 3.2 μg/kg for DCD, MEL, and CYR, which was three orders of magnitude smaller than the maximum residue limits (MRLs. The intra- and inter-day precisions (in terms of the relative standard deviation, RSD of the three analytes were in the range of 1.7–3.1% and 3.1–6.3%, respectively. The average recoveries of analytes from blank chicken, beef, mutton, pork, and pig liver samples spiked with the three levels varied from 91.2% to 107% with RSD of 1.7–8.3% for DCD, 89.0–104% with RSD of 2.1–6.1% for CYR, and 94.8–105% with RSD of 1.1–6.6% for MEL. The proposed method has the characteristics of speed, sensitivity, and accuracy, and can be used for the routine determination of DCD, CYR, and MEL at the μg/kg level in complex animal tissue foods.

  15. Qualitative and quantitative analysis of the saponins in Panax notoginseng leaves using ultra-performance liquid chromatography coupled with time-of-flight tandem mass spectrometry and high performance liquid chromatography coupled with UV detector.

    Science.gov (United States)

    Liu, Fang; Ma, Ni; He, Chengwei; Hu, Yuanjia; Li, Peng; Chen, Meiwan; Su, Huanxing; Wan, Jian-Bo

    2018-04-01

    Panax notoginseng leaves (PNL) exhibit extensive activities, but few analytical methods have been established to exclusively determine the dammarane triterpene saponins in PNL. Ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC/Q-TOF MS) and HPLC-UV methods were developed for the qualitative and quantitative analysis of ginsenosides in PNL, respectively. Extraction conditions, including solvents and extraction methods, were optimized, which showed that ginsenosides Rc and Rb3, the main components of PNL, are transformed to notoginsenosides Fe and Fd, respectively, in the presence of water, by removing a glucose residue from position C-3 via possible enzymatic hydrolysis. A total of 57 saponins were identified in the methanolic extract of PNL by UPLC/Q-TOF MS. Among them, 19 components were unambiguously characterized by their reference substances. Additionally, seven saponins of PNL-ginsenosides Rb1, Rc, Rb2, and Rb3, and notoginsenosides Fc, Fe, and Fd-were quantified using the HPLC-UV method after extraction with methanol. The separation of analytes, particularly the separation of notoginsenoside Fc and ginsenoside Rc, was achieved on a Zorbax ODS C8 column at a temperature of 35°C. This developed HPLC-UV method provides an adequate linearity ( r 2  > 0.999), repeatability (relative standard deviation, RSD PNL. These findings are beneficial to the quality control of PNL and its relevant products.

  16. Analysis of an Adulterated Herbal Medicinal Product Using Ultra-Performance Liquid Chromatography Coupled with QTOF Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Kate Yu

    2016-11-01

    Full Text Available The reports of severe adverse effects and fatalities associated with herbal medicinal products adulterated with synthetic compounds have raised global concerns. The objective of this study is to analyze one commercial herbal medicinal product suspected to be adulterated with synthetic drugs in order to identify potential adulterants, to verify if the product contained the herbs listed as ingredients in label claim and to determine quality consistency among different batches of the product. Analyses of suspected product obtained from seven different batches were performed using ultra performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS with multiple data processing tools and multivariate analyses. In addition, 23 individual powdered herbs (12 as per label claim and 11 suspected herbs, 11 marker compounds of the labeled herbs and five suspected synthetic drugs as adulterants were also concurrently analyzed to have clear understanding of product composition. Based on our analysis, the major ingredients of studied product were found to be 5 synthetic compounds: caffeine, chlorphenamine, piroxicam, betamethasone and oxethazaine. Three of them have been found to exceed their recommended doses. From the herbal composition analysis, GanCao (Glycyrrhizae radix et rhizoma was found to be the main ingredient, which is not among the claimed 12 herbs that were supposed to be in the product. Other herbs detected as minor ingredients were MuGua (Chaenomelis fructus, DangGui (Angelicae sinensis radix, and HuangQi (Astragali radix, which are among the 12 herbs that were supposed to be in the product. Based on our results we demonstrated that UPLC-QTOF MS is an effective and versatile tool for the analysis of herbal medicinal products. It is highly desirable to have a streamlined process with automatic workflow and fit-for-purpose database to increase efficiency and productivity of sample analysis. Results of

  17. Simultaneous Determination of Black Tea-Derived Catechins and Theaflavins in Tissues of Tea Consuming Animals Using Ultra-Performance Liquid-Chromatography Tandem Mass Spectrometry

    Science.gov (United States)

    Ganguly, Souradipta; G., Taposh Kumar; Mantha, Sudarshan

    2016-01-01

    The bioavailability, tissue distribution and metabolic fate of the major tea polyphenols, catechins and theaflavins as well as their gallated derivatives are yet to be precisely elucidated on a single identification platform for assessment of their relative bioefficacy in vivo. This is primarily due to the lack of suitable analytical tools for their simultaneous determination especially in an in vivo setting, which continues to constrain the evaluation of their relative health beneficiary potential and therefore prospective therapeutic application. Herein, we report a rapid and sensitive Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS) based method for the simultaneous determination of the major catechins and theaflavins in black tea infusions as well as in different vital tissues and body fluids of tea-consuming guinea pigs. This method allowed efficient separation of all polyphenols within seven minutes of chromatographic run and had a lower limit of quantification (LLOQ) of ~5 ng/ml. Using this method, almost all bioactive catechins and theaflavins could be simultaneously detected in the plasma of guinea pigs orally administered 5% black tea for 14 days. Our method could further detect the majority of these polyphenols in the lung and kidney as well as identify the major catechin metabolites in the urine of the tea-consuming animals. Overall, our study presents a novel tool for simultaneous detection and quantitation of both catechins and theaflavins in a single detection platform that could potentially enable precise elucidation of their relative bioavailability and bioefficacy as well as true health beneficiary potential in vivo. Such information would ultimately facilitate the accurate designing of therapeutic strategies utilizing high efficacy formulations of tea polyphenols for effective mitigation of oxidative damage and inflammation in humans as well as prevention of associated diseases. PMID:27695123

  18. Application of ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry in identification of three isoflavone glycosides and their corresponding metabolites.

    Science.gov (United States)

    Xu, Xiafen; Li, Xinhui; Liang, Xianrui

    2018-02-15

    Metabolites of isoflavones have attracted much attention in recent years due to their potential bioactivities. However, the complex constituents of the metabolic system and the low level of metabolites make them difficult to analyze. A mass spectrometry (MS) method was applied in our identification of metabolites and study of their fragmentation pathways due to the advantages of rapidity, sensitivity, and low level of sample consumption. Three isoflavone glycosides and their metabolites were identified using ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC/QTOF-MS). These metabolites were obtained by anaerobically incubating three isoflavone glycosides with human intestinal flora. The characteristic fragments of isoflavone glycosides and their metabolites were used for the identification work. Two metabolites from ononin, three metabolites from irilone-4'-O-β-D-glucoside, and five metabolites from sissotrin were identified respectively by the retention time (RT), accurate mass, and mass spectral fragmentation patterns. The losses of the glucosyl group, CO from the [M+H] + ion were observed for all the three isoflavone glycosides. The characteristic retro-Diels-Alder (RDA) fragmentation patterns were used to differentiate the compounds. The metabolic pathways of the three isoflavone glycosides were proposed according to the identified chemical structures of the metabolites. A selective, sensitive and rapid method was established for detecting and identifying three isoflavone glycosides and their metabolites using UPLC/QTOF-MS. The established method can be used for further rapid structural identification studies of metabolites and natural products. Furthermore, the proposed metabolic pathways will be helpful for understanding the in vivo metabolic process of isoflavone. Copyright © 2017 John Wiley & Sons, Ltd.

  19. Metabonomics evaluation of urine from rats administered with phorate under long-term and low-level exposure by ultra-performance liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Sun, Xiaowei; Xu, Wei; Zeng, Yan; Hou, Yurong; Guo, Lin; Zhao, Xiujuan; Sun, Changhao

    2014-02-01

    The purpose of this study was to investigate the toxic effect of long-term and low-level exposure to phorate using a metabonomics approach based on ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). Male Wistar rats were given phorate daily in drinking water at low doses of 0.05, 0.15 or 0.45 mg kg⁻¹ body weight (BW) for 24 weeks consecutively. Rats in the control group were given an equivalent volume of drinking water. Compared with the control group, serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (TBIL), urea nitrogen (BUN) and creatinine (CR) were increased in the middle- and high-dose groups whereas albumin (ALB) and cholinesterase (CHE) were decreased. Urine metabonomics profiles were analyzed by UPLC-MS. Compared with the control group, 12 metabolites were significantly changed in phorate-treated groups. In the negative mode, metabolite intensities of uric acid, suberic acid and citric acid were significantly decreased in the middle- and high-dose groups, whereas indoxyl sulfic acid (indican) and cholic acid were increased. In the positive mode, uric acid, creatinine, kynurenic acid and xanthurenic acid were significantly decreased in the middle- and high-dose groups, but 7-methylguanine (N⁷G) was increased. In both negative and positive modes, diethylthiophosphate (DETP) was significantly increased, which was considered as a biomarker of exposure to phorate. In conclusion, long-term and low-level exposure to phorate can cause disturbances in energy-related metabolism, liver and kidney function, the antioxidant system, and DNA damage. Moreover, more information can be provided on the evaluation of toxicity of phorate using metabonomics combined with clinical chemistry. Copyright © 2012 John Wiley & Sons, Ltd.

  20. A urinary metabonomics analysis of long-term effect of acetochlor exposure on rats by ultra-performance liquid chromatography/mass spectrometry.

    Science.gov (United States)

    Li, Longxue; Wang, Maoqing; Chen, Shuhong; Zhao, Wei; Zhao, Yue; Wang, Xu; Zhang, Yang

    2016-03-01

    The study was to assess the long-term toxic effects of acetochlor on rats. Two different doses (42.96 and 107.4 mg/kg body weight/day) of acetochlor were administered to Wistar rats through their food for over 24 weeks. Rat urine samples were collected at two time-points for the measurements of the metabonomics profiles with ultra-performance liquid chromatography-mass spectrometry (UPLC-MSMS). The results of clinical chemistry and histopathology suggested that long-term use of acetochlor in rats caused liver and kidney damage, and dysfunction of antioxidant system. The urinary metabonomics analysis indicated that the high and low-dose exposure of acetochlor could cause alterations of these metabonomics in urine in the rat. Significant changes of the levels of hippuric acid (0.403-fold decrease), citric acid (0.430-fold decrease), pantothenic acid (0.486-fold decrease), uracil (0.419-fold decrease), β-Alanine (0.325-fold decrease), nonanedioic acid (0.445-fold decrease), L-tyrosine (0.410-fold decrease), D-glucuronic acid (8.389-fold increase) and 2-ethyl-6-methyl-N-methyl-2-chloro-acetanilide in urine were observed. In addition, it may interfere with the fatty acid synthesis, the pyrimidine degradation and pantothenate biosynthesis. The level of 2-ethyl-6-methyl-N-methyl-2-chloro-acetanilide is detected in all treated groups which is not found in the control groups, indicating which can be used as an early, sensitive marker of acetochlor exposure in rat. This study illustrates the important utility of metabonomics approaches to understand the toxicity of long-term exposure of acetochlor. Copyright © 2015. Published by Elsevier Inc.

  1. The toxicity of 3-chloropropane-1,2-dipalmitate in Wistar rats and a metabonomics analysis of rat urine by ultra-performance liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Li, Jianshuang; Wang, Sen; Wang, Maoqing; Shi, Wenxiu; Du, Xiaoyan; Sun, Changhao

    2013-11-25

    3-Monochloropropane-1,2-diol(3-MCPD) fatty acid esters can release free 3-MCPD in a certain condition. Free 3-MCPD is a well-known food contaminant and is toxicological well characterized, however, in contrast to free 3-MCPD, the toxicological characterization of 3-MCPD fatty acid esters is puzzling. In this study, toxicological and metabonomics studies of 3-chloropropane-1,2-dipalmitate(3-MCPD dipalmitate) were carried out based on an acute oral toxicity test, a 90-day feeding test and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) analysis. The LD50 value of 3-MCPD dipalmitate was determined to be 1780 mg/kg body weight (bw) for Wistar rats. The results of the 90-day feeding test in male Wistar rats showed that 3-MCPD dipalmitate caused a significant increase in blood urea nitrogen and creatinine in the high-dose group (267 mg/kg bw/day) compared to control rats. Renal tubular epithelium cell degeneration and renal tubular hyaline cast accumulation were the major histopathological changes in rats administered 3-MCPD dipalmitate. Urine samples obtained after the 90-day feeding test and analyzed by UPLC-MS showed that the differences in metabolic profiles between control and treated rats were clearly distinguished by partial least squares-discriminant analysis (PLS-DA) of the chromatographic data. Five metabolite biomarkers which had earlier and significant variations had been identified, they were first considered to be the early, sensitive biomarkers in evaluating the effect of 3-MCPD dipalmitate exposure, and the possible mechanism of these biomarkers variation was elucidated. The combination of histopathological examination, clinical chemistry and metabolomics analyses in rats resulted in a systematic and comprehensive assessment of the long-term toxicity of 3-MCPD dipalmitate. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  2. Pre-analytical and analytical variation of drug determination in segmented hair using ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Nielsen, Marie Katrine Klose; Johansen, Sys Stybe; Linnet, Kristian

    2014-01-01

    Assessment of total uncertainty of analytical methods for the measurements of drugs in human hair has mainly been derived from the analytical variation. However, in hair analysis several other sources of uncertainty will contribute to the total uncertainty. Particularly, in segmental hair analysis pre-analytical variations associated with the sampling and segmentation may be significant factors in the assessment of the total uncertainty budget. The aim of this study was to develop and validate a method for the analysis of 31 common drugs in hair using ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) with focus on the assessment of both the analytical and pre-analytical sampling variations. The validated method was specific, accurate (80-120%), and precise (CV≤20%) across a wide linear concentration range from 0.025-25 ng/mg for most compounds. The analytical variation was estimated to be less than 15% for almost all compounds. The method was successfully applied to 25 segmented hair specimens from deceased drug addicts showing a broad pattern of poly-drug use. The pre-analytical sampling variation was estimated from the genuine duplicate measurements of two bundles of hair collected from each subject after subtraction of the analytical component. For the most frequently detected analytes, the pre-analytical variation was estimated to be 26-69%. Thus, the pre-analytical variation was 3-7 folds larger than the analytical variation (7-13%) and hence the dominant component in the total variation (29-70%). The present study demonstrated the importance of including the pre-analytical variation in the assessment of the total uncertainty budget and in the setting of the 95%-uncertainty interval (±2CVT). Excluding the pre-analytical sampling variation could significantly affect the interpretation of results from segmental hair analysis. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  3. Simultaneous determination of four water-soluble vitamins in fortified infant foods by ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry.

    Science.gov (United States)

    Lu, Baiyi; Ren, Yiping; Huang, Baifen; Liao, Wenqun; Cai, Zengxuan; Tie, Xiaowei

    2008-03-01

    A novel ultra-performance liquid chromatography electrospray ionization tandem triple quadrupole mass spectrometry method for the simultaneous determination of four water-soluble vitamins, including vitamin B5 (VB5), vitamin B8 (VB8), vitamin B9 (VB9), and vitamin B12 (VB12) in fortified infant foods is developed and validated. A reverse phase UPLC separation system consisting of a Waters ACQUITY UPLC BEH C-18 column (2.1 mm x 100 mm i.d., 1.7 microm) and a binary gradient acetonitrile-water mobile phase is applied for the separation of the four water-soluble vitamins. Formic acid is spiked into the mobile phase to enhance the ionization efficiency. Tandem MS-MS analysis is performed in multi-reaction monitoring mode (MRM). Product-ion traces at m/z 220.1 --> 89.9 for VB5, 245.1 --> 227.1 for VB8, 442.3 --> 295.2 for VB9, and 678.9 --> 147.0 for VB12 are used for quantitation of the corresponding vitamins, and traces at m/z 455.5 --> 308.0 are used for methotrexate (internal standard). Limits of quantitation (LOQs) are 0.016, 0.090, 0.020, and 0.019 microg/L for VB5, VB8, VB9, and VB12, respectively. Intra- and inter-day precisions for the determination of the four vitamins are better than 6.84% and 12.26% in relative standard deviations, and recoveries for the four vitamins are in the range of 86.0~101.5%. The developed approach is applied for the determination of the trace amounts of the vitamins in fortified milk powers and fortified rice powers.

  4. [Simultaneous determination of 33 primary aromatic amines in polystyrene and polyethylene masterbatches for foods by ultra-performance liquid chromatography-tandem mass spectrometry

    Science.gov (United States)

    Man, Zhengyin; Wang, Quanlin; Li, Hesheng; Zhang, Aizhi; Shen, Jian

    2015-03-01

    A comprehensive analytical method based on ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-MS/MS) has been developed for the simultaneous determination of 33 primary aromatic amines (PAAs) in polystyrene (PS) and polyethylene (PE) masterbatches for foods. The PS masterbatches were dissolved with dichloromethane, and methanol was added to precipitate after extraction by ultrasound extraction. Then the extract was purified by passing through a carbon graphite solid phase extraction column. The PE masterbatches were swelled and extracted with dichloromethane by ultrasound. The purified PS solution and PE extract were concentrated, and diluted to 2 mL with methanol-water (1:9, v/v), and filtered through the membranes of 0.22 µm before UPLC-MS/MS analysis. The analytes were separated on a BEH Phenyl column (100 mm x 2.1 mm, 1.7 µm), eluted by gradient with 0.07% (v/v) formic acid in methanol-water (1:9, v/v). The PAAs were detected by UPLC-MS/MS under multiple reaction monitoring (MRM) mode and quantified by the internal standard method. The separation conditions, fragment voltages and collision energies were optimized. The impacts of extraction times, extraction solvents and concentration methods on recoveries were studied. The limits of detection for the 33 primary aromatic amines were 6-10 µg/kg, and the limits of quantitation were 20-30 µg/kg. The mean recoveries of the two different masterbatch products at three spiked levels of 20, 100, 200 µg/kg were 61.3%-119.8%, and the relative standard deviations were 1.4%-14.8%. The experimental results indicated that the method is simple, rapid, sensitive, accurate, and can meet the related requirements for determination.

  5. Analysis of glycosaminoglycans in cerebrospinal fluid from patients with mucopolysaccharidoses by isotope-dilution ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zhang, Haoyue; Young, Sarah P; Auray-Blais, Christiane; Orchard, Paul J; Tolar, Jakub; Millington, David S

    2011-07-01

    New therapies for the treatment of mucopolysaccharidoses that target the brain, including intrathecal enzyme replacement, are being explored. Quantitative analysis of the glycosaminoglycans (GAGs) that accumulate in these disorders is required to assess the disease burden and monitor the effect of therapy in affected patients. Because current methods lack the required limit of quantification and specificity to analyze GAGs in small volumes of cerebrospinal fluid (CSF), we developed a method based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Samples of CSF (25 μL) were evaporated to dryness and subjected to methanolysis. The GAGs were degraded to uronic acid-N-acetylhexosamine dimers and mixed with internal standards derived from deuteriomethanolysis of GAG standards. Specific dimers derived from heparan, dermatan and chondroitin sulfates (HS, DS and CS) were separated by UPLC and analyzed by electrospray ionization MS/MS using selected reaction monitoring for each targeted GAG product and its corresponding internal standard. CSF from control pediatric subjects (n = 22) contained <0.38 mg/L HS, 0.26 mg/L DS, and 2.8 mg/L CS, whereas CSF from patients with Hurler syndrome (n = 7) contained concentrations of DS and HS that were at least 6-fold greater than the upper control limits. These concentrations were reduced by 17.5% to 82.5% after allogeneic transplantation and treatment with intrathecal and intravenous enzyme replacement therapy. The method described here has potential value in monitoring patients with mucopolysaccharidoses receiving treatment targeted to the brain.

  6. Qualitative and quantitative analysis of the saponins in Panax notoginseng leaves using ultra-performance liquid chromatography coupled with time-of-flight tandem mass spectrometry and high performance liquid chromatography coupled with UV detector

    Directory of Open Access Journals (Sweden)

    Fang Liu

    2018-04-01

    Full Text Available Background: Panax notoginseng leaves (PNL exhibit extensive activities, but few analytical methods have been established to exclusively determine the dammarane triterpene saponins in PNL. Methods: Ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC/Q-TOF MS and HPLC-UV methods were developed for the qualitative and quantitative analysis of ginsenosides in PNL, respectively. Results: Extraction conditions, including solvents and extraction methods, were optimized, which showed that ginsenosides Rc and Rb3, the main components of PNL, are transformed to notoginsenosides Fe and Fd, respectively, in the presence of water, by removing a glucose residue from position C-3 via possible enzymatic hydrolysis. A total of 57 saponins were identified in the methanolic extract of PNL by UPLC/Q-TOF MS. Among them, 19 components were unambiguously characterized by their reference substances. Additionally, seven saponins of PNL—ginsenosides Rb1, Rc, Rb2, and Rb3, and notoginsenosides Fc, Fe, and Fd—were quantified using the HPLC-UV method after extraction with methanol. The separation of analytes, particularly the separation of notoginsenoside Fc and ginsenoside Rc, was achieved on a Zorbax ODS C8 column at a temperature of 35°C. This developed HPLC-UV method provides an adequate linearity (r2>0.999, repeatability (relative standard deviation, RSD < 2.98%, and inter- and intraday variations (RSD < 4.40% with recovery (98.7–106.1% of seven saponins concerned. This validated method was also conducted to determine seven components in 10 batches of PNL. Conclusion: These findings are beneficial to the quality control of PNL and its relevant products. Keywords: ginsenoside transformation, notoginsenoside Fd, notoginsenoside Fe, Panax notoginseng leaves, UPLC/Q-TOF MS

  7. Can Riboflavin Penetrate Stroma Without Disrupting Integrity of Corneal Epithelium in Rabbits? Iontophoresis and Ultraperformance Liquid Chromatography With Electrospray Ionization Tandem Mass Spectrometry.

    Science.gov (United States)

    Novruzlu, Şahin; Türkcü, Ümmühani Özel; Kvrak, İbrahim; Kvrak, Şeyda; Yüksel, Erdem; Deniz, Nuriye Gökçen; Bilgihan, Ayşe; Bilgihan, Kamil

    2015-08-01

    To examine riboflavin concentrations in corneas and aqueous humor from rabbits with standard and transepithelial methods and iontophoresis without disrupting the integrity of the corneal epithelium before corneal collagen cross-linking. Twenty-four eyes of 12 adult New Zealand rabbits were used. They were assigned to 4 groups, each including 6 eyes. Group 1 was exposed to the standard method and given riboflavin 0.1% after epithelial debridement. Group 2 was exposed to the transepithelial method and given benzalkonium chloride (BAC), ethylenediaminetetraacetic acid (EDTA), trometamol (TRIS), hydroxypropylmethylcellulose (HPMC), and riboflavin 0.2% 3 times at 1.5-minute intervals followed by riboflavin 0.2%. Group 3 was given riboflavin 0.1% by using 1-mA electric current for 10 minutes with the help of iontophoresis without using substances disrupting the integrity of the corneal epithelium. Group 4 received the same treatment as did group 3, except that it was given riboflavin 0.2%. Following these treatments, riboflavin concentrations in aqueous humor and corneas were measured with ultraperformance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS). Riboflavin concentrations in the cornea and aqueous humor were higher in group 1 (42.4 ± 5.4 μg/g) than in the other groups. They were significantly higher in group 4 (34.2 ± 6.6 μg/g) than in group 2 (24.4 ± 1.2 μg/g) (P = 0.009) and group 3 (23.6 ± 6.1 μg/g) (P = 0.026). There was not a significant difference in corneal riboflavin concentrations between group 2 and group 3 (P = 0.937). Intrastromal and aqueous riboflavin concentrations after administration of riboflavin 0.2% through iontophoresis without disrupting the integrity of the corneal epithelium were lower than those after the standard method, but higher than those after the transepithelial method. In this study, in which riboflavin concentrations were measured with a very sensitive method

  8. Measurement of serum 3-epi-25-hydroxyvitamin D3, 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 in infant, paediatric and adolescent populations of Korea using ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Cho, Sung E; Kim, Sollip; Kim, Young D; Lee, Hyojung; Seo, Dong H; Song, Junghan; Um, Tae H; Cho, Chong R; Kim, Nam H; Hwang, Jong H

    2017-09-01

    Background We evaluated the performance of ultra-performance liquid chromatography-tandem mass spectrometry to measure serum 3-epi-25-hydroxyvitamin D 3 , 25-hydroxyvitamin D 3 and 25-hydroxyvitamin D 2 concentrations in 519 infant, paediatric and adolescent serum samples in Korea. Methods We used a Kinetex XB-C18 column and isocratic methanol/water (77.5/22.5, v/v) with 0.025% (v/v) high-performance liquid chromatography solvent additive flowing at 0.25 mL/min, yielding an 11 min/sample run time. A TQD triple quadrupole mass spectrometer in electrospray ionization positive ion mode with multiple reaction monitoring transition via an MSMS vitamin D kit was used to evaluate precision, carryover, ion suppression and linearity. Samples were prepared using the 4-phenyl-1,2,4-triazoline-3,5-dione derivatization method. Results Intra- and inter-run precisions were 1.23-13.28% and 1.02-10.08%, respectively. Group carryovers were -0.27% and 0.10%, respectively. There was no ion suppression. The calibration curve showed good linearity from calibrator Level 1 (11.75 nmol/L) to 6 (375 nmol/L) with R 2  > 0.9999. The 3-epi-25-hydroxyvitamin D 3 and 25-hydroxyvitamin D 3 peaks were clearly separated in the extracted ion chromatogram. Infant serum samples 3-epi-25-hydroxyvitamin D 3 concentrations were significantly higher than paediatric and adolescent concentrations. Conclusions The ultra-performance liquid chromatography-tandem mass spectrometry assay performed acceptably, clearly separating 3-epi-25-hydroxyvitamin D 3 from 25-hydroxyvitamin D 3 . High 3-epi-25-hydroxyvitamin D 3 concentrations were observed in infant but not in paediatric and adolescent serum samples.

  9. Cytokinin profiling in plant tissues using ultra-performance liquid chromatography–electrospray tandem mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Novák, Ondřej; Hauserová, Eva; Amakorová, Petra; Doležal, Karel; Strnad, Miroslav

    2008-01-01

    Roč. 69, č. 11 (2008), s. 2214-2224 ISSN 0031-9422 R&D Projects: GA AV ČR KAN200380801 Institutional research plan: CEZ:AV0Z50380511 Keywords : Ultra-performance liquid chromatography (UPLC) * Tandem mass spectrometry (MS/MS) * Microextraction Subject RIV: EC - Immunology Impact factor: 2.946, year: 2008

  10. Ultra-performance liquid chromatography MS/MS method for the determination of parabens in compost from sewage sludge: comparison of the efficiency of two extraction techniques.

    Science.gov (United States)

    Benítez-Villalba, Julio César; Zafra-Gómez, Alberto; Dorival-García, Noemí; Camino-Sánchez, Francisco Javier; Cantarero, Samuel; Vílchez, José Luis

    2013-08-01

    The efficiency of two extraction techniques--ultrasound-assisted extraction and pressurized liquid extraction--are compared and evaluated in the determination of parabens in compost samples. The extraction parameters for each technique were accurately optimized. The selected compounds were detected and quantified using ultra-performance LC MS/MS, operating in negative ESI and in SRM mode. The analytes were separated in less than 5 min. Ethylparaben (ring-(13)C6 labeled) was used as an internal standard. Two selective, sensitive, and accurate analytical methods were developed and validated. The LODs of the methods ranged from 3 to 7 ng/g and the LOQs from 10 to 23 ng/g, while inter- and intraday variability was under 6% in all cases. The methods were validated separately by using matrix-matched calibration and recovery assays with spiked samples. Recovery rates ranged from 94.0 to 105.0%. Compost samples were taken from different composting plants. Although the statistical comparison demonstrated no statistically significant differences between the two extraction techniques, the method based on pressurized liquid extraction was more sensitive than the ultrasound extraction based method. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Identification of non-volatile compounds and their migration from hot melt adhesives used in food packaging materials characterized by ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Vera, Paula; Canellas, Elena; Nerín, Cristina

    2013-05-01

    The identification of unknown non-volatile migrant compounds from adhesives used in food contact materials is a very challenging task because of the number of possible compounds involved, given that adhesives are complex mixtures of chemicals. The use of ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-MS/QTOF) is shown to be a successful tool for identifying non-targeted migrant compounds from two hot melt adhesives used in food packaging laminates. Out of the seven migrants identified and quantified, five were amides and one was a compound classified in Class II of the Cramer toxicity. None of the migration values exceeded the recommended Cramer exposure values.

  12. Urinary metabolomic profiling in rats exposed to dietary di(2-ethylhexyl) phthalate (DEHP) using ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS).

    Science.gov (United States)

    Dong, Xinwen; Zhang, Yunbo; Dong, Jin; Zhao, Yue; Guo, Jipeng; Wang, Zhanju; Liu, Mingqi; Na, Xiaolin; Wang, Cheng

    2017-07-01

    Di(2-ethylhexyl) phthalate (DEHP) is an omnipresent environmental chemical with widespread nonoccupational human exposure through multiple ways. Although considerable efforts have been invested to investigate mechanisms of DEHP toxicity, the key metabolic biomarkers of DEHP toxicity remain to be identified. The aim of this study was to assess the urinary metabonomics of dietary DEHP in rats using the technique of ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS). Fourteen female Wistar rats were divided into two groups and given increasing dietary doses of DEHP for 30 consecutive days. The urinary metabolite profile was studied using ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry. Principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) enabled clusters to be clearly separated. Eleven principal urinary metabolites were identified as contributing to the clusters. The clusters in the positive electrospray ionization (ESI) mode were xanthurenic acid, kynurenic acid, nonate, N6-methyladenosine, and L-isoleucyl-L-proline. The clusters in the negative ESI mode were hippuric acid, tetrahydrocortisol, citric acid, phenylpropionylglycine, cPA(18:2(9Z, 12Z)/0:0), and LysoPC(14:1(9Z)). The urinary metabonomic changes indicated that exposure to dietary DEHP can affect energy-related metabolism, liver and renal function, fatty acid metabolism, and cause DNA damage in rats. The findings of this study on the urinary metabolites and metabolic pathways of DEHP may form the basis for future studies on the mechanisms of toxicity of this commonly found environmental chemical.

  13. Chemical Fingerprint and Quantitative Analysis for the Quality Evaluation of Platycladi cacumen by Ultra-performance Liquid Chromatography Coupled with Hierarchical Cluster Analysis.

    Science.gov (United States)

    Shan, Mingqiu; Li, Sam Fong Yau; Yu, Sheng; Qian, Yan; Guo, Shuchen; Zhang, Li; Ding, Anwei

    2018-01-01

    Platycladi cacumen (dried twigs and leaves of Platycladus orientalis (L.) Franco) is a frequently utilized Chinese medicinal herb. To evaluate the quality of the phytomedcine, an ultra-performance liquid chromatographic method with diode array detection was established for chemical fingerprinting and quantitative analysis. In this study, 27 batches of P. cacumen from different regions were collected for analysis. A chemical fingerprint with 20 common peaks was obtained using Similarity Evaluation System for Chromatographic Fingerprint of Traditional Chinese Medicine (Version 2004A). Among these 20 components, seven flavonoids (myricitrin, isoquercitrin, quercitrin, afzelin, cupressuflavone, amentoflavone and hinokiflavone) were identified and determined simultaneously. In the method validation, the seven analytes showed good regressions (R ≥ 0.9995) within linear ranges and good recoveries from 96.4% to 103.3%. Furthermore, with the contents of these seven flavonoids, hierarchical clustering analysis was applied to distinguish the 27 batches into five groups. The chemometric results showed that these groups were almost consistent with geographical positions and climatic conditions of the production regions. Integrating fingerprint analysis, simultaneous determination and hierarchical clustering analysis, the established method is rapid, sensitive, accurate and readily applicable, and also provides a significant foundation for quality control of P. cacumen efficiently. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. High-throughput and simultaneous analysis of eight central-acting muscle relaxants in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry in the positive and negative ionization modes.

    Science.gov (United States)

    Ogawa, Tadashi; Hattori, Hideki; Kaneko, Rina; Ito, Kenjiro; Iwai, Masae; Mizutani, Yoko; Arinobu, Tetsuya; Ishii, Akira; Seno, Hiroshi

    2011-06-01

    In this report, a high-throughput and sensitive method for analysis of eight central-acting muscle relaxants in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) in the positive and negative ionization modes using tolbutamide as internal standard is presented. After pretreatment of a plasma sample by solid-phase extraction with an Oasis HLB cartridge, muscle relaxants were analyzed by UPLC with Acquity UPLC BEH C(18) column and Acquity TQD tandem quadrupole mass spectrometer equipped with an electrospray ionization interface. The calibration curves for muscle relaxants spiked into human plasma equally showed good linearities in the nanogram per milliliter order range. The detection limits (signal-to-noise ratio = 3) was as low as 0.1-2 ng/mL. The method gave satisfactory recovery rates, accuracy, and precision for quality control samples spiked with muscle relaxants. To further validate the present method, 250 mg of chlorphenesin carbamate was orally administered to a healthy male volunteer, and the concentrations of chlorphenesin carbamate in plasma were measured 0.5, 1, 2, 4, 6, and 8 h after dosing; their concentrations in human plasma were between 0.62 and 2.44 μg/mL. To our knowledge, this is the first report describing simultaneous analysis of over more than two central-acting muscle relaxants by liquid chromatography-tandem mass spectrometry. This has been realized by the capability of our instrument for simultaneous multiple reaction monitoring of the target compounds in both positive and negative ionization modes. Therefore, the present method seems very useful in forensic and clinical toxicology and pharmacokinetic studies.

  15. Evaluation of Hypolipidemic and Antioxidant Effects in Phenolrich Fraction of Crataegus pinnatifida Fruit in Hyperlipidemia Rats and Identification of Chemical Composition by Ultra-performance Liquid Chromatography Coupled with Quadropole Time-of-flight Mass Spectrometry

    Science.gov (United States)

    Shao, Feng; Gu, Lifei; Chen, Huijuan; Liu, Ronghua; Huang, Huilian; Chen, Lanying; Yang, Ming

    2017-01-01

    Background: Hawthorn (Crataegus pinnatifida) fruit has enjoyed a great popularity as a pleasant-tasting food associated with hypolipidemic and antioxidant effects. Objective: Our aim was to screen the effective fraction of hawthorn fruit in the treatment of hyperlipidemia rats. Materials and Methods: In this study, ethanol extract of hawthorn fruit (Fr.1) and four fractionated extracts (Fr.2, Fr.3, Fr.4, and Fr.5) were compared to total phenol content evaluated using Folin–Ciocalteu method, and hypolipidemic and antioxidant effects were assessed in hyperlipidemic rats. Results: Total phenol content of Fr.4 was higher than other fractions by at least 2 fold. Furthermore, this fraction possessed the strongest hypolipidemic and antioxidant effects in hyperlipidemic rats. On this basis, 15 phenolic compounds and four organic acids in Fr.4 were positively or tentatively identified using ultra-performance liquid chromatography coupled with quadropole time-of-flight mass spectrometry. In addition, 5-O-caffeoyl quinic acid butyl ester was first reported in hawthorn fruit. Conclusion: Phenol-rich fraction in hawthorn fruit exhibited satisfactory hypolipidemic and antioxidant effects, and this could be exploited for further promotion of functional foods. SUMMARY Phenol-rich fraction in hawthorn fruit possesses most potent hypolipidemic and antioxidant effects in hyperlidemia rats. Abbreviations used: UPLC-Q-TOF-MS/MS: Ultra performance liquid chromatography coupled with quadropole time-of-flight mass spectrometry; TC: Total cholesterol; TG: Triglyceride; LDL-C: Low-density lipoprotein-cholesterol; HDL-C: High-density lipoprotein-cholesterol; GSH-Px: Glutathione peroxidase; SOD: Superoxide dismutase; MDA: Malondialdehyde; CAT: Catalase; NO: Nitric oxide; NOS: Nitric oxide synthase; ROS: Reactive oxygen species; •OOH: Superoxide anions, •OH: Hydroxyl radicals. PMID:29200740

  16. Metabolomics Study of Resina Draconis on Myocardial Ischemia Rats Using Ultraperformance Liquid Chromatography/Quadrupole Time-of-Flight Mass Spectrometry Combined with Pattern Recognition Methods and Metabolic Pathway Analysis

    Directory of Open Access Journals (Sweden)

    Yunpeng Qi

    2013-01-01

    Full Text Available Resina draconis (bright red resin isolated from Dracaena cochinchinensis, RD has been clinically used for treatment of myocardial ischemia (MI for many years. However, the mechanisms of its pharmacological action on MI are still poorly understood. This study aimed to characterize the plasma metabolic profiles of MI and investigate the mechanisms of RD on MI using ultraperformance liquid chromatography/quadrupole time-of-flight mass spectrometry-based metabolomics combined with pattern recognition methods and metabolic pathway analysis. Twenty metabolite markers characterizing metabolic profile of MI were revealed, which were mainly involved in aminoacyl-tRNA biosynthesis, phenylalanine, tyrosine, and tryptophan biosynthesis, vascular smooth muscle contraction, sphingolipid metabolism, and so forth. After RD treatment, however, levels of seven MI metabolite markers, including phytosphingosine, sphinganine, acetylcarnitine, cGMP, cAMP, L-tyrosine, and L-valine, were turned over, indicating that RD is likely to alleviate MI through regulating the disturbed vascular smooth muscle contraction, sphingolipid metabolism, phenylalanine metabolism, and BCAA metabolism. To our best knowledge, this is the first comprehensive study to investigate the mechanisms of RD for treating MI, from a metabolomics point of view. Our findings are very valuable to gain a better understanding of MI metabolic profiles and provide novel insights for exploring the mechanisms of RD on MI.

  17. Rapid and sensitive analysis of phthalate metabolites, bisphenol A, and endogenous steroid hormones in human urine by mixed-mode solid-phase extraction, dansylation, and ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry.

    Science.gov (United States)

    Wang, He-xing; Wang, Bin; Zhou, Ying; Jiang, Qing-wu

    2013-05-01

    Steroid hormone levels in human urine are convenient and sensitive indicators for the impact of phthalates and/or bisphenol A (BPA) exposure on the human steroid hormone endocrine system. In this study, a rapid and sensitive method for determination of 14 phthalate metabolites, BPA, and ten endogenous steroid hormones in urine was developed and validated on the basis of ultra-performance liquid chromatography coupled with electrospray ionization triple quadrupole mass spectrometry. The optimized mixed-mode solid phase-extraction separated the weakly acidic or neutral BPA and steroid hormones from acidic phthalate metabolites in urine: the former were determined in positive ion mode with a methanol/water mobile phase containing 10 mM ammonium formate; the latter were determined in negative ion mode with a acetonitrile/water mobile phase containing 0.1 % acetic acid, which significantly alleviated matrix effects for the analysis of BPA and steroid hormones. Dansylation of estrogens and BPA realized simultaneous and sensitive analysis of the endogenous steroid hormones and BPA in a single chromatographic run. The limits of detection were less than 0.84 ng/mL for phthalate metabolites and less than 0.22 ng/mL for endogenous steroid hormones and BPA. This proposed method had satisfactory precision and accuracy, and was successfully applied to the analyses of human urine samples. This method could be valuable when investigating the associations among endocrine-disrupting chemicals, endogenous steroid hormones, and relevant adverse outcomes in epidemiological studies.

  18. Determination of 21 antibiotics in sea cucumber using accelerated solvent extraction with in-cell clean-up coupled to ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zhu, Minghua; Zhao, Hongxia; Xia, Deming; Du, Juan; Xie, Huaijun; Chen, Jingwen

    2018-08-30

    An accelerated solvent extraction (ASE) with in-cell clean-up method coupled to ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed to determine 21 antibiotics in sea cucumber. The analytes include 10 sulfonamides, 4 fluoroquinolones, 3 amphenicols, 2 beta-lactams, 1 lincosamide and trimethoprim. Optimal parameters of ASE method were obtained at 80 °C, 1 static cycle of 5 min with methanol/acetonitrile (1/1, v/v) using 2 g of C18 as adsorbent. Recoveries at 50.1-129.2% were achieved with RSD under 20%. Method detection limits ranged from 0.03 to 2.9 μg kg -1 . Compared to the reported ultrasound-assisted extraction method, the proposed method offered comparable extraction efficiency for sulfonamides from sea cucumber, but higher for other categories of antibiotics. This validated method was then successfully applied to sea cucumber samples and 9 antibiotics were detected with the highest concentration up to 57.7 μg kg -1 for norfloxacin. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Application of ultraperformance liquid chromatography/mass spectrometry-based metabonomic techniques to analyze the joint toxic action of long-term low-level exposure to a mixture of organophosphate pesticides on rat urine profile.

    Science.gov (United States)

    Du, Longfei; Wang, Hong; Xu, Wei; Zeng, Yan; Hou, Yurong; Zhang, Yuqiu; Zhao, Xiujuan; Sun, Changhao

    2013-07-01

    In previously published articles, we evaluated the toxicity of four organophosphate (OP) pesticides (dichlorvos, dimethoate, acephate, and phorate) to rats using metabonomic technology at their corresponding no observed adverse effect level (NOAEL). Results show that a single pesticide elicits no toxic response. This study aimed to determine whether chronic exposure to a mixture of the above four pesticides (at their corresponding NOAEL) can lead to joint toxic action in rats using the same technology. Pesticides were administered daily to rats through drinking water for 24 weeks. The above mixture of the four pesticides showed joint toxic action at the NOAEL of each pesticide. The metabonomic profiles of rats urine were analyzed by ultraperformance liquid chromatography/mass spectrometry. The 16 metabolites statistically significantly changed in all treated groups compared with the control group. Dimethylphosphate and dimethyldithiophosphate exclusively detected in all treated groups can be used as early, sensitive biomarkers for exposure to a mixture of the OP pesticides. Moreover, exposure to the OP pesticides resulted in increased 7-methylguanine, ribothymidine, cholic acid, 4-pyridoxic acid, kynurenine, and indoxyl sulfate levels, as well as decreased hippuric acid, creatinine, uric acid, gentisic acid, C18-dihydrosphingosine, phytosphingosine, suberic acid, and citric acid. The results indicated that a mixture of OP pesticides induced DNA damage and oxidative stress, disturbed the metabolism of lipids, and interfered with the tricarboxylic acid cycle. Ensuring food safety requires not only the toxicology test data of each pesticide for the calculation of the acceptable daily intake but also the joint toxic action.

  20. Removal of BrO₃⁻ from drinking water samples using newly developed agricultural waste-based activated carbon and its determination by ultra-performance liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Naushad, Mu; Khan, Mohammad R; ALOthman, Zeid A; AlSohaimi, Ibrahim; Rodriguez-Reinoso, Francisco; Turki, Turki M; Ali, Rahmat

    2015-10-01

    Activated carbon was prepared from date pits via chemical activation with H3PO4. The effects of activating agent concentration and activation temperature on the yield and surface area were studied. The optimal activated carbon was prepared at 450 °C using 55 % H3PO4. The prepared activated carbon was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric-differential thermal analysis, and Brunauer, Emmett, and Teller (BET) surface area. The prepared date pit-based activated carbon (DAC) was used for the removal of bromate (BrO3 (-)). The concentration of BrO3 (-) was determined by ultra-performance liquid chromatography-mass tandem spectrometry (UPLC-MS/MS). The experimental equilibrium data for BrO3 (-) adsorption onto DAC was well fitted to the Langmuir isotherm model and showed maximum monolayer adsorption capacity of 25.64 mg g(-1). The adsorption kinetics of BrO3 (-) adsorption was very well represented by the pseudo-first-order equation. The analytical application of DAC for the analysis of real water samples was studied with very promising results.

  1. Chemical Profiling of Re-Du-Ning Injection by Ultra-Performance Liquid Chromatography Coupled with Electrospray Ionization Tandem Quadrupole Time-of-Flight Mass Spectrometry through the Screening of Diagnostic Ions in MSE Mode

    Science.gov (United States)

    Wang, Zhenzhong; Geng, Jianliang; Dai, Yi; Xiao, Wei; Yao, Xinsheng

    2015-01-01

    The broad applications and mechanism explorations of traditional Chinese medicine prescriptions (TCMPs) require a clear understanding of TCMP chemical constituents. In the present study, we describe an efficient and universally applicable analytical approach based on ultra-performance liquid chromatography coupled to electrospray ionization tandem quadrupole time-of-flight mass spectrometry (UPLC-ESI-Q/TOF-MS) with the MSE (E denotes collision energy) data acquisition mode, which allowed the rapid separation and reliable determination of TCMP chemical constituents. By monitoring diagnostic ions in the high energy function of MSE, target peaks of analogous compounds in TCMPs could be rapidly screened and identified. “Re-Du-Ning” injection (RDN), a eutherapeutic traditional Chinese medicine injection (TCMI) that has been widely used to reduce fever caused by viral infections in clinical practice, was studied as an example. In total, 90 compounds, including five new iridoids and one new sesquiterpene, were identified or tentatively characterized by accurate mass measurements within 5 ppm error. This analysis was accompanied by MS fragmentation and reference standard comparison analyses. Furthermore, the herbal sources of these compounds were unambiguously confirmed by comparing the extracted ion chromatograms (EICs) of RDN and ingredient herbal extracts. Our work provides a certain foundation for further studies of RDN. Moreover, the analytical approach developed herein has proven to be generally applicable for profiling the chemical constituents in TCMPs and other complicated mixtures. PMID:25875968

  2. Metabolites identification of harmane in vitro/in vivo in rats by ultra-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Li, Shuping; Liu, Wei; Teng, Liang; Cheng, Xuemei; Wang, Zhengtao; Wang, Changhong

    2014-04-01

    Harmane, a β-carboline alkaloid with a wide spectrum of pharmacological activities, is naturally present in the human diet, in numerous foodstuffs and in hallucinogenic plants such as Peganum harmala, Banisteriopsis caapi and Tribulus terrestris. However, the precise metabolic fate of harmane remains unknown. In order to know whether harmane is extensively metabolized, a rapid and sensitive method using ultra-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC/ESI-QTOF-MS) was used to analyze the metabolic profile of harmane in vitro and in vivo in rats. A total of 21 metabolites were identified from the rat liver microsomes and rat liver S9 (9), rat urine (11), feces (16), bile (16), and plasma (10) after a single oral administration of harmane using MetaboLynx™ and MassFragment ™ software tools. It indicated that the biliary and faecal clearance were the major excretion routes for harmane as well as its metabolites. The specific CLogP values combined with different acidic and alkaline mobile phase were helpful and useful for distinguishing N-oxidation and monohydroxylation metabolites. The metabolic transformation pathways of harmane included monohydroxylation, dihydroxylation, N-oxidation, O-glucuronide conjugation, O-sulphate conjugation, and glutathione conjugation. In conclusion, this study showed an insight into the metabolism of harmane. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Analysis of Therapeutic Effect of Ilex hainanensis Merr. Extract on Nonalcoholic Fatty Liver Disease through Urine Metabolite Profiling by Ultraperformance Liquid Chromatography/Quadrupole Time of Flight Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Jing-jing Li

    2013-01-01

    Full Text Available Nonalcoholic fatty liver disease (NAFLD, the most common form of chronic liver disease, is increased worldwide in parallel with the obesity epidemic. Our previous studies have showed that the extract of I. hainanensis (EIH can prevent NAFLD in rat fed with high-fat diet. In this work, we aimed to find biomarkers of NAFLD and investigate the therapeutic effects of EIH. NAFLD model was induced in male Sprague-Dawley rats by high-fat diet. The NAFLD rats were administered EIH orally (250 mg/kg for two weeks. After the experimental period, samples of 24 h urine were collected and analyzed by ultraperformance liquid chromatography/quadrupole time of flight mass spectrometry (UPLC-Q-TOF. Orthogonal partial least squares analysis (OPLSs models were built to find biomarkers of NAFLD and investigate the therapeutic effects of EIH. 22 metabolites, which are distributed in several metabolic pathways, were identified as potential biomarkers of NAFLD. Taking these biomarkers as screening indexes, EIH could reverse the pathological process of NAFLD through regulating the disturbed pathway of metabolism. The metabolomic results not only supply a systematic view of the development and progression of NAFLD but also provide a theoretical basis for the prevention or treatment of NAFLD.

  4. Research of nitroxynil residues in bovine milk following a single administration in the dry period by ultra-performance liquid chromatography tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Claudia Chirollo

    2013-10-01

    Full Text Available Nitroxynil (NIT is a halogenated phenol used to control fascioliasis in cattle and sheep. The Commission Regulation EU No 37/2010 has established maximum residue limits for NIT in bovine and ovine muscle (400 μg kg−1, fat (200 μg kg−1, liver (20 μg kg−1 and kidney (400 μg kg−1, and more recently in bovine and ovine milk (20 μg kg−1. Thirty-five pregnant dairy cows were treated in this study with nitroxynil (340 mg/mL solution for injection at the recommended dose of 10 mg/kg body weight at the start of the dry period, i.e. 53 to 74 days before the expected calving. Calving occurred between 43 days and 79 days after treatment. The concentrations of NIT in the milk were monitored for up to 120 days after calving. NIT residues were extracted using acetonitrile; magnesium sulfate and sodium chloride were added to induce liquid-liquid partitioning and purified by dispersive solid phase extraction for clean-up. NIT was detected by ultra high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS in negative ionization mode. The highest concentrations of this drug were found in two animals at the first milking, 48 and 53 day post treatment with levels of 362 and 657 μg kg–1, respectively. NIT residues were below the limit of detection of the method (0.24 μg/kg–1 between 67 and 106 day post-treatment. Following calving, residues rapidly depleted in animals and were non-detectable from 10 to 38 days post-calving. In particular, in all animals milk resulted compliant (<20 μg/kg−1 three days post partum.

  5. Determination of moxifloxacin and its oxidation products with kinetic evaluation under potassium permanganate treatment in acidic solution by ultra-performance liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Hubicka, Urszula; Zmudzki, Paweł; Zajdel, Paweł; Krzek, Jan

    2013-01-01

    A simple, sensitive, and reproducible ultra-performance LC method for the determination of moxifloxacin (MOXI) oxidation stability under permanganate treatment in acidic conditions (pH 3.0-6.0) was developed. Besides the MOXI peak [retention time (RT) = 2.58], four additional products (RT = 0.86, 0.91, 1.42, and 1.89) were observed in all conditions tested. The oxidation process followed second-order reaction kinetics and depended upon solution acidity. The highest reaction rate constant was observed at pH 3.0, and this value decreased as the pH was increased to 6.0. The oxidation products were characterized, and their fragmentation pathways, derived from MS/MS data, were proposed. Two of these products were identified as hydroxyl derivatives of MOXI and two others as their oxidation product analogs with molecular ions of 418.4 and 416.4 m/z, respectively.

  6. Rapid, Sensitive and Validated Ultra-Performance Liquid Chromatography/Mass Spectrometric Method for the Determination of Fenofibric Acid and its Application to Human Pharmacokinetic Study

    Directory of Open Access Journals (Sweden)

    Sunil K. Dubey

    2010-01-01

    Full Text Available The first, rapid and sensitive ultra performance liquid chromatography mass spectrometric method for the determination of fenofibric acid, the active metabolite of fenofibrate, a lipid regulating agent, in human EDTA plasma has been developed and validated using fenofibric d6 acid as internal standard and Waters LC-MS/MS. Negative ions of fenofibric acid and fenofibric d6 acid were detected in multiple reaction-monitoring (MRM mode. The method was validated over a concentration range of 0.176 μg/mL to 19.837 μg/mL (r ≥ 0.99. It took only 1.5 minute to analyse a sample. Intra- and inter-run precision of fenofibric acid assay at four concentrations ranged from 0.5% to 4.3% with accuracy varied from 93.1 to 108.1% indicating good precision and accuracy. Analytical recoveries of fenofibric acid and internal standard in plasma were less than 90%. This method was successfully applied for evaluation of pharmacokinetics of fenofibric acid after a single oral dose of 145 mg fenofibrate to 10 Indian healthy volunteers

  7. 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.

  8. Profiling ABA metabolites in Nicotiana tabacum L. leaves by ultra-performance liquid chromatography–electrospray tandem mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Turečková, Veronika; Novák, Ondřej; Strnad, Miroslav

    2009-01-01

    Roč. 80, č. 1 (2009), s. 390-399 ISSN 0039-9140 R&D Projects: GA AV ČR KAN200380801 Institutional research plan: CEZ:AV0Z50380511 Keywords : Abscisic acid * Ultra-performance liquid chromatography (UPLC) * Tandem mass spectrometry (MS/MS) Subject RIV: EC - Immunology Impact factor: 3.290, year: 2009

  9. A rapid quantitative analysis of bile acids, lysophosphatidylcholines and polyunsaturated fatty acids in biofluids based on ultraperformance liquid chromatography coupled with triple quadrupole tandem massspectrometry.

    Science.gov (United States)

    Peng, Zhangxiao; Zhang, Qian; Mao, Ziming; Wang, Jie; Liu, Chunying; Lin, Xuejing; Li, Xin; Ji, Weidan; Fan, Jianhui; Wang, Maorong; Su, Changqing

    2017-11-15

    Much evidence suggested that quantitative analysis of bile acids (BAs), lysophosphatidylcholines (LPCs), and polyunsaturated fatty acids (PUFAs) in biofluids may be very useful for diagnosis and prevention of hepatobiliary disease with a non-invasive manner. However, simultaneously fast analysis of these metabolites has been challenging for their huge differences of physicochemical properties and concentration levels in biofluids. In this study, we present a liquid chromatography-mass spectrometry method with a high throughput analytical cycle (10min) to fast and accurately quantify fifteen potential biomarkers (eight BAs, four LPCs and three PUFAs) of hepatobiliary disease. The accuracy for the fifteen analytes in plasma and urine matrices was 80.45%-118.99% and 84.55%-112.66%, respectively. The intra- and inter- precisions for the fifteen analytes in plasma and urine matrices were all less than 20% and the lower limit of quantification (LLOQ) of analytes is up to 0.0283-8.2172nmol/L. Therefore, this method is fast, sensitive and accurate for the quantitative analysis of BAs, LPCs and PUFAs in biofluids. Moreover, the stability and concentration differences of the analytes in plasma and serum were evaluated, and the results demonstrated that LPCs is stable, but PUFAs is very unstable in freeze and thaw cycles, and the concentrations of the analytes in serum were slightly higher than those in plasma. We suggested plasma may be a kind of better bio-sample than serum using for quantitative analysis of metabolites in blood, due to the characteristics of plasma are more close to blood than those of serum. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Protein-bound tyrosine oxidation, nitration and chlorination by-products assessed by ultraperformance liquid chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Torres-Cuevas, Isabel; Kuligowski, Julia; Cárcel, María; Cháfer-Pericás, Consuelo; Asensi, Miguel; Solberg, Rønnaug; Cubells, Elena; Nuñez, Antonio; Saugstad, Ola Didrik; Vento, Máximo; Escobar, Javier

    2016-03-24

    Free radicals cause alterations in cellular protein structure and function. Oxidized, nitrated, and chlorinated modifications of aromatic amino acids including phenylalanine and tyrosine are reliable biomarkers of oxidative stress and inflammation in clinical conditions. To develop, validate and apply a rapid method for the quantification of known hallmarks of tyrosine oxidation, nitration and chlorination in plasma and tissue proteins providing a snapshot of the oxidative stress and inflammatory status of the organism and of target organs respectively. The extraction and clean up procedure entailed protein precipitation, followed by protein re-suspension and enzymatic digestion with pronase. An Ultra Performance Liquid Chromatography-tandem Mass Spectrometry (UPLC-MS/MS) method was developed to quantify protein released ortho-tyrosine (o-Tyr), meta-tyrosine (m-Tyr), 3-nitrotyrosine (3NO2-Tyr) and 3-chlorotyrosine (3Cl-Tyr) as well as native phenylalanine (Phe) and tyrosine (p-Tyr) in plasma and tissue from a validated hypoxic newborn piglet experimental model. In plasma there was a significant increase in the 3NO2-Tyr/p-Tyr ratio. On the other hand m-Tyr/Phe and 3Cl-Tyr/p-Tyr ratios were significantly increased in liver of hypoxic compared with normoxic animals. Although no significant differences were found in brain tissue, a clear tendency to increased ratios was observed under hypoxic conditions. UPLC-MS/MS has proven suitable for the analysis of plasma and tissue samples from newborn piglets. The analysis of biomarkers of protein oxidation, nitration and chlorination will be applied in future studies aiming to provide a deeper insight into the mechanisms of oxidation-derived protein modification caused during neonatal asphyxia and resuscitation. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Determination of quaternary ammonium compounds in oranges and cucumbers using QuEChERS extraction and ultra-performance liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Arrebola-Liébanas, Francisco Javier; Abdo, María Angeles Herrera; Moreno, José Luis Fernandez; Martínez-Vidal, José L; Frenich, Antonia Garrido

    2014-01-01

    A simple and fast method has been developed for determining relevant quaternary ammonium compounds in cucumber and orange samples. The target compounds were benzoalkonium chloride (BAC-10, BAC-12, BAC-14, and BAC-16), didecyldimethylammonium chloride, and benzethonium chloride, all frequently used biocides in the agrifood industry. An extraction based on the buffered Quick, Easy, Cheap, Effective, Rugged, and Safe method and determination by ultra-performance LC/MS/MS that eluted the biocides in less than 5 min were used. The method was fully validated and implemented in a UNE-EN-ISO/IEC 17025 accredited laboratory for its application to the analysis of real samples. Performance characteristics of the method are reported, including an estimation of measurement uncertainty. Calibration curves were set between 0.01 and 0.150 mg/kg, LOD values were always between 0.4 and 1.0 microg/kg, LOQ values were in the range 1-4 microg/kg, recovery was between 81 and 115%, intraday and interday precision were always lower than 17% (expressed as RSD), and expanded uncertainty was always lower than 40%. The validation was accomplished for the two studied matrixes at spiking concentrations of 0.011 and 0.050 mg/kg. The method has been applied to the analysis of 30 cucumber and orange samples that were found to contain concentrations of BAC-12 that ranged between 0.015 and 0.210 mg/kg and of BAC-14 between 0.018 and 0.081 mg/kg.

  12. 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.

  13. Validation of an automated solid-phase extraction method for the analysis of 23 opioids, cocaine, and metabolites in urine with ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Ramírez Fernández, María del Mar; Van Durme, Filip; Wille, Sarah M R; di Fazio, Vincent; Kummer, Natalie; Samyn, Nele

    2014-06-01

    The aim of this work was to automate a sample preparation procedure extracting morphine, hydromorphone, oxymorphone, norcodeine, codeine, dihydrocodeine, oxycodone, 6-monoacetyl-morphine, hydrocodone, ethylmorphine, benzoylecgonine, cocaine, cocaethylene, tramadol, meperidine, pentazocine, fentanyl, norfentanyl, buprenorphine, norbuprenorphine, propoxyphene, methadone and 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine from urine samples. Samples were extracted by solid-phase extraction (SPE) with cation exchange cartridges using a TECAN Freedom Evo 100 base robotic system, including a hydrolysis step previous extraction when required. Block modules were carefully selected in order to use the same consumable material as in manual procedures to reduce cost and/or manual sample transfers. Moreover, the present configuration included pressure monitoring pipetting increasing pipetting accuracy and detecting sampling errors. The compounds were then separated in a chromatographic run of 9 min using a BEH Phenyl analytical column on a ultra-performance liquid chromatography-tandem mass spectrometry system. Optimization of the SPE was performed with different wash conditions and elution solvents. Intra- and inter-day relative standard deviations (RSDs) were within ±15% and bias was within ±15% for most of the compounds. Recovery was >69% (RSD automated SPE system was observed. The extracted samples were stable for 72 h in the autosampler (4°C). This method was applied to authentic samples (from forensic and toxicology cases) and to proficiency testing schemes containing cocaine, heroin, buprenorphine and methadone, offering fast and reliable results. Automation resulted in improved precision and accuracy, and a minimum operator intervention, leading to safer sample handling and less time-consuming procedures.

  14. Metabolites profile of Gualou Xiebai Baijiu decoction (a classical traditional Chinese medicine prescription) in rats by ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Lin, Pei; Qin, Zifei; Yao, Zhihong; Wang, Li; Zhang, Weiyang; Yu, Yang; Dai, Yi; Zhou, Hua; Yao, Xinsheng

    2018-05-15

    Gualou Xiebai Baijiu decoction (GLXB), a well-known classic traditional Chinese medicine prescription, has been widely used to treat coronary heart diseases for thousands of years in Eastern Asian countries due to its remarkable clinical effect. However, due to lack of in vivo metabolism research, the chemical components responsible for the therapeutic effects still remain unclear. In this work, a reliable "representative structure based homologous xenobiotics identification" (RSBHXI) strategy based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS) were applied to investigate the chemical components in GLXB extracts. As a result, 133 chemical components were characterized based on summarized fragmentation patterns, of which 41 components were confirmed unambiguously with authentic standards. Furthermore, a total of 138 GLXB-related xenobiotics were identified or tentatively characterized after oral administration of GLXB extracts. Moreover, to better understand the metabolic pathways of characteristic components in GLXB, metabolites profiles of five steroidal saponins and two flavonoids were performed, respectively. Since the metabolic pathways of five representative saponins had been finished in our previous study, we focused on the in vivo metabolism of two flavonoids. A total of 36 and 20 metabolites were detected in rat biological samples after oral administration of luteolin-7-O-β-D-glucopyranoside and rutin, respectively. The results indicated that dehydration, hydrolysis, hydroxylation, methylation, glucuronidation and sulfation were the main metabolic reactions, following the metabolic soft spots of GLXB-related flavonoids. Taken altogether, this study would be helpful for the further pharmacokinetics, pharmacological evaluation and quality control of GLXB. Copyright © 2018. Published by Elsevier B.V.

  15. Biotransformation and metabolic profile of Xian-Ling-Gu-Bao capsule, a traditional Chinese medicine prescription, with rat intestinal microflora by ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry analysis.

    Science.gov (United States)

    Gao, Meng-Xue; Tang, Xi-Yang; Zhang, Feng-Xiang; Yao, Zhi-Hong; Yao, Xin-Sheng; Dai, Yi

    2018-04-01

    Xian-Ling-Gu-Bao capsule (XLGB), a well-known traditional Chinese medicine prescription, has been used for the prevention and treatment of osteoporosis. The safety and efficacy of XLGB have been confirmed based on the principle of evidence-based medicine. XLGB is usually administered orally, after which its multiple components are brought into contact with intestinal microflora in the alimentary tract and biotransformed. However, investigations on the comprehensive metabolic profile of XLGB are absent. In this study, 12 representative compounds bearing different typical structures (including iridoid glycosides, prenylated flavonol glycosides, prenylated flavonoids, triterpenoid saponins, steroidal saponins, coumarins and monoterpene phenols) were selected and then investigated for their biotransformation in rat intestinal microflora. In addition, the metabolic profile of XLGB in rat intestinal microflora was investigated by ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry. As a result, a total of 87 biotransformation components were identified from incubated solutions of 12 representative compounds and XLGB, which underwent 16 metabolic reactions (including deglycosylation, glycosylation, dehydrogenation, hydrogenation, oxidation, epoxidation, hydroxylation, dehydration, hydration, hydrolysis, methylation, isomerization, cyclization, pyrolysis reaction, amino acid conjugation and nucleophilic addition reaction with NH 3 ). This demonstrated that the deglycosylation reaction by cleavage of the sugar moieties is the main metabolic pathway of a variety of glycosides, including prenylated flavonol glycosides, coumarin glycosides, iridoid glycosides and saponins. In addition, compared with the biotransformation of 12 representative compounds, a different biotransformed fate was observed in the XLGB incubated samples of rat intestinal microflora. It is worth noting that the amino acid conjugation was first discovered

  16. Metabonomics study of the therapeutic mechanism of fenugreek galactomannan on diabetic hyperglycemia in rats, by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Jiang, Wenyue; Gao, Lu; Li, Pengdong; Kan, Hong; Qu, Jiale; Men, Lihui; Liu, Zhiqiang; Liu, Zhongying

    2017-02-15

    Fenugreek is a traditional plant for the treatment of diabetes. Galactomannan, an active major component in fenugreek seeds, has shown hypoglycemic activity. The present study was performed to investigate the therapeutic mechanism underlying fenugreek galactomannan (F-GAL) in treating diabetes, using a metabonomics approach based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS). The F-GAL used for study was highly purified, and its yield, purity, and galactose/mannose ratio were characterized by capillary zone electrophoresis (CZE) and a modified phenol-sulfuric acid method. After treatment of streptozotocin (STZ)-induced diabetic rats with F-GAL for 28days, urine and serum samples were analyzed by UPLC-QTOF/MS. Multivariate statistical approaches such as principal component analysis (PCA) and orthogonal projection to latent structures squares-discriminant analysis (OPLS-DA) were applied to distinguish the non-diabetic/untreated, diabetic/untreated, and diabetic/F-GAL-treated groups. Then, potential biomarkers were identified that may help elucidate the underlying therapeutic mechanism of F-GAL in diabetes. The results demonstrated that there was a clear separation among the three groups in the PCA model. Fourteen potential biomarkers were identified by OPLS-DA, and they were determined to be produced in response to the therapeutic effects of F-GAL. These biomarkers were involved in histidine metabolism, tryptophan metabolism, energy metabolism, phenylalanine metabolism, sphingolipid metabolism, glycerophospholipid metabolism, and arachidonic acid metabolism. In conclusion, our study demonstrates that a metabonomics approach is a powerful, novel tool that can be used to evaluate the underlying therapeutic mechanisms of herb extracts. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Residue analysis of four diacylhydrazine insecticides in fruits and vegetables by Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method using ultra-performance liquid chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Liu, Xingang; Xu, Jun; Dong, Fengshou; Li, Yuanbo; Song, Wenchen; Zheng, Yongquan

    2011-08-01

    The new analytical method using Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) procedure for simultaneous determination of diacylhydrazine insecticide residues in fruits and vegetables was developed using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The four insecticides (tebufenozide, methoxfenozide, chromafenozide, and halofenozide) were extracted from six fruit and vegetable matrices using acetonitrile and subsequently cleaned up using primary secondary amine (PSA) or octadecylsilane (C18) as sorbent prior to UPLC-MS/MS analysis. The determination of the target compounds was achieved in less than 3.0 min using an electrospray ionization source in positive mode (ESI+) for tebufenozide, methoxfenozide, and halofenozide and in negative mode (ESI-) for chromafenozide. The limits of detection were below 0.6 μg kg(-1), while the limit of quantification did not exceed 2 μg kg(-1) in different matrices. The QuEChERS procedure by using two sorbents (PSA and C18) and the matrix-matched standards gave satisfactory recoveries and relative standard deviation (RSD) values in different matrices at four spiked levels (0.01, 0.05, 0.1, and 1 mg kg(-1)). The overall average recoveries for this method in apple, grape, cucumber, tomato, cabbage, and spinach at four levels ranged from 74.2% to 112.5% with RSDs in the range of 1.4-13.8% (n = 5) for all analytes. This study provides a theoretical basis for China to draw up maximum residue limits and analytical method for diacylhydrazine insecticide in vegetables and fruits.

  18. Quantitation of amyloid beta peptides Aβ(1-38), Aβ(1-40), and Aβ(1-42) in human cerebrospinal fluid by ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Lame, Mary E; Chambers, Erin E; Blatnik, Matthew

    2011-12-15

    Critical events in Alzheimer's disease (AD) involve an imbalance between the production and clearance of amyloid beta (Aβ) peptides from the brain. Current methods for Aβ quantitation rely heavily on immuno-based techniques. However, these assays require highly specific antibodies and reagents that are time-consuming and expensive to develop. Immuno-based assays are also characterized by poor dynamic ranges, cross-reactivity, matrix interferences, and dilution linearity problems. In particular, noncommercial immunoassays are especially subject to high intra- and interassay variability because they are not subject to more stringent manufacturing controls. Combinations of these factors make immunoassays more labor-intensive and often challenging to validate in support of clinical studies. Here we describe a mixed-mode solid-phase extraction method and an ultra-performance liquid chromatography tandem mass spectrometry (SPE UPLC-MS/MS) assay for the simultaneous quantitation of Aβ(1-38), Aβ(1-40), and Aβ(1-42) from human cerebrospinal fluid (CSF). Negative ion versus positive ion species were compared using their corresponding multiple reaction monitoring (MRM) transitions, and negative ions were approximately 1.6-fold greater in intensity but lacked selectivity in matrix. The positive ion MRM assay was more than sufficient to quantify endogenous Aβ peptides. Aβ standards were prepared in artificial CSF containing 5% rat plasma, and quality control samples were prepared in three pooled CSF sources. Extraction efficiency was greater than 80% for all three peptides, and the coefficient of variation during analysis was less than 15% for all species. Mean basal levels of Aβ species from three CSF pools were 1.64, 2.17, and 1.26 ng/ml for Aβ(1-38); 3.24, 3.63, and 2.55 ng/ml for Aβ(1-40); and 0.50, 0.63, and 0.46 ng/ml for Aβ(1-42). Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Validated ultra-performance liquid chromatography-tandem mass spectrometry method for analyzing LSD, iso-LSD, nor-LSD, and O-H-LSD in blood and urine.

    Science.gov (United States)

    Chung, Angela; Hudson, John; McKay, Gordon

    2009-06-01

    The Royal Canadian Mounted Police Forensic Science and Identification Services was looking for a confirmatory method for lysergic acid diethylamide (LSD). As a result, an ultra-performance liquid chromatography-tandem mass spectrometry method was validated for the confirmation and quantitation of LSD, iso-LSD, N-demethyl-LSD (nor-LSD), and 2-oxo-3-hydroxy-LSD (O-H-LSD). Relative retention time and ion ratios were used as identification parameters. Limits of detection (LOD) in blood were 5 pg/mL for LSD and iso-LSD and 10 pg/mL for nor-LSD and O-H-LSD. In urine, the LOD was 10 pg/mL for all analytes. Limits of quantitation (LOQ) in blood and urine were 20 pg/mL for LSD and iso-LSD and 50 pg/mL for nor-LSD and O-H-LSD. The method was linear, accurate, and precise from 10 to 2000 pg/mL in blood and 20 to 2000 pg/mL in urine for LSD and iso-LSD and from 20 to 2000 pg/mL in blood and 50 to 2000 pg/mL in urine for nor-LSD and O-H-LSD with a coefficient of determination (R(2)) > or = 0.99. The method was applied to blinded biological control samples and biological samples taken from a suspected LSD user. This is the first reported detection of O-H-LSD in blood from a suspected LSD user.

  20. Extraction Methodological Contributions Toward Ultra-Performance Liquid ChromatographyTime-of-Flight Mass Spectrometry: Quantification of Free GB from Various Food Matrices

    Science.gov (United States)

    2016-02-01

    J.R.; Stubbs, S.J.; Read, R.W.; Evans, R.A.; Thomas , J.D.; Blake, T.A.; Johnson, R.C. Simultaneous Measurement of Tabun, Sarin, Soman, Cyclosarin, VR...Pesticide Residues in Food? J. Chromatogr. A 2000, 868, 51–61. 19. Schenck, F.J.; Podhorniak, L.V.; Hobbs , J.; Casanova, J.; Donoghue, D. Liquid

  1. Biomarker discovery in biological specimens (plasma, hair, liver and kidney) of diabetic mice based upon metabolite profiling using ultra-performance liquid chromatography with electrospray ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Tsutsui, Haruhito; Maeda, Toshio; Min, Jun Zhe; Inagaki, Shinsuke; Higashi, Tatsuya; Kagawa, Yoshiyuki; Toyo'oka, Toshimasa

    2011-05-12

    The number of diabetic patients has recently been increasing worldwide. Diabetes is a multifactorial disorder based on environmental factors and genetic background. In many cases, diabetes is asymptomatic for a long period and the patient is not aware of the disease. Therefore, the potential biomarker(s), leading to the early detection and/or prevention of diabetes mellitus, are strongly required. However, the diagnosis of the prediabetic state in humans is a very difficult issue, because the lifestyle is variable in each person. Although the development of a diagnosis method in humans is the goal of our research, the extraction and structural identification of biomarker candidates in several biological specimens (i.e., plasma, hair, liver and kidney) of ddY strain mice, which undergo naturally occurring diabetes along with aging, were carried out based upon a metabolite profiling study. The low-molecular-mass compounds including metabolites in the biological specimens of diabetic mice (ddY-H) and normal mice (ddY-L) were globally separated by ultra-performance liquid chromatography (UPLC) using different reversed-phase columns (i.e., T3-C18 and HS-F5) and detected by electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS). The biomarker candidates related to diabetes mellitus were extracted from a multivariate statistical analysis, such as an orthogonal partial least-squares-discriminant analysis (OPLS-DA), followed by a database search, such as ChemSpider, KEGG and HMDB. Many metabolites and unknown compounds in each biological specimen were detected as the biomarker candidates related to diabetic mellitus. Among them, the elucidation of the chemical structures of several possible metabolites, including more than two biological specimens, was carried out along with the comparison of the tandem MS/MS analyses using authentic compounds. One metabolite was clearly identified as N-acetyl-L-leucine based upon the MS/MS spectra and the retention time on

  2. Inhibitory profiles of spices against free and protein-bound heterocyclic amines of roast beef patties as revealed by ultra-performance liquid chromatography-tandem mass spectrometry and principal component analysis.

    Science.gov (United States)

    Chen, Jing; He, Zhiyong; Qin, Fang; Chen, Jie; Cao, Dongsheng; Guo, Fengxian; Zeng, Maomao

    2017-11-15

    The effects of various levels of chili pepper, Sichuan pepper, and black pepper on the amounts of 17 heterocyclic amines (HAs) from seven categories of both free and protein-bound states in roast beef patties were assessed by ultra-performance liquid chromatography-tandem mass spectrometry combined with principal component analysis. Three groups of HA, including imidazopyridines (DMIP), imidazoquinoxalines (MeIQx and 4,8-MeIQx), and β-carbolines (norharman and harman), were detected and quantified in both their free and protein-bound states, whereas PhIP was detected only in its free state, and imidazoquinolines (IQ, IQ[4,5-b], and MeIQ), α-carbolines (AαC and MeAαC), and phenylpyridines (Phe-P-1) were detected only in their protein-bound states. The results demonstrate that the peppers at all three levels had significant inhibitory effects on free PhIP, DMIP, MeIQx, and 4,8-DiMeIQx and could promote free norharman. Harman was significantly suppressed by chili pepper and black pepper, but enhanced by Sichuan pepper. All 11 protein-bound HAs, with the exception of IQ, IQ[4,5-b], and MeIQx with added chili pepper, were significantly reduced by the three peppers. The total amounts of the free and protein-bound states of all 11 HAs (1692.4 ± 78.9 ng g -1 ), imidazopyridines (5.5 ± 0.2 ng g -1 ), imidazoquinolines (7.2 ± 0.2 ng g -1 ), imidazoquinoxalines (6.9 ± 0.2 ng g -1 ), α-carbolines (20.1 ± 0.4 ng g -1 ), and β-carbolines (1651.7 ± 79.5 ng g -1 ) were suppressed by each level of all of the three peppers except for 0.5% and 1.0% chili pepper. Our findings may facilitate the inhibition of HA formation in the processing of meat products.

  3. Ultra-performance liquid chromatography tandem mass-spectrometry (uplc-ms/ms) for the rapid, simultaneous analysis of thiamin, riboflavin, flavin adenine dinucleotide, nicotinamide and pyridoxal in human milk

    Science.gov (United States)

    A novel, rapid and sensitive Ultra Performance Liquid-Chromatography tandem Mass-Spectrometry (UPLC-MS/MS) method for the simultaneous determination of several B-vitamins in human milk was developed. Resolution by retention time or multiple reaction monitoring (MRM) for thiamin, riboflavin, flavin a...

  4. Liquid Chromatography in 1982.

    Science.gov (United States)

    Freeman, David H.

    1982-01-01

    Reviews trends in liquid chromatography including apparatus, factors affecting efficient separation of a mixture (peak sharpness and speed), simplified problem-solving, adsorption, bonded phase chromatography, ion selectivity, and size exclusion. The current trend is to control chemical selectivity by the liquid phase. (Author/JN)

  5. Column Liquid Chromatography.

    Science.gov (United States)

    Majors, Ronald E.; And Others

    1984-01-01

    Reviews literature covering developments of column liquid chromatography during 1982-83. Areas considered include: books and reviews; general theory; columns; instrumentation; detectors; automation and data handling; multidimensional chromatographic and column switching techniques; liquid-solid chromatography; normal bonded-phase, reversed-phase,…

  6. Quantification of 31 illicit and medicinal drugs and metabolites in whole blood by fully automated solid-phase extraction and ultra-performance liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Bjørk, Marie Kjærgaard; Simonsen, Kirsten Wiese; Andersen, David Wederkinck

    2013-01-01

    , and benzodiazepines, was used. In order to increase the efficiency of routine analysis, a robotic system based on automated liquid handling and capable of handling all unit operation for sample preparation was built on a Freedom Evo 200 platform with several add-ons from Tecan and third-party vendors. Solid-phase...... extraction was performed using Strata X-C plates. Extraction time for 96 samples was less than 3 h. Chromatography was performed using an ACQUITY UPLC system (Waters Corporation, Milford, USA). Analytes were separated on a 100 mm × 2.1 mm, 1.7 μm Acquity UPLC CSH C18 column using a 6.5 min 0.1 % ammonia (25...

  7. Identification and quantification of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide (THC-COOH-glu) in hair by ultra-performance liquid chromatography tandem mass spectrometry as a potential hair biomarker of cannabis use.

    Science.gov (United States)

    Pichini, Simona; Marchei, Emilia; Martello, Simona; Gottardi, Massimo; Pellegrini, Manuela; Svaizer, Fiorenza; Lotti, Andrea; Chiarotti, Marcello; Pacifici, Roberta

    2015-04-01

    We developed and validated an ultra-high-pressure liquid chromatography-tandem mass spectrometry method to identify and quantify 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide in hair of cannabis consumers. After hair washing with methyl alcohol and diethyl ether and subsequent addition of amiodarone as internal standard hair samples were treated with 500 μl VMA-T M3 buffer reagent for 1 h at 100 °C. After cooling, 10 μl VMA-T M3 extract were injected into chromatographic system. Chromatographic separation was carried out on a reversed phase column using a linear gradient elution with two solvents: 5 mM ammonium formate pH 3.0 (solvent A) and 0.1% formic acid in acetonitrile (solvent B). The flow rate was kept constant at 0.4 ml/min during the analysis. The separated analytes were detected with a triple quadrupole mass spectrometer operated in multiple reaction monitoring mode via positive electrospray ionization. Linear calibration curves were obtained for 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide with correlation coefficients (r(2)) of 0.99 and a limit of quantification of 0.25 pg/mg hair. Analytical recovery was between 79.6% and 100.7% and intra- and inter-assay imprecision and inaccuracy were always lower than 15%. Ultra-high-pressure liquid chromatography-tandem mass spectrometry analysis of 20 different hair samples of cannabis consumers disclosed the presence of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide in the range of 0.5-8.6 pg/mg hair. These data provided a good start to consider 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide as alternative hair biomarker of cannabis consumption. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  8. Quantification of 31 illicit and medicinal drugs and metabolites in whole blood by fully automated solid-phase extraction and ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Bjørk, Marie Kjærgaard; Simonsen, Kirsten Wiese; Andersen, David Wederkinck; Dalsgaard, Petur Weihe; Sigurðardóttir, Stella Rögn; Linnet, Kristian; Rasmussen, Brian Schou

    2013-03-01

    An efficient method for analyzing illegal and medicinal drugs in whole blood using fully automated sample preparation and short ultra-high-performance liquid chromatography-tandem mass spectrometry (MS/MS) run time is presented. A selection of 31 drugs, including amphetamines, cocaine, opioids, and benzodiazepines, was used. In order to increase the efficiency of routine analysis, a robotic system based on automated liquid handling and capable of handling all unit operation for sample preparation was built on a Freedom Evo 200 platform with several add-ons from Tecan and third-party vendors. Solid-phase extraction was performed using Strata X-C plates. Extraction time for 96 samples was less than 3 h. Chromatography was performed using an ACQUITY UPLC system (Waters Corporation, Milford, USA). Analytes were separated on a 100 mm × 2.1 mm, 1.7 μm Acquity UPLC CSH C(18) column using a 6.5 min 0.1 % ammonia (25 %) in water/0.1 % ammonia (25 %) in methanol gradient and quantified by MS/MS (Waters Quattro Premier XE) in multiple-reaction monitoring mode. Full validation, including linearity, precision and trueness, matrix effect, ion suppression/enhancement of co-eluting analytes, recovery, and specificity, was performed. The method was employed successfully in the laboratory and used for routine analysis of forensic material. In combination with tetrahydrocannabinol analysis, the method covered 96 % of cases involving driving under the influence of drugs. The manual labor involved in preparing blood samples, solvents, etc., was reduced to a half an hour per batch. The automated sample preparation setup also minimized human exposure to hazardous materials, provided highly improved ergonomics, and eliminated manual pipetting.

  9. Ultra-performance liquid chromatographic determination of tocopherols and retinol in human plasma.

    Science.gov (United States)

    Bell, Edward C; John, Mathew; Hughes, Rodney J; Pham, Thu

    2014-10-01

    A rapid, selective and sensitive ultra-performance liquid chromatography method has been developed for the detection and quantification of tocopherols and retinol in human plasma. Alpha-tocopherol, gamma-tocopherol and retinol are assayed using fluorescence detection. Excitation/emission wavelengths are 295/330 nm and 325/470 nm for the analysis of both tocopherols and retinol, respectively. Retinol acetate is employed as the internal standard. The reversed-phase method incorporates gradient elution with a mobile phase consisting of methanol and acetonitrile. Separation of vitamin compounds is achieved using a bridged ethyl hybrid C18 column. The retention times for retinol, retinol acetate, gamma-tocopherol and alpha-tocopherol are 1.6, 1.8, 3.9 and 4.3 min, respectively. The limits of quantification for retinol, gamma-tocopherol and alpha-tocopherol were 0.02, 0.02 and 0.1 µg/mL, respectively. The assay method is suitable for the analysis of tocopherols and retinol in human plasma. The method may be applied following the ingestion of foods fortified with these fat-soluble vitamins. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Improved ultra-performance liquid chromatography with electrospray ionization quadrupole-time-of-flight high-definition mass spectrometry method for the rapid analysis of the chemical constituents of a typical medical formula: Liuwei Dihuang Wan.

    Science.gov (United States)

    Wang, Ping; Lv, Hai tao; Zhang, Ai hua; Sun, Hui; Yan, Guang li; Han, Ying; Wu, Xiu hong; Wang, Xi jun

    2013-11-01

    Liuwei Dihuang Wan (LDW), a classic Chinese medicinal formula, has been used to improve or restore declined functions related to aging and geriatric diseases, such as impaired mobility, vision, hearing, cognition, and memory. It has attracted increasing attention as one of the most popular and valuable herbal medicines. However, the systematic analysis of the chemical constituents of LDW is difficult and thus has not been well established. In this paper, a rapid, sensitive, and reliable ultra-performance LC with ESI quadrupole TOF high-definition MS method with automated MetaboLynx analysis in positive and negative ion mode was established to characterize the chemical constituents of LDW. The analysis was performed on a Waters UPLC™ HSS T3 using a gradient elution system. MS/MS fragmentation behavior was proposed for aiding the structural identification of the components. Under the optimized conditions, a total of 50 peaks were tentatively characterized by comparing the retention time and MS data. It is concluded that a rapid and robust platform based on ultra-performance LC with ESI quadrupole TOF high-definition MS has been successfully developed for globally identifying multiple constituents of traditional Chinese medicine prescriptions. This is the first report on the systematic analysis of the chemical constituents of LDW. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. performance liquid chromatography

    African Journals Online (AJOL)

    user

    2010-11-22

    Nov 22, 2010 ... ISSN 1684–5315 © 2010 Academic Journals. Full Length Research Paper. Determination ... Key words: Processed food, high-performance liquid chromatography, acrylamide, health hazard. INTRODUCTION. In the year 2002, the ... potatoes, breakfast cereals etc. It was thus confirmed that acrylamide has ...

  12. Micellar liquid chromatography

    International Nuclear Information System (INIS)

    Basova, Elena M; Ivanov, Vadim M; Shpigun, Oleg A

    1999-01-01

    Background and possibilities of practical applications of micellar liquid chromatography (MLC) are considered. Various retention models in MLC, the effects of the nature and concentration of surfactants and organic modifiers, pH, temperature and ionic strength on the MLC efficiency and selectivity are discussed. The advantages and limitations of MLC are demonstrated. The performance of MLC is critically evaluated in relationship to the reversed-phase HPLC and ion-pair chromatography. The potential of application of MLC for the analysis of pharmaceuticals including that in biological fluids and separation of inorganic anions, transition metal cations, metal chelates and heteropoly compounds is described. The bibliography includes 146 references.

  13. Simultaneous enantioselective determination of triadimefon and its metabolite triadimenol in edible vegetable oil by gel permeation chromatography and ultraperformance convergence chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Yao, Zhoulin; Li, Xiaoge; Miao, Yelong; Lin, Mei; Xu, Mingfei; Wang, Qiang; Zhang, Hu

    2015-11-01

    A novel, sensitive, and efficient enantioselective method for the determination of triadimefon and its metabolite triadimenol in edible vegetable oil, was developed by gel permeation chromatography and ultraperformance convergence chromatography/tandem triple quadrupole mass spectrometry. After the vegetable oil samples were prepared using gel permeation chromatography, the eluent was collected, evaporated, and dried with nitrogen gas. The residue was redissolved by adding methanol up to a final volume of 1 mL. The analytes of six enantiomers were analyzed on Chiralpak IA-3 column (150 × 4.6 mm) using compressed liquid CO2-mixed 14 % co-solvents, comprising methanol/acetonitrile/isopropanol = 20/20/60 (v/v/v) in the mobile phase at 30 °C, and the total separation time was less than 4 min at a flow rate of 2 mL/min. Quantification was achieved using matrix-matched standard calibration curves. The overall mean recoveries for six enantiomers from vegetable oil were 90.1-97.3 %, with relative standard deviations of 0.8-5.4 % intra-day and 2.3-5.0 % inter-day at 0.5, 5, and 50 μg/kg levels. The limits of quantification were 0.5 μg/kg for all enantiomers based on five replicate extractions at the lowest fortified level in vegetable oil. Moreover, the absolute configuration of six enantiomers had been determined based on comparisons of the vibrational circular dichroism experimental spectra with the theoretical curve obtained by density functional theory calculations. Application of the proposed method to the 40 authentic vegetable oil samples from local markets suggests its potential use in enantioselective determination of triadimefon and triadimenol enantiomers. Graphical Abstract Chemical structures and UPC(2)-MS/MS separation chromatograms of triadimefon and triadimenol.

  14. New Highly-Sensitive Ultra-Performance Liquid Chromatography ...

    African Journals Online (AJOL)

    Waters, USA) using a mobile phase consisting of acetonitrile: 8 mM ammonium acetate containing 0.15. % formic acid (v/v) (70:30) ... suggest that the effects of telmisartan are ... (Millipore, Moscheim Cedex, France) having pore .... ratio, m is slope of the calibration curve, b is the ... Stability of TEL in plasma was assessed by.

  15. Ultra-performance liquid chromatographic determination of L-ergothioneine in commercially available classes of cow milk.

    Science.gov (United States)

    Sotgia, Salvatore; Pisanu, Elisabetta; Cambedda, Debora; Pintus, Gianfranco; Carru, Ciriaco; Zinellu, Angelo

    2014-09-01

    A new efficient and sensitive precolumn hydrophilic interaction ultra-performance liquid chromatography (HILIC-UPLC) method was established for the quantitative determination of L-ergothioneine (ERT) in milk. After derivatization of ERT with 7-diethylamino-3-[4-(iodoacetamido)phenyl]-4-methylcoumarin, chromatographic separation was achieved in a fairly short time, less than 5 min, on a 100 × 2.1 mm Waters Cortecs UPLC HILIC 1.6-μm column, by using a mixture of 30 mmol/L ammonium acetate/acetonitrile (10:90, v/v) as a mobile phase flowing isocratically at 0.9 mL/min. Limit of detection and the limit of quantification were 0.03 and 0.10 μmol/L, respectively. The method exhibited linearity in a concentration range of 0.16 and 5.08 μmol/L. Mean recovery was 106.66%, whereas intra- and interassay precisions were determined to be within 6 RSD%. On average, ERT concentration in different commercially available classes of cow milk was found to be 0.442 ± 0.191 μmol/L, with the highest levels in the ultra-high temperature milks and low values in the unprocessed and HTST whole milks. In this light, our experiments suggest that ERT could be used as a marker for the heat treatment of milk. © 2014 Institute of Food Technologists®

  16. Forensic Analysis of Blue Ball point Pen Inks Using Ultraviolet-Visible Spectrometer and Ultra-Performance Liquid Chromatograph

    International Nuclear Information System (INIS)

    Lee, L.C.; Shandu, K.T.S.; Nor Syahirah Mohamad Razi; Ab Aziz Ishak; Khairul Osman

    2015-01-01

    Twelve varieties of blue ball point pens were selected and analyzed using UV-Vis spectrometer and ultra-performance liquid chromatography (UPLC). The aim of the study was to determine discrimination power (DP) of these methods in differentiating pen inks collected from the market in Malaysia. Discrimination analysis of 66 possible pen-pair of blue ball point pens was carried out via one-way ANOVA based on obtained chromatogram and spectra. A total of 18 peaks were determined as coming from inks based on the chromatographic data extracted at three different wavelengths (279, 370 and 400 nm). While for the UV-Vis spectrometer analysis, presence of peaks at 303, 545, 577 and 584 nm wavelengths were recorded. UV-Vis spectral data were mainly produced by the colorant components (for example, dyes) found in inks and UPLC may detect ink components other than dyes, for example, additives. As conclusion, the DP for UV-Vis and UPLC were determined to be 72.12 % and 98.48 %, respectively. This manuscript demonstrates the potential of UPLC for discriminating pen inks based on non-dye components. Additionally, the dye components in inks do not seem to play important role in discrimination of pen inks. (author)

  17. Introduction to modern liquid chromatography

    National Research Council Canada - National Science Library

    Snyder, Lloyd R; Kirkland, J. J; Dolan, John W

    2010-01-01

    "High-performance liquid chromatography (HPLC) is today the leading technique for chemical analysis and related applications, with an ability to separate, analyze, and/or purify virtually any sample...

  18. Liquid chromatography in migration studies

    International Nuclear Information System (INIS)

    Carlsen, L.; Batsberg, W.

    1982-01-01

    Liquid chromatography ahs been suggested as a facile experimental technique to determine important physico-chemical properties, as permeability, porosity, dispersion-, diffusion-, and sorption charcteristics for geological material as chalk samples. The feasibility of the trechnique as a rapid method to evaluate the possible influence of changes in ground water composition on the migration behavior of radionuclides has been demonstrated

  19. Liquid phase chromatography on microchips

    DEFF Research Database (Denmark)

    Kutter, Jörg Peter

    2012-01-01

    explosive development of, in particular, chromatographic separation systems on microchips, has, however, slowed down in recent years. This review takes a closer, critical look at how liquid phase chromatography has been implemented in miniaturized formats over the past several years, what is important...

  20. Liquid chromatography-tandem mass spectrometric assay for the T790M mutant EGFR inhibitor osimertinib (AZD9291) in human plasma

    NARCIS (Netherlands)

    Rood, Johannes J M; van Bussel, Mark T J; Schellens, Jan H M; Beijnen, Jos H; Sparidans, Rolf W

    2016-01-01

    A method for the quantitative analysis by ultra-performance liquid chromatography-tandem mass spectrometry of the highly selective irreversible covalent inhibitor of EGFR-TK, osimertinib in human plasma was developed and validated, using pazopanib as an internal standard. The validation was

  1. UPLC and LC-MS studies on degradation behavior of irinotecan hydrochloride and development of a validated stability-indicating ultra-performance liquid chromatographic method for determination of irinotecan hydrochloride and its impurities in pharmaceutical dosage forms.

    Science.gov (United States)

    Kumar, Navneet; Sangeetha, Dhanaraj; Reddy, Sunil P

    2012-10-01

    The objective of the current investigation was to study the degradation behavior of irinotecan hydrochloride under different International Conference on Harmonization (ICH) recommended stress conditions using ultra-performance liquid chromatography and liquid chromatography-mass spectrometry and to establish a validated stability-indicating reverse-phase ultra-performance liquid chromatographic method for the quantitative determination of irinotecan hydrochloride and its seven impurities and degradation products in pharmaceutical dosage forms. Irinotecan hydrochloride was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. Irinotecan hydrochloride was found to degrade significantly in oxidative and base hydrolysis and photolytic degradation conditions. The degradation products were well resolved from the main peak and its impurities, thus proving the stability-indicating power of the method. Chromatographic separation was achieved on a Waters Acquity BEH C8 (100 × 2.1 mm) 1.7-µm column with a mobile phase containing a gradient mixture of solvent A (0.02M KH(2)PO(4) buffer, pH 3.4) and solvent B (a mixture of acetonitrile and methanol in the ratio of 62:38 v/v). The mobile phase was delivered at a flow rate of 0.3 mL/min with ultraviolet detection at 220 nm. The run time was 8 min, within which irinotecan and its seven impurities and degradation products were satisfactorily separated. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness. This method was also suitable for the assay determination of irinotecan hydrochloride in pharmaceutical dosage forms.

  2. [High-performance liquid-liquid chromatography in beverage analysis].

    Science.gov (United States)

    Bricout, J; Koziet, Y; de Carpentrie, B

    1978-01-01

    Liquid liquid chromatography was performed with columns packed with stationary phases chemically bonded to silica microparticules. These columns show a high efficiency and are used very easily. Flavouring compounds like aromatic aldehydes which have a low volatility were analyzed in brandy using a polar phase alkylnitrile. Sapid substances like amarogentin in Gentiana lutea or glyryrrhizin in Glycyrrhiza glabra were determined by reversed phase chromatography. Finally ionizable substances like synthetic dyes can be analyzed by paired ion chromatography witha non polar stationary phase.

  3. Gradient High Performance Liquid Chromatography Method ...

    African Journals Online (AJOL)

    Purpose: To develop a gradient high performance liquid chromatography (HPLC) method for the simultaneous determination of phenylephrine (PHE) and ibuprofen (IBU) in solid ..... nimesulide, phenylephrine. Hydrochloride, chlorpheniramine maleate and caffeine anhydrous in pharmaceutical dosage form. Acta Pol.

  4. UHPLC: The Greening Face of Liquid Chromatography

    OpenAIRE

    Cielecka-Piontek, Judyta; Zalewski, Przemys?aw; Jeli?ska, Anna; Garbacki, Piotr

    2013-01-01

    Pharmaceutical analysis based on chromatographic separation is an important part of studies aimed at developing routine quality analysis of drugs. High-performance liquid chromatography (HPLC) is one of the main analytical techniques recommended for drug analysis. Although it meets many criteria vital for analysis, it is time-consuming and uses a relatively high amount of organic solvents compared to other analytical techniques. Recently, Ultra-high-performance liquid chromatography (UHPLC) h...

  5. Liquid chromatography detection unit, system, and method

    Science.gov (United States)

    Derenzo, Stephen E.; Moses, William W.

    2015-10-27

    An embodiment of a liquid chromatography detection unit includes a fluid channel and a radiation detector. The radiation detector is operable to image a distribution of a radiolabeled compound as the distribution travels along the fluid channel. An embodiment of a liquid chromatography system includes an injector, a separation column, and a radiation detector. The injector is operable to inject a sample that includes a radiolabeled compound into a solvent stream. The position sensitive radiation detector is operable to image a distribution of the radiolabeled compound as the distribution travels along a fluid channel. An embodiment of a method of liquid chromatography includes injecting a sample that comprises radiolabeled compounds into a solvent. The radiolabeled compounds are then separated. A position sensitive radiation detector is employed to image distributions of the radiolabeled compounds as the radiolabeled compounds travel along a fluid channel.

  6. Ionic liquid stationary phases for gas chromatography.

    Science.gov (United States)

    Poole, Colin F; Poole, Salwa K

    2011-04-01

    This article provides a summary of the development of ionic liquids as stationary phases for gas chromatography beginning with early work on packed columns that established details of the retention mechanism and established working methods to characterize selectivity differences compared with molecular stationary phases through the modern development of multi-centered cation and cross-linked ionic liquids for high-temperature applications in capillary gas chromatography. Since there are many reviews on ionic liquids dealing with all aspects of their chemical and physical properties, the emphasis in this article is placed on the role of gas chromatography played in the design of ionic liquids of low melting point, high thermal stability, high viscosity, and variable selectivity for separations. Ionic liquids provide unprecedented opportunities for extending the selectivity range and temperature-operating range of columns for gas chromatography, an area of separation science that has otherwise been almost stagnant for over a decade. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Validated High Performance Liquid Chromatography Method for ...

    African Journals Online (AJOL)

    Purpose: To develop a simple, rapid and sensitive high performance liquid chromatography (HPLC) method for the determination of cefadroxil monohydrate in human plasma. Methods: Schimadzu HPLC with LC solution software was used with Waters Spherisorb, C18 (5 μm, 150mm × 4.5mm) column. The mobile phase ...

  8. Electronic spectral detection in liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Biggs, Wilton R. [ChevronTexaco Chemical Co., P. O. Box 1627, Richmond, CA 94802 (United States); Fetzer, John C. [Fetzpahs Consulting, 1283 Santa Fe St., Hercules, CA 94547 (United States)

    2002-07-01

    The use of absorbance and fluorescence spectrometers as liquid chromatography detectors is described. These detectors offer sensitive detection that can also identify the peaks in a chromatogram. Many examples, mainly from the separation of polycyclic aromatic hydrocarbons, are given that show the selectivity and usefulness of these detectors. (orig.)

  9. Instrument platforms for nano liquid chromatography

    Czech Academy of Sciences Publication Activity Database

    Šesták, Jozef; Moravcová, Dana; Kahle, Vladislav

    2015-01-01

    Roč. 1421, NOV (2015), s. 2-17 ISSN 0021-9673 R&D Projects: GA MV VG20112015021 Institutional support: RVO:68081715 Keywords : nano liquid chromatography * splitless gradient generation * nano LC platforms Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.926, year: 2015 http://hdl.handle.net/11104/0250900

  10. Instrument platforms for nano liquid chromatography.

    Science.gov (United States)

    Šesták, Jozef; Moravcová, Dana; Kahle, Vladislav

    2015-11-20

    The history of liquid chromatography started more than a century ago and miniaturization and automation are two leading trends in this field. Nanocolumn liquid chromatography (nano LC) and largely synonymous capillary liquid chromatography (capillary LC) are the most recent results of this process where miniaturization of column dimensions and sorbent particle size play crucial role. Very interesting results achieved in the research of extremely miniaturized LC columns at the end of the last century lacked distinctive raison d'être and only advances in mass spectrometry brought a real breakthrough. Configuration of nano LC-electrospray ionization mass spectrometry (LC-ESI-MS) has become a basic tool in bioanalytical chemistry, especially in proteomics. This review discusses and summarizes past and current trends in the realization of nano liquid chromatography (nano LC) platforms. Special attention is given to the mobile phase delivery under nanoflow rates (isocratic, gradient) and sample injection to the nanocolumn. Available detection techniques applied in nano LC separations are also briefly discussed. We followed up the key themes from the original scientific reports over gradual improvements up to the contemporary commercial solutions. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Ultra Performance Liquid Chromatography Tandem Mass ...

    African Journals Online (AJOL)

    NICOLAAS

    drugs alone.16. After a single oral dose of 120–800 mg of NTB in healthy sub- jects in a fasting state the peak plasma NTB concentration (tmax) was found to be 4–7 h, with a half-life of approximately 9–17 h.17 ... performance liquid chromatography mass spectrometry/mass .... to the likely biological plasma constituents.

  12. High Performance Liquid Chromatography Experiments to Undergraduate Laboratories

    Science.gov (United States)

    Kissinger, Peter T.; And Others

    1977-01-01

    Reviews the principles of liquid chromatography with electrochemical detection (LCEC), an analytical technique that incorporates the advantages of both liquids chromatography and electrochemistry. Also suggests laboratory experiments using this technique. (MLH)

  13. Development of a high performance liquid chromatography method ...

    African Journals Online (AJOL)

    Development of a high performance liquid chromatography method for simultaneous ... Purpose: To develop and validate a new low-cost high performance liquid chromatography (HPLC) method for ..... Several papers have reported the use of ...

  14. Optimizing separations in online comprehensive two‐dimensional liquid chromatography

    OpenAIRE

    Pirok, Bob W.J.; Gargano, Andrea F.G.; Schoenmakers, Peter J.

    2017-01-01

    Abstract Online comprehensive two‐dimensional liquid chromatography has become an attractive option for the analysis of complex nonvolatile samples found in various fields (e.g. environmental studies, food, life, and polymer sciences). Two‐dimensional liquid chromatography complements the highly popular hyphenated systems that combine liquid chromatography with mass spectrometry. Two‐dimensional liquid chromatography is also applied to the analysis of samples that are not compatible with mass...

  15. Comparative determination of phenytoin by spectrophotometry, gas chromatography, liquid chromatography, enzyme immunoassay, and radioimmunoassay

    International Nuclear Information System (INIS)

    Castro, A.; Ibanez, J.; DiCesare, J.L.; Adams, R.F.; Malkus, H.

    1978-01-01

    Sera from patients being treated with phenytoin were analyzed for the drug by spectrophotometry, gas chromatography, radioimmunoasay, enzyme immunoassay, and liquid chromatography. The assay values obtained were intercompared statistically. Enzyme immunoassay and liquid chromatography appear to be attractive alternatives to the more traditional methods of spectrophotometry and gas chromatography. Our radioimmunoassay data correlated poorly with results by the four other methods

  16. High perfomance liquid chromatography in pharmaceutical analyses.

    Science.gov (United States)

    Nikolin, Branko; Imamović, Belma; Medanhodzić-Vuk, Saira; Sober, Miroslav

    2004-05-01

    In testing the pre-sale procedure the marketing of drugs and their control in the last ten years, high performance liquid chromatography replaced numerous spectroscopic methods and gas chromatography in the quantitative and qualitative analysis. In the first period of HPLC application it was thought that it would become a complementary method of gas chromatography, however, today it has nearly completely replaced gas chromatography in pharmaceutical analysis. The application of the liquid mobile phase with the possibility of transformation of mobilized polarity during chromatography and all other modifications of mobile phase depending upon the characteristics of substance which are being tested, is a great advantage in the process of separation in comparison to other methods. The greater choice of stationary phase is the next factor which enables realization of good separation. The separation line is connected to specific and sensitive detector systems, spectrafluorimeter, diode detector, electrochemical detector as other hyphernated systems HPLC-MS and HPLC-NMR, are the basic elements on which is based such wide and effective application of the HPLC method. The purpose high performance liquid chromatography (HPLC) analysis of any drugs is to confirm the identity of a drug and provide quantitative results and also to monitor the progress of the therapy of a disease.1) Measuring presented on the Fig. 1. is chromatogram obtained for the plasma of depressed patients 12 h before oral administration of dexamethasone. It may also be used to further our understanding of the normal and disease process in the human body trough biomedical and therapeutically research during investigation before of the drugs registration. The analyses of drugs and metabolites in biological fluids, particularly plasma, serum or urine is one of the most demanding but one of the most common uses of high performance of liquid chromatography. Blood, plasma or serum contains numerous endogenous

  17. Recent development of ionic liquid stationary phases for liquid chromatography.

    Science.gov (United States)

    Shi, Xianzhe; Qiao, Lizhen; Xu, Guowang

    2015-11-13

    Based on their particular physicochemical characteristics, ionic liquids have been widely applied in many fields of analytical chemistry. Many types of ionic liquids were immobilized on a support like silica or monolith as stationary phases for liquid chromatography. Moreover, different approaches were developed to bond covalently ionic liquids onto the supporting materials. The obtained ionic liquid stationary phases show multi-mode mechanism including hydrophobic, hydrophilic, hydrogen bond, anion exchange, π-π, and dipole-dipole interactions. Therefore, they could be used in different chromatographic modes including ion-exchange, RPLC, NPLC and HILIC to separate various classes of compounds. This review mainly summarizes the immobilized patterns and types of ionic liquid stationary phases, their retention mechanisms and applications in the recent five years. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Determination of methylparaben from cosmetic products by ultra performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    MANUELA M. MINCEA

    2009-06-01

    Full Text Available A new method for the determination of methylparaben by ultra-performance liquid chromatography (UPLC was developed. Methylparaben is often used as preservative, alone or in combination with other parabens, being added to cosmetic products, pharmaceutical products and foods to avoid microbial contamination. Due to its widespread use and potential risk to human health, assessing human exposure to this compound is of interest. A good determination and quantification of methylparaben was developed with a gradient elution using a mixture of methanol and water (60:40, v/v within 1.455 min. Under optimized conditions, the linear working range extends over two orders of magnitude with relative standard deviations of intra- and inter-day precision below 2.3 %, and a detection limit of 0.02 ng μL-1 for methylparaben. The proposed method was successfully applied to the assay of methylparaben in cosmetic products with minimal sample preparation.

  19. UHPLC: The Greening Face of Liquid Chromatography.

    Science.gov (United States)

    Cielecka-Piontek, Judyta; Zalewski, Przemysław; Jelińska, Anna; Garbacki, Piotr

    2013-01-01

    Pharmaceutical analysis based on chromatographic separation is an important part of studies aimed at developing routine quality analysis of drugs. High-performance liquid chromatography (HPLC) is one of the main analytical techniques recommended for drug analysis. Although it meets many criteria vital for analysis, it is time-consuming and uses a relatively high amount of organic solvents compared to other analytical techniques. Recently, Ultra-high-performance liquid chromatography (UHPLC) has been frequently proposed as an alternative to HPLC, which means introducing an environment-friendly approach to drug analysis achieved by reducing the consumption of solvents. It also offers greater chromatographic resolution and higher sensitivity as well as requiring less time due to faster analysis. This review focuses on the basics of UHPLC, compares that technique with HPLC and discusses the possibilities of applying UHPLC for the analysis of different pharmaceuticals and biopharmaceuticals.

  20. High performance liquid chromatography in pharmaceutical analyses

    Directory of Open Access Journals (Sweden)

    Branko Nikolin

    2004-05-01

    Full Text Available In testing the pre-sale procedure the marketing of drugs and their control in the last ten years, high performance liquid chromatographyreplaced numerous spectroscopic methods and gas chromatography in the quantitative and qualitative analysis. In the first period of HPLC application it was thought that it would become a complementary method of gas chromatography, however, today it has nearly completely replaced gas chromatography in pharmaceutical analysis. The application of the liquid mobile phase with the possibility of transformation of mobilized polarity during chromatography and all other modifications of mobile phase depending upon the characteristics of substance which are being tested, is a great advantage in the process of separation in comparison to other methods. The greater choice of stationary phase is the next factor which enables realization of good separation. The separation line is connected to specific and sensitive detector systems, spectrafluorimeter, diode detector, electrochemical detector as other hyphernated systems HPLC-MS and HPLC-NMR, are the basic elements on which is based such wide and effective application of the HPLC method. The purpose high performance liquid chromatography(HPLC analysis of any drugs is to confirm the identity of a drug and provide quantitative results and also to monitor the progress of the therapy of a disease.1 Measuring presented on the Fig. 1. is chromatogram obtained for the plasma of depressed patients 12 h before oral administration of dexamethasone. It may also be used to further our understanding of the normal and disease process in the human body trough biomedical and therapeutically research during investigation before of the drugs registration. The analyses of drugs and metabolites in biological fluids, particularly plasma, serum or urine is one of the most demanding but one of the most common uses of high performance of liquid chromatography. Blood, plasma or

  1. Ion exchange and liquid column chromatography

    International Nuclear Information System (INIS)

    Walton, H.F.

    1980-01-01

    Major accomplishments in liquid chromatography for the past two years and reported in journals available to December 31, 1979 are reviewed. Emphasis has been placed on principles and methodology with some representative examples of application included. Applications are illustrated in two rather lenghtly tables, one covering inorganic ions and the other covering organic compounds. 544 references, 8 books, and 15 reviews are listed in the bibliography

  2. Flow Rates in Liquid Chromatography, Gas Chromatography and Supercritical Fluid Chromatography: A Tool for Optimization

    Directory of Open Access Journals (Sweden)

    Joris Meurs

    2016-08-01

    Full Text Available This paper aimed to develop a standalone application for optimizing flow rates in liquid chromatography (LC, gas chromatography (GC and supercritical fluid chromatography (SFC. To do so, Van Deemter’s equation, Knox’ equation and Golay’s equation were implemented in a MATLAB script and subsequently a graphical user interface (GUI was created. The application will show the optimal flow rate or linear velocity and the corresponding plate height for the set input parameters. Furthermore, a plot will be shown in which the plate height is plotted against the linear flow velocity. Hence, this application will give optimized flow rates for any set conditions with minimal effort.

  3. Application of ionic liquids in liquid chromatography and electrodriven separation.

    Science.gov (United States)

    Huang, Yi; Yao, Shun; Song, Hang

    2013-08-01

    Ionic liquids (ILs) are salts in the liquid state at ambient temperature, which are nonvolatile, nonflammable with high thermal stability and dissolve easily for a wide range of inorganic and organic materials. As a kind of potential green solvent, they show high efficiency and selectivity in the field of separation research, especially in instrumental analysis. Thus far, ILs have been successfully applied by many related researchers in high-performance liquid chromatography and capillary electrophoresis as chromatographic stationary phases, mobile phase additives or electroosmotic flow modifiers. This paper provides a detailed review of these applications in the study of natural products, foods, drugs and other fine chemicals. Furthermore, the prospects of ILs in liquid chromatographic and electrodriven techniques are discussed.

  4. Spillage detector for liquid chromatography systems

    Science.gov (United States)

    Jarvis, M. J.; Fulton, D. S. (Inventor)

    1986-01-01

    A spillage detector device for use in conjunction with fractionation of liquid chromatography systems which includes a spillage recieving enclosure beneath the fractionation area is described. A sensing device having a plurality of electrodes of alternating polarity is mounted within the spillage recieving enclosure. Detection circuitry, responsive to conductivity between electrodes, is operatively connected to the sensing device. The detection circuitry feeds into the output circuitry. The output circuit has relaying and switching circuitry directed to a solenoid, an alarm system and a pump. The solenoid is connected to the pliable conduit of the chromatography system. The alarm system comprises an audio alarm and a visual signal. A 115-volt power system interconnected with the pump, the solenoid, the sensing device, and the detection and output circuitry.

  5. Characterisation of uremic "Middle molecular"fractions by gas chromatography mass spectrometry, isotachophoresis, and liquid chromatography

    NARCIS (Netherlands)

    Schoots, A.C.; Mikkers, F.E.P.; Claessens, H.A.; Smet, de R.; Landschoot, van N.; Ringoir, S.M.G.

    1982-01-01

    Uremic ultrafiltrates (and normal serum, for comparison) were fractionated by means of gel filtration. The collected fractions were further investigated by combined analytical techniques: "high- performance" liquid chromatography, gas chromatography, mass spectrometry, and isotachophoresis.

  6. Liquid chromatography - mass spectrometry analysis of pharmaceuticals

    International Nuclear Information System (INIS)

    Macasek, F.

    2003-01-01

    The drugs represent mostly non-volatile and thermally labile solutes, often available only in small amounts like it is in case of radiopharmaceuticals. Therefor, the favourable separation techniques for such compounds are HPLC, capillary electrophoresis and also TLC 1. Liquid chromatography with mass spectrometric detector (LC/MS) is especially powerful for their microanalysis. Mass spectrometry separating the ions in high vacuum was presumably used as detector for gas chromatography effluent but the on-line coupling with liquid eluant flow 0.1-1 mL/min is far more challenging. New types of ion sources were constructed for simultaneous removal of solvent and ionisation of solutes at atmospheric pressure (API). At present, a relatively wide choice of successfully designed commercial equipment is available either for small organic molecules and larger biomolecules (Perkin-Elmer, Agilent, Jeol, Bruker Daltonics, ThermoQuest, Shimadzu). The features of the LC/MS systems are presented. LC/MS as a new quality control tool for [F-18]fluorodeoxyglucose (FDG) radiopharmaceutical, which has became the most spread radiopharmaceutical for positron emission tomography (PET), was proposed. Other applications of the LC/MS are reviewed. (author)

  7. Optimizing separations in online comprehensive two‐dimensional liquid chromatography

    Science.gov (United States)

    Gargano, Andrea F.G.; Schoenmakers, Peter J.

    2017-01-01

    Abstract Online comprehensive two‐dimensional liquid chromatography has become an attractive option for the analysis of complex nonvolatile samples found in various fields (e.g. environmental studies, food, life, and polymer sciences). Two‐dimensional liquid chromatography complements the highly popular hyphenated systems that combine liquid chromatography with mass spectrometry. Two‐dimensional liquid chromatography is also applied to the analysis of samples that are not compatible with mass spectrometry (e.g. high‐molecular‐weight polymers), providing important information on the distribution of the sample components along chemical dimensions (molecular weight, charge, lipophilicity, stereochemistry, etc.). Also, in comparison with conventional one‐dimensional liquid chromatography, two‐dimensional liquid chromatography provides a greater separation power (peak capacity). Because of the additional selectivity and higher peak capacity, the combination of two‐dimensional liquid chromatography with mass spectrometry allows for simpler mixtures of compounds to be introduced in the ion source at any given time, improving quantitative analysis by reducing matrix effects. In this review, we summarize the rationale and principles of two‐dimensional liquid chromatography experiments, describe advantages and disadvantages of combining different selectivities and discuss strategies to improve the quality of two‐dimensional liquid chromatography separations. PMID:29027363

  8. Optimizing separations in online comprehensive two-dimensional liquid chromatography.

    Science.gov (United States)

    Pirok, Bob W J; Gargano, Andrea F G; Schoenmakers, Peter J

    2018-01-01

    Online comprehensive two-dimensional liquid chromatography has become an attractive option for the analysis of complex nonvolatile samples found in various fields (e.g. environmental studies, food, life, and polymer sciences). Two-dimensional liquid chromatography complements the highly popular hyphenated systems that combine liquid chromatography with mass spectrometry. Two-dimensional liquid chromatography is also applied to the analysis of samples that are not compatible with mass spectrometry (e.g. high-molecular-weight polymers), providing important information on the distribution of the sample components along chemical dimensions (molecular weight, charge, lipophilicity, stereochemistry, etc.). Also, in comparison with conventional one-dimensional liquid chromatography, two-dimensional liquid chromatography provides a greater separation power (peak capacity). Because of the additional selectivity and higher peak capacity, the combination of two-dimensional liquid chromatography with mass spectrometry allows for simpler mixtures of compounds to be introduced in the ion source at any given time, improving quantitative analysis by reducing matrix effects. In this review, we summarize the rationale and principles of two-dimensional liquid chromatography experiments, describe advantages and disadvantages of combining different selectivities and discuss strategies to improve the quality of two-dimensional liquid chromatography separations. © 2017 The Authors. Journal of Separation Science published by WILEY-VCH Verlag GmbH & Co. KGaA.

  9. Comprehensive two-dimensional liquid chromatography: Ion chromatography × reversed-phase liquid chromatography for separation of low-molar-mass organic acids

    NARCIS (Netherlands)

    Brudin, S.S.; Shellie, R.A.; Haddad, P.R.; Schoenmakers, P.J.

    2010-01-01

    In the work presented here a novel approach to comprehensive two-dimensional liquid chromatography is evaluated. Ion chromatography is chosen for the first-dimension separation and reversed-phase liquid chromatography is chosen for the second-dimension separation mode. The coupling of these modes is

  10. A novel multidimensional protein identification technology approach combining protein size exclusion prefractionation, peptide zwitterion-ion hydrophilic interaction chromatography, and nano-ultraperformance RP chromatography/nESI-MS2 for the in-depth analysis of the serum proteome and phosphoproteome: application to clinical sera derived from humans with benign prostate hyperplasia.

    Science.gov (United States)

    Garbis, Spiros D; Roumeliotis, Theodoros I; Tyritzis, Stavros I; Zorpas, Kostas M; Pavlakis, Kitty; Constantinides, Constantinos A

    2011-02-01

    The current proof-of-principle study was aimed toward development of a novel multidimensional protein identification technology (MudPIT) approach for the in-depth proteome analysis of human serum derived from patients with benign prostate hyperplasia (BPH) using rational chromatographic design principles. This study constituted an extension of our published work relating to the identification and relative quantification of potential clinical biomarkers in BPH and prostate cancer (PCa) tissue specimens. The proposed MudPIT approach encompassed the use of three distinct yet complementary liquid chromatographic chemistries. High-pressure size-exclusion chromatography (SEC) was used for the prefractionation of serum proteins followed by their dialysis exchange and solution phase trypsin proteolysis. The tryptic peptides were then subjected to offline zwitterion-ion hydrophilic interaction chromatography (ZIC-HILIC) fractionation followed by their online analysis with reversed-phase nano-ultraperformance chromatography (RP-nUPLC) hyphenated to nanoelectrospray ionization-tandem mass spectrometry using an ion trap mass analyzer. For the spectral processing, the sequential use of the SpectrumMill, Scaffold, and InsPecT software tools was applied for the tryptic peptide product ion MS(2) spectral processing, false discovery rate (FDR) assessment, validation, and protein identification. This milestone serum analysis study allowed the confident identification of over 1955 proteins (p ≤ 0.05; FDR ≤ 5%) with a broad spectrum of biological and physicochemical properties including secreted, tissue-specific proteins spanning approximately 12 orders of magnitude as they occur in their native abundance levels in the serum matrix. Also encompassed in this proteome was the confident identification of 375 phosphoproteins (p ≤ 0.05; FDR ≤ 5%) with potential importance to cancer biology. To demonstrate the performance characteristics of this novel MudPIT approach, a comparison

  11. In Vitro and in Vivo Metabolite Profiling of Valnemulin Using Ultraperformance Liquid Chromatography–Quadrupole/Time-of-Flight Hybrid Mass Spectrometry

    Science.gov (United States)

    2015-01-01

    Valnemulin, a semisynthetic pleuromutilin derivative related to tiamulin, is broadly used to treat bacterial diseases of animals. Despite its widespread use, metabolism in animals has not yet been fully investigated. To better understand valnemulin biotransformation, in this study, metabolites of valnemulinin in in vitro and in vivo rats, chickens, swines, goats, and cows were identified and elucidated using ultraperformance liquid chromatography–quadrupole/time-of-flight hybrid mass spectrometry (UPLC-Q/TOF-MS). As a result, there were totally 7 metabolites of valnemulin identified in vitro and 75, 61, and 74 metabolites detected in in vivo rats, chickens, and swines, respectively, and the majority of metabolites were reported for the first time. The main metabolic pathways of valnemulin were found to be hydroxylation in the mutilin part (the ring system) and the side chain, oxidization on the sulfur of the side chain to form S-oxides, hydrolysis of the amido bond, and acetylization in the amido of the side chain. In addition, hydroxylation in the mutilin part was proposed to be the primary metabolic route. Furthermore, the results revealed that 2β-hydroxyvalnemulin (V1) and 8α-hydroxyvalnemulin (V2) were the major metabolites for rats and swines and S-oxides (V6) in chickens. PMID:25156794

  12. Microchip-based monolithic column for high performance liquid chromatography

    Data.gov (United States)

    National Aeronautics and Space Administration — We have developed microchip based monolithic columns that can be used for liquid chromatography of small organic molecules, as well as, macromolecules such as...

  13. High Performance Liquid Chromatography of Vitamin A: A Quantitative Determination.

    Science.gov (United States)

    Bohman, Ove; And Others

    1982-01-01

    Experimental procedures are provided for the quantitative determination of Vitamin A (retinol) in food products by analytical liquid chromatography. Standard addition and calibration curve extraction methods are outlined. (SK)

  14. A generalized theory of chromatography and multistep liquid extraction

    Science.gov (United States)

    Chizhkov, V. P.; Boitsov, V. N.

    2017-03-01

    A generalized theory of chromatography and multistep liquid extraction is developed. The principles of highly efficient processes for fine preparative separation of binary mixture components on a fixed sorbent layer are discussed.

  15. Integration of Electrochemistry with Ultra Performance Liquid Chromatography/Mass Spectrometry (UPLC/MS)

    Science.gov (United States)

    Cai, Yi; Zheng, Qiuling; Liu, Yong; Helmy, Roy; Loo, Joseph A.; Chen, Hao

    2015-01-01

    This study presents the development of ultra-performance liquid chromatography/mass spectrometry (UPLC/MS) combined with electrochemistry (EC) for the first time and its application for the structural analysis of disulfide bond-containing proteins/peptides. In our approach, a protein/peptide mixture sample undergoes fast UPLC separation and subsequent electrochemical reduction in an electrochemical flow cell followed by online MS and MS/MS analyses. The electrochemical cell is coupled to MS using our recently developed desorption electrospray ionization (DESI) interface. Using this UPLC/EC/DESI-MS method, disulfide bond-containing peptides can be differentiated from those without disulfide bonds as the former are electroactive and reducible. Tandem MS analysis of the disulfide-reduced peptide ions provides increased sequence and disulfide linkage pattern information. In a reactive DESI-MS detection experiment in which a supercharging reagent was used to dope the DESI spray solvent, increased charging was obtained for the UPLC-separated proteins. Strikingly, upon online electrolytic reduction, supercharged proteins (e.g., α-lactalbumin) showed even higher charging, which would be useful in top-down protein structure analysis as increased charges are known to promote protein ion dissociation. Also, the separation speed and sensitivity are enhanced by approximately 1~2 orders of magnitude by using UPLC for the LC/EC/MS platform, in comparison to the previously used high performance liquid chromatography (HPLC). This UPLC/EC/DESI-MS method combines the power of fast UPLC separation, fast electrochemical conversion and online MS structural analysis for a potentially valuable tool for proteomics research and bioanalysis. PMID:26307715

  16. Radioactivity monitor for high-performance liquid chromatography

    International Nuclear Information System (INIS)

    Reeve, D.R.; Crozier, A.

    1977-01-01

    The coupling of a homogeneous radioactivity monitor to a liquid chromatograph involves compromises between the sensitivity of the monitor and the resolution and speed of analysis of the chromatograph. The theoretical relationships between these parameters are considered and expressions derived which make it possible to calculate suitable monitor operating conditions for most types of high-performance liquid chromatography

  17. Analysis of multiple vitamin D metabolites by ultra-performance supercritical fluid chromatography-tandem mass spectrometry (UPSFC-MS/MS).

    Science.gov (United States)

    Jenkinson, Carl; Taylor, Angela; Storbeck, Karl-Heinz; Hewison, Martin

    2018-06-15

    In recent years, increased interest in the human health benefits of vitamin D has led to demand for improved analysis of patient vitamin D 'status'. Studies to date have focused primarily on a single vitamin D metabolite, 25-hydroxyvitamin D, despite the existence of a broad range of vitamin D metabolites, referred to as the vitamin D metabolome. This study reports on the development of a rapid UPSFC-MS/MS method for the analysis of nine vitamin D metabolites in human serum. Optimum separation was obtained with a Lux-Cellulose chiral column. We observed an orthogonal elution order when compared with ultra-high performance liquid chromatography (UHPLC). The order of elution was reversed based on hydroxyl- group number, however elution order did not differ between isomeric changes in hydroxyl- group position or epimers. Although UPSFC yielded superior resolution and selectivity over previously developed UHPLC-MS/MS methods, improvements in sensitivity could not be achieved owing to the lower injection volume required for UPSFC relative to UHPLC. Method validation was performed on the developed UPSFC-MS/MS method and found to be within acceptable limits. Applying the method to the analysis of human serum samples showed a significant correlation with serum concentrations of metabolites measured by UHPLC-MS/MS (25OHD3 r = 0.997, P=<0.001, and 3-epi-25OHD3 r = 0.996, P ≤0.001). These data indicate that UPSFC provides an efficient analytical platform for rapid analysis of multiple vitamin D metabolites from serum. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

  18. Ultra-high Performance Liquid Chromatography in Steroid Analysis

    OpenAIRE

    Salonen, Fanny

    2017-01-01

    The latest version of liquid chromatography is ultra-high performance (or pressure) chromatography (UHPLC). In the technique, short and narrow-bore columns with particle sizes below 3 µm are used. The extremely high pressure used results in very short analysis times, excellent separation, and good resolution. This makes UHPLC a good choice for steroidal analysis. Steroids are a highly interesting area of study; they can be recognized as biomarkers for several diseases and are a relevant topic...

  19. Fractionation of fecal neutral steroids by high performance liquid chromatography

    International Nuclear Information System (INIS)

    Jackson, E.M.; Kloss, C.A.; Weintraub, S.T.; Mott, G.E.

    1985-01-01

    Fecal neutral steroids were fractionated by high performance liquid chromatography (HPLC) into three major fractions: 5 beta-H, 3-keto steroids; 5 beta-H, 3 beta-hydroxy steroids; and 5 alpha-H and delta 5-3 beta-hydroxy steroids. This separation was achieved in about 10 minutes, with greater than 97% recovery of standards in each fraction. Gas-liquid chromatographic quantitation of fecal steroids fractionated by either HPLC or thin-layer chromatography gave nearly identical results. A method using both C18 reverse phase and silica HPLC to purify radiolabeled sterols is also described

  20. Development and Validation of Liquid Chromatography- Mass ...

    African Journals Online (AJOL)

    HP

    Method: A novel liquid chromatography–tandem mass spectrometry method for the quantitative determination of naproxen in human K2-EDTA plasma in negative ion mode was employed ..... Practice and Applications of Bio-analytical Method.

  1. Liquid Chromatography Applied to Space System

    Science.gov (United States)

    Poinot, Pauline; Chazalnoel, Pascale; Geffroy, Claude; Sternberg, Robert; Carbonnier, Benjamin

    Searching for signs of past or present life in our Solar System is a real challenge that stirs up the curiosity of scientists. Until now, in situ instrumentation was designed to detect and determine concentrations of a wide number of organic biomarkers. The relevant method which was and still is employed in missions dedicated to the quest of life (from Viking to ExoMars) corresponds to the pyrolysis-GC-MS. Along the missions, this approach has been significantly improved in terms of extraction efficiency and detection with the use of chemical derivative agents (e.g. MTBSTFA, DMF-DMA, TMAH…), and in terms of analysis sensitivity and resolution with the development of in situ high-resolution mass spectrometer (e.g. TOF-MS). Thanks to such an approach, organic compounds such as amino acids, sugars, tholins or polycyclic aromatic hydrocarbons (PAHs) were expected to be found. However, while there’s a consensus that the GC-MS of Viking, Huygens, MSL and MOMA space missions worked the way they had been designed to, pyrolysis is much more in debate (Glavin et al. 2001; Navarro-González et al. 2006). Indeed, (1) it is thought to remove low levels of organics, (2) water and CO2 could interfere with the detection of likely organic pyrolysis products, and (3) only low to mid-molecular weight organic molecules can be detected by this technique. As a result, researchers are now focusing on other in situ techniques which are no longer based on the volatility of the organic matter, but on the liquid phase extraction and analysis. In this line, micro-fluidic systems involving sandwich and/or competitive immunoassays (e.g. LMC, SOLID; Parro et al. 2005; Sims et al. 2012), micro-chip capillary electrophoreses (e.g. MOA; Bada et al. 2008), or nanopore-based analysis (e.g. BOLD; Schulze-Makuch et al. 2012) have been conceived for in situ analysis. Thanks to such approaches, molecular biological polymers (polysaccharides, polypeptides, polynucleotides, phospholipids, glycolipids

  2. Characterization of the pigment fraction in sweet bell peppers (Capsicum annuum L.) harvested at green and overripe yellow and red stages by offline multidimensional convergence chromatography/liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Bonaccorsi, Ivana; Cacciola, Francesco; Utczas, Margita; Inferrera, Veronica; Giuffrida, Daniele; Donato, Paola; Dugo, Paola; Mondello, Luigi

    2016-09-01

    Offline multidimensional supercritical fluid chromatography combined with reversed-phase liquid chromatography was employed for the carotenoid and chlorophyll characterization in different sweet bell peppers (Capsicum annuum L.) for the first time. The first dimension consisted of an Acquity HSS C18 SB (100 × 3 mm id, 1.8 μm particles) column operated with a supercritical mobile phase in an ultra-performance convergence chromatography system, whereas the second dimension was performed in reversed-phase mode with a C30 (250 × 4.6 mm id, 3.0 μm particles) stationary phase combined with photodiode array and mass spectrometry detection. This approach allowed the determination of 115 different compounds belonging to chlorophylls, free xanthophylls, free carotenes, xanthophyll monoesters, and xanthophyll diesters, and proved to be a significant improvement in the pigments determination compared to the conventional one-dimensional liquid chromatography approach so far applied to the carotenoid analysis in the studied species. Moreover, the present study also aimed to investigate and to compare the carotenoid stability and composition in overripe yellow and red bell peppers collected directly from the plant, thus also evaluating whether biochemical changes are linked to carotenoid degradation in the nonclimacteric investigated fruits, for the first time. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Liquid chromatography and liquid chromatography-mass spectrometry analysis of donepezil degradation products

    Directory of Open Access Journals (Sweden)

    Mladenović Aleksandar R.

    2015-01-01

    Full Text Available This study describes the investigation of degradation products of donepezil (DP using stability indicating RP-HPLC method for determination of donepezil, which is a centrally acting reversible acetylcholinesterase inhibitor. In order to investigate the stability of drug and formed degradation products, a forced degradation study of drug sample and finished product under different forced degradation conditions has been conducted. Donepezil hydrochloride and donepezil tablets were subjected to stress degradation conditions recommended by International Conference on Harmonization (ICH. Donepezil hydrochloride solutions were subjected to acid and alkali hydrolysis, chemical oxidation and thermal degradation. Significant degradation was observed under alkali hydrolysis and oxidative degradation conditions. Additional degradation products were observed under the conditions of oxidative degradation. The degradation products observed during forced degradation studies were monitored using the high performance liquid chromatography (HPLC method developed. The parent method was modified in order to obtain LC-MS compatible method which was used to identify the degradation products from forced degradation samples using high resolution mass spectrometry. The mass spectrum provided the precise mass from which derived molecular formula of drug substance and degradation products formed and proved the specificity of the method unambiguously. [Projekat Ministarstva nauke Republike Srbije, br. 172013

  4. Instrumental liquid chromatography: a practical manual on high-performance liquid chromatographic methods

    National Research Council Canada - National Science Library

    Parris, N. A

    1976-01-01

    Available texts on liquid chromatography have tended to emphasize the developments in the theoretical understanding of the technique and methodology or to list numerous applications, complete with experimental details...

  5. Liquid-adsorption chromatography of metal 8-hydroxyquinolinates

    International Nuclear Information System (INIS)

    Basova, E.M.; Bol'shova, T.A.; Shirshova, T.S.

    1988-01-01

    Using the method of liquid-adsorption chromatography separation of 8-hydroxyquinolinates of Cu, Fe, Ga, In, Al, Ni is realized. Thin-layer chromatography (TLC) is used to define the optimum conditions of separation and highly efficient liquid column chromatography (HELC) - for chelate separation. Applicaton of the same sorbent is a very important condition of transition from TLC to HELC. Solica gel Partisil, mobile phase: benzene - isopropanol mixture, containing 1 x 10 -3 M of 8-hydroxyquinoline, are the optimal conditions for the studied chelates separation. But In and Ga in TLC move together, and in HELC they are partially separated, therefore, for their separation the column selectivity should be improved by selection of mobile phase

  6. Validated High Performance Liquid Chromatography Method for ...

    African Journals Online (AJOL)

    Purpose: To develop a simple, rapid and sensitive high performance liquid ... response, tailing factor and resolution of six replicate injections was < 3 %. ... Cefadroxil monohydrate, Human plasma, Pharmacokinetics Bioequivalence ... Drug-free plasma was obtained from the local .... Influence of probenicid on the renal.

  7. Determination of Caffeine in Beverages by High Performance Liquid Chromatography.

    Science.gov (United States)

    DiNunzio, James E.

    1985-01-01

    Describes the equipment, procedures, and results for the determination of caffeine in beverages by high performance liquid chromatography. The method is simple, fast, accurate, and, because sample preparation is minimal, it is well suited for use in a teaching laboratory. (JN)

  8. Beta-induced fluorescence detection in liquid chromatography

    International Nuclear Information System (INIS)

    Malcolme-Lawes, D.J.; Massey, S.; Warwick, P.

    1981-01-01

    A theoretical analysis of beta-induced fluorescence is used to determine the factors which influence the sensitivity of the technique as applied to liquid chromatography. Equations are presented for detector response and for signal-to-noise ratios and the theoretical response for a typical detector is compared with experimentally determined values. (author)

  9. Mallow carotenoids determined by high-performance liquid chromatography

    Science.gov (United States)

    Mallow (corchorus olitorius) is a green vegetable, which is widely consumed either fresh or dry by Middle East population. This study was carried out to determine the contents of major carotenoids quantitatively in mallow, by using a High Performance Liquid Chromatography (HPLC) equipped with a Bis...

  10. High-Performance Liquid Chromatography-Mass Spectrometry.

    Science.gov (United States)

    Vestal, Marvin L.

    1984-01-01

    Reviews techniques for online coupling of high-performance liquid chromatography with mass spectrometry, emphasizing those suitable for application to nonvolatile samples. Also summarizes the present status, strengths, and weaknesses of various techniques and discusses potential applications of recently developed techniques for combined liquid…

  11. Monitoring aged reversed-phase high performance liquid chromatography columns

    NARCIS (Netherlands)

    Bolck, A; Smilde, AK; Bruins, CHP

    1999-01-01

    In this paper, a new approach for the quality assessment of routinely used reversed-phase high performance liquid chromatography columns is presented. A used column is not directly considered deteriorated when changes in retention occur. If attention is paid to the type and magnitude of the changes,

  12. Ultra high performance liquid chromatography of seized drugs

    NARCIS (Netherlands)

    Lurie, I.S.

    2010-01-01

    The primary goal of this thesis is to investigate the use of ultra high performance liquid chromatography (UHPLC) for the analysis of seized drugs. This goal was largely achieved and significant progress was made in achieving improved separation and detection of drugs of forensic interest.

  13. Quantification of Tea Flavonoids by High Performance Liquid Chromatography

    Science.gov (United States)

    Freeman, Jessica D.; Niemeyer, Emily D.

    2008-01-01

    We have developed a laboratory experiment that uses high performance liquid chromatography (HPLC) to quantify flavonoid levels in a variety of commercial teas. Specifically, this experiment analyzes a group of flavonoids known as catechins, plant-derived polyphenolic compounds commonly found in many foods and beverages, including green and black…

  14. Characterization of porous silicon integrated in liquid chromatography chips

    NARCIS (Netherlands)

    Tiggelaar, Roald M.; Verdoold, Vincent; Eghbali, H.; Desmet, G.; Gardeniers, Johannes G.E.

    2009-01-01

    Properties of porous silicon which are relevant for use of the material as a stationary phase in liquid chromatography chips, like porosity, pore size and specific surface area, were determined with high-resolution SEM and N2 adsorption–desorption isotherms. For the anodization conditions

  15. Towards early detection of the hydrolytic degradation of poly(bisphenol A)carbonate by hyphenated liquid chromatography and comprehensive two-dimensional liquid chromatography

    NARCIS (Netherlands)

    Coulier, L.; Kaal, E.R.; Hankemeier, Th.

    2006-01-01

    The hydrolytic degradation of poly(bisphenol A)carbonate (PC) has been characterized by various liquid chromatography techniques. Size exclusion chromatography (SEC) showed a significant decrease in molecular mass as a result of hydrolytic degradation, while 'liquid chromatography at critical

  16. Ionic Liquid-Liquid Chromatography: A New General Purpose Separation Methodology

    OpenAIRE

    Brown, Leslie; Earle, Martyn J; Gilea, Manuela; Plechkova, Natalia V; Seddon, Kenneth R

    2017-01-01

    Ionic liquids can form biphasic solvent systems with many organic solvents and water, and these solvent systems can be used in liquid-liquid separations and countercurrent chromatography. The wide range of ionic liquids that can by synthesised, with specifically tailored properties, represents a new philosophy for the separation of organic, inorganic and bio-based materials. A customised countercurrent chromatograph has been designed and constructed specifically to allow the more viscous char...

  17. Simultaneous determination of sulphoraphane and sulphoraphane nitrile in Brassica vegetables using ultra-performance liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Alvarez-Jubete, Laura; Smyth, Thomas J; Valverde, Juan; Rai, Dilip K; Barry-Ryan, Catherine

    2014-01-01

    Several analytical methods exist for the determination of sulphoraphane or sulphoraphane nitrile from biological matrices and plant extracts. However, no UPLC-MS/MS method exists for the simultaneous detection of both. To develop and validate an UPLC-MS/MS method for the simultaneous analysis of sulphoraphane and sulphoraphane nitrile from Brassica oleracea L. ssp. italica This method was developed utilising an Acquity BEH C8 column with gradient elution combined with tandem mass spectrometry, using positive electrospray ionisation in multiple reaction monitoring mode. The retention times for sulphoraphane and sulphoraphane nitrile were 0.4 and 0.6 min respectively, and total run time was 3 min. The method was validated for linearity, sensitivity, precision, accuracy, matrix effects and recovery. The method was employed to determine glucoraphanin hydrolysis products in broccoli and the predominant product was found to vary depending on the variety tested. It was also applied to the accurate determination of sulphoraphane and sulphoraphane nitrile in broccoli samples hydrolysed under different conditions. It was observed that the formation of sulphoraphane and sulphoraphane nitrile was influenced by the temperature of the reaction. The validated UPLC-MS/MS method for simultaneous detection of sulphoraphane and sulphoraphane nitrile was shown to be applicable to broccoli plants and is expected to be applicable to other cruciferous sources. Copyright © 2013 John Wiley & Sons, Ltd.

  18. Determination of protein-unbound rhynchiphylline brain distribution by microdialysis and ultra-performance liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Lee, Chia-Jung; Hsueh, Thomas Y; Lin, Lie-Chwen; Tsai, Tung-Hu

    2014-06-01

    The stem with hook of Uncaria rhynchophylla (Chinese herbal name Gou-Teng) is a traditional Chinese medicine that has been ethnopharmacologically used to extinguish wind and clean interior heat. Rhynchophylline (RHY), a tetracyclic oxindole alkaloid isolated from U. rhynchophylla, displays significant antineuroinflammatory effects. However, there is no evidence to indicate that rhynchophylline can cross the blood-brain barrier and be detected in the brain. In this study, an in vivo microdialysis sampling method coupled with UPLC/MS/MS was employed for the continuous simultaneous monitoring of unbound RHY in rat blood and brain. The precursor ion → product ion transition at m/z 385.2 → 160.0 for rhynchophylline was monitored. A calibration curve gave good linearity (r>0.996) over the concentration range from 0.5 to 1000 ng/mL. The results demonstrated that rhynchophylline could be detected in the brain and plasma from 15 min to 6 h after its administration (1 or 10 mg/kg, i.v.). All the pharmacokinetic parameters of rhynchophylline in the brain and plasma were obtained. These results show that rhynchophylline can cross the blood-brain barrier and they provide useful clinical information. Copyright © 2014 John Wiley & Sons, Ltd.

  19. Analysis of Zolpidem in Postmortem Fluids and Tissues Using Ultra-Performance Liquid Chromatography-Mass Spectrometry

    Science.gov (United States)

    2014-02-01

    in postmortem fluids and tissues. 17. Key Words 18. Distribution Statement Forensic Toxicology , Zolpidem, Ambien, Postmortem Distribution, LC/MS/MS...Institute (CAMI) toxicology database identified 10 fatalities from separate avia- tion accidents that were reported positive for zolpidem and also...Sample Selection and Storage A search of the CAMI toxicology database (ToxFLO, DiscoverSoft Development, LLC; Oklahoma City, OK) identi- fied 10

  20. Analysis of zolpidem in postmortem fluids and tissues using ultra-performance liquid chromatography-mass spectrometry.

    Science.gov (United States)

    2014-02-01

    Zolpidem is a nonbenzodiazepine sedative hypnotic drug used for the short-term treatment of insomnia. Its : use is common and wide-spread. While quite effective in producing sedation, zolpidem has potentially : hazardous side effects when put in the ...

  1. Optimizing heterosurface adsorbent synthesis for liquid chromatography

    Science.gov (United States)

    Bogoslovskii, S. Yu.; Serdan, A. A.

    2016-03-01

    The structural and geometric parameters of a silica matrix (SM) for the synthesis of heterosurface adsorbents (HAs) are optimized. Modification is performed by shielding the external surfaces of alkyl-modified silica (AS) using human serum albumin and its subsequent crosslinking. The structural and geometric characteristics of the SM, AS, and HA are measured via low-temperature nitrogen adsorption. It is found that the structural characteristics of AS pores with diameters D 9 nm reduces significantly due to adsorption of albumin. It is concluded that silica gel with a maximum pore size distribution close to 5 nm and a minimal proportion of pores with D > 9 nm is optimal for HA synthesis; this allows us to achieve the greatest similarity between the chromatographic retention parameters for HA and AS. The suitability of the synthesized adsorbents for analyzing drugs in biological fluids through direct sample injection is confirmed by chromatography. It was found that the percentage of the protein fraction detected at the outlet of the chromatographic column is 98%.

  2. Theories to support method development in comprehensive two-dimensional liquid chromatography - A review

    NARCIS (Netherlands)

    Bedani, F.; Schoenmakers, P.J.; Janssen, H.-G.

    2012-01-01

    On-line comprehensive two-dimensional liquid chromatography techniques promise to resolve samples that current one-dimensional liquid chromatography methods cannot adequately deal with. To make full use of the potential of two-dimensional liquid chromatography, optimization is required. Optimization

  3. 21 CFR 862.2250 - Gas liquid chromatography system for clinical use.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gas liquid chromatography system for clinical use... Instruments § 862.2250 Gas liquid chromatography system for clinical use. (a) Identification. A gas liquid chromatography system for clinical use is a device intended to separate one or more drugs or compounds from a...

  4. 21 CFR 862.2260 - High pressure liquid chromatography system for clinical use.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false High pressure liquid chromatography system for... Clinical Laboratory Instruments § 862.2260 High pressure liquid chromatography system for clinical use. (a) Identification. A high pressure liquid chromatography system for clinical use is a device intended to separate...

  5. Application of genetic algorithms for parameter estimation in liquid chromatography

    International Nuclear Information System (INIS)

    Hernandez Torres, Reynier; Irizar Mesa, Mirtha; Tavares Camara, Leoncio Diogenes

    2012-01-01

    In chromatography, complex inverse problems related to the parameters estimation and process optimization are presented. Metaheuristics methods are known as general purpose approximated algorithms which seek and hopefully find good solutions at a reasonable computational cost. These methods are iterative process to perform a robust search of a solution space. Genetic algorithms are optimization techniques based on the principles of genetics and natural selection. They have demonstrated very good performance as global optimizers in many types of applications, including inverse problems. In this work, the effectiveness of genetic algorithms is investigated to estimate parameters in liquid chromatography

  6. Thin-layer chromatography - liquid chromatography, an ideal supplement demonstrated by the separation of lanthanoids

    International Nuclear Information System (INIS)

    Specker, H.; Hufnagel, A.

    1984-01-01

    All lanthanoids have been separated by thin-layer chromatography (TLC) with short retention times by using a mixture of ether/tetrahydrofurane (THF)/bis-(2-ethylhexyl)-phosphate (HDEHP)/nitric acid. The eluent was empirically tested by synergistic effects. The results have been transferred to high-performance liquid chromatography /HPLC). It was possible to use the same eluent in TLC and HPLC both for the analytical separation of all lanthanoids and for the separation of fission products. The experimental experience gained in HPLC could be applied to the pre-concentration of isotopes in TLC. Both methods excellently supplemented each other in the separation of lanthanoids. (orig.) [de

  7. Multi-constituent determination and fingerprint analysis of Scutellaria indica L. using ultra high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Liang, Xianrui; Zhao, Cui; Su, Weike

    2015-11-01

    An ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry method integrating multi-constituent determination and fingerprint analysis has been established for quality assessment and control of Scutellaria indica L. The optimized method possesses the advantages of speediness, efficiency, and allows multi-constituents determination and fingerprint analysis in one chromatographic run within 11 min. 36 compounds were detected, and 23 of them were unequivocally identified or tentatively assigned. The established fingerprint method was applied to the analysis of ten S. indica samples from different geographic locations. The quality assessment was achieved by using principal component analysis. The proposed method is useful and reliable for the characterization of multi-constituents in a complex chemical system and the overall quality assessment of S. indica. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Simultaneous determination of 11 β-agonists in human urine using high-performance liquid chromatography/tandem mass spectrometry with isotope dilution.

    Science.gov (United States)

    Wang, Xiaoli; Guo, Tao; Wang, Shanshan; Yuan, Jinpeng; Zhao, Rusong

    2015-04-01

    The misuse of β-agonists constitutes a potential risk to public health and has been forbidden in many countries. In this study, we describe a method for specific, sensitive and rapid detection of β-agonists in human urine. Urine samples were extracted with ethyl acetate, without any additional purification step, and analyzed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) with Clenbuterol-D9 and Salbuterol-D3 as internal standards. The intra- and interday precision values of the method were all application of UPLC-MS-MS method in β-agonists detection of human urine will be helpful in veterinary control of β-agonists and for studying the effect of β-agonists on human health. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Ionic Liquid-Liquid Chromatography: A New General Purpose Separation Methodology.

    Science.gov (United States)

    Brown, Leslie; Earle, Martyn J; Gîlea, Manuela A; Plechkova, Natalia V; Seddon, Kenneth R

    2017-08-10

    Ionic liquids can form biphasic solvent systems with many organic solvents and water, and these solvent systems can be used in liquid-liquid separations and countercurrent chromatography. The wide range of ionic liquids that can by synthesised, with specifically tailored properties, represents a new philosophy for the separation of organic, inorganic and bio-based materials. A customised countercurrent chromatograph has been designed and constructed specifically to allow the more viscous character of ionic liquid-based solvent systems to be used in a wide variety of separations (including transition metal salts, arenes, alkenes, alkanes, bio-oils and sugars).

  10. Nano-liquid chromatography applied to enantiomers separation.

    Science.gov (United States)

    Fanali, Salvatore

    2017-02-24

    This paper presents the state of the art concerning the separation of chiral compounds by means of nano-liquid chromatography (nano-LC). The enantiomers' separation and determination are a subject of fundamental importance in various application fields such as pharmaceutical industry, biomedicine, food, agrochemical etc. Nano-LC is a miniaturized chromatographic technique offering some advantages over conventional ones such as low consumption of mobile phase, sample volume and amount of chiral stationary phase, reduced costs etc. This is reported in the first part of the paper illustrating the features of the nano-LC. In addition, chiral resolution methods are briefly illustrated. Some chiral selectors, used in high-performance liquid chromatography have also been applied in nano-LC including cyclodextrins, glycopeptide antibiotics, modified polysaccharides etc. This is discussed in the second part of the review. Finally some examples of the applications available in literature are reported. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Combined high-performance liquid chromatography-radioimmunoassay for cytokinins

    International Nuclear Information System (INIS)

    MacDonald, E.M.S.; Akiyoshi, D.E.; Morris, R.O.

    1981-01-01

    The cytokinins isopentenyladenosine and ribosylzeatin were conjugated to bovine serum albumin and the conjugates used to raise antisera in rabbits. The resulting antisera had high specificity towards the cytokinin haptens and low cross-reactivity towards other purines. They were used as the basis for a radioimmunoassay for cytokinins, which, when applied in conjunction with high-performance liquid chromatography, allowed rapid and sensitive (to the picogram range) estimation and identification of multiple cytokinins from natural plant and bacterial sources. (orig.)

  12. High performance liquid chromatography in studies of radiolabeled antibodies

    International Nuclear Information System (INIS)

    Hnatowich, D.J.

    1986-01-01

    High performance liquid chromatography (HPLC) as applied to the separation of antibodies displays the same advantages as in its other applications, namely good resolution accompanied by fast analysis. It is therefore not surprising that many HPLC columns designed for use with antibodies and other proteins are now available commercially. The properties of proteins which provide the separation are size, hydrophobicity, charge and affinity. The features of each are discussed. (author)

  13. Evolution and Current Trends in Liquid and Supercritical Fluid Chromatography

    OpenAIRE

    Fekete, Szabolcs; Grand-Guillaume-Perrenoud, Alexandre; Guillarme, Davy

    2014-01-01

    The current trend in high performance liquid chromatography (HPLC) tends toward the achievement of higher separation efficiency and shorter analysis time. Indeed, better performance in LC has become increasingly important in recent years mainly driven by the challenges of either analyzing more complex samples or increasing the numbers of samples per time unit. In the recent development of particle technology, the use of fully porous sub-2 m particles and sub-3 m shell particles have received ...

  14. Liquid Chromatography for Analysis of Metformin in Myrmeleon sp.

    OpenAIRE

    Afidatul Muadifah; Hermin Sulistyarti; Sasangka Prasetyawan

    2017-01-01

    Myrmeleon sp is a typical of insect larva which has been used in Indonesia for diabetes treatment. However, there is no sufficient scientific report explaining the bioactive compounds in this insect. Based on our preliminary research, this insect contained metformin, i.e. one of bioactive compounds for the treatment of type-2 diabetes. Therefore, this study is focused on the development of separation technique using high performance liquid chromatography (HPLC) on a reverse phase C-18 column ...

  15. Liquid to liquid extraction and liquid chromatography-tandem mass spectrometry determination of hainanmycin in feed.

    Science.gov (United States)

    Wang, Ze Ping; Shen, Jian Zhong; Linhardt, Robert J; Jiang, Hui; Cheng, Lin Li

    2017-03-01

    Hainanmycin is a new veterinary polyether antibiotic and has few sensitive analytical method in present days. In this study, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) relying on multiple reaction monitoring (MRM) detection was developed for analysis of hainanmycin in animal feed. Feed samples were extracted with ethyl acetate and purified by two steps of liquid-liquid extraction (LLE) to get rid of water solvable matrix and lipids one by one. The final simple was analyzed by LC-MS/MS. The LC mobile phase was composed of 0.1% aqueous formic acid and 0.1% formic acidified acetonitrile by gradient elution. Average recoveries ranged from 74.22% to 87.85%, as determined by spiking with 2.0 (LOQ) ∼2500μgkg -1 of hainanmycin. The inter-day and intra-day coefficient of variation was 9.21% to 11.77% and 7.67% to 13.49%, respectively. The limit of detection (LOD) and the limit of quantitation (LOQ) were 0.36μgkg -1 and 2.0μgkg -1 , respectively. Copyright © 2016. Published by Elsevier B.V.

  16. Comprehensive two-dimensional liquid chromatography and hyphenated liquid chromatography to study the degradation of poly(bisphenol A)carbonate

    NARCIS (Netherlands)

    Coulier, L.; Kaal, E.R.; Hankemeier, T.

    2005-01-01

    Size exclusion chromatography (SEC), gradient polymer elution chromatography (GPEC) and liquid chromatography at critical conditions (LC-CC) have been developed and applied to observe chemical changes in poly(bisphenol A)carbonate (PC) due to hydrolytic degradation. Especially LC-CC appeared to be

  17. Protein separations using enhanced-fluidity liquid chromatography.

    Science.gov (United States)

    Bennett, Raffeal; Olesik, Susan V

    2017-11-10

    Enhanced-fluidity liquid chromatography (EFLC) methods using methanol/H 2 O/CO 2 and hydrophilic interaction liquid chromatography (HILIC) were explored for the separation of proteins and peptides. EFLC is a separation mode that uses a mobile phase made of conventional solvents combined with liquid carbon dioxide (CO 2 ) in subcritical conditions. The addition of liquid CO 2 enhances diffusivity and decreases viscosity while maintaining mixture polarity, which typically results in reduced time of analysis. TFA additive and elevated temperature were leveraged as key factors in the separation of a 13-analyte intact protein mixture in under 5min. Under these conditions EFLC showed modest improvement in terms of peak asymmetry and analysis time over the competing ACN/H 2 O separation. Protein analytes detected by electrospray ionization - quadrupole time of flight, were shown to be unaffected by the addition of CO 2 in the mobile phase. Herein, the feasibility of separating hydrophilic proteins up to 80kDa (with transferrin) is demonstrated for CO 2 -containing mobile phases. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Csaba Horváth and preparative liquid chromatography.

    Science.gov (United States)

    Guiochon, Georges

    2005-06-24

    Few chromatographers have been interested in furthering preparative liquid chromatography. The pioneers, Tswett, Kuhn and Lederer, A.J.P. Martin, Tiselius, isolated fractions but as an intermediate step in the analysis of their samples. The progress in electronics and sensors, and in their miniaturization has lead to the paradoxical situation that the analysts never see the transient pure fractions that their detector quantitates. Yet, over the last 25 years, preparative liquid chromatography has become an important industrial process for the separation, the extraction, and/or the purification of many pharmaceuticals or pharmaceutical intermediates, including pure enantiomers, purified peptides and proteins, compounds that are manufactured at the relatively large industrial scale of a few kilograms to several hundred tons per year. This development that has strongly affected the modem pharmaceutical industry is mainly due to the pioneering work of Csaba Horváth. His work in preparative HPLC was critical at both the practical and the theoretical levels. He was the first scientist in modem times to pay serious attention to the relationships between the curvature of the equilibrium isotherms, the competitive nature of nonlinear isotherms, and the chromatographic band profiles of complex mixtures. The thermodynamics of multi-component phase equilibria and mass transfer kinetics in chromatography attracted his interest and were the focus of ground-breaking contributions. He investigated displacement chromatography, an old method invented by Tiselius that Csaba was first to implement in HPLC. This choice was explained by the essential characteristic of displacement chromatography, in that it delivers fractions that can be far more concentrated than the feed. Remarkably, once the basics of nonlinear chromatography had been mastered in his group, most of the applications that were studied by his coworkers dealt with peptides of various sizes and with proteins. Thus, all

  19. Multianalyte, high-throughput liquid chromatography tandem mass spectrometry method for the sensitive determination of fungicides and insecticides in wine.

    Science.gov (United States)

    Castro, Gabriela; Pérez-Mayán, Leticia; Rodríguez-Cabo, Tamara; Rodríguez, Isaac; Ramil, Maria; Cela, Rafael

    2018-01-01

    Evidence of pesticide transfer from grapes to wine, added to differences in the national regulations regarding the number and the maximum concentration of these species in wine, demands analytical procedures suitable for their routine control in this foodstuff. In this research, solid-phase extraction (SPE) and ultra-performance liquid chromatography (UPLC), with tandem mass spectrometry (MS/MS) detection, are combined to obtain a sensitive and rapid procedure to determine 50 pesticides in red and white wines. Efficiency and selectivity of sample preparation are correlated with the type of sorbent, the elution solvent, and the physicochemical properties of pesticides. SPE of 2-mL wine samples followed by direct injection of the extract in the UPLC-MS/MS system provides quantification limits (LOQs) below 1 ng mL -1 for 48 out of 50 compounds, linear responses up to 200 ng mL -1 , and acceptable accuracy, employing quantification against solvent-based standards, for 45 species. A total analysis time of 10 min, including compounds separation and re-equilibration of the UPLC column, was achieved. The developed methodology was applied to 25 wines (20 conventional and 5 ecological), produced in 7 different countries. Out of 27 pesticides quantified in these wines, 12 displayed occurrence frequencies above 24%; moreover, all wines, except one of the ecological ones, contained residues from at least one pesticide.

  20. Profiling the Metabolism of Astragaloside IV by Ultra Performance Liquid Chromatography Coupled with Quadrupole/Time-of-Flight Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Xu-Dong Cheng

    2014-11-01

    Full Text Available Astragaloside IV is a compound isolated from the Traditional Chinese Medicine Astragalus membranaceus, that has been reported to have bioactivities against cardiovascular disease and kidney disease. There is limited information on the metabolism of astragaloside IV, which impedes comprehension of its biological actions and pharmacology. In the present study, an ultra-performance liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS-based approach was developed to profile the metabolites of astragaloside IV in rat plasma, bile, urine and feces samples. Twenty-two major metabolites were detected. The major components found in plasma, bile, urine and feces included the parent chemical and phases I and II metabolites. The major metabolic reactions of astragaloside IV were hydrolysis, glucuronidation, sulfation and dehydrogenation. These results will help to improve understanding the metabolism and reveal the biotransformation profiling of astragaloside IV in vivo. The metabolic information obtained from our study will guide studies into the pharmacological activity and clinical safety of astragaloside IV.

  1. Air and Surface Sampling Method for Assessing Exposures to Quaternary Ammonium Compounds Using Liquid Chromatography Tandem Mass Spectrometry.

    Science.gov (United States)

    LeBouf, Ryan F; Virji, Mohammed Abbas; Ranpara, Anand; Stefaniak, Aleksandr B

    2017-07-01

    This method was designed for sampling select quaternary ammonium (quat) compounds in air or on surfaces followed by analysis using ultraperformance liquid chromatography tandem mass spectrometry. Target quats were benzethonium chloride, didecyldimethylammonium bromide, benzyldimethyldodecylammonium chloride, benzyldimethyltetradecylammonium chloride, and benzyldimethylhexadecylammonium chloride. For air sampling, polytetrafluoroethylene (PTFE) filters are recommended for 15-min to 24-hour sampling. For surface sampling, Pro-wipe® 880 (PW) media was chosen. Samples were extracted in 60:40 acetonitrile:0.1% formic acid for 1 hour on an orbital shaker. Method detection limits range from 0.3 to 2 ng/ml depending on media and analyte. Matrix effects of media are minimized through the use of multiple reaction monitoring versus selected ion recording. Upper confidence limits on accuracy meet the National Institute for Occupational Safety and Health 25% criterion for PTFE and PW media for all analytes. Using PTFE and PW analyzed with multiple reaction monitoring, the method quantifies levels among the different quats compounds with high precision (detection limits to capture quats on air sampling filters with only a 15-min sample duration with a maximum assessed storage time of 103 days before sample extraction. This method will support future exposure assessment and quantitative epidemiologic studies to explore exposure-response relationships and establish levels of quats exposures associated with adverse health effects. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  2. Determination of pesticide residues in olives by liquid extraction surface analysis followed by liquid chromatography/tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Gómez-Almenar, M. C.

    2015-06-01

    Full Text Available Nowadays, pesticides are essential in modern agriculture for crop protection, however, this use supposes a potential risk for human health and the environment. Traditional techniques of pesticide determination require the use of laborious and complex extraction methods to separate pesticides from the matrix, above all in fatty matrices like olives. For this reason, a new simple, rapid, cheap and selective method for the extraction and quantification of the most frequently used pesticides in olive growing has been developed. Pesticide determination was carried out by ultra-performance liquid chromatography (UPLC coupled with triple-quadrupole tandem mass spectrometry (MS/MS. Mean recoveries were found in a range between 73 and 114% with relative standard deviations lower than 20% in most pesticides evaluated and the limits of detection (LODs and quantification (LOQs were lower than 4 μg· kg-1 and 8 μg· kg-1, respectively. Finally, this method was applied to the analysis of 25 olive samples where Dimethoate and Terbuthylazine were detected in some cases, but their results were lower than 15 μg· kg-1.Hoy en día los pesticidas son esenciales en la agricultura moderna para la protección de los cultivos pero su uso supone un riesgo para la salud y el medio ambiente. Las técnicas tradicionales de determinación de pesticidas requieren el uso de métodos de extracción complejos a fin de separar los pesticidas de la matriz, sobre todo en matrices grasas como las aceitunas. Por ello, se ha desarrollado un nuevo método simple, rápido, barato y selectivo para la extracción y cuantificación de los pesticidas más frecuentemente utilizados en el cultivo del olivo, empleando cromatografía líquida de ultra-resolución (UPLC acoplada a espectrometría de masas (MS/MS. Las recuperaciones alcanzadas variaron entre el 73 y 114% obteniendo desviaciones estándar relativas inferiores al 20%. Los límites de detección (LD y cuantificación (LQ fueron

  3. Nanomaterials as stationary phases and supports in liquid chromatography.

    Science.gov (United States)

    Beeram, Sandya R; Rodriguez, Elliott; Doddavenkatanna, Suresh; Li, Zhao; Pekarek, Allegra; Peev, Darin; Goerl, Kathryn; Trovato, Gianfranco; Hofmann, Tino; Hage, David S

    2017-10-01

    The development of various nanomaterials over the last few decades has led to many applications for these materials in liquid chromatography (LC). This review will look at the types of nanomaterials that have been incorporated into LC systems and the applications that have been explored for such systems. A number of carbon-based nanomaterials and inorganic nanomaterials have been considered for use in LC, ranging from carbon nanotubes, fullerenes and nanodiamonds to metal nanoparticles and nanostructures based on silica, alumina, zirconia and titanium dioxide. Many ways have been described for incorporating these nanomaterials into LC systems. These methods have included covalent immobilization, adsorption, entrapment, and the synthesis or direct development of nanomaterials as part of a chromatographic support. Nanomaterials have been used in many types of LC. These applications have included the reversed-phase, normal-phase, ion-exchange, and affinity modes of LC, as well as related methods such as chiral separations, ion-pair chromatography and hydrophilic interaction liquid chromatography. Both small and large analytes (e.g., dyes, drugs, amino acids, peptides and proteins) have been used to evaluate possible applications for these nanomaterial-based methods. The use of nanomaterials in columns, capillaries and planar chromatography has been considered as part of these efforts. Potential advantages of nanomaterials in these applications have included their good chemical and physical stabilities, the variety of interactions many nanomaterials can have with analytes, and their unique retention properties in some separation formats. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Analysis of radioactive mixed hazardous waste using derivatization gas chromatography/mass spectrometry, liquid chromatography, and liquid chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Campbell, J.A.; Lerner, B.D.; Bean, R.M.; Grant, K.E.; Lucke, R.B.; Mong, G.M.; Clauss, S.A.

    1994-08-01

    Six samples of core segments from Tank 101-SY were analyzed for chelators, chelator fragments, and several carboxylic acids by derivatization gas chromatography/mass spectrometry. The major components detected were ethylenediaminetetraacetic acid, nitroso-iminodiacetic acid, nitrilotriacetic acid, citric acid, succinic acid, and ethylenediaminetriacetic acid. The chelator of highest concentration was ethylenediaminetetraacetic acid in all six samples analyzed. Liquid chromatography was used to quantitate low molecular weight acids including oxalic, formic, glycolic, and acetic acids, which are present in the waste as acid salts. From 23 to 61% of the total organic carbon in the samples analyzed was accounted for by these acids

  5. Determination of trimethyllead reference material using high performance liquid chromatography-inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Lu Hai; Wei Chao; Wang Jun; Chao Jingbo; Zhou Tao; Chen Dazhou

    2005-01-01

    A high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICPMS) was combined, and the chromatography conditions were optimized. The stability and homogeneity of a trimethyllead reference material were determined using this method. (authors)

  6. The high pressure electronic control system in liquid chromatography

    International Nuclear Information System (INIS)

    Popescu, Stefan; Popeneciu, Gabriel; Toadere, Florin

    2002-01-01

    The Liquid Chromatography system can perform a wide variety of measurements and separations especially for the organic liquids, with maximum applications flexibility for less than half price of Gas Chromatography. The repeatability and accuracy of results in quantitative high pressure liquid chromatography are highly dependent on the reproducibility and accuracy of both integrated flow rate and mobile phase composition. Flow rate fluctuation leads to poor reproducibility in both integrated peak areas and retention times. Similarly, poor control of mobile phase composition will cause poor repeatability of retention time and peak heights. The our Solvent Delivery System SDS 200 is a single pump system which provides precise compensated flow rates from 0.01 to 10 mL/min, selectable upper pressure limits of 0 to 100 bar or 10 to 450 bar, and solvent compressibility correction. Ternary solvent system on-line mixing capability saves time, reduces solvent waste and provides more flexibility for difficult separations. The pump itself has two different displacement pistons which are used alternately on both suction and discharge, so that intake of the solvent are synchronous. The evacuated solvent from the two pump's chambers is mixed in the reference unit and then is supplied to the damping unit for flow ripple reduction. The SDS Electronic Module ensures the functions: controls the programmed flow rate, detects and shows the solvent pressure in solvent, supplies the step motor, measures and limits the solvent pressure. The control panel of SDS 200, contains a two-stages flow decimal programmer, a eight-positions knob for upper pressure limits, an alarm LED and a parallel port for connection to a PC system. (authors)

  7. VIII All-Russian symposium on molecular liquid chromatography and capillary electrophoresis. Program. Summary of reports

    International Nuclear Information System (INIS)

    2001-01-01

    Program and summary of reports of the VIII All-Russian symposium on molecular liquid chromatography and capillary electrophoresis are performed. The meeting took place 15-19 October, 2001 in Moscow. Many problems of liquid and ion exchange chromatography, capillary electrophoresis, thin-layer chromatography have been discussed extensively. Reports covering properties of sorbents and devices for chromatography are incorporated in the collection [ru

  8. Hydrazine Determination in Sludge Samples by High Performance Liquid Chromatography

    Energy Technology Data Exchange (ETDEWEB)

    G. Elias; G. A. Park

    2006-02-01

    A high-performance liquid chromatographic method using ultraviolet (UV) detection was developed to detect and quantify hydrazine in a variety of environmental matrices. The method was developed primarily for sludge samples, but it is also applicable to soil and water samples. The hydrazine in the matrices was derivatized to their hydrazones with benzaldehyde. The derivatized hydrazones were separated using high performance liquid chromatography (HPLC) with a reversed-phase C-18 column in an isocratic mode with methanol-water (95:5, v/v), and detected with UV detection at 313 nm. The detection limit (25 ml) for the new analytical method is 0.0067 mg ml-1of hydrazine. Hydrazine showed low recovery in soil samples because components in soil oxidized hydrazine. Sludge samples that contained relatively high soil content also showed lower recovery. The technique is relatively simple and cost-effective, and is applicable for hydrazine analysis in different environmental matrices.

  9. Analysis of penicillin G in milk by liquid chromatography.

    Science.gov (United States)

    Boison, J O; Keng, L J; MacNeil, J D

    1994-01-01

    A liquid chromatographic (LC) method that was previously developed for penicillin G residues in animal tissues has been adapted to milk and milk products. After protein precipitation with sodium tungstate, samples are applied to a C18 solid-phase extraction cartridge, from which penicillin is eluted, derivatized with 1,2,4-triazole-mercuric chloride solution, and analyzed by isocratic liquid chromatography (LC) on a C18 column with UV detection at 325 nm. Quantitation is done with reference to penicillin V as an internal standard. Penicillin G recoveries were determined to be > 70% on standards fortified at 3-60 ppb. Accuracy approached 100% using the penicillin V internal standard. The detection limit for penicillin G residues was 3 ppb in fluid milk. Samples may be confirmed by thermospray/LC at concentrations approaching the detection limit of the UV method.

  10. Free silanols and ionic liquids as their suppressors in liquid chromatography.

    Science.gov (United States)

    Buszewska-Forajta, Magdalena; Markuszewski, Michał J; Kaliszan, Roman

    2018-07-20

    In this review, we will firstly discuss the types and the general properties of silica, focusing on the silica support used in chromatography and capillary electrophoresis. Additionally, the characterization of functional groups (silanols and siloxanes) will be considered in terms of activity of the stationary phases. We will then discuss physical chemistry of the stationary phases applied in liquid chromatography and capillary electrophoresis. The use of ionic liquids as a silanols' suppressors will be presented in the next parts of the study, along with the examples of specific applications. The review is completed with conclusions and an outlook for the future developments in the area of analytical applications of ionic liquids. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Fiber-based monolithic columns for liquid chromatography.

    Science.gov (United States)

    Ladisch, Michael; Zhang, Leyu

    2016-10-01

    Fiber-based monoliths for use in liquid chromatographic separations are defined by columns packed with aligned fibers, woven matrices, or contiguous fiber structures capable of achieving rapid separations of proteins, macromolecules, and low molecular weight components. A common denominator and motivating driver for this approach, first initiated 25 years ago, was reducing the cost of bioseparations in a manner that also reduced residence time of retained components while achieving a high ratio of mass to momentum transfer. This type of medium, when packed into a liquid chromatography column, minimized the fraction of stagnant liquid and resulted in a constant plate height for non-adsorbing species. The uncoupling of dispersion from eluent flow rate enabled the surface chemistry of the stationary phase to be considered separately from fluid transport phenomena and pointed to new ways to apply chemistry for the engineering of rapid bioseparations. This paper addresses developments and current research on fiber-based monoliths and explains how the various forms of this type of chromatographic stationary phase have potential to provide new tools for analytical and preparative scale separations. The different stationary phases are discussed, and a model that captures the observed constant plate height as a function of mobile phase velocity is reviewed. Methods that enable hydrodynamically stable fiber columns to be packed and operated over a range of mobile phase flow rates, together with the development of new fiber chemistries, are shown to provide columns that extend the versatility of liquid chromatography using monoliths, particularly at the preparative scale. Graphical Abstract Schematic representation of a sample mixture being separated by a rolled-stationary phase column, resulting separated peaks shown in the chromatogram.

  12. Development and validation of ultra-performance liquid chromatographic method with tandem mass spectrometry for determination of lenalidomide in rabbit and human plasma

    Directory of Open Access Journals (Sweden)

    Iqbal Muzaffar

    2013-01-01

    Full Text Available Abstract Background Lenalidomide (LND is a potent novel thalidomide analog which demonstrated remarkable clinical activity in treatment of multiple myeloma disease via a multiple-pathways mechanism. Validated sensitive method with high throughput is required for the determination of lenalidomide for pharmacokinetics and toxicokinetic studies. Ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS is a preeminent analytical tool for rapid biomedical analysis. Results A simple, highly sensitive UPLC-MS/MS method was developed and validated for the determination of LND in rabbit and human plasma. After a simple protein precipitation using methanol, LND and carbamazepine (IS were separated on Acquity UPLC BEH™ C18 column (50 × 2.1 mm, i.d. 1.7 μm, Waters, USA using a mobile phase consisted of acetonitrile:water:formic acid (65:35:0.1%, v/v/v pumped at a flow rate of 0.2 mL/min. LND and IS were eluted at 0.71 and 1.92 min, respectively. The mass spectrometric determination was carried out using an electrospray interface operated in the positive mode with multiple reaction monitoring (MRM mode. The precursor to product ion transitions of m/z 260.1 > 149.0 and m/z 237.0 > 179.0 were used to quantify LND and IS, respectively. The method was linear in the concentration range of 0.23–1000 ng/mL with a limit of quantitation of 0.23 ng/mL. All the validation parameters were in the ranges acceptable by the guidelines of analytical method validation. Conclusion The proposed UPLC-MS/MS method is simple, rapid and highly sensitive, and hence it could be reliable for pharmacokinetic and toxicokinetic study in both animals and humans.

  13. Comparison of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography for the separation of synthetic cathinones.

    Science.gov (United States)

    Carnes, Stephanie; O'Brien, Stacey; Szewczak, Angelica; Tremeau-Cayel, Lauriane; Rowe, Walter F; McCord, Bruce; Lurie, Ira S

    2017-09-01

    A comparison of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography for the separation of synthetic cathinones has been conducted. Nine different mixtures of bath salts were analyzed in this study. The three different chromatographic techniques were examined using a general set of controlled synthetic cathinones as well as a variety of other synthetic cathinones that exist as positional isomers. Overall 35 different synthetic cathinones were analyzed. A variety of column types and chromatographic modes were examined for developing each separation. For the ultra high performance supercritical fluid chromatography separations, analyses were performed using a series of Torus and Trefoil columns with either ammonium formate or ammonium hydroxide as additives, and methanol, ethanol or isopropanol organic solvents as modifiers. Ultra high performance liquid chromatographic separations were performed in both reversed phase and hydrophilic interaction chromatographic modes using SPP C18 and SPP HILIC columns. Gas chromatography separations were performed using an Elite-5MS capillary column. The orthogonality of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography was examined using principal component analysis. For the best overall separation of synthetic cathinones, the use of ultra high performance supercritical fluid chromatography in combination with gas chromatography is recommended. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Determination of pertechnetate by liquid chromatography with reductive electrochemical detection

    International Nuclear Information System (INIS)

    Lewis, J.Y.; Zodda, J.P.; Deutsch, E.; Heineman, W.R.

    1983-01-01

    A method utilizing liquid chromatography with electrochemical detection has been developed for the determination of total TcO 4 - (/sup 99m/TcO 4 - and /sup 99m/TcO 4 - ) in 99 Mo//sup 99m/Tc generator eluents. Pertechnetate, which is the starting material for the preparation of many diagnostic radiopharmaceuticals, is generally present in these eluents in the concentration range of 5 X 10 -8 M to 5 X 10 -6 M. No sample pretreatment is necessary since impurities and other components are separated by the high-pressure liquid chromatography (HPLC) NH 2 -bonded column. By use of both static mercury drop (SMDE) and solid electrode detectors, in conjuction with rigorous deoxygenation procedures, total TcO 4 - in generator eluents is readily determined. A severe electrode fouling phenomenon limits the use of solid electrode detectors to TcO 4 - concentrations less than 10 -7 M, the working range for a carbon electrode being 8.5 X 10 -9 to 1.0 X 10 -7 M. The working range for the SMDE is 2.1 X 10 -8 to 1.0 X 10 -4 M TcO 4 -

  15. Determination of four forms of vitamin B12 and other B vitamins in seawater by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Heal, Katherine R; Carlson, Laura Truxal; Devol, Allan H; Armbrust, E Virginia; Moffett, James W; Stahl, David A; Ingalls, Anitra E

    2014-11-30

    Vitamin B(12) is an essential nutrient for more than half of surveyed marine algae species, but methods for directly measuring this important cofactor in seawater are limited. Current mass spectrometry methods do not quantify all forms of B(12), potentially missing a significant portion of the B(12) pool. We present a method to measure vitamins B(1), B(2), B(6), B(7) and four forms of B(12) dissolved in seawater. The method entails solid-phase extraction, separation by ultra-performance liquid chromatography, and detection by triple-quadrupole tandem mass spectrometry using stable-isotope-labeled internal standards. We demonstrated the use of this method in the environment by analyzing B(12) concentrations at different depths in the Hood Canal, part of the Puget Sound estuarine system in Washington State. Recovery of vitamin B(12) forms during the preconcentration steps was >71% and the limits of detection were B(12) in seawater at our field site. We developed a method for quantifying four forms of B(12) in seawater by liquid chromatography/mass spectrometry with the option of simultaneous analysis of vitamins B(1), B(2), B(6), and B(7). We validated the method and demonstrated its application in the field. Copyright © 2014 John Wiley & Sons, Ltd.

  16. Description of Adsorption in Liquid Chromatography under Nonideal Conditions.

    Science.gov (United States)

    Ortner, Franziska; Ruppli, Chantal; Mazzotti, Marco

    2018-05-15

    A thermodynamically consistent description of binary adsorption in reversed-phase chromatography is presented, accounting for thermodynamic nonidealities in the liquid and adsorbed phases. The investigated system involves the adsorbent Zorbax 300SB-C18, as well as phenetole and 4- tert-butylphenol as solutes and methanol and water as inert components forming the eluent. The description is based on adsorption isotherms, which are a function of the liquid-phase activities, to account for nonidealities in the liquid phase. Liquid-phase activities are calculated with a UNIQUAC model established in this work, based on experimental phase equilibrium data. The binary interaction in the adsorbed phase is described by the adsorbed solution theory, assuming an ideal (ideal adsorbed solution theory) or real (real adsorbed solution theory) adsorbed phase. Implementation of the established adsorption model in a chromatographic code achieves a quantitative description of experimental elution profiles, with feed compositions exploiting the entire miscible region, and involving a broad range of different eluent compositions (methanol/water). The quantitative agreement of the model and experimental data serves as a confirmation of the underlying physical (thermodynamic) concepts and of their applicability to a broad range of operating conditions.

  17. Ultra-Performance Liquid Chromatographic Determination of Manufacturing Intermediates and Subsidiary Colors in D&C Red No. 6, D&C Red No. 7, and Their Lakes.

    Science.gov (United States)

    Perez-Gonzalez, Marianita; Vu, Nga; Harp, Bhakti Petigara

    2015-01-01

    An ultra-performance LC (UPLC) method was developed to determine the manufacturing intermediates and subsidiary colors in the monosulfo monoazo color additives D&C Red No. 6 and D&C Red No. 7 and their lakes. This method is intended for use in batch certification of the color additives by the U. S. Food and Drug Administration to ensure that each lot meets published specifications for coloring drugs and cosmetics. The intermediates are 2-amino-5-methylbenzenesulfonic acid (PTMS) and 3-hydroxy-2-naphthalenecarboxylic acid (3-hydroxy-2-naphthoic acid). The subsidiary colors are 3-hydroxy-4-[(4-methylphenyl)azo]-2-naphthalenecarboxylic acid (unsulfonated subsidiary color) and 1-[(4-methylphenyl) azo]-2-naphthalenol (4-methyl Sudan I). The analytes were identified by comparing their UPLC retention times and UV-Vis absorption spectra with those of standards. Validation studies showed that calibration curves were linear (average R2=0.9994), and recoveries were 96-106%. Average LOD was 0.0014-0.0061% and average LOQ was 0.0047-0.020%. Results for RSD at the specification levels ranged from 0.67 to 5.79%. Survey analyses of 42 samples from 14 domestic and foreign manufacturers yielded results by the new UPLC method and a previously reported HPLC method that were consistent within experimental error. The new UPLC method provided increased sensitivity, faster analysis times, and improved separations compared to the HPLC method.

  18. Purification of flavonoids from licorice using an off-line preparative two-dimensional normal-phase liquid chromatography/reversed-phase liquid chromatography method.

    Science.gov (United States)

    Fan, Yunpeng; Fu, Yanhui; Fu, Qing; Cai, Jianfeng; Xin, Huaxia; Dai, Mei; Jin, Yu

    2016-07-01

    An orthogonal (71.9%) off-line preparative two-dimensional normal-phase liquid chromatography/reversed-phase liquid chromatography method coupled with effective sample pretreatment was developed for separation and purification of flavonoids from licorice. Most of the nonflavonoids were firstly removed using a self-made Click TE-Cys (60 μm) solid-phase extraction. In the first dimension, an industrial grade preparative chromatography was employed to purify the crude flavonoids. Click TE-Cys (10 μm) was selected as the stationary phase that provided an excellent separation with high reproducibility. Ethyl acetate/ethanol was selected as the mobile phase owing to their excellent solubility for flavonoids. Flavonoids co-eluted in the first dimension were selected for further purification using reversed-phase liquid chromatography. Multiple compounds could be isolated from one normal-phase fraction and some compounds with bad resolution in one-dimensional liquid chromatography could be prepared in this two-dimensional system owing to the orthogonal separation. Moreover, this two-dimensional liquid chromatography method was beneficial for the preparation of relatively trace flavonoid compounds, which were enriched in the first dimension and further purified in the second dimension. Totally, 24 flavonoid compounds with high purity were obtained. The results demonstrated that the off-line two-dimensional liquid chromatography method was effective for the preparative separation and purification of flavonoids from licorice. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Evaluation between ultrahigh pressure liquid chromatography and high-performance liquid chromatography analytical methods for characterizing natural dyestuffs.

    Science.gov (United States)

    Serrano, Ana; van Bommel, Maarten; Hallett, Jessica

    2013-11-29

    An evaluation was undertaken of ultrahigh pressure liquid chromatography (UHPLC) in comparison to high-performance liquid chromatography (HPLC) for characterizing natural dyes in cultural heritage objects. A new UHPLC method was optimized by testing several analytical parameters adapted from prior UHPLC studies developed in diverse fields of research. Different gradient elution programs were tested on seven UHPLC columns with different dimensions and stationary phase compositions by applying several mobile phases, flow rates, temperatures, and runtimes. The UHPLC method successfully provided more improved data than that achieved by the HPLC method. Indeed, even though carminic acid has shown circa 146% higher resolution with HPLC, UHPLC resulted in an increase of 41-61% resolution and a decrease of 91-422% limit of detection, depending on the dye compound. The optimized method was subsequently assigned to analyse 59 natural reference materials, in which 85 different components were ascribed with different physicochemical properties, in order to create a spectral database for future characterization of dyes in cultural heritage objects. The majority of these reference samples could be successfully distinguished with one single method through the examination of these compounds' retention times and their spectra acquired with a photodiode array detector. These results demonstrate that UHPLC analyses are extremely valuable for the acquisition of more precise chromatographic information concerning natural dyes with complex mixtures of different and/or closely related physicochemical properties, essential for distinguishing similar species of plants and animals used to colour cultural heritage objects. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Method transfer from high-pressure liquid chromatography to ultra-high-pressure liquid chromatography. II. Temperature and pressure effects.

    Science.gov (United States)

    Åsberg, Dennis; Samuelsson, Jörgen; Leśko, Marek; Cavazzini, Alberto; Kaczmarski, Krzysztof; Fornstedt, Torgny

    2015-07-03

    The importance of the generated temperature and pressure gradients in ultra-high-pressure liquid chromatography (UHPLC) are investigated and compared to high-pressure liquid chromatography (HPLC). The drug Omeprazole, together with three other model compounds (with different chemical characteristics, namely uncharged, positively and negatively charged) were used. Calculations of the complete temperature profile in the column at UHPLC conditions showed, in our experiments, a temperature difference between the inlet and outlet of 16 °C and a difference of 2 °C between the column center and the wall. Through van't Hoff plots, this information was used to single out the decrease in retention factor (k) solely due to the temperature gradient. The uncharged solute was least affected by temperature with a decrease in k of about 5% while for charged solutes the effect was more pronounced, with k decreases up to 14%. A pressure increase of 500 bar gave roughly 5% increase in k for the uncharged solute, while omeprazole and the other two charged solutes gave about 25, 20 and 15% increases in k, respectively. The stochastic model of chromatography was applied to estimate the dependence of the average number of adsorption/desorption events (n) and the average time spent by a molecule in the stationary phase (τs) on temperature and pressure on peak shape for the tailing, basic solute. Increasing the temperature yielded an increase in n and decrease in τs which resulted in less skew at high temperatures. With increasing pressure, the stochastic modeling gave interesting results for the basic solute showing that the skew of the peak increased with pressure. The conclusion is that pressure effects are more pronounced for both retention and peak shape than the temperature effects for the polar or charged compounds in our study. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Rapid methods to determine procyanidins, anthocyanins, theobromine and caffeine in rat tissues by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Serra, Aida; Macià, Alba; Romero, Maria-Paz; Piñol, Carme; Motilva, Maria-José

    2011-06-01

    Rapid, selective and sensitive methods were developed and validated to determine procyanidins, anthocyanins and alkaloids in different biological tissues, such as liver, brain, the aorta vein and adipose tissue. For this purpose, standards of procyanidins (catechin, epicatechin, and dimer B(2)), anthocyanins (cyanidin-3-glucoside and malvidin-3-glucoside) and alkaloids (theobromine, caffeine and theophylline) were used. The methods included the extraction of homogenized tissues by off-line liquid-solid extraction, and then solid-phase extraction to analyze alkaloids, or microelution solid-phase extraction plate for the analysis of procyanidins and anthocyanins. The eluted extracts were then analyzed by ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry, using a triple quadrupole as the analyzer. The optimum extraction solution was water/methanol/phosphoric acid 4% (94/4.5/1.5, v/v/v). The extraction recoveries were higher than 81% for all the studied compounds in all the tissues, except the anthocyanins, which were between 50 and 65% in the liver and brain. In order to show the applicability of the developed methods, different rat tissues were analyzed to determine the procyanidins, anthocyanins and alkaloids and their generated metabolites. The rats had previously consumed 1g of a grape pomace extract (to analyze procyanidins and anthocyanins) or a cocoa extract (to analyze alkaloids) per kilogram of body weight. Different tissues were extracted 4h after administration of the respective extracts. The analysis of the metabolites revealed a hepatic metabolism of procyanidins. The liver was the tissue which produced a greater accumulation of these metabolites. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. (Vapour + liquid) equilibria of ternary systems with ionic liquids using headspace gas chromatography

    International Nuclear Information System (INIS)

    Mokhtarani, Babak; Gmehling, Juergen

    2010-01-01

    (Vapour + liquid) equilibrium (VLE) data for the ternary systems (hexane + benzene), (hexane + cyclohexane), (benzene + cyclohexane), and (ethanol + water) with an ionic liquid as entrainer for extractive distillation were measured by headspace gas chromatography. As ionic liquids, 1-hexyl-3-methyl-imidazolium bis (trifluoromethyl-sulfonyl) imide [HMIM][BTI], 1-octyl-3-methyl-imidazolium bis (trifluoromethyl-sulfonyl) imide [OMIM][BTI], 1-octyl-3-methyl-imidazolium trifluoro-methanesulfonate [OMIM][OTF], and 1-butyl-3-methyl-imidazolium trifluoro-methanesulfonate [BMIM][OTF] were used. The experimental data show that the ionic liquids investigated have a great influence on the separation factors of the systems (hexane + benzene), (hexane + cyclohexane), and (benzene + cyclohexane). The experimental data were compared with the predicted results using mod. UNIFAC (Do). The predicted results are in good agreement with the experimental data.

  3. (Vapour + liquid) equilibria of ternary systems with ionic liquids using headspace gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtarani, Babak [Chemistry and Chemical Engineering Research Center of Iran, P.O. Box 14335-186, Tehran (Iran, Islamic Republic of); Gmehling, Juergen, E-mail: gmehling@tech.chem.uni-oldenburg.d [Carl von Ossietzky Universitaet Oldenburg, Technische Chemie, D-26111 Oldenburg (Germany)

    2010-08-15

    (Vapour + liquid) equilibrium (VLE) data for the ternary systems (hexane + benzene), (hexane + cyclohexane), (benzene + cyclohexane), and (ethanol + water) with an ionic liquid as entrainer for extractive distillation were measured by headspace gas chromatography. As ionic liquids, 1-hexyl-3-methyl-imidazolium bis (trifluoromethyl-sulfonyl) imide [HMIM][BTI], 1-octyl-3-methyl-imidazolium bis (trifluoromethyl-sulfonyl) imide [OMIM][BTI], 1-octyl-3-methyl-imidazolium trifluoro-methanesulfonate [OMIM][OTF], and 1-butyl-3-methyl-imidazolium trifluoro-methanesulfonate [BMIM][OTF] were used. The experimental data show that the ionic liquids investigated have a great influence on the separation factors of the systems (hexane + benzene), (hexane + cyclohexane), and (benzene + cyclohexane). The experimental data were compared with the predicted results using mod. UNIFAC (Do). The predicted results are in good agreement with the experimental data.

  4. Reduction of silanophilic interactions in liquid chromatography with the use of ionic liquids

    International Nuclear Information System (INIS)

    MarszaII, MichaI Piotr; Baczek, Tomasz; Kaliszan, Roman

    2005-01-01

    A suppression of silanophilic interactions by the selected ionic liquids added to the mobile phase in thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) is reported. Acetonitrile was used as the eluent, alone or with various concentrations of water and phosphoric buffer pH 3. Selectivity of the normal (NP) and the reversed (RP) stationary phase material was examined using a series of proton-acceptor basic drugs analytes. The ionic liquids studied appeared to significantly affect analyte retention in NP-TLC, RP-TLC and RP-HPLC systems tested. Consequently, the increased separation selectivity was attained. Due to ionic liquid additives to eluent even analytes could be chromatographed, which were not eluted from the silica-based stationary phase materials with 100% of acetonitrile in the mobile phase. Addition of ionic liquid already in very small concentration (0.5%, v/v) could reduce the amount of acetonitrile used during the optimization of basic analytes separations in TLC and HPLC systems. Moreover, the influence of temperature on the separation of basic analytes was demonstrated and considered in practical HPLC method development

  5. Reduction of silanophilic interactions in liquid chromatography with the use of ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    MarszaII, MichaI Piotr [Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdansk, Gen. J. Hallera 107, 80-416 Gdansk (Poland); Baczek, Tomasz [Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdansk, Gen. J. Hallera 107, 80-416 Gdansk (Poland); Kaliszan, Roman [Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdansk, Gen. J. Hallera 107, 80-416 Gdansk (Poland)]. E-mail: roman.kaliszan@amg.gda.pl

    2005-08-22

    A suppression of silanophilic interactions by the selected ionic liquids added to the mobile phase in thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) is reported. Acetonitrile was used as the eluent, alone or with various concentrations of water and phosphoric buffer pH 3. Selectivity of the normal (NP) and the reversed (RP) stationary phase material was examined using a series of proton-acceptor basic drugs analytes. The ionic liquids studied appeared to significantly affect analyte retention in NP-TLC, RP-TLC and RP-HPLC systems tested. Consequently, the increased separation selectivity was attained. Due to ionic liquid additives to eluent even analytes could be chromatographed, which were not eluted from the silica-based stationary phase materials with 100% of acetonitrile in the mobile phase. Addition of ionic liquid already in very small concentration (0.5%, v/v) could reduce the amount of acetonitrile used during the optimization of basic analytes separations in TLC and HPLC systems. Moreover, the influence of temperature on the separation of basic analytes was demonstrated and considered in practical HPLC method development.

  6. Hydrophilic interaction liquid chromatography in the speciation analysis of selenium.

    Science.gov (United States)

    Sentkowska, Aleksandra; Pyrzynska, Krystyna

    2018-02-01

    The hydrophilic interaction liquid chromatography (HILIC) coupled to mass spectrometry was employed to study retention behavior of selected selenium compounds using two different HILIC stationary phases: silica and zwitterionic. Two organic solvents - acetonitrile and methanol - were compared as a component of mobile phase. Separation parameters such as a content of organic modifier, the eluent pH and inorganic buffer concentration were investigated. Based on all observations, methanol seems to be beneficial for the separation of studied compounds. The optimal HILIC separation method involved silica column and eluent composed of 85% MeOH and CH 3 COONH 4 (8 mM, pH 7) was compared to RP method in terms of time of the single run, the separation efficiency and limit of detection. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Cortisol production rates measured by liquid chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Esteban, N.V.; Yergey, A.L.

    1990-01-01

    Cortisol production rates (FPRs) in physiologic and pathologic states in humans have been investigated over the past 30 years. However, there has been conflicting evidence concerning the validity of the currently accepted value of FPRs in humans (12 to 15 mg/m2/d) as determined by radiotracer methodology. The present study reviews previous methods proposed for the measurement of FPRs in humans and discusses the applications of the first method for the direct determination of 24-hour plasma FPRs during continuous administration of a stable isotope, using a thermospray high-pressure liquid chromatography-mass spectrometry technique. The technique is fast, sensitive, and, unlike gas chromatography-mass spectrometry methods, does not require derivatization, allowing on-line detection and quantification of plasma cortisol after a simple extraction procedure. The results of determination of plasma FPRs by stable tracer/mass spectrometry are directly in units of mass/time and, unlike radiotracer methods, are independent of any determination of volume of distribution or cortisol concentration. Our methodology offers distinct advantages over radiotracer techniques in simplicity and reliability since only single measurements of isotope ratios are required. The technique was validated in adrenalectomized patients. Circadian variations in daily FRPs were observed in normal volunteers, and, to date, results suggest a lower FRP in normal children and adults than previously believed. 88 references

  8. Modern Aspects Of Fluorometric Detection In Liquid-Phase Chromatography

    Science.gov (United States)

    Bousquet, Bernard; Garnier, Jean P.; Dreux, Claude

    1983-10-01

    Recent advances are described in the combined use of fluorometric derivatization and high performance liquid chromatography (HPLC) for clinical chemistry determinations. Derivatives (especially dansyl derivatives) can be formed prior to chromatography in the case of estrogens, amino acids, and catecholamines. In post-column reactions, we preferred to use air-segmented reactions as they conform better to all the optimized chromatographic and spectrofluorometric parameters. Fluorescent derivatives produced from cate-cholamines, tryptophan and its metabolites, hydroxyindoles, tryptamine, amino acids, sugars, polyamines, and other substances are often sufficiently sensitive to be detected in picogram quantities by HPLC. Their reaction principle and some of their applications to samples are described. Recently, chemical excitation of fluorophore-like dansyl amino acid was proposed as a detection system for HPLC. By a post-column reaction, a fluorophore can be made to emit light by its reaction with trichlorophenyl oxalate (TCPO) and hydrogen peroxide. The detection limit of this system is about 10 fmol for each dansyl amino acid. Application of this new reaction to catecholamines opens up new prospects for fluorometric detection.

  9. Group type analysis of asphalt by column liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, C.; Yang, J.; Xue, Y.; Li, Y. [Chinese Academy of Science, Taiyuan (China)

    2008-07-01

    An improved analysis method for characterization of asphalt was established. The method is based on column chromatography technique. The asphalts were separated into four groups: saturates, aromatics, resins, and asphaltenes, quantitatively. About 0.1 g of sample was required in each analysis. About 20 mL of n-heptanes was used to separate out saturates first. Then about 35 mL of n-heptanes/dichloromethane (.5, v/v) mixture was used to separate out aromatics. About 30 mL of dichloromethane/tetrahydrofuran (1/3, v/v) mixture was used to separate out resin. The quality of the separation was confirmed by infrared spectra (IR) and {sup 1}H NMR analysis. The model compounds, tetracosan for saturates, dibenz(o)anthracen for aromatics, and acetanilide for resins were used for verification. The IR and {sup 1}H NMR analysis of the prepared fractions from the column liquid chromatography were in good agreement that of pure reagents.

  10. Fast and parallel determination of PCB 77 and PCB 180 in plasma using ultra performance liquid chromatography with diode array detection: A pharmacokinetic study in Swiss albino mouse.

    Science.gov (United States)

    Ramanujam, N; Sivaselvakumar, M; Ramalingam, S

    2017-11-01

    A simple, sensitive and reproducible ultra-performance liquid chromatography (UPLC) method has been developed and validated for simultaneous estimation of polychlorinated biphenyl (PCB) 77 and PCB 180 in mouse plasma. The sample preparation was performed by simple liquid-liquid extraction technique. The analytes were chromatographed on a Waters Acquity H class UPLC system using isocratic mobile phase conditions at a flow rate of 0.3 mL/min and Acquity UPLC BEH shield RP 18 column maintained at 35°C. Quantification was performed on a photodiode array detector set at 215 nm and PCB 101 was used as internal standard (IS). PCB 77, PCB 180, and IS retention times were 2.6, 4.7 and 2.8 min, respectively, and the total run time was 6 min. The method was validated for specificity, selectivity, recovery, linearity, accuracy, precision and sample stability. The calibration curve was linear over the concentration range 10-3000 ng/mL for PCB 77 and PCB 180. Intra- and inter-day precisions for PCBs 77 and 180 were found to be good with CV <4.64%, and the accuracy ranged from 98.90 to 102.33% in mouse plasma. The validated UPLC method was successfully applied to the pharmacokinetic study of PCBs 77 and 180 in mouse plasma. Copyright © 2017 John Wiley & Sons, Ltd.

  11. Analytical method for high resolution liquid chromatography for quality control French Macaw

    International Nuclear Information System (INIS)

    Garcia Penna, Caridad M; Torres Amaro, Leonid; Menendez Castillo, Rosa; Sanchez, Esther; Martinez Espinosa, Vivian; Gonzalez, Maria Lidia; Rodriguez, Carlos

    2007-01-01

    Was developed and validated an analytical method for high resolution liquid chromatography applicable to quality control of drugs dry French Macaw (Senna alata L. Roxb.) With ultraviolet detection at 340 nm. The method for high resolution liquid chromatography used to quantify the sennosides A and B, main components, was validated and proved to be specific, linear, precise and accurate. (Author)

  12. Recent advances in ultra-high performance liquid chromatography for the analysis of traditional chinese medicine

    Science.gov (United States)

    Traditional Chinese medicines (TCMs) have been widely used for the prevention and treatment of various diseases for thousands of years in China. Ultra Performance Liquid Chromatography (UHPLC) is a relatively new technique offering new possibilities in liquid chromatography. This paper reviews recen...

  13. Investigating the Retention Mechanisms of Liquid Chromatography Using Solid-Phase Extraction Cartridges

    Science.gov (United States)

    O'Donnell, Mary E.; Musial, Beata A.; Bretz, Stacey Lowery; Danielson, Neil D.; Ca, Diep

    2009-01-01

    Liquid chromatography (LC) experiments for the undergraduate analytical laboratory course often illustrate the application of reversed-phase LC to solve a separation problem, but rarely compare LC retention mechanisms. In addition, a high-performance liquid chromatography instrument may be beyond what some small colleges can purchase. Solid-phase…

  14. Towards Chip Scale Liquid Chromatography and High Throughput Immunosensing

    Energy Technology Data Exchange (ETDEWEB)

    Ni, Jing [Iowa State Univ., Ames, IA (United States)

    2000-09-21

    This work describes several research projects aimed towards developing new instruments and novel methods for high throughput chemical and biological analysis. Approaches are taken in two directions. The first direction takes advantage of well-established semiconductor fabrication techniques and applies them to miniaturize instruments that are workhorses in analytical laboratories. Specifically, the first part of this work focused on the development of micropumps and microvalves for controlled fluid delivery. The mechanism of these micropumps and microvalves relies on the electrochemically-induced surface tension change at a mercury/electrolyte interface. A miniaturized flow injection analysis device was integrated and flow injection analyses were demonstrated. In the second part of this work, microfluidic chips were also designed, fabricated, and tested. Separations of two fluorescent dyes were demonstrated in microfabricated channels, based on an open-tubular liquid chromatography (OT LC) or an electrochemically-modulated liquid chromatography (EMLC) format. A reduction in instrument size can potentially increase analysis speed, and allow exceedingly small amounts of sample to be analyzed under diverse separation conditions. The second direction explores the surface enhanced Raman spectroscopy (SERS) as a signal transduction method for immunoassay analysis. It takes advantage of the improved detection sensitivity as a result of surface enhancement on colloidal gold, the narrow width of Raman band, and the stability of Raman scattering signals to distinguish several different species simultaneously without exploiting spatially-separated addresses on a biochip. By labeling gold nanoparticles with different Raman reporters in conjunction with different detection antibodies, a simultaneous detection of a dual-analyte immunoassay was demonstrated. Using this scheme for quantitative analysis was also studied and preliminary dose-response curves from an immunoassay of a

  15. Determination of sulfonamides in butter samples by ionic liquid magnetic bar liquid-phase microextraction high-performance liquid chromatography.

    Science.gov (United States)

    Wu, Lijie; Song, Ying; Hu, Mingzhu; Xu, Xu; Zhang, Hanqi; Yu, Aimin; Ma, Qiang; Wang, Ziming

    2015-01-01

    A novel, simple, and environmentally friendly pretreatment method, ionic liquid magnetic bar liquid-phase microextraction, was developed for the determination of sulfonamides in butter samples by high-performance liquid chromatography. The ionic liquid magnetic bar was prepared by inserting a stainless steel wire into the hollow of a hollow fiber and immobilizing ionic liquid in the micropores of the hollow fiber. In the extraction process, the ionic liquid magnetic bars were used to stir the mixture of sample and extraction solvent and enrich the sulfonamides in the mixture. After extraction, the analyte-adsorbed ionic liquid magnetic bars were readily isolated with a magnet from the extraction system. It is notable that the present method was environmentally friendly since water and only several microliters of ionic liquid were used in the whole extraction process. Several parameters affecting the extraction efficiency were investigated and optimized, including the type of ionic liquid, sample-to-extraction solvent ratio, the number of ionic liquid magnetic bars, extraction temperature, extraction time, salt concentration, stirring speed, pH of the extraction solvent, and desorption conditions. The recoveries were in the range of 73.25-103.85 % and the relative standard deviations were lower than 6.84 %. The experiment results indicated that the present method was effective for the extraction of sulfonamides in high-fat content samples.

  16. Analysis of short-chain acids from anaerobic bacteria by high-performance liquid chromatography.

    OpenAIRE

    Guerrant, G O; Lambert, M A; Moss, C W

    1982-01-01

    A standard mixture of 25 short-chain fatty acids was resolved by high-performance liquid chromatography, using an Aminex HPX-87 column. The acids produced in culture media by anaerobic bacteria were analyzed by high-performance liquid chromatography after extraction with ether and reextraction into a small volume of 0.1 N NaOH. The presence of fumaric acid in culture extracts of Peptostreptococcus anaerobius was confirmed by gas chromatography-mass spectrometry analysis of the trapped eluent ...

  17. Quantitation of Metformin in Human Plasma and Urine by Hydrophilic Interaction Liquid Chromatography and Application to a Pharmacokinetic Study

    DEFF Research Database (Denmark)

    Nielsen, Flemming; Hougaard Christensen, Mette Marie; Brøsen, Kim

    2014-01-01

    : We describe an analytical method for the quantification of the widely used antihyperglycemic agent, metformin, in human plasma and urine. The separation was performed using isocratic hydrophilic interaction liquid chromatography on a Luna hydrophilic interaction liquid chromatography column (125...

  18. Phytochemical Profile of Erythrina variegata by Using High-Performance Liquid Chromatography and Gas Chromatography-Mass Spectroscopy Analyses

    OpenAIRE

    Suriyavathana Muthukrishnan; Subha Palanisamy; Senthilkumar Subramanian; Sumathi Selvaraj; Kavitha Rani Mari; Ramalingam Kuppulingam

    2016-01-01

    Natural products derived from plant sources have been utilized to treat patients with numerous diseases. The phytochemical constituents present in ethanolic leaf extract of Erythrina variegata (ELEV) were identified by using high-performance liquid chromatography (HPLC) and gas chromatography-mass spectroscopy (GC-MS) analyses. Shade dried leaves were powdered and extracted with ethanol for analyses through HPLC to identify selected flavonoids and through GC-MS to identify other molecules. Th...

  19. Study of Separation and Identification of the Active Ingredients in Gardenia jasminoides Ellis Based on a Two-Dimensional Liquid Chromatography by Coupling Reversed Phase Liquid Chromatography and Hydrophilic Interaction Liquid Chromatography.

    Science.gov (United States)

    Zhou, Xuan; Chen, Cen; Ye, Xiaolan; Song, Fenyun; Fan, Guorong; Wu, Fuhai

    2017-01-01

    In this paper, by coupling reversed phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC), a two-dimensional liquid chromatography system was developed for separation and identification of the active ingredients in Gardenia jasminoides Ellis (GJE). By applying the semi-preparative C18 column as the first dimension and the core-shell column as the second dimension, a total of 896 peaks of GJE were separated. Among the 896 peaks, 16 active ingredients including geniposide, gardenoside, gardoside, etc. were identified by mass spectrometry analysis. The results indicated that the proposed two-dimensional RPLC/HILIC system was an effective method for the analysis of GJE and might hold a high potential to become a useful tool for analysis of other complex mixtures. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Characterization and quantitative analysis of surfactants in textile wastewater by liquid chromatography/quadrupole-time-of-flight mass spectrometry.

    Science.gov (United States)

    González, Susana; Petrović, Mira; Radetic, Maja; Jovancic, Petar; Ilic, Vesna; Barceló, Damià

    2008-05-01

    A method based on the application of ultra-performance liquid chromatography (UPLC) coupled to hybrid quadrupole-time-of-flight mass spectrometry (QqTOF-MS) with an electrospray (ESI) interface has been developed for the screening and confirmation of several anionic and non-ionic surfactants: linear alkylbenzenesulfonates (LAS), alkylsulfate (AS), alkylethersulfate (AES), dihexyl sulfosuccinate (DHSS), alcohol ethoxylates (AEOs), coconut diethanolamide (CDEA), nonylphenol ethoxylates (NPEOs), and their degradation products (nonylphenol carboxylate (NPEC), octylphenol carboxylate (OPEC), 4-nonylphenol (NP), 4-octylphenol (OP) and NPEO sulfate (NPEO-SO4). The developed methodology permits reliable quantification combined with a high accuracy confirmation based on the accurate mass of the (de)protonated molecules in the TOFMS mode. For further confirmation of the identity of the detected compounds the QqTOF mode was used. Accurate masses of product ions obtained by performing collision-induced dissociation (CID) of the (de)protonated molecules of parent compounds were matched with the ions obtained for a standard solution. The method was applied for the quantitative analysis and high accuracy confirmation of surfactants in complex mixtures in effluents from the textile industry. Positive identification of the target compounds was based on accurate mass measurement of the base peak, at least one product ion and the LC retention time of the analyte compared with that of a standard. The most frequently surfactants found in these textile effluents were NPEO and NPEO-SO4 in concentrations ranging from 0.93 to 5.68 mg/L for NPEO and 0.06 to 4.30 mg/L for NPEO-SO4. AEOs were also identified.

  1. Determination of Organic Pollutants in Small Samples of Groundwaters by Liquid-Liquid Extraction and Capillary Gas Chromatography

    DEFF Research Database (Denmark)

    Harrison, I.; Leader, R.U.; Higgo, J.J.W.

    1994-01-01

    A method is presented for the determination of 22 organic compounds in polluted groundwaters. The method includes liquid-liquid extraction of the base/neutral organics from small, alkaline groundwater samples, followed by derivatisation and liquid-liquid extraction of phenolic compounds after neu...... neutralisation. The extracts were analysed by capillary gas chromatography. Dual detection by flame Ionisation and electron capture was used to reduce analysis time....

  2. Investigation of the effect of plasma albumin levels on regorafenib-induced hepatotoxicity using a validated liquid chromatography-tandem mass spectrometry method.

    Science.gov (United States)

    Pang, Yi Yun; Tan, Yeong Lan; Ho, Han Kiat

    2017-09-01

    Regorafenib is an oral multikinase inhibitor indicated for metastatic colorectal cancer and gastrointestinal stromal tumour. Due to its extensive plasma protein binding and low calculated hepatic extraction ratio, the hepatotoxicity observed with usage of the drug may be related to its plasma exposure. To investigate the highly dynamic free:bound drug concentration for regorafenib in the plasma, a bioanalytical liquid chromatography-tandem mass spectrometric assay was developed and validated in human plasma. The concentration range of the assay was 2-1000ng/mL. Sample preparation was via protein precipitation using acetonitrile with sorafenib as the internal standard. The supernatant was injected into an ultra-performance liquid chromatographic system coupled to a triple quadrupole mass spectrometer. The analytes were separated on an AQUITY UPLC BEH C 18 column (120Å, 1.7μm, 2.1mm×50mm) and eluted with a gradient elution system. The ions were detected in multiple reaction monitoring mode. The linearity, lower limit of quantification, intra-day and inter-day precision and accuracy conformed to FDA guidelines. The validated method was successfully applied to determine the effect of albumin levels in plasma on the extent of protein binding of regorafenib. The results indicated that physiologically-relevant levels of albumin were found to have no significant effect on the extent of protein binding of regorafenib, hence imposing minimal effect on drug disposition. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Unified pH values of liquid chromatography mobile phases.

    Science.gov (United States)

    Suu, Agnes; Jalukse, Lauri; Liigand, Jaanus; Kruve, Anneli; Himmel, Daniel; Krossing, Ingo; Rosés, Martí; Leito, Ivo

    2015-03-03

    This work introduces a conceptually new approach of measuring pH of mixed-solvent liquid chromatography (LC) mobile phases. Mobile phase pH is very important in LC, but its correct measurement is not straightforward, and all commonly used approaches have deficiencies. The new approach is based on the recently introduced unified pH (pH(abs)) scale, which enables direct comparison of acidities of solutions made in different solvents based on chemical potential of the proton in the solutions. This work represents the first experimental realization of the pH(abs) concept using differential potentiometric measurement for comparison of the chemical potentials of the proton in different solutions (connected by a salt bridge), together with earlier published reference points for obtaining the pH(abs) values (referenced to the gas phase) or pH(abs)(H₂O) values (referenced to the aqueous solution). The liquid junction potentials were estimated in the framework of Izutsu's three-component method. pH(abs) values for a number of common LC and LC-MS mobile phases have been determined. The pH(abs) scale enables for the first time direct comparison of acidities of any LC mobile phases, with different organic additives, different buffer components, etc. A possible experimental protocol of putting this new approach into chromatographic practice has been envisaged and its applicability tested. It has been demonstrated that the ionization behavior of bases (cationic acids) in the mobile phases can be better predicted by using the pH(abs)(H₂O) values and aqueous pKa values than by using the alternative means of expressing mobile phase acidity. Description of the ionization behavior of acids on the basis of pH(abs)(H₂O) values is possible if the change of their pKa values with solvent composition change is taken into account.

  4. Liquid chromatography-mass spectrometry in forensic toxicology.

    Science.gov (United States)

    Van Bocxlaer, J F; Clauwaert, K M; Lambert, W E; Deforce, D L; Van den Eeckhout, E G; De Leenheer, A P

    2000-01-01

    Liquid chromatography-mass spectrometry has evolved from a topic of mainly research interest into a routinely usable tool in various application fields. With the advent of new ionization approaches, especially atmospheric pressure, the technique has established itself firmly in many areas of research. Although many applications prove that LC-MS is a valuable complementary analytical tool to GC-MS and has the potential to largely extend the application field of mass spectrometry to hitherto "MS-phobic" molecules, we must recognize that the use of LC-MS in forensic toxicology remains relatively rare. This rarity is all the more surprising because forensic toxicologists find themselves often confronted with the daunting task of actually searching for evidence materials on a scientific basis without any indication of the direction in which to search. Through the years, mass spectrometry, mainly in the GC-MS form, has gained a leading role in the way such quandaries are tackled. The advent of robust, bioanalytically compatible combinations of liquid chromatographic separation with mass spectrometric detection really opens new perspectives in terms of mass spectrometric identification of difficult molecules (e.g., polar metabolites) or biopolymers with toxicological relevance, high throughput, and versatility. Of course, analytical toxicologists are generally mass spectrometry users rather than mass spectrometrists, and this difference certainly explains the slow start of LC-MS in this field. Nevertheless, some valuable applications have been published, and it seems that the introduction of the more universal atmospheric pressure ionization interfaces really has boosted interests. This review presents an overview of what has been realized in forensic toxicological LC-MS. After a short introduction into LC-MS interfacing operational characteristics (or limitations), it covers applications that range from illicit drugs to often abused prescription medicines and some

  5. Identification of novel autophagic Radix Polygalae fraction by cell membrane chromatography and UHPLC-(Q)TOF-MS for degradation of neurodegenerative disease proteins

    OpenAIRE

    An-Guo Wu; Vincent Kam-Wai Wong; Wu Zeng; Liang Liu; Betty Yuen-Kwan Law

    2015-01-01

    With its traditional use in relieving insomnia and anxiety, our previous study has identified onjisaponin B from Radix Polygalae (RP), as a novel autophagic enhancer with potential neuroprotective effects. In current study, we have further identified a novel active fraction from RP, contains 17 major triterpenoid saponins including the onjisaponin B, by the combinational use of cell membrane chromatography (CMC) and ultra-performance liquid chromatography coupled to (quadrupole) time-of-fligh...

  6. Microcystin Detection Characteristics of Fluorescence Immunochromatography and High Performance Liquid Chromatography

    International Nuclear Information System (INIS)

    Pyo, Dong Jin; Park, Geun Young; Choi, Jong Chon; Oh, Chang Suk

    2005-01-01

    Different detection characteristics of fluorescence immunochromatography method and high performance liquid chromatography (HPLC) method for the analysis of cyanobacterial toxins were studied. In particular, low and high limits of detection, detection time and reproducibility and detectable microcystin species were compared when fluorescence immunochromatography method and high performance liquid chromatography method were applied for the detection of microcystin (MC), a cyclic peptide toxin of the freshwater cyanobacterium Microcystis aeruginosa. A Fluorescence immunochromatography assay system has the unique advantages of short detection time and low detection limit, and high performance liquid chromatography detection method has the strong advantage of individual quantifications of several species of microcystins

  7. Simultaneous analysis for water- and fat-soluble vitamins by a novel single chromatography technique unifying supercritical fluid chromatography and liquid chromatography.

    Science.gov (United States)

    Taguchi, Kaori; Fukusaki, Eiichiro; Bamba, Takeshi

    2014-10-03

    Chromatography techniques usually use a single state in the mobile phase, such as liquid, gas, or supercritical fluid. Chromatographers manage one of these techniques for their purpose but are sometimes required to use multiple methods, or even worse, multiple techniques when the target compounds have a wide range of chemical properties. To overcome this challenge, we developed a single method covering a diverse compound range by means of a "unified" chromatography which completely bridges supercritical fluid chromatography and liquid chromatography. In our method, the phase state was continuously changed in the following order; supercritical, subcritical and liquid. Moreover, the gradient of the mobile phase starting at almost 100% CO2 was replaced with 100% methanol at the end completely. As a result, this approach achieved further extension of the polarity range of the mobile phase in a single run, and successfully enabled the simultaneous analysis of fat- and water-soluble vitamins with a wide logP range of -2.11 to 10.12. Furthermore, the 17 vitamins were exceptionally separated in 4min. Our results indicated that the use of dense CO2 and the replacement of CO2 by methanol are practical approaches in unified chromatography covering diverse compounds. Additionally, this is a first report to apply the novel approach to unified chromatography, and can open another door for diverse compound analysis in a single chromatographic technique with single injection, single column and single system. Copyright © 2014. Published by Elsevier B.V.

  8. Investigation of Symphytum cordatum alkaloids by liquid-liquid partitioning, thin-layer chromatography and liquid chromatography-ion-trap mass spectrometry

    International Nuclear Information System (INIS)

    Mroczek, Tomasz; Ndjoko-Ioset, Karine; Glowniak, Kazimierz; Mietkiewicz-Capala, Agnieszka; Hostettmann, Kurt

    2006-01-01

    From the alkalised crude extract of Symphytum cordatum (L.) W.K. roots, pyrrolizidine alkaloids (PAs) were extracted as free tertiary bases and polar N-oxides in a merely one-step liquid-liquid partitioning (LLP) in separation funnel and subsequently pre-fractionated by preparative multiple-development (MD) thin-layer chromatography (TLC) on silica gel plates. In this way three alkaloid fractions of different polarities and retention on silica gel plates were obtained as: the most polar N-oxides of the highest retention, the tertiary bases of medium retention, and diesterified N-oxides of the lowest retention. The former fraction was reduced into free bases by sodium hydrosulfite and purified by LLP on Extrelut-NT3 cartridge. It was further analysed together with the two other fractions by high-performance liquid chromatography (HPLC)-ion-trap mass spectrometry with atmospheric pressure chemical ionization (APCI) interface on XTerra C 18 column using a gradient elution. Based on MS n spectra, 18 various alkaloids have been tentatively determined for the first time in this plant as the following types of structure: echimidine-N-oxide (three diasteroisomers), 7-sarracinyl-9-viridiflorylretronecine (two diasteroisomers), echimidine (two diasteroisomers), lycopsamine (two diasteroisomers), dihydroechinatine-N-oxide, dihydroheliospathuline-N-oxide, lycopsamine-N-oxide (three diasteroisomers), 7-acetyllycopsamine-N-oxide, symphytine-N-oxide (two diasteroisomers) and 2'',3''-epoxyechiumine-N-oxide

  9. Investigation of Symphytum cordatum alkaloids by liquid-liquid partitioning, thin-layer chromatography and liquid chromatography-ion-trap mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Mroczek, Tomasz [Department of Pharmacognosy with Medicinal Plants Laboratory, Medical University, 1 Chodzki St., 20-093 Lublin (Poland)]. E-mail: tmroczek@pharmacognosy.org; Ndjoko-Ioset, Karine [Laboratoire de Pharmacognosie et Phytochimie, Ecole de Pharmacie Geneve-Lausanne, Universite de Geneve, Quai Ernest-Ansermet 30, CH-1211 Geneva 4 (Switzerland); Glowniak, Kazimierz [Department of Pharmacognosy with Medicinal Plants Laboratory, Medical University, 1 Chodzki St., 20-093 Lublin (Poland); Mietkiewicz-Capala, Agnieszka [Department of Pharmacognosy with Medicinal Plants Laboratory, Medical University, 1 Chodzki St., 20-093 Lublin (Poland); Hostettmann, Kurt [Laboratoire de Pharmacognosie et Phytochimie, Ecole de Pharmacie Geneve-Lausanne, Universite de Geneve, Quai Ernest-Ansermet 30, CH-1211 Geneva 4 (Switzerland)

    2006-05-04

    From the alkalised crude extract of Symphytum cordatum (L.) W.K. roots, pyrrolizidine alkaloids (PAs) were extracted as free tertiary bases and polar N-oxides in a merely one-step liquid-liquid partitioning (LLP) in separation funnel and subsequently pre-fractionated by preparative multiple-development (MD) thin-layer chromatography (TLC) on silica gel plates. In this way three alkaloid fractions of different polarities and retention on silica gel plates were obtained as: the most polar N-oxides of the highest retention, the tertiary bases of medium retention, and diesterified N-oxides of the lowest retention. The former fraction was reduced into free bases by sodium hydrosulfite and purified by LLP on Extrelut-NT3 cartridge. It was further analysed together with the two other fractions by high-performance liquid chromatography (HPLC)-ion-trap mass spectrometry with atmospheric pressure chemical ionization (APCI) interface on XTerra C{sub 18} column using a gradient elution. Based on MS {sup n} spectra, 18 various alkaloids have been tentatively determined for the first time in this plant as the following types of structure: echimidine-N-oxide (three diasteroisomers), 7-sarracinyl-9-viridiflorylretronecine (two diasteroisomers), echimidine (two diasteroisomers), lycopsamine (two diasteroisomers), dihydroechinatine-N-oxide, dihydroheliospathuline-N-oxide, lycopsamine-N-oxide (three diasteroisomers), 7-acetyllycopsamine-N-oxide, symphytine-N-oxide (two diasteroisomers) and 2'',3''-epoxyechiumine-N-oxide.

  10. Electrochemically modulated liquid chromatography: Theoretical investigations and applications from the perspectives of chromatography and interfacial electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Keller, David W. [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    Electrochemically modulated liquid chromatography (EMLC) employs a conductive material as both a stationary phase for chromatographic separations and as a working electrode for performing electrochemistry experiments. This dual functionality gives EMLC the capacity to manipulate chromatographic separations by changing the potential applied (Eapp) to the stationary phase with respect to an external reference. The ability to monitor retention as a function of Eapp provides a means to chromatographically monitor electrosorption processes at solid-liquid interfaces. In this dissertation, the retention mechanism for EMLC is examined from the perspective of electrical double layer theory and interfacial thermodynamics. From the chromatographic data, it is possible to determine the interfacial excess (Λ) of a solute and changes in interfacial tension (dγ) as a function of both Eapp and the supporting electrolyte concentration. Taken together, these two experimentally manipulated parameters can be examined within the context of the Gibbs adsorption equation to delineate the contribution of a variety of interfacial properties, including the charge of solute on the stationary phase and the potential of zero charge (PZC), to the mechanism behind EMLC-based retention. The chromatographic probing of interfacial phenomena is complemented by electroanalytical experiments that exploit the ability to monitor the electronic current flowing through an EMLC column. Cyclic voltammetry and chronoamperometry of an EMLC column are used to determine the electronic performance characteristics of an EMLC column. An electrochemical flow injection analysis of a column is provided in which the current required to maintain a constant Eapp is monitored and provides a way to examine the influence that acetonitrile and supporting electrolyte composition, flow rate, column backpressure, and ionic strength have on the structure of electrified interfaces.

  11. How to separate ionic liquids: Use of Hydrophilic Interaction Liquid Chromatography and mixed mode phases

    International Nuclear Information System (INIS)

    Lamouroux, C.

    2011-01-01

    This chromatographic study deals with the development of a convenient and versatile method to separate Room Temperature Ionic Liquids. Different modes of chromatography were studied. The study attempts to answer the following question: 'what were the most important interactions for the separation of ionic liquids?'. The results show that the essential interactions to assure a good retention of RTILs are the ionic ones and that hydrophobic interactions play a role in the selectivity of the separation. The separation of five imidazolium salt with a traditional dial columns in Hydrophilic Interaction Chromatography (HILIC) was demonstrated. It shows that neutral diol grafted column allows an important retention that we assume is due to the capability of diol to develop a thick layer of water. Furthermore, stationary phase based on mixed interaction associating ion exchange and hydrophobic properties were studied. Firstly, it will be argued that it is possible to separate RTILs with a convenient retention and resolution according to a reverse phase elution with the Primesep columns made of a brush type long alkyl chain with an embedded negatively charged functional group. Secondly, a successful separation of RTILs in HILIC mode with a mixed phase column containing a cationic exchanger and a hydrophobic octyl chain length will be demonstrated. (author)

  12. Surface-bonded ionic liquid stationary phases in high-performance liquid chromatography--a review.

    Science.gov (United States)

    Pino, Verónica; Afonso, Ana M

    2012-02-10

    Ionic liquids (ILs) are a class of ionic, nonmolecular solvents which remain in liquid state at temperatures below 100°C. ILs possess a variety of properties including low to negligible vapor pressure, high thermal stability, miscibility with water or a variety of organic solvents, and variable viscosity. IL-modified silica as novel high-performance liquid chromatography (HPLC) stationary phases have attracted considerable attention for their differential behavior and low free-silanol activity. Indeed, around 21 surface-confined ionic liquids (SCIL) stationary phases have been developed in the last six years. Their chromatographic behavior has been studied, and, despite the presence of a positive charge on the stationary phase, they showed considerable promise for the separation of neutral solutes (not only basic analytes), when operated in reversed phase mode. This aspect points to the potential for truly multimodal stationary phases. This review attempts to summarize the state-of-the-art about SCIL phases including their preparation, chromatographic behavior, and analytical performance. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Process of quantity determination of uranium by chromatography in liquid zone

    International Nuclear Information System (INIS)

    Muller, J.P.; Cojean, J.; Daubizit, M.

    1993-01-01

    The invention concerns a process of quantity determination of uranium by chromatography in liquid zone, usable to determine the quantity of uranium traces. Solutions to be treated can be aqueous or organic

  14. Qualitative and quantitative determination of ubiquinones by the method of high-efficiency liquid chromatography

    International Nuclear Information System (INIS)

    Yanotovskii, M.T.; Mogilevskaya, M.P.; Obol'nikova, E.A.; Kogan, L.M.; Samokhvalov, G.I.

    1986-01-01

    A method has been developed for the qualitative and quantitative determination of ubiquinones CoQ 6 -CoQ 10 , using high-efficiency reversed-phase liquid chromatography. Tocopherol acetate was used as the internal standard

  15. Determination of Aspartame, Caffeine, Saccharin, and Benzoic Acid in Beverages by High Performance Liquid Chromatography.

    Science.gov (United States)

    Delaney, Michael F.; And Others

    1985-01-01

    Describes a simple and reliable new quantitative analysis experiment using liquid chromatography for the determinaiton of caffeine, saccharin, and sodium benzoate in beverages. Background information, procedures used, and typical results obtained are provided. (JN)

  16. Experimental hydrophobicity parameters of perfluorinated alkylated substances from reversed-phase high performance liquid chromatography

    NARCIS (Netherlands)

    de Voogt, P.; Zurano, L.; Serné, P.; Haftka, J.J.H.

    2012-01-01

    Capacity factors of perfluorinated alkylated substances were obtained from isocratic reversed-phase high-performance liquid chromatography-mass spectrometry experiments at different organic modifier strengths of the mobile phase. The resulting capacity factor v. modifier strengths plots were

  17. Determination of maduramicin in feedingstuffs and premixtures by liquid chromatography : development, validation and interlaboratory study

    NARCIS (Netherlands)

    Jong, de J.; Stoisser, B.; Wagner, K.; Tomassen, M.J.H.; Driessen, J.J.M.; Hofman, P.; Putzka, H.A.

    2004-01-01

    A reversed-phase liquid chromatography method for determination of maduramicin in feedingstuffs and premixtures was developed, validated, and interlaboratory studied. The extraction solvent was methanol. Maduramicin was detected at 520 nm after postcolumn derivatization with vanillin. Recovery was

  18. Assay for dihydroorotase using high-performance liquid chromatography with radioactivity detection

    International Nuclear Information System (INIS)

    Mehdi, S.; Wiseman, J.S.

    1989-01-01

    An assay for measuring dihydroorotase activity was devised. Radiolabeled substrate and product were separated by high-performance liquid chromatography using a reverse-phase column with ion-pairing, and the radioactivity was quantitated by flow detection

  19. An efficient hydrophilic interaction liquid chromatography separation of 7 phospholipid classes based on a diol column

    NARCIS (Netherlands)

    Zhu, C.; Dane, A.; Spijksma, G.; Wang, M.; Greef, J. van der; Luo, G.; Hankemeier, T.; Vreeken, R.J.

    2012-01-01

    A hydrophilic interaction liquid chromatography (HILIC) - ion trap mass spectrometry method was developed for separation of a wide range of phospholipids. A diol column which is often used with normal phase chromatography was adapted to separate different phospholipid classes in HILIC mode using a

  20. Determination of triazine herbicides in juice samples by microwave-assisted ionic liquid/ionic liquid dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography.

    Science.gov (United States)

    Su, Rui; Li, Dan; Wu, Lijie; Han, Jing; Lian, Wenhui; Wang, Keren; Yang, Hongmei

    2017-07-01

    A novel microextraction method, termed microwave-assisted ionic liquid/ionic liquid dispersive liquid-liquid microextraction, has been developed for the rapid enrichment and analysis of triazine herbicides in fruit juice samples by high-performance liquid chromatography. Instead of using hazardous organic solvents, two kinds of ionic liquids, a hydrophobic ionic liquid (1-hexyl-3-methylimidazolium hexafluorophosphate) and a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate), were used as the extraction solvent and dispersion agent, respectively, in this method. The extraction procedure was induced by the formation of cloudy solution, which was composed of fine drops of 1-hexyl-3-methylimidazolium hexafluorophosphate dispersed entirely into sample solution with the help of 1-butyl-3-methylimidazolium tetrafluoroborate. In addition, an ion-pairing agent (NH 4 PF 6 ) was introduced to improve recoveries of the ionic liquid phase. Several experimental parameters that might affect the extraction efficiency were investigated. Under the optimum experimental conditions, the linearity for determining the analytes was in the range of 5.00-250.00 μg/L, with the correlation coefficients of 0.9982-0.9997. The practical application of this effective and green method is demonstrated by the successful analysis of triazine herbicides in four juice samples, with satisfactory recoveries (76.7-105.7%) and relative standard deviations (lower than 6.6%). In general, this method is fast, effective, and robust to determine triazine herbicides in juice samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Determination of methylphenidate in Calliphorid larvae by liquid-liquid extraction and liquid chromatography mass spectrometry - Forensic entomotoxicology using an in vivo rat brain model

    DEFF Research Database (Denmark)

    Bushby, Sarah K.; Thomas, Nicky; Priemel, Petra A.

    2012-01-01

    and Calliphorid larvae) by liquid-liquid extraction with recovery of >80%, and quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The LC-MS/MS assay was validated for entomotoxicological use and initially applied to male Sprague-Dawley rats (n=6) that were dosed with MPH (20mg/kg) ante...

  2. Chromatography.

    Science.gov (United States)

    Brantley, L. Reed, Sr.; Demanche, Edna L.; Klemm, E. Barbara; Kyselka, Will; Phillips, Edwin A.; Pottenger, Francis M.; Yamamoto, Karen N.; Young, Donald B.

    This booklet presents some activities on chromatography. Directions for preparing leaf pigment extracts using alcohol are given, and paper chromatography and thin-layer chromatography are described as modifications of the basic principles of chromatography. (KHR)

  3. Arsenic speciation by liquid chromatography coupled with ionspray tandem mass spectrometry

    DEFF Research Database (Denmark)

    Corr, J. J.; Larsen, Erik Huusfeldt

    1996-01-01

    Ionspray mass spectrometry, a well established organic analysis technique, has been coupled to high-performance liquid chromatography for speciation of organic arsenic compounds, The ionspray source and differentially pumped interface of the mass spectrometer were operated in dual modes...... fragmentation patterns showing molecular dissociation through an expected common product ion were obtained for the four arsenosugars, Molecular mode detection was utilized for qualitative verification of speciation analysis by high-performance liquid chromatography coupled to inductively coupled plasma mass...

  4. Liquid chromatography-mass spectrometry coupling by the intermediary of a liquid micro chromatography-electro spray interface; Couplage chromatographie liquide-spectrometrie de masse par l`intermediaire d`une interface electrospray-microchromatographie liquide

    Energy Technology Data Exchange (ETDEWEB)

    Gillard Factor, C

    1996-12-06

    The objective of this work is to realize a liquid chromatography- mass spectrometry coupling by the intermediary of an electro spray interface and the evaluation of performances of tis analytical tool to study pollutants in water, and more particularly pesticides whom maximum admissible concentration in a table water is 0.1{mu}g/l. This study has allowed to bring to the fore the interest of the ionization mode by electro spray in a LC/MS coupling to identify and quantify pesticides in the state of traces without treating the sample. Then, it was demonstrated the usefulness of this analytical tool to detect high molecular masses molecules. (N.C.)

  5. Tryptophan and kynurenine determination in human hair by liquid chromatography.

    Science.gov (United States)

    Dario, Michelli F; Freire, Thamires Batello; Pinto, Claudinéia Aparecida Sales de Oliveira; Prado, María Segunda Aurora; Baby, André R; Velasco, Maria Valéria R

    2017-10-15

    Tryptophan, an amino acid found in hair proteinaceous structure is used as a marker of hair photodegradation. Also, protein loss caused by several chemical/physical treatments can be inferred by tryptophan quantification. Kynurenine is a photo-oxidation product of tryptophan, expected to be detected when hair is exposed mainly to UVB (290-320nm) radiation range. Tryptophan from hair is usually quantified directly as a solid or after alkaline hydrolysis, spectrofluorimetrically. However, these types of measure are not sufficiently specific and present several interfering substances. Thus, this work aimed to propose a quantification method for both tryptophan and kynurenine in hair samples, after alkali hydrolysis process, by using high-performance liquid chromatography (HPLC) with fluorimetric and UV detection. The tryptophan and kynurenine quantification method was developed and validated. Black, white, bleached and dyed (blond and auburn) hair tresses were used in this study. Tryptophan and kynurenine were separated within ∼9min by HPLC. Both black and white virgin hair samples presented similar concentrations of tryptophan, while bleaching caused a reduction in the tryptophan content as well as dyeing process. Unexpectedly, UV/vis radiation did not promote significantly the conversion of tryptophan into its photo-oxidation product and consequently, kynurenine was not detected. Thus, this works presented an acceptable method for quantification of tryptophan and its photooxidation metabolite kynurenine in hair samples. Also, the results indicated that bleaching and dyeing processes promoted protein/amino acids loss but tryptophan is not extensively degraded in human hair by solar radiation. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Liquid chromatography method to determine polyamines in thermosetting polymers

    Energy Technology Data Exchange (ETDEWEB)

    Dopico-Garcia, M.S. [Laboratorio de Quimica - Centro de Investigacions Tecnoloxicas, Universidade da Coruna, Campus de Esteiro s/n, 15403 Ferrol (Spain); Centro Galego do Plastico, A Cabana s/n, 15590 Ferrol (Spain); Lopez-Vilarino, J.M. [Laboratorio de Quimica - Centro de Investigacions Tecnoloxicas, Universidade da Coruna, Campus de Esteiro s/n, 15403 Ferrol (Spain); Fernandez-Martinez, G. [Unidad de Tecnicas Cromatograficas, Servizos de Apoio a Investigacion, Edificio Servizos Centrais de Investigacion, Universidade da Coruna, Campus de Elvina s/n, 15071 A Coruna (Spain); Gonzalez-Rodriguez, M.V., E-mail: victoria@udc.es [Dpto. de Quimica Analitica - E.U. Politecnica, Universidade da Coruna, Avda. 19 de Febrero s/n, 15405 Ferrol (Spain)

    2010-05-14

    A simple, robust and sensitive analytical method to determine three polyamines commonly used as hardeners in epoxy resin systems and in the manufacture of polyurethane is reported. The studied polyamines are: one tetramine, TETA (triethylenetetramine), and two diamines, IPDA (Isophorone diamine) and TCD-diamine (4,7-methano-1H-indene-5,?-dimethanamine, octahydro-). The latter has an incompletely defined structure, and, as far as we know, has not been previously determined by other methods. All three polyamines contain primary amines; TETA also contains secondary amines. The analytical method involves derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate, used for the first time for these compounds, followed by high performance liquid chromatography (HPLC) analysis with a fluorescence (FL) detector ({lambda} excitation 248 nm, {lambda} emision 395 nm). The HPLC-DAD-LTQ Orbitrap MS was used in order to provide structural information about the obtained derivatized compounds. The hybrid linear ion trap LTQ Orbitrap mass spectrometer has been introduced in recent years and provides a high mass accuracy. The structures of the derivatized analytes were identified from the protonated molecular ions [M+H]{sup +} and corresponded to the fully labelled analytes. The following analytical parameters were determined for the method using the HPLC-FL: linearity, precision (2.5-10%), instrumental precision intraday (0.8-1.5%) and interday (2.9-6.3%), and detection limits (0.02-0.14 mg L{sup -1}). The stability of stock solutions and derivatized compounds was also investigated. The method was applied to determine the amine free content in epoxy resin dust collected in workplaces.

  7. Liquid chromatography method to determine polyamines in thermosetting polymers.

    Science.gov (United States)

    Dopico-García, M S; López-Vilariño, J M; Fernández-Martínez, G; González-Rodríguez, M V

    2010-05-14

    A simple, robust and sensitive analytical method to determine three polyamines commonly used as hardeners in epoxy resin systems and in the manufacture of polyurethane is reported. The studied polyamines are: one tetramine, TETA (triethylenetetramine), and two diamines, IPDA (Isophorone diamine) and TCD-diamine (4,7-methano-1H-indene-5,?-dimethanamine, octahydro-). The latter has an incompletely defined structure, and, as far as we know, has not been previously determined by other methods. All three polyamines contain primary amines; TETA also contains secondary amines. The analytical method involves derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate, used for the first time for these compounds, followed by high performance liquid chromatography (HPLC) analysis with a fluorescence (FL) detector (lambda excitation 248nm, lambda emision 395nm). The HPLC-DAD-LTQ Orbitrap MS was used in order to provide structural information about the obtained derivatized compounds. The hybrid linear ion trap LTQ Orbitrap mass spectrometer has been introduced in recent years and provides a high mass accuracy. The structures of the derivatized analytes were identified from the protonated molecular ions [M+H](+) and corresponded to the fully labelled analytes. The following analytical parameters were determined for the method using the HPLC-FL: linearity, precision (2.5-10%), instrumental precision intraday (0.8-1.5%) and interday (2.9-6.3%), and detection limits (0.02-0.14mgL(-1)). The stability of stock solutions and derivatized compounds was also investigated. The method was applied to determine the amine free content in epoxy resin dust collected in workplaces. Copyright 2010 Elsevier B.V. All rights reserved.

  8. Liquid chromatography method to determine polyamines in thermosetting polymers

    International Nuclear Information System (INIS)

    Dopico-Garcia, M.S.; Lopez-Vilarino, J.M.; Fernandez-Martinez, G.; Gonzalez-Rodriguez, M.V.

    2010-01-01

    A simple, robust and sensitive analytical method to determine three polyamines commonly used as hardeners in epoxy resin systems and in the manufacture of polyurethane is reported. The studied polyamines are: one tetramine, TETA (triethylenetetramine), and two diamines, IPDA (Isophorone diamine) and TCD-diamine (4,7-methano-1H-indene-5,?-dimethanamine, octahydro-). The latter has an incompletely defined structure, and, as far as we know, has not been previously determined by other methods. All three polyamines contain primary amines; TETA also contains secondary amines. The analytical method involves derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate, used for the first time for these compounds, followed by high performance liquid chromatography (HPLC) analysis with a fluorescence (FL) detector (λ excitation 248 nm, λ emision 395 nm). The HPLC-DAD-LTQ Orbitrap MS was used in order to provide structural information about the obtained derivatized compounds. The hybrid linear ion trap LTQ Orbitrap mass spectrometer has been introduced in recent years and provides a high mass accuracy. The structures of the derivatized analytes were identified from the protonated molecular ions [M+H] + and corresponded to the fully labelled analytes. The following analytical parameters were determined for the method using the HPLC-FL: linearity, precision (2.5-10%), instrumental precision intraday (0.8-1.5%) and interday (2.9-6.3%), and detection limits (0.02-0.14 mg L -1 ). The stability of stock solutions and derivatized compounds was also investigated. The method was applied to determine the amine free content in epoxy resin dust collected in workplaces.

  9. Separation of anionic oligosaccharides by high-performance liquid chromatography

    International Nuclear Information System (INIS)

    Green, E.D.; Baenziger, J.U.

    1986-01-01

    The authors have developed methods for rapid fractionation of anionic oligosaccharides containing sulfate and/or sialic acid moieties by high-performance liquid chromatography (HPLC). Ion-exchange HPLC on amine-bearing columns (Micropak AX-10 and AX-5) at pH 4.0 is utilized to separate anionic oligosaccharides bearing zero, one, two, three, or four charges, independent of the identity of the anionic moieties (sulfate and/or sialic acid). Ion-exchange HPLC at pH 1.7 allows separation of neutral, mono-, di-, and tetrasialylated, monosulfated, and disulfated oligosaccharides. Oligosaccharides containing three sialic acid residues and those bearing one each of sulfate and sialic acid, however, coelute at pH 1.7. Since the latter two oligosaccharide species separate at pH 4.0, analysis at pH 4.0 followed by analysis at pH 1.7 can be utilized to completely fractionate complex mixtures of sulfated and sialylated oligosaccharides. Ion-suppression amine adsorption HPLC has previously been shown to separate anionic oligosaccharides on the basis of net carbohydrate content (size). In this study they demonstrate the utility of ion-suppression amine adsorption HPLC for resolving sialylated oligosaccharide isomers which differ only in the linkages of sialic acid residues (α2,3 vs α2,6) and/or location of α2,3- and α2,6-linked sialic acid moieties on the peripheral branches of oligosaccharides. These two methods can be used in tandem to separate oligosaccharides, both analytically and preparatively, based on their number, types, and linkages of anionic moieties

  10. Histamine and tele-methylhistamine quantification in cerebrospinal fluid from narcoleptic subjects by liquid chromatography tandem mass spectrometry with precolumn derivatization.

    Science.gov (United States)

    Croyal, Mikaël; Dauvilliers, Yves; Labeeuw, Olivier; Capet, Marc; Schwartz, Jean-Charles; Robert, Philippe

    2011-02-01

    An ultra-performance liquid chromatography tandem mass spectrometry (UPLC™-MS/MS) assay was developed for the simultaneous analysis of histamine, its major metabolite tele-methylhistamine, and an internal standard (N-tele-(R)-α-dimethylhistamine) from human cerebrospinal fluid (CSF) samples. The method involves derivatization of primary amines with 4-bromobenzenesulfonyl chloride and subsequent analysis by reversed phase liquid chromatography with mass spectrometry detection and positive electrospray ionization. The separation of derivatized biogenic amines was achieved within 3.5 min on an Acquity® BEH C(18) column by elution with a linear gradient of acetonitrile/water/formic acid (0.1%). The assay was linear in the concentration range of 50-5000 pM for each amine (5.5-555 pg/ml for histamine and 6.25-625 pg/ml for tele-methylhistamine). For repeatability and precision determination, coefficients of variation (CVs) were less than 11.0% over the tested concentration ranges, within acceptance criteria. Thus, the developed method provides the rapid, easy, highly sensitive, and selective requirement to quantify these amines in human CSF. No significant difference was found in the mean ± standard error levels of these amines between a group of narcoleptic patients (histamine=392 ± 64 pM, tele-methylhistamine=2431 ± 461 pM, n=7) and of neurological control subjects (histamine=402 ± 72 pM, tele-methylhistamine=2209 ± 463 pM, n=32). Copyright © 2010 Elsevier Inc. All rights reserved.

  11. Study of high performance liquid chromatography fingerprint for traditional chinese medicine yigongningxue oral liquid

    International Nuclear Information System (INIS)

    Feng, C.; Ruan, J.L.

    2010-01-01

    A simple, reliable and accurate fingerprinting method has been developed for quality control of YiGongNingXue oral liquid. The separation was done by reverse phase chromatography using Zorbax eclipse XDB C/sub 18/ column (250mmx4.6mmi. d. with 5.0 micro m particle size) and detection at 246nm. Methanol (5-95 % in 70 min)-buffer solution (water-phosphorica cid, pH 3.0, 95-0 percent in 70 min) as mobile phase for linear gradient elution. The flow rate was 1.0 mLmin/sup 1/ and the column temperature was at 25 deg. C. The similarity of 20 batches of YGNX oral liquid was more than 90 %. Also 15 common peaks of chromatogram have been detected, ten of them were identified by comparing fingerprint chromatogram with reference substances The HPLC fingerprint can be used to control the quality of YiGongNingXue oral liquid. (author)

  12. Development of an on-line mixed-mode gel liquid chromatography×reversed phase liquid chromatography method for separation of water extract from Flos Carthami.

    Science.gov (United States)

    Wang, Yu-Qing; Tang, Xu; Li, Jia-Fu; Wu, Yun-Long; Sun, Yu-Ying; Fang, Mei-Juan; Wu, Zhen; Wang, Xiu-Min; Qiu, Ying-Kun

    2017-10-13

    A novel on-line comprehensive two-dimensional liquid chromatography (2D-LC) method by coupling mixed-mode gel liquid chromatography (MMG-LC) with reversed phase liquid chromatography (RPLC) was developed. A mixture of 17 reference compounds was used to study the separation mechanism. A crude water extract of Flos Carthami was applied to evaluate the performance of the novel 2D-LC system. In the first dimension, the extract was eluted with a gradient of water/methanol over a cross-linked dextran gel Sephadex LH-20 column. Meanwhile, the advantages of size exclusion, reversed phase partition and adsorption separation mechanism were exploited before further on-line reversed phase purification on the second dimension. This novel on-line mixed-mode Sephadex LH-20×RPLC method provided higher peak resolution, sample processing ability (2.5mg) and better orthogonality (72.9%) versus RPLC×RPLC and hydrophilic interaction liquid chromatography (HILIC)×RPLC. To the best of our knowledge, this is the first report of a mixed-mode Sephadex LH-20×RPLC separation method with successful applications in on-line mode, which might be beneficial for harvesting targets from complicated medicinal plants. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Quantification of Lansoprazole in Oral Suspension by Ultra-High-Performance Liquid Chromatography Hybrid Ion-Trap Time-of-Flight Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Stacy D. Brown

    2011-01-01

    Full Text Available An LC-MS/MS method was developed and validated to be used as a stability indicating assay for the study of a 3 mg/mL lansoprazole oral suspension. The method utilizes a UPLC (ultra-performance liquid chromatography column and unique mass spectrometric detection (ion-trap time-of-flight (IT-TOF to achieve a sensitive (LOD 2 ng/mL, accurate, and reproducible quantification of lansoprazole. This method reports an intraday and interday coefficient of variation of 2.98 ± 2.17% (n=5 for each concentration for each day and 3.07 ± 0.89% (n=20 for each concentration, respectively. Calibration curves (5–25 μg/mL were found to be linear with an R2 value ranging from 0.9972 to 0.9991 on 4 different days. Accuracy of the assay, expressed as % error, ranged from 0.30 to 5.22%. This method is useful for monitoring the stability of lansoprazole in oral suspension.

  14. Distribution Assessments of Coumarins from Angelicae Pubescentis Radix in Rat Cerebrospinal Fluid and Brain by Liquid Chromatography Tandem Mass Spectrometry Analysis

    Directory of Open Access Journals (Sweden)

    Yan-Fang Yang

    2018-01-01

    Full Text Available Angelicae Pubescentis Radix (APR is a widely-used traditional Chinese medicine. Pharmacological studies have begun to probe its biological activities on neurological disorders recently. To assess the brain penetration and distribution of APR, a validated ultra-performance liquid chromatography tandem mass spectrometry method was applied to the simultaneous determinations of the main coumarins from APR in the rat cerebrospinal fluid (CSF and brain after oral administration of APR extract, including psoralen, xanthotoxin, bergapten, isoimperatorin, columbianetin, columbianetin acetate, columbianadin, oxypeucedanin hydrate, angelol B, osthole, meranzin hydrate and nodakenetin. Most of the tested coumarins entered the rat CSF and brain quickly, and double-peak phenomena in concentration-time curves were similar to those of their plasma pharmacokinetics. Columbianetin had the highest concentration in the CSF and brain, while psoralen and columbianetin acetate had the largest percent of CSF/plasma and brain/plasma, indicating that these three coumarins may be worthy of further research on the possible nervous effects. Correlations between the in vivo brain distributions and plasma pharmacokinetics of these coumarins were well verified. These results provided valuable information for the overall in vivo brain distribution characteristics of APR and also for its further studies on the active substances for the central nervous system.

  15. Distribution Assessments of Coumarins from Angelicae Pubescentis Radix in Rat Cerebrospinal Fluid and Brain by Liquid Chromatography Tandem Mass Spectrometry Analysis.

    Science.gov (United States)

    Yang, Yan-Fang; Zhang, Lei; Yang, Xiu-Wei

    2018-01-20

    Angelicae Pubescentis Radix (APR) is a widely-used traditional Chinese medicine. Pharmacological studies have begun to probe its biological activities on neurological disorders recently. To assess the brain penetration and distribution of APR, a validated ultra-performance liquid chromatography tandem mass spectrometry method was applied to the simultaneous determinations of the main coumarins from APR in the rat cerebrospinal fluid (CSF) and brain after oral administration of APR extract, including psoralen, xanthotoxin, bergapten, isoimperatorin, columbianetin, columbianetin acetate, columbianadin, oxypeucedanin hydrate, angelol B, osthole, meranzin hydrate and nodakenetin. Most of the tested coumarins entered the rat CSF and brain quickly, and double-peak phenomena in concentration-time curves were similar to those of their plasma pharmacokinetics. Columbianetin had the highest concentration in the CSF and brain, while psoralen and columbianetin acetate had the largest percent of CSF/plasma and brain/plasma, indicating that these three coumarins may be worthy of further research on the possible nervous effects. Correlations between the in vivo brain distributions and plasma pharmacokinetics of these coumarins were well verified. These results provided valuable information for the overall in vivo brain distribution characteristics of APR and also for its further studies on the active substances for the central nervous system.

  16. Development of a sensitive method for the determination of acrylamide in coffee using high-performance liquid chromatography coupled to a hybrid quadrupole Orbitrap mass spectrometer.

    Science.gov (United States)

    Pugajeva, Iveta; Jaunbergs, Janis; Bartkevics, Vadims

    2015-01-01

    The emerging trend towards high-resolution mass spectrometry (MS) alternatives was evaluated by the application of Orbitrap MS for the determination of acrylamide in coffee samples. The high resolving power of the Orbitrap MS provided the high selectivity and sensitivity that enabled quantitative analysis of acrylamide in complex matrices, such as coffee. Several sample preparation methods and scanning modes of the MS (full MS, t-SIM, t-MS2) were assessed in order to optimise parameters of the analytical method. The final procedure involved the extraction of acrylamide with acetonitrile, solid-phase extraction with dispersive primary secondary amine (PSA) and amino columns, and the detection by ultra-performance liquid chromatography coupled to a hybrid quadrupole-Orbitrap MS (HPLC-Q-Orbitrap) operated in targeted MS2 scanning mode. The repeatability of the method at the lowest calibration level (10 μg kg(-1)), expressed as relative standard deviation, was 7.8% and the average recovery of acrylamide was 111%. The proposed method was applied to the determination of acrylamide in 22 samples of roasted coffee obtained from the Latvian retail market. Acrylamide concentration in coffee samples was in the range of 166-503 μg kg(-1).

  17. Purification Efficacy of Synthetic Cannabinoid Conjugates Using High-Pressure Liquid Chromatography

    Science.gov (United States)

    conducted using high-pressure liquid chromatography and gradient screens to determine the most effective means of purifying the SC:dark quencher conjugates...to obtain the highest yields and purity. The purity was verified using liquid chromatographycoupled mass spectroscopy and nuclear magnetic resonance.

  18. Prostate cell membrane chromatography-liquid chromatography-mass spectrometry for screening of active constituents from Uncaria rhynchophylla.

    Science.gov (United States)

    He, Jianyu; Han, Shengli; Yang, Fangfang; Zhou, Nan; Wang, Sicen

    2013-01-01

    Uncaria rhynchophylla is a traditional Chinese medicinal herb used to treat hypertension and convulsive disorders such as epilepsy. Rat prostate cell membrane chromatography combined with liquid chromatography-mass spectrometry (LC-MS) was used to identify active constituents from U. rhynchophylla extracts. Four compounds (corynoxeine, isorhynchophylline, isocorynoxeine and rhynchophylline) were discovered. Competitive binding assay results indicated that the four compounds were in direct competition at a single common binding site and interacted with α1A adrenergic receptors (α1A-AR) in a manner similar to tamsulosin. Affinity constant values of the four compounds binding with α1A-AR were also measured using rat prostate cell membrane chromatography (CMC). Finally, their pharmacodynamic effects were tested on rat caudal arteries. This CMC combined LC-MS system offers a means of drug discovery by screening natural medicinal herbs for new pharmacologically active molecules targeting specific receptors.

  19. [Analysis of microalbuminuria with immunonephelometry and high performance liquid chromatography. Evaluation of new criteria].

    Science.gov (United States)

    Markó, Lajos; Molnár, Gergo Attila; Wagner, Zoltán; Koszegi, Tamás; Matus, Zoltán; Mohás, Márton; Kuzma, Mónika; Szijártó, István András; Wittmann, István

    2008-01-13

    Hypertension as well as type 2 diabetes mellitus is a major factor in population mortality. Both diseases damage the endothelium, the early sign of which is microalbuminuria, which can be screened by dipstick and can be diagnosed by using immuno-based and high performance liquid chromatography methods. Using high performance liquid chromatography, the non-immunoreactive albumin can be detected as well. The authors aimed at the examination of albuminuria in the case of immunonephelometrically negative patients with high performance liquid chromatography, in diabetic and hypertensive and non-diabetic hypertensive populations. The authors also wanted to compare the present (albumin-creatinine ratio: male: > or =2.5 mg/mmol, female: > or =3.5 mg/mmol) and a new criteria of the Heart Outcomes Prevention Evaluation study (patients without diabetes: immunological method, > or =0.7 mg/mmol; high performance liquid chromatography, > or =3.1 mg/mmol; individuals with diabetes: immunological method, > or =1.4 mg/mmol; high performance liquid chromatography, > or =5.2 mg/mmol) of microalbuminuria. Examination of fresh urines of 469 microalbuminuria negative patients by dipstick were performed by immunonephelometry. Patients, who were microalbuminuria negative by immunonephelometry as well, were further analyzed by high performance liquid chromatography using the Accumintrade mark Kit, based on size-exclusion chromatography. Three times higher albuminuria were found with high performance liquid chromatography than with immunonephelometry. The intraindividual coefficient of variation did not differ in the two methods (37 +/- 31% vs. 40 +/- 31%, p = 0.869; immunonephelometry vs. high performance liquid chromatography; mean +/- standard deviation). Using the present criteria for microalbuminuria, 43% of immunonephelometrically negative patients proved to be microalbuminuric by high performance liquid chromatography. Using the new criteria of the Heart Outcomes Prevention

  20. Preparation and evaluation of surface-bonded tricationic ionic liquid silica as stationary phases for high-performance liquid chromatography.

    Science.gov (United States)

    Qiao, Lizhen; Shi, Xianzhe; Lu, Xin; Xu, Guowang

    2015-05-29

    Two tricationic ionic liquids were prepared and then bonded onto the surface of supporting silica materials through "thiol-ene" click chemistry as new stationary phases for high-performance liquid chromatography. The obtained columns of tricationic ionic liquids were evaluated respectively in the reversed-phase liquid chromatography (RPLC) mode and hydrophilic interaction liquid chromatography (HILIC) mode, and possess ideal column efficiency of 80,000 plates/m in the RPLC mode with naphthalene as the test solute. The tricationic ionic liquid stationary phases exhibit good hydrophobic and shape selectivity to hydrophobic compounds, and RPLC retention behavior with multiple interactions. In the HILIC mode, the retention and selectivity were evaluated through the efficient separation of nucleosides and bases as well as flavonoids, and the typical HILIC retention behavior was demonstrated by investigating retention changes of hydrophilic solutes with water volume fraction in mobile phase. The results show that the tricationic ionic liquid columns possess great prospect for applications in analysis of hydrophobic and hydrophilic samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Application of Ionic Liquids in High Performance Reversed-Phase Chromatography

    Directory of Open Access Journals (Sweden)

    Wentao Bi

    2009-06-01

    Full Text Available Ionic liquids, considered “green” chemicals, are widely used in many areas of analytical chemistry due to their unique properties. Recently, ionic liquids have been used as a kind of novel additive in separation and combined with silica to synthesize new stationary phase as separation media. This review will focus on the properties and mechanisms of ionic liquids and their potential applications as mobile phase modifier and surface-bonded stationary phase in reversed-phase high performance liquid chromatography (RP-HPLC. Ionic liquids demonstrate advantages and potential in chromatographic field.

  2. Quality evaluation of moluodan concentrated pill using high-performance liquid chromatography fingerprinting coupled with chemometrics.

    Science.gov (United States)

    Tao, Lingyan; Zhang, Qing; Wu, Yongjiang; Liu, Xuesong

    2016-12-01

    In this study, a fast and effective high-performance liquid chromatography method was developed to obtain a fingerprint chromatogram and quantitative analysis simultaneously of four indexes including gallic acid, chlorogenic acid, albiflorin and paeoniflorin of the traditional Chinese medicine Moluodan Concentrated Pill. The method was performed by using a Waters X-bridge C 18 reversed phase column on an Agilent 1200S high-performance liquid chromatography system coupled with diode array detection. The mobile phase of the high-performance liquid chromatography method was composed of 20 mmol/L phosphate solution and acetonitrile with a 1 mL/min eluent velocity, under a detection temperature of 30°C and a UV detection wavelength of 254 nm. After the methodology validation, 16 batches of Moluodan Concentrated Pill were analyzed by this high-performance liquid chromatography method and both qualitative and quantitative evaluation results were achieved by similarity analysis, principal component analysis and hierarchical cluster analysis. The results of these three chemometrics were in good agreement and all indicated that batch 10 and batch 16 showed significant differences with the other 14 batches. This suggested that the developed high-performance liquid chromatography method could be applied in the quality evaluation of Moluodan Concentrated Pill. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Isolation and purification of six iridoid glycosides from gardenia jasminoides fruit by medium-pressure liquid chromatography combined with macroporous resin chromatography.

    Science.gov (United States)

    Wang, Yun; Liu, Hui; Shen, Lifeng; Yao, Lan; Ma, Yinlian; Yu, Dingrong; Chen, Jianhong; Li, Puling; Chen, Ying; Zhang, Cun

    2015-12-01

    Gardeniae fructus is one of the most frequently used herbs in traditional Chinese medicine. In the present study, a process for the enrichment of six iridoid glycosides from Gardeniae fructus was developed using medium-pressure liquid chromatography combined with macroporous resin and reversed-phase chromatography. The purities of different fractions from Gardeniae fructus were assessed using quantitative high-performance liquid chromatography. After fractionation using HPD-100 column chromatography, a 30% ethanol fraction was selected based on high-performance liquid chromatography and liquid chromatography with mass spectrometry qualitative analysis to separate and purify. Based on the orientation analysis results, six compounds-deacetyl asperulosidic acid methyl ester, gardenoside, ixoroside, scandoside methyl ester, genipin-1-O-β-d-gentiobioside, and geniposide-were successfully isolated and purified in three to four combined steps from Gardeniae fructus. The purities of these compounds were found by high-performance liquid chromatography analysis to be 97.9, 98.1, 95.5, 96.3, 97.1, and 98.7%, respectively. Moreover, their structures were elucidated by NMR spectroscopy and liquid chromatography with tandem mass spectrometry. The separation process was highly efficient, rapid, and accurate, making it a potential approach for the large-scale production of iridoids in the laboratory and providing several marker compounds for quality control. This procedure may be meaningful for the purification of other natural products used in traditional Chinese medicine. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Analysis of chlorpheniramine in human urine samples using dispersive liquid-liquid microextraction combined with high-performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Mehdi Maham

    2014-09-01

    Full Text Available A simple and environmentally friendly microextraction technique was used for determination of chlorpheniramine (CPM, an antihistamine drug, in human urine samples using dispersive liquid-liquid microextraction (DLLME followed by high performance liquid chromatography with diode array detection (HPLC-DAD. In this extraction technique, an appropriate mixture of acetonitrile (disperser solvent and carbon tetrachloride (extraction solvent was rapidly injected into the urine sample containing the target analyte. Tiny droplets of extractant were formed and dispersed into the sample solution and then sedimented at the bottom of the conical test tube by centrifugation. Under optimal conditions, the calibration curve was linear in the range of 0.055-5.5 µg mL-1, with a detection limit of 16.5 ng mL-1. This proposed method was successfully applied to the analysis of real urine samples. Low consumption of toxic organic solvents, simplicity of operation, low cost and acceptable figures of merit are the main advantages of the proposed technique.

  5. A liquid chromatography – tandem mass spectrometry method to measure a selected panel of uremic retention solutes derived from endogenous and colonic microbial metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Loor, Henriette de; Poesen, Ruben [KU Leuven – University of Leuven, Department of Microbiology and Immunology, Laboratory of Nephrology, B-3000 Leuven (Belgium); De Leger, Wout; Dehaen, Wim [KU Leuven – University of Leuven, Department of Chemistry, Division of Molecular Design and Synthesis, B-3000 Leuven (Belgium); Augustijns, Patrick [KU Leuven – University of Leuven, Department of Pharmaceutical and Pharmacological Sciences, Drug Delivery and Disposition, B-3000 Leuven (Belgium); Evenepoel, Pieter [KU Leuven – University of Leuven, Department of Microbiology and Immunology, Laboratory of Nephrology, B-3000 Leuven (Belgium); University Hospitals Leuven, Department of Nephrology and Renal Transplantation, B-3000 Leuven (Belgium); Meijers, Björn, E-mail: bjorn.meijers@uzleuven.be [KU Leuven – University of Leuven, Department of Microbiology and Immunology, Laboratory of Nephrology, B-3000 Leuven (Belgium); University Hospitals Leuven, Department of Nephrology and Renal Transplantation, B-3000 Leuven (Belgium)

    2016-09-14

    Chronic kidney disease (CKD) is associated with an increased risk of mortality and cardiovascular disease, which is, at least partly, mediated by the accumulation of so-called uremic retention solutes. Although there has been an increasing interest in the behavior of these solutes, derived from both the endogenous and colonic microbial metabolism, methods to simultaneously and accurately measure a broad panel of relevant uremic retention solutes remain scarce. We developed a highly sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. A high throughput sample preparation was used with extraction of analytes from 50 μl serum using Ostro plate technology. For most solutes, stable isotopes labelled metabolites were used as internal standards. Chromatography was achieved using an Acquity UPLC CSH Fluoro Phenyl column. The total run time was 8 min, the mobile phase was a gradient of 0.1% formic acid in Milli-Q water and pure methanol at a flow rate of 0.5 ml min{sup −1}. Detection was performed using a tandem mass spectrometer with alternated positive and negative electrospray ionization. Calibration curves were linear for all solutes. Precision was assessed according to the NCCLS EP5-T guideline, being below 15% for all metabolites. Mean recoveries were between 83 and 104% for all metabolites. The validated method was successfully applied in a cohort of 488 patients with CKD. We developed and validated a sensitive and robust UPLC-MS/MS method for quantification of 15 uremic retention solutes derived from endogenous and colonic microbial metabolism. This method allows for studying the behavior and relevance of these solutes in patients with CKD. - Highlights: • Simultaneous quantification of fifteen relevant uremic retention solutes. • Comprehensive validation, highly sensitive and high through-put LC-MSMS method. • Comparison of different blood tubes. • Freeze-thaw stability. • Successful implementation in a

  6. Recent advances in liquid and gas chromatography methodology for extending coverage of the metabolome.

    Science.gov (United States)

    Haggarty, Jennifer; Burgess, Karl Ev

    2017-02-01

    The metabolome is the complete complement of metabolites (small organic biomolecules). In order to comprehensively understand the effect of stimuli on a biological system, it is important to detect as many of the metabolites within that system as possible. This review briefly describes some new advances in liquid and gas chromatography to improve coverage of the metabolome, including the serial combination of two columns in tandem, column switching and different variations of two-dimensional chromatography. Supercritical fluid chromatography could provide complimentary data to liquid and gas chromatography. Although there have been many recent advancements in the field of metabolomics, it is evident that a combination, rather than a single method, is required to approach full coverage of the metabolome. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Application of liquid column chromatography to preconcentration, separation and determination of platinum metals

    International Nuclear Information System (INIS)

    Alimarin, I.P.; Basova, E.M.; Bol'shova, T.A.; Ivanov, V.M.

    1986-01-01

    Separation and determination of platimum metals using the methods of adsorption, ion-pair, ion-exchange, distributing and sieve chromatography are discussed in the review of literature in 1971-1984. Separation and determination of metals as chelates using the method of adsorption and ion-pair chromatograpy are noted to be most perspective directions of developing highly effective liquid chromatography of inorganic systems

  8. Immunoaffinity chromatography of abscisic acid combined with electrospray liquid chromatography–mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Hradecká, Veronika; Novák, Ondřej; Havlíček, Libor; Strnad, Miroslav

    2007-01-01

    Roč. 847, č. 2 (2007), s. 162-173 ISSN 1570-0232 R&D Projects: GA MŠk(CZ) LC06034; GA AV ČR IBS5038351 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje Keywords : abscisic acid * immunoaffinity chromatography * liquid chromatography-mass spectrometry Subject RIV: ED - Physiology Impact factor: 2.935, year: 2007

  9. Monodisperse microbeads of hypercrosslinked polystyrene for liquid and supercritical fluid chromatography

    Science.gov (United States)

    Tsyurupa, M. P.; Blinnikova, Z. K.; Il'in, M. M.; Davankov, V. A.; Parenago, O. O.; Pokrovskii, O. I.; Usovich, O. I.

    2015-11-01

    Monodisperse styrene-divinylbenzene (1 wt %) copolymer microbeads are obtained via the elaborate method of high-productivity precipitation polymerization. The crosslinking of this copolymer with chloromethyl methyl ether in the presence of Friedel-Crafts catalyst yields porous hypercrosslinked polymers with degrees of crosslinking that range from 200 to 500%. Microbead sorbents are shown to be suited for selective stationary phases for high-performance liquid chromatography and supercritical fluid chromatography.

  10. Improved method for the determination of the cortisol production rate using high-performance liquid chromatography and liquid scintillation counting

    NARCIS (Netherlands)

    van Ingen, H. E.; Endert, E.

    1988-01-01

    Two new methods for the determination of the cortisol production rate using reversed-phase high-performance liquid chromatography are described. One uses ultraviolet detection at 205 nm, the other on-line post-column derivatization with benzamidine, followed by fluorimetric detection. The specific

  11. Characterization of natural organic colorants in historical and art objects by high-performance liquid chromatography.

    Science.gov (United States)

    Pauk, Volodymyr; Barták, Petr; Lemr, Karel

    2014-12-01

    High-performance liquid chromatography plays an important role in analysis of historical organic colorants. A number of papers have been published in this field over the last 30 years. Classification of the most commonly used natural dyes and an overview of high-performance liquid chromatography methods with main focus on recent works (2008 to the beginning of 2014) are provided. The review deals with an entire analytical protocol covering sample preparation, chromatographic separation, and suitable detection (UV/visible and fluorescent spectroscopy and mass spectrometric techniques). High-performance liquid chromatography has been successfully used in the complete characterization of some organic dyestuffs present in historical and art objects. The possibilities and difficulties for identification of natural sources of historical colorants are also discussed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Screening and quantitative determination of twelve acidic and neutral pharmaceuticals in whole blood by liquid-liquid extraction and liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Simonsen, Kirsten Wiese; Steentoft, Anni; Buck, Maike

    2010-01-01

    . The method was fully validated for salicylic acid, paracetamol, phenobarbital, carisoprodol, meprobamate, topiramate, etodolac, chlorzoxazone, furosemide, ibuprofen, warfarin, and salicylamide. The method also tentatively includes thiopental, theophylline, piroxicam, naproxen, diclophenac, and modafinil......We describe a multi-method for simultaneous identification and quantification of 12 acidic and neutral compounds in whole blood. The method involves a simple liquid-liquid extraction, and the identification and quantification are performed using liquid chromatography-tandem mass spectrometry...

  13. Crosslinked polymeric ionic liquids as solid-phase microextraction sorbent coatings for high performance liquid chromatography.

    Science.gov (United States)

    Yu, Honglian; Merib, Josias; Anderson, Jared L

    2016-03-18

    Neat crosslinked polymeric ionic liquid (PIL) sorbent coatings for solid-phase microextraction (SPME) compatible with high-performance liquid chromatography (HPLC) are reported for the first time. Six structurally different PILs were crosslinked to nitinol supports and applied for the determination of select pharmaceutical drugs, phenolics, and insecticides. Sampling conditions including sample solution pH, extraction time, desorption solvent, desorption time, and desorption solvent volume were optimized using design of experiment (DOE). The developed PIL sorbent coatings were stable when performing extractions under acidic pH and remained intact in various organic desorption solvents (i.e., methanol, acetonitrile, acetone). The PIL-based sorbent coating polymerized from the IL monomer 1-vinyl-3-(10-hydroxydecyl) imidazolium chloride [VC10OHIM][Cl] and IL crosslinker 1,12-di(3-vinylbenzylimidazolium) dodecane dichloride [(VBIM)2C12] 2[Cl] exhibited superior extraction performance compared to the other studied PILs. The extraction efficiency of pharmaceutical drugs and phenolics increased when the film thickness of the PIL-based sorbent coating was increased while many insecticides were largely unaffected. Satisfactory analytical performance was obtained with limits of detection (LODs) ranging from 0.2 to 2 μg L(-1) for the target analytes. The accuracy of the analytical method was examined by studying the relative recovery of analytes in real water samples, including tap water and lake water, with recoveries varying from 50.2% to 115.9% and from 48.8% to 116.6%, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. High-performance liquid chromatography of oligoguanylates at high pH

    Science.gov (United States)

    Stribling, R.; Deamer, D. (Principal Investigator)

    1991-01-01

    Because of the stable self-structures formed by oligomers of guanosine, standard high-performance liquid chromatography techniques for oligonucleotide fractionation are not applicable. Previously, oligoguanylate separations have been carried out at pH 12 using RPC-5 as the packing material. While RPC-5 provides excellent separations, there are several limitations, including the lack of a commercially available source. This report describes a new anion-exchange high-performance liquid chromatography method using HEMA-IEC BIO Q, which successfully separates different forms of the guanosine monomer as well as longer oligoguanylates. The reproducibility and stability at high pH suggests a versatile role for this material.

  15. Glucose and glycerol concentrations and their tracer enrichment measurements using liquid chromatography tandem mass spectrometry

    DEFF Research Database (Denmark)

    Bornø, Andreas; Foged, Lene; van Hall, Gerrit

    2014-01-01

    The present study describes a new liquid chromatography tandem mass spectrometry method for high-throughput quantification of glucose and glycerol in human plasma using stable isotopically labeled internal standards and is suitable for simultaneous measurements of glucose and glycerol enrichments...... of variation were 2.0% and 9.7%, respectively. After derivatization, plasma samples were stable for at least 14 days. In conclusion, we have developed and validated a novel, accurate, and sensitive high-throughput liquid chromatography tandem mass spectrometry method for simultaneous determination of glucose...

  16. A simple liquid extraction protocol for overcoming the ion suppression of triacylglycerols by phospholipids in liquid chromatography mass spectrometry studies.

    Science.gov (United States)

    Araujo, Pedro; Tilahun, Ephrem; Breivik, Joar Fjørtoft; Abdulkader, Bashir M; Frøyland, Livar; Zeng, Yingxu

    2016-02-01

    It is well-known that triacylglycerol (TAG) ions are suppressed by phospholipid (PL) ions in regiospecific analysis of TAG by mass spectrometry (MS). Hence, it is essential to remove the PL during sample preparation prior to MS analysis. The present article proposes a cost-effective liquid-liquid extraction (LLE) method to remove PL from TAG in different kinds of biological samples by using methanol, hexane and water. High performance thin layer chromatography confirmed the lack of PL in krill oil and salmon liver samples, submitted to the proposed LLE protocol, and liquid chromatography tandem MS confirmed that the identified TAG ions were highly enhanced after implementing the LLE procedure. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Bioanalysis of 6-Diazo-5-oxo-L-norleucine (DON) in plasma and brain by ultra-performance liquid chromatography mass spectrometry

    Science.gov (United States)

    Alt, Jesse; Potter, Michelle C.; Rojas, Camilo; Slusher, Barbara S.

    2015-01-01

    Glutamine is an abundant amino acid that plays pivotal roles in cell growth, cell metabolism and neurotransmission. Dysregulation of glutamine-utilizing pathways has been associated with pathological conditions such as cancer and neurodegenerative diseases. 6-Diazo-5-Oxo-L-Norleucine (DON) is a reactive glutamine analog that inhibits enzymes affecting glutamine metabolism such as glutaminase, 2-N-amidotransferase, L-asparaginase and several enzymes involved in pyrimidine and purine de novo synthesis. As a result, DON is actively used in preclinical models of cancer and neurodegenerative disease. Moreover, there have been several clinical trials using DON to treat a variety of cancers. Considerations of dose and exposure are especially important with DON treatment due to its narrow therapeutic window and significant side effects. Consequently, a robust quantification bioassay is of interest. DON is a polar unstable molecule which has made quantification challenging. Here we report on the characterization of a bioanalytical method to quantify DON in tissue samples involving DON derivatization with 3N HCl in butanol. The derivatized product is lipophilic and stable. Detection of this analyte by mass spectrometry is fast, specific and can be used to quantify DON in plasma and brain tissue with a limit of detection in the low nanomolar level. PMID:25584882

  18. Pre-analytical and analytical variation of drug determination in segmented hair using ultra-performance liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Nielsen, Marie Katrine Klose; Johansen, Sys Stybe; Linnet, Kristian

    2014-01-01

    variation was estimated to be less than 15% for almost all compounds. The method was successfully applied to 25 segmented hair specimens from deceased drug addicts showing a broad pattern of poly-drug use. The pre-analytical sampling variation was estimated from the genuine duplicate measurements of two...

  19. Analysis of Serum Metabolic Profile by Ultra-performance Liquid Chromatography-mass Spectrometry for Biomarkers Discovery: Application in a Pilot Study to Discriminate Patients with Tuberculosis

    Directory of Open Access Journals (Sweden)

    Shuang Feng

    2015-01-01

    Full Text Available Background: Tuberculosis (TB is a chronic wasting inflammatory disease characterized by multisystem involvement, which can cause metabolic derangements in afflicted patients. Metabolic signatures have been exploited in the study of several diseases. However, the serum that is successfully used in TB diagnosis on the basis of metabolic profiling is not by much. Methods: Orthogonal partial least-squares discriminant analysis was capable of distinguishing TB patients from both healthy subjects and patients with conditions other than TB. Therefore, TB-specific metabolic profiling was established. Clusters of potential biomarkers for differentiating TB active from non-TB diseases were identified using Mann-Whitney U-test. Multiple logistic regression analysis of metabolites was calculated to determine the suitable biomarker group that allows the efficient differentiation of patients with TB active from the control subjects. Results: From among 271 participants, 12 metabolites were found to contribute to the distinction between the TB active group and the control groups. These metabolites were mainly involved in the metabolic pathways of the following three biomolecules: Fatty acids, amino acids, and lipids. The receiver operating characteristic curves of 3D, 7D, and 11D-phytanic acid, behenic acid, and threoninyl-γ-glutamate exhibited excellent efficiency with area under the curve (AUC values of 0.904 (95% confidence interval [CI]: 0863-0.944, 0.93 (95% CI: 0.893-0.966, and 0.964 (95% CI: 00.941-0.988, respectively. The largest and smallest resulting AUCs were 0.964 and 0.720, indicating that these biomarkers may be involved in the disease mechanisms. The combination of lysophosphatidylcholine (18:0, behenic acid, threoninyl-γ-glutamate, and presqualene diphosphate was used to represent the most suitable biomarker group for the differentiation of patients with TB active from the control subjects, with an AUC value of 0.991. Conclusion: The metabolic analysis results identified new serum biomarkers that can distinguish TB from non-TB diseases. The metabolomics-based analysis provides specific insights into the biology of TB and may offer new avenues for TB diagnosis.

  20. Automated method for the direct analysis of 8-oxo-guanosine and 8-oxo-2'-deoxyguanosine in human urine using ultraperformance liquid chromatography and tandem mass spectrometry

    DEFF Research Database (Denmark)

    Henriksen, Trine; Hillestrøm, Peter R; Poulsen, Henrik E

    2009-01-01

    The potential use of oxidative stress-induced DNA and RNA damage products as biomarkers is an important aspect of biomedical research. There is a need for assays with high specificity and sensitivity that also can be used in molecular epidemiology studies with a large number of subjects. In addit......The potential use of oxidative stress-induced DNA and RNA damage products as biomarkers is an important aspect of biomedical research. There is a need for assays with high specificity and sensitivity that also can be used in molecular epidemiology studies with a large number of subjects...

  1. Ultra-performance liquid chromatography tandem mass spectrometry for simultaneous determination of natural steroid hormones in sea lamprey (Petromyzon marinus) plasma and tissues.

    Science.gov (United States)

    Wang, Huiyong; Bussy, Ugo; Chung-Davidson, Yu-Wen; Li, Weiming

    2016-01-15

    This study aims to provide a rapid, sensitive and precise UPLC-MS/MS method for target steroid quantitation in biological matrices. We developed and validated an UPLC-MS/MS method to simultaneously determine 16 steroids in plasma and tissue samples. Ionization sources of Electrospray Ionization (ESI) and Atmospheric Pressure Chemical Ionization (APCI) were compared in this study by testing their spectrometry performances at the same chromatographic conditions, and the ESI source was found up to five times more sensitive than the APCI. Different sample preparation techniques were investigated for an optimal extraction of steroids from the biological matrices. The developed method exhibited excellent linearity for all analytes with regression coefficients higher than 0.99 in broad concentration ranges. The limit of detection (LOD) was from 0.003 to 0.1ng/mL. The method was validated according to FDA guidance and applied to determine steroids in sea lamprey plasma and tissues (fat and testes) by the developed method. Copyright © 2015. Published by Elsevier B.V.

  2. A simple validated multi-analyte method for detecting drugs in oral fluid by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

    Science.gov (United States)

    Zheng, Yufang; Sparve, Erik; Bergström, Mats

    2018-06-01

    A UPLC-MS/MS method was developed to identify and quantitate 37 commonly abused drugs in oral fluid. Drugs of interest included amphetamines, benzodiazepines, cocaine, opiates, opioids, phencyclidine and tetrahydrocannabinol. Sample preparation and extraction are simple, and analysis times short. Validation showed satisfactory performance at relevant concentrations. The possibility of contaminated samples as well as the interpretation in relation to well-knows matrices, such as urine, will demand further study. Copyright © 2017 John Wiley & Sons, Ltd.

  3. Characterization of chiral amino acids from different milk origins using ultra-performance liquid chromatography coupled to ion-mobility mass spectrometry

    Science.gov (United States)

    Tian, He; Zheng, Nan; Li, Songli; Zhang, Yangdong; Zhao, Shengguo; Wen, Fang; Wang, Jiaqi

    2017-04-01

    Milk contains free amino acids (AAs) that play essential roles in maintaining the growth and health of infants, and D-AA isomers are increasingly being recognized as important signalling molecules. However, there are no studies of the different characteristics of chiral AA (C-AA) from different milk origins. Here, UPLC coupled to ion-mobility high-resolution MS (IM-HRMS) was employed to characterize 18 pairs of C-AAs in human, cow, yak, buffalo, goat, and camel milk. The results proved that milk origins can be differentiated based on the D- to L- AA ratio-based projection scores by principal component analysis. The present study gives a deeper understanding of the D- to L- AA ratio underlying the biological functions of different animal milks, and provide a new strategy for the study of AA metabolic pathways.

  4. Bacterial Cell Wall Precursor Phosphatase Assays Using Thin-layer Chromatography (TLC) and High Pressure Liquid Chromatography (HPLC).

    Science.gov (United States)

    Pazos, Manuel; Otten, Christian; Vollmer, Waldemar

    2018-03-20

    Peptidoglycan encases the bacterial cytoplasmic membrane to protect the cell from lysis due to the turgor. The final steps of peptidoglycan synthesis require a membrane-anchored substrate called lipid II, in which the peptidoglycan subunit is linked to the carrier lipid undecaprenol via a pyrophosphate moiety. Lipid II is the target of glycopeptide antibiotics and several antimicrobial peptides, and is degraded by 'attacking' enzymes involved in bacterial competition to induce lysis. Here we describe two protocols using thin-layer chromatography (TLC) and high pressure liquid chromatography (HPLC), respectively, to assay the digestion of lipid II by phosphatases such as Colicin M or the LXG toxin protein TelC from Streptococcus intermedius . The TLC method can also monitor the digestion of undecaprenyl (pyro)phosphate, whereas the HPLC method allows to separate the di-, mono- or unphosphorylated disaccharide pentapeptide products of lipid II.

  5. Lipidomic analysis of biological samples: Comparison of liquid chromatography, supercritical fluid chromatography and direct infusion mass spectrometry methods.

    Science.gov (United States)

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

    2017-11-24

    Lipidomic analysis of biological samples in a clinical research represents challenging task for analytical methods given by the large number of samples and their extreme complexity. In this work, we compare direct infusion (DI) and chromatography - mass spectrometry (MS) lipidomic approaches represented by three analytical methods in terms of comprehensiveness, sample throughput, and validation results for the lipidomic analysis of biological samples represented by tumor tissue, surrounding normal tissue, plasma, and erythrocytes of kidney cancer patients. Methods are compared in one laboratory using the identical analytical protocol to ensure comparable conditions. Ultrahigh-performance liquid chromatography/MS (UHPLC/MS) method in hydrophilic interaction liquid chromatography mode and DI-MS method are used for this comparison as the most widely used methods for the lipidomic analysis together with ultrahigh-performance supercritical fluid chromatography/MS (UHPSFC/MS) method showing promising results in metabolomics analyses. The nontargeted analysis of pooled samples is performed using all tested methods and 610 lipid species within 23 lipid classes are identified. DI method provides the most comprehensive results due to identification of some polar lipid classes, which are not identified by UHPLC and UHPSFC methods. On the other hand, UHPSFC method provides an excellent sensitivity for less polar lipid classes and the highest sample throughput within 10min method time. The sample consumption of DI method is 125 times higher than for other methods, while only 40μL of organic solvent is used for one sample analysis compared to 3.5mL and 4.9mL in case of UHPLC and UHPSFC methods, respectively. Methods are validated for the quantitative lipidomic analysis of plasma samples with one internal standard for each lipid class. Results show applicability of all tested methods for the lipidomic analysis of biological samples depending on the analysis requirements

  6. Liquid chromatography tandem mass spectrometry determination of total budesonide levels in dog plasma after inhalation exposure.

    Science.gov (United States)

    Berg, Seija; Melamies, Marika; Rajamäki, Minna; Vainio, Outi; Peltonen, Kimmo

    2012-01-01

    A sensitive and selective method to quantify budesonide in dog plasma samples was developed and fully validated. Liquid-liquid extraction was followed by solid-phase extraction and liquid chromatography-tandem mass spectrometry with electrospray ionization. After reconstitution of the analytes in the mobile phase, samples were analysed by reversed-phase liquid chromatography with isocratic elution. d8-Budesonide was used as an internal standard, and characteristic transitions of d8-budesonide and budesonide were used for quantification. The method was validated with respect to selectivity, specificity, linearity, recovery, repeatability, reproducibility and limits of detection and quantification. The validated method was successfully applied to monitor the plasma levels of budesonide in dogs exposed to clinical doses of inhaled and intravenous drug.

  7. Determination of five antiarrhythmic drugs in human plasma by dispersive liquid-liquid microextraction and high-performance liquid chromatography.

    Science.gov (United States)

    Jouyban, Abolghasem; Sorouraddin, Mohammad Hossein; Farajzadeh, Mir Ali; Somi, Mohammad Hossein; Fazeli-Bakhtiyari, Rana

    2015-03-01

    A fast and sensitive high-performance liquid chromatography (HPLC) method with ultraviolet (UV) detection was developed and validated for the simultaneous quantitation of five antiarrhythmic drugs (metoprolol, propranolol, carvedilol, diltiazem, and verapamil) in human plasma samples. It involves dispersive liquid-liquid microextraction (DLLME) of the desired drugs from 660 µL plasma and separation using isocratic elution with UV detection at 200 nm. The complete separation of all analytes was achieved within 7 min. Acetonitrile (as disperser solvent) resulting from the protein precipitation procedure was mixed with 100 µL dichloromethane (as an extraction solvent) and rapidly injected into 5 mL aqueous solution (pH 11.5) containing 1% (w/v), NaCl. After centrifugation, the sedimented phase containing enriched analytes was collected and evaporated to dryness. The residue was re-dissolved in 50 µL de-ionized water (acidified to pH 3) and injected into the HPLC system for analysis. Under the optimal conditions, the enrichment factors and extraction recoveries ranged between 4.4-10.8 and 33-82%, respectively. The suggested method was linear (r(2) ≥0.997) over a dynamic range of 0.02-0.80 µg mL(-1) in plasma. The intra- and inter-days relative standard deviation (RSD%) and relative error (RE%) values of the method were below 20%, which shows good precision and accuracy. Finally, this method was applied to the analysis of real plasma samples obtained from the patients treated with these drugs. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Analysis of drugs of abuse in human plasma by dispersive liquid-liquid microextraction and high-performance liquid chromatography.

    Science.gov (United States)

    Fernández, P; Regenjo, M; Bermejo, A M; Fernández, A M; Lorenzo, R A; Carro, A M

    2015-04-01

    Opioids and cocaine are widely used at present, both for recreational purposes and as drugs of abuse. This raises the need to develop new analytical methods specifically designed for the simultaneous detection of several drugs of abuse in biological samples. In this work, dispersive liquid-liquid microextraction (DLLME) was assessed as a new sample treatment for the simultaneous extraction of morphine (MOR), 6-acetylmorphine (6AM), cocaine (COC), benzoylecgonine (BZE) and methadone (MET) from human plasma. Preliminary assays were done before developing an experimental design based on a Uniform Network Doehlert which allowed the optimum extraction conditions to be identified, namely: a volume of extractant solvent (chloroform) and dispersant solvent (acetonitrile) of 220 µl and 3.2 ml, respectively; 0.2 g of NaCl as a salting-out additive; pH 10.6 and ultrasound stirring for 3.5 min. The resulting extracts were analyzed by high-performance liquid chromatography with photodiode array detection (HPLC-PDA), using an XBridge® RP18 column (250 × 4.6 mm i.d., 5 µm particle size). Calibration graphs were linear over the concentration range 0.1-10 µg ml⁻¹, and detection limits ranged from 13.9 to 28.5 ng ml⁻¹. Precision calculated at three different concentration levels in plasma was included in the range 0.1-6.8% RSD. Recoveries of the five drugs were all higher than 84% on average. Finally the proposed method was successfully applied to 22 plasma samples from heroin, cocaine and/or methadone users, and the most frequently detected drug was benzoylecgonine, followed by methadone, cocaine and morphine. Copyright © 2014 John Wiley & Sons, Ltd.

  9. Determination of statin drugs in hospital effluent with dispersive liquid-liquid microextraction and quantification by liquid chromatography.

    Science.gov (United States)

    Martins, Ayrton F; Frank, Carla da S; Altissimo, Joseline; de Oliveira, Júlia A; da Silva, Daiane S; Reichert, Jaqueline F; Souza, Darliana M

    2017-08-24

    Statins are classified as being amongst the most prescribed agents for treating hypercholesterolaemia and preventing vascular diseases. In this study, a rapid and effective liquid chromatography method, assisted by diode array detection, was designed and validated for the simultaneous quantification of atorvastatin (ATO) and simvastatin (SIM) in hospital effluent samples. The solid phase extraction (SPE) of the analytes was optimized regarding sorbent material and pH, and the dispersive liquid-liquid microextraction (DLLME), in terms of pH, ionic strength, type and volume of extractor/dispersor solvents. The performance of both extraction procedures was evaluated in terms of linearity, quantification limits, accuracy (recovery %), precision and matrix effects for each analyte. The methods proved to be linear in the concentration range considered; the quantification limits were 0.45 µg L -1 for ATO and 0.75 µg L -1 for SIM; the matrix effect was almost absent in both methods and the average recoveries remained between 81.5-90.0%; and the RSD values were <20%. The validated methods were applied to the quantification of the statins in real samples of hospital effluent; the concentrations ranged from 18.8 µg L -1 to 35.3 µg L -1 for ATO, and from 30.3 µg L -1 to 38.5 µg L -1 for SIM. Since the calculated risk quotient was ≤192, the occurrence of ATO and SIM in hospital effluent poses a potential serious risk to human health and the aquatic ecosystem.

  10. Rapid determination of fumonisins in corn-based products by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Li, Wei; Herrman, Timothy J; Dai, Susie Y

    2010-01-01

    A simple, fast, and robust method was developed for the determination of fumonisin B1 (FB1), fumonisin B2 (FB2), and fumonisin B3 (FB3) in corn-based human food and animal feed (cornmeal). The method involves a single extraction step followed by centrifugation and filtration before analysis by ultra-performance liquid chromatographylelectrospray ionization (UPLC/ESI)-MS/MS. The LC/MS/MS method developed here represents the fastest and simplest procedure (<30 min) among both conventional HPLC methods and other LC/MS methods using SPE cleanup. The potential for high throughput analysis makes the method particularly beneficial for regulatory agencies and analytical laboratories with a high sample volume. A single-laboratory validation was conducted by testing three different spiking levels (200, 500, and 1000 ng/g for FB1 and FB2; 100, 250, and 500 ng/g for FB3) for accuracy and precision. Recoveries of FB1 ranged from 93 to 98% with RSD values of 3-8%. Recoveries of FB2 ranged from 104 to 108%, with RSD values of 2-6%. Recoveries of FB3 ranged from 94 to 108%, with RSD values of 2-5%.

  11. Liquid chromatography and supercritical fluid chromatography as alternative techniques to gas chromatography for the rapid screening of anabolic agents in urine.

    Science.gov (United States)

    Desfontaine, Vincent; Nováková, Lucie; Ponzetto, Federico; Nicoli, Raul; Saugy, Martial; Veuthey, Jean-Luc; Guillarme, Davy

    2016-06-17

    This work describes the development of two methods involving supported liquid extraction (SLE) sample treatment followed by ultra-high performance liquid chromatography or ultra-high performance supercritical fluid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS and UHPSFC-MS/MS) for the screening of 43 anabolic agents in human urine. After evaluating different stationary phases, a polar-embedded C18 and a diol columns were selected for UHPLC-MS/MS and UHPSFC-MS/MS, respectively. Sample preparation, mobile phases and MS conditions were also finely tuned to achieve highest selectivity, chromatographic resolution and sensitivity. Then, the performance of these two methods was compared to the reference routine procedure for steroid analyses in anti-doping laboratories, which combines liquid-liquid extraction (LLE) followed by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). For this purpose, urine samples spiked with the compounds of interest at five different concentrations were analyzed using the three analytical platforms. The retention and selectivity of the three techniques were very different, ensuring a good complementarity. However, the two new methods displayed numerous advantages. The overall procedure was much faster thanks to high throughput SLE sample treatment using 48-well plates and faster chromatographic analysis. Moreover, the highest sensitivity was attained using UHPLC-MS/MS with 98% of the doping agents detected at the lowest concentration level (0.1ng/mL), against 76% for UHPSFC-MS/MS and only 14% for GC-MS/MS. Finally, the weakest matrix effects were obtained with UHPSFC-MS/MS with 76% of the analytes displaying relative matrix effect between -20 and 20%, while the GC-MS/MS reference method displayed very strong matrix effects (over 100%) for all of the anabolic agents. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, Tanja C. W.; Schierbeek, Henk; Houtekamer, Marco; van Engeland, Tom; Derrien, Delphine; Stal, Lucas J.; Boschker, Henricus T. S.

    2015-01-01

    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ(13)C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

  13. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

    2015-01-01

    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of d13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

  14. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

    2015-01-01

    Rationale: We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence,

  15. Extraction protocol and liquid chromatography/tandem mass spectrometry method for determining micelle-entrapped paclitaxel at the cellular and subcellular levels: Application to a cellular uptake and distribution study.

    Science.gov (United States)

    Zheng, Nan; Lian, Bin; Du, Wenwen; Xu, Guobing; Ji, Jiafu

    2018-01-01

    Paclitaxel-loaded polymeric micelles (PTX-PM) are commonly used as tumor-targeted nanocarriers and display outstanding antitumor features in clinic, but its accumulation and distribution in vitro are lack of investigation. It is probably due to the complex micellar system and its low concentration at the cellular or subcellular levels. In this study, we developed an improved extraction method, which was a combination of mechanical disruption and liquid-liquid extraction (LLE), to extract the total PTX from micelles in the cell lysate and subcellular compartments. An ultra-performance liquid chromatography tandem mass spectroscopy (UPLC-MS/MS) method was optimized to detect the low concentration of PTX at cellular and subcellular levels simultaneously, using docetaxel as internal standard (IS). The method was proved to release PTX totally from micelles (≥95.93%) with a consistent and reproducible extraction recovery (≥75.04%). Good linearity was obtained at concentrations ranging from 0.2 to 20ng/mL. The relative error (RE%) for accuracy varied from 0.68 to 7.56%, and the intra- and inter-precision (relative standard deviation, RSD%) was less than 8.64% and 13.14%, respectively. This method was fully validated and successfully applied to the cellular uptake and distribution study of PTX-loaded PLGA-PEG micelles in human breast cancer cells (MCF-7). Copyright © 2017 Elsevier B.V. All rights reserved.

  16. High-performance liquid chromatography of human glycoprotein hormones.

    Science.gov (United States)

    Chlenov, M A; Kandyba, E I; Nagornaya, L V; Orlova, I L; Volgin, Y V

    1993-02-12

    The chromatographic behavior of the glycoprotein hormones from human pituitary glands and of placental origin [thyroid-stimulating hormone, luteinizing hormone and chorionic gonadotropin (CG)] was studied. It was shown that hydrophobic interaction chromatography on a microparticulate packing and anion-exchange HPLC can be applied for the purification of these hormones. Reversed-phase HPLC on wide-pore C4-bonded silica at neutral pH can be applied for the determination of the above hormones and for the isolation of pure CG and its subunits.

  17. Separation of hemagglutination-inhibiting immunoglobulin M antibody to rubella virus in human serum by high-performance liquid chromatography.

    OpenAIRE

    Kobayashi, N; Suzuki, M; Nakagawa, T; Matumoto, M

    1986-01-01

    High-performance liquid chromatography was successfully used to separate hemagglutination-inhibiting immunoglobulin M (IgM) rubella virus antibody from IgG rubella virus antibody in human serum. The fractionation by high-performance liquid chromatography was as effective as sucrose density gradient centrifugation in separating IgM antibody from IgG antibody.

  18. Application in pesticide analysis: Liquid chromatography - A review of the state of science for biomarker discovery and identification

    Science.gov (United States)

    Book Chapter 18, titled Application in pesticide analysis: Liquid chromatography - A review of the state of science for biomarker discovery and identification, will be published in the book titled High Performance Liquid Chromatography in Pesticide Residue Analysis (Part of the C...

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

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Steven [Iowa State Univ., Ames, IA (United States)

    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.

  20. Resolution of RNA using high-performance liquid chromatography

    NARCIS (Netherlands)

    Mclaughlin, L.W.; Bischoff, Rainer

    1987-01-01

    High-performance liquid chromatographic techniques can be very effective for the resolution and isolation of nucleic acids. The characteristic ionic (phosphodiesters) and hydrophobic (nucleobases) properties of RNAs can be exploited for their separation. In this respect anion-exchange and

  1. Buffer-Free High Performance Liquid Chromatography Method for ...

    African Journals Online (AJOL)

    Purpose: To develop and validate a simple, economical and reproducible high performance liquid chromatographic (HPLC) method for the determination of theophylline in pharmaceutical dosage forms. Method: Caffeine was used as the internal standard and reversed phase C-18 column was used to elute the drug and ...

  2. Determination of ribavirin in human serum using liquid chromatography tandem mass spectrometry

    NARCIS (Netherlands)

    van der Lijke, H.; Alffenaar, J.-W. C.; Kok, W.Th.; Greijdanus, B.; Uges, D.R.A.

    2012-01-01

    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

  3. Determination of low molecular weight thiols using monobromobimane fluorescent labeling and high-performance liquid chromatography

    Science.gov (United States)

    Fahey, Robert C.; Newton, Gerald L.

    1988-01-01

    Methods are described for the preparation and high-performance liquid chromatography (HPLC) analysis of monobromobimane derivatives of low molecular weight thiols in extracts of biological samples. Typical problems encountered in the development and application of these methods are discussed. Analysis of mung bean extract is used as an example.

  4. Sugar Determination in Foods with a Radially Compressed High Performance Liquid Chromatography Column.

    Science.gov (United States)

    Ondrus, Martin G.; And Others

    1983-01-01

    Advocates use of Waters Associates Radial Compression Separation System for high performance liquid chromatography. Discusses instrumentation and reagents, outlining procedure for analyzing various foods and discussing typical student data. Points out potential problems due to impurities and pump seal life. Suggests use of ribose as internal…

  5. Determination of Peroxide-Based Explosives Using Liquid Chromatography with On-Line Infrared Detection

    NARCIS (Netherlands)

    Schulte-Ladbeck, Rasmus; Edelmann, Andrea; Quintas, Guillermo; Lendl, Bernhard; Karst, U.

    2006-01-01

    A nondestructive analytical method for peroxide-based explosives determination in solid samples is described. Reversed-phase high-performance liquid chromatography in combination with on-line Fourier transform infrared (FT-IR) detection is used for the analysis of triacetonetriperoxide (TATP) and

  6. 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,

  7. High-Performance Liquid Chromatography in the Undergraduate Chemical Engineering Laboratory

    Science.gov (United States)

    Frey, Douglas D.; Guo, Hui; Karnik, Nikhila

    2013-01-01

    This article describes the assembly of a simple, low-cost, high-performance liquid chromatography (HPLC) system and its use in the undergraduate chemical engineering laboratory course to perform simple experiments. By interpreting the results from these experiments students are able to gain significant experience in the general method of…

  8. Isotope Fractionation in Methane Reactions Studied by Gas Chromatography and Liquid Scintillation

    DEFF Research Database (Denmark)

    Andersen, Bertel Lohmann; Bidoglio, G.; Leip, A.

    1997-01-01

    Determination of C-14-marked methane by gas chromatography and liquid scintillation counting is shown to be useful in studies of isotope effects. Data on the specific activity is used to separate the contributions of (CH4)-C-14, and (CH4)-C-12 to the gas-chromatographic peak area. As an application...

  9. Improvement of recovery and repeatability in liquid chromatography-mass spectrometry analysis of peptides

    NARCIS (Netherlands)

    van Midwoud, Paul M.; Rieux, Laurent; Bischoff, Rainer; Verpoorte, Elisabeth; Niederlander, Harm A. G.

    2007-01-01

    Poor repeatability of peak areas is a problem frequently encountered in peptide analysis with nanoLiquid Chromatography coupled on-line with Mass Spectrometry (nanoLC-MS). As a result, quantitative analysis will be seriously hampered unless the observed variability can be corrected in some way.

  10. Serum Protein Profile Study of Clinical Samples Using High Performance Liquid Chromatography-Laser Induced Fluorescence

    DEFF Research Database (Denmark)

    Karemore, Gopal Raghunath; Ukendt, Sujatha; Rai, Lavanya

    2009-01-01

    The serum protein profiles of normal subjects, patients diagnosed with cervical cancer, and oral cancer were recorded using High Performance Liquid Chromatography combined with Laser Induced Fluorescence detection (HPLC-LIF). Serum protein profiles of the above three classes were tested for estab...

  11. Nitrate and nitrite content in bottled beverages by ion-pair high-performance liquid chromatography.

    Science.gov (United States)

    Song, Yang; Deng, Gui-Fang; Xu, Xiang-Rong; Chen, Yong-Hong; Chen, Feng; Li, Hua-Bin

    2013-01-01

    Nitrate and nitrite levels in six types of beverages--total of 292 individual samples from 73 brands (four bottles each)--from Guangzhou city in China were evaluated by ion-pair high-performance liquid chromatography. All samples contained nitrate. Nitrate and nitrite ranges were 0.43-46.08 and safety of Chinese bottled beverages.

  12. DETERMINATION OF CHLOROPHEONIS, NITROPHENOIS AND METHYLPHENOIS IN GROUND-WATER SAMPLES USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

    Science.gov (United States)

    A high performance liquid chromatography (HPLC) method was developed to quantitatively determine phenolic compounds and their isomers in aqueous samples. The HPLC method can analyze a mixture of 15 contaminants in the same analytical run with an analysis time of 25 minutes. The...

  13. High Performance Liquid Chromatography of Some Analgesic Compounds: An Instrumental Analysis Experiment.

    Science.gov (United States)

    Haddad, Paul; And Others

    1983-01-01

    Background information, procedures, and results are provided for an experiment demonstrating techniques of solvent selection, gradient elution, pH control, and ion-pairing in the analysis of an analgesic mixture using reversed-phase liquid chromatography on an octadecylsilane column. Although developed using sophisticated/expensive equipment, less…

  14. DETERMINATION OF CHLOROPHENOLS, NITROPHENOLS, AND METHYLPHENOLS IN GROUND-WATER SAMPLES USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

    Science.gov (United States)

    A high performance liquid chromatography (HPLC) method was developed to quantitatively determine phenolic compounds and their isomers in aqueous samples. The HPLC method can analyze a mixture of 15 contaminants in the same analytical run with an analysis time of 25 minutes. The...

  15. Coupling nanoliter high-performance liquid chromatography to inductively coupled plasma mass spectrometry for arsenic speciation.

    Science.gov (United States)

    Cheng, Heyong; Shen, Lihuan; Liu, Jinhua; Xu, Zigang; Wang, Yuanchao

    2018-04-01

    Nanoliter high-performance liquid chromatography shows low consumption of solvents and samples, offering one of the best choices for arsenic speciation in precious samples in combination with inuctively coupled plasma mass spectrometry. A systematic investigation on coupling nanoliter high-performance liquid chromatography to inductively coupled plasma mass spectrometry from instrument design to injected sample volume and mobile phase was performed in this study. Nanoflow mobile phase was delivered by flow splitting using a conventional high-pressure pump with reuse of mobile phase waste. Dead volume was minimized to 60 nL for the sheathless interface based on the previously developed nanonebulizer. Capillary columns for nanoliter high-performance liquid chromatography were found to be sensitive to sample loading volume. An apparent difference was also found between the mobile phases for nanoliter and conventional high-performance liquid chromatography. Baseline separation of arsenite, arsenate, monomethylarsenic, and dimethylarsenic was achieved within 11 min on a 15 cm C 18 capillary column and within 12 min on a 25 cm strong anion exchange column. Detection limits of 0.9-1.8 μg/L were obtained with precisions variable in the range of 1.6-4.2%. A good agreement between determined and certified values of a certified reference material of human urine (GBW 09115) validated its accuracy along with good recoveries (87-102%). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. 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.

  17. High-performance liquid chromatography determination of dapsone, monoacetyldapsone, and pyrimethamine in filter paper blood spots

    DEFF Research Database (Denmark)

    Rønn, A M; Lemnge, M M; Angelo, H R

    1995-01-01

    A high-performance liquid chromatography method for the simultaneous analysis of dapsone (DDS), the major metabolite of DDS, monoacetyldapsone (MADDS), and pyrimethamine (PYR) was modified for capillary blood samples obtained by finger prick and dried on filter paper. Limit of quantitation using...

  18. Alternative sample-introduction technique to avoid breakthrough in gradient-elution liquid chromatography of polymers

    NARCIS (Netherlands)

    Reingruber, E.; Bedani, F.; Buchberger, W.; Schoenmakers, P.

    2010-01-01

    Gradient-elution liquid chromatography (GELC) is a powerful tool for the characterization of synthetic polymers. However, gradient-elution chromatograms often suffer from breakthrough phenomena. Breakthrough can be averted by using a sample solvent as weak as the mobile phase. However, this approach

  19. Determination of organophosphorus acids by thermo-spray liquid chromatography-mass spectrometry

    NARCIS (Netherlands)

    Wils, E.R.J.; Hulst, A.G.

    1988-01-01

    The determination of thirteen organophosphorus acids, hydrolysis products of nerve agents and pesticides, by a combination of ion-pair liquid chromatography on a reversed-phase C18 column and thermospray mass spectrometry was investigated. Ammonium acetate and three tetraalkylammonium salts with

  20. Novel approach to determine ghrelin analogs by liquid chromatography with mass spectrometry using a monolithic column

    Czech Academy of Sciences Publication Activity Database

    Zemenová, Jana; Sýkora, D.; Adámková, H.; Maletínská, Lenka; Elbert, Tomáš; Marek, Aleš; Blechová, Miroslava

    2017-01-01

    Roč. 40, č. 5 (2017), s. 1032-1039 ISSN 1615-9306 Institutional support: RVO:61388963 Keywords : enzyme-linked immunosorbent assay * ghrelin * lipopeptides * liquid chromatography mass spectrometry * monolithic columns Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 2.557, year: 2016

  1. Deformation and degradation of polymers in ultra-high-pressure liquid chromatography

    NARCIS (Netherlands)

    Uliyanchenko, E.; van der Wal, S.; Schoenmakers, P.J.

    2011-01-01

    Ultra-high-pressure liquid chromatography (UHPLC) using columns packed with sub-2 μm particles has great potential for separations of many types of complex samples, including polymers. However, the application of UHPLC for the analysis of polymers meets some fundamental obstacles. Small particles

  2. Extraction and Purification of Glucoraphanin by Preparative High-Performance Liquid Chromatography (HPLC)

    Science.gov (United States)

    Lee, Iris; Boyce, Mary C.

    2011-01-01

    A student activity that focuses on the isolation of glucoraphanin from broccoli using preparative high-performance liquid chromatography (HPLC) is presented here. Glucoraphanin is a glucosinolate, whose byproducts are known to possess anticancer properties. It is present naturally at high levels in broccoli and other "Brassica" vegetables. This…

  3. Analysis of Currently Available Analgesic Tablets by Modern Liquid Chromatography: An Undergraduate Laboratory Introduction to HPLC.

    Science.gov (United States)

    Kagel, R. A.; Farwell, S. O.

    1983-01-01

    Background information, procedures, and results, are provided for an undergraduate experiment in which analgesic tablets are analyzed using liquid chromatography. The experiment, an improved, modified version of the Waters Associates Inc. experiment, is simple to prepare, requiring little glassware and minimal sample manipulation by students. (JN)

  4. 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

  5. An Advanced, Interactive, High-Performance Liquid Chromatography Simulator and Instructor Resources

    Science.gov (United States)

    Boswell, Paul G.; Stoll, Dwight R.; Carr, Peter W.; Nagel, Megan L.; Vitha, Mark F.; Mabbott, Gary A.

    2013-01-01

    High-performance liquid chromatography (HPLC) simulation software has long been recognized as an effective educational tool, yet many of the existing HPLC simulators are either too expensive, outdated, or lack many important features necessary to make them widely useful for educational purposes. Here, a free, open-source HPLC simulator is…

  6. Simulated Moving Bed Chromatography: Separation and Recovery of Sugars and Ionic Liquid from Biomass Hydrolysates

    Science.gov (United States)

    Caes, Benjamin R.; Van Oosbree, Thomas R.; Lu, Fachuang; Ralph, John; Maravelias, Christos T.

    2015-01-01

    Simulated moving bed chromatography, a continuous separation method, enables the nearly quantitative recovery of sugar products and ionic liquid solvent from chemical hydrolysates of biomass. The ensuing sugars support microbial growth, and the residual lignin from the process is intact. PMID:23939991

  7. Determination of chlormequat in pears by liquid chromatography/mass spectrometry

    NARCIS (Netherlands)

    Mol, H.G.J.; Dam, R.C.J. van; Vreeken, R.J.; Steijger, O.M.

    2000-01-01

    A straightforward and reliable method was developed for the determination of chlormequat in pears by liquid chromatography/mass spectrometry (LC/MS). Water and methanol were compared as extraction solvents. Because no significant differences in extraction efficiency or repeatability were found,

  8. Assay of free urinary cortisol with inverted phase liquid chromatography and radiocompetition

    International Nuclear Information System (INIS)

    Franck, C.; Patricot, M.C.; Mathian, B.; Revol, A.

    1984-01-01

    The authors present an assay method for free urinary cortisol using inverted phase liquid chromatography for purification and radiocompetition for the assay. The usual values for adult men and women were established. The results of 150 routine assays were compared with those of 17 OHCS revealing the value of this assay [fr

  9. Analysis of 2-methylthio-derivatives of isoprenoid cytokinins by liquid chromatography-tandem mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Tarkowski, Petr; Václavíková, Kateřina; Novák, Ondřej; Pertry, I.; Hanuš, Jan; Whenham, R.; Vereecke, D.; Šebela, M.; Strnad, Miroslav

    2010-01-01

    Roč. 680, 1-2 (2010), s. 86-91 ISSN 0003-2670 R&D Projects: GA ČR GA301/08/1649 Institutional research plan: CEZ:AV0Z50380511 Keywords : Cytokinins * Rhodococcus fascians * High-performance liquid chromatography Subject RIV: CE - Biochemistry Impact factor: 4.310, year: 2010

  10. Monoliths in capillary electrochromatography and capillary liquid chromatography in conjunction with mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Moravcová, Dana; Rantamäki, A. H.; Duša, Filip; Wiedmer, S. K.

    2016-01-01

    Roč. 37, 7-8 (2016), s. 880-912 ISSN 0173-0835 Institutional support: RVO:68081715 Keywords : capillary electrochromatography * capillary liquid chromatography * mass spec- trometry * monolithic columns Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.744, year: 2016

  11. Separation and quantification of ropinirole and some impurities using capillary liquid chromatography

    NARCIS (Netherlands)

    Coufal, P.; Stulik, K.; Claessens, H.A.; Hardy, M.J.; Webb, M.

    1999-01-01

    Ropinirole, 4-[2-(dipropylamino)ethyl]-1,3-dihydro-2H-indol-2-one, is a potent anti-Parkinson’s disease drug developed by SmithKline Beecham Pharmaceuticals. Capillary liquid chromatography (CLC) was used for the separation and quantification of ropinirole and its five related impurities,

  12. An on-line high performance liquid chromatography-crocin bleaching assay for detection of antioxidants

    NARCIS (Netherlands)

    Bountagkidou, O.; Klift, van der E.J.C.; Tsimidou, M.Z.; Ordoudi, S.A.; Beek, van T.A.

    2012-01-01

    An on-line HPLC (high performance liquid chromatography) method for the rapid screening of individual antioxidants in mixtures was developed using crocin as a substrate (i.e. oxidation probe) and 2,2'-azobis(2-amidinopropane dihydrochloride (AAPH)) in phosphate buffer (pH 7.5) as a radical

  13. Separation of Poly(styrene-block-t-butyl methacrylate) Copolymers by Various Liquid Chromatography Techniques

    Science.gov (United States)

    Šmigovec Ljubič, Tina; Pahovnik, David; Žigon, Majda; Žagar, Ema

    2012-01-01

    The separation of a mixture of three poly(styrene-block-t-butyl methacrylate) copolymers (PS-b-PtBMA), consisting of polystyrene (PS) blocks of similar length and t-butyl methacrylate (PtBMA) blocks of different lengths, was performed using various chromatographic techniques, that is, a gradient liquid chromatography on reversed-phase (C18 and C8) and normal-phase columns, a liquid chromatography under critical conditions for polystyrene as well as a fully automated two-dimensional liquid chromatography that separates block copolymers by chemical composition in the first dimension and by molar mass in the second dimension. The results show that a partial separation of the mixture of PS-b-PtBMA copolymers can be achieved only by gradient liquid chromatography on reversed-phase columns. The coelution of the two block copolymers is ascribed to a much shorter PtBMA block length, compared to the PS block, as well as a small difference in the length of the PtBMA block in two of these copolymers, which was confirmed by SEC-MALS and NMR spectroscopy. PMID:22489207

  14. Column liquid chromatography- mass spectrometry: selected techniques in environmental applications for polar pesticides and related compounds.

    NARCIS (Netherlands)

    Slobodnik, J.; van Baar, B.L.M.; Brinkman, U.A.T.

    1995-01-01

    A review covering the field of environmental applications of liquid chromatography-mass spectrometry (LC-MS) is presented. Recent developments and advances are discussed with emphasis on the presently popular thermospray, particle beam and atmospheric pressure ionisation interfaces. Each interface

  15. Characterization of goat colostrum oligosaccharides by nano-liquid chromatography on chip quadrupole time-of-flight mass spectrometry and hydrophilic interaction liquid chromatography-quadrupole mass spectrometry.

    Science.gov (United States)

    Martín-Ortiz, A; Salcedo, J; Barile, D; Bunyatratchata, A; Moreno, F J; Martin-García, I; Clemente, A; Sanz, M L; Ruiz-Matute, A I

    2016-01-08

    A detailed qualitative and quantitative characterization of goat colostrum oligosaccharides (GCO) has been carried out for the first time. Defatted and deproteinized colostrum samples, previously treated by size exclusion chromatography (SEC) to remove lactose, were analyzed by nanoflow liquid chromatography-quadrupole-time of flight mass spectrometry (Nano-LC-Chip-Q-TOF MS). Up to 78 oligosaccharides containing hexose, hexosamine, fucose, N-acetylneuraminic acid or N-glycolylneuraminic acid monomeric units were identified in the samples, some of them detected for the first time in goat colostra. As a second step, a hydrophilic interaction liquid chromatography coupled to mass spectrometry (HILIC-MS) methodology was developed for the separation and quantitation of the main GCO, both acidic and neutral carbohydrates. Among other experimental chromatographic conditions, mobile phase additives and column temperature were evaluated in terms of retention time, resolution, peak width and symmetry of target carbohydrates. Narrow peaks (wh: 0.2-0.6min) and good symmetry (As: 0.8-1.4) were obtained for GCO using an acetonitrile:water gradient with 0.1% ammonium hydroxide at 40°C. These conditions were selected to quantify the main oligosaccharides in goat colostrum samples. Values ranging from 140 to 315mgL(-1) for neutral oligosaccharides and from 83 to 251mgL(-1) for acidic oligosaccharides were found. The combination of both techniques resulted to be useful to achieve a comprehensive characterization of GCO. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Separation of carbohydrates using hydrophilic interaction liquid chromatography.

    Science.gov (United States)

    Fu, Qing; Liang, Tu; Li, Zhenyu; Xu, Xiaoyong; Ke, Yanxiong; Jin, Yu; Liang, Xinmiao

    2013-09-20

    A strategy was developed to rapidly evaluate chromatographic properties of hydrophilic interaction chromatography (HILIC) columns for separating carbohydrates. Seven HILIC columns (Silica, Diol, TSK Amide-80, XAmide, Click Maltose, Click β-CD, and Click TE-Cys columns) were evaluated by using three monosaccharide and seven disaccharides as probes. The influence of column temperature on the peak shape and tautomerization of carbohydrates, as well as column selectivity were investigated. The influence of surface charge property on the retention was also studied by using glucose, glucuronic acid, and glucosamine, which indicated that buffer salt concentration and pH value in mobile phase was necessary to control the ionic interactions between ionic carbohydrates and HILIC columns. According to evaluation results, the XAmide column was selected as an example to establish experimental schemes for separation of complex mixtures of oligosaccharide. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Review of in situ derivatization techniques for enhanced bioanalysis using liquid chromatography with mass spectrometry.

    Science.gov (United States)

    Baghdady, Yehia Z; Schug, Kevin A

    2016-01-01

    Accurate and specific analysis of target molecules in complex biological matrices remains a significant challenge, especially when ultra-trace detection limits are required. Liquid chromatography with mass spectrometry is often the method of choice for bioanalysis. Conventional sample preparation and clean-up methods prior to the analysis of biological fluids such as liquid-liquid extraction, solid-phase extraction, or protein precipitation are time-consuming, tedious, and can negatively affect target recovery and detection sensitivity. An alternative or complementary strategy is the use of an off-line or on-line in situ derivatization technique. In situ derivatization can be incorporated to directly derivatize target analytes in their native biological matrices, without any prior sample clean-up methods, to substitute or even enhance the extraction and preconcentration efficiency of these traditional sample preparation methods. Designed appropriately, it can reduce the number of sample preparation steps necessary prior to analysis. Moreover, in situ derivatization can be used to enhance the performance of the developed liquid chromatography with mass spectrometry-based bioanalysis methods regarding stability, chromatographic separation, selectivity, and ionization efficiency. This review presents an overview of the commonly used in situ derivatization techniques coupled to liquid chromatography with mass spectrometry-based bioanalysis to guide and to stimulate future research. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. High-performance liquid chromatography analysis methods developed for quantifying enzymatic esterification of flavonoids in ionic liquids

    DEFF Research Database (Denmark)

    Lue, Bena-Marie; Guo, Zheng; Xu, X.B.

    2008-01-01

    Methods using reversed-phase high-performance liquid chromatography (RP-HPLC) with ELSD were investigated to quantify enzymatic reactions of flavonoids with fatty acids in the presence of diverse room temperature ionic liquids (RTILs). A buffered salt (preferably triethylamine-acetate) was found...... essential for separation of flavonoids from strongly polar RTILs, whereby RTILs were generally visible as two major peaks identified based on an ion-pairing/exchanging hypothesis. C8 and C12 stationary phases were optimal while mobile phase pH (3-7) had only a minor influence on separation. The method...

  19. Ionic liquid-based air-assisted liquid-liquid microextraction followed by high performance liquid chromatography for the determination of five fungicides in juice samples.

    Science.gov (United States)

    You, Xiangwei; Chen, Xiaochu; Liu, Fengmao; Hou, Fan; Li, Yiqiang

    2018-01-15

    A novel and simple ionic liquid-based air-assisted liquid-liquid microextraction technique combined with high performance liquid chromatography was developed to analyze five fungicides in juice samples. In this method, ionic liquid was used instead of a volatile organic solvent as the extraction solvent. The emulsion was formed by pulling in and pushing out the mixture of aqueous sample solution and extraction solvent repeatedly using a 10mL glass syringe. No organic dispersive solvent was required. Under the optimized conditions, the limits of detection (LODs) were 0.4-1.8μgL -1 at a signal-to-noise ratio of 3. The limits of quantification (LOQs) set as the lowest spiking levels with acceptable recovery in juices were 10μgL -1 , except for fludioxonil whose LOQ was 20μgL -1 . The proposed method was applied to determine the target fungicides in juice samples, and acceptable recoveries ranging from 74.9% to 115.4% were achieved. Copyright © 2017. Published by Elsevier Ltd.

  20. High-throughput Quantification of Lincomycin Traces in Fermentation Broth of Genetically Modified Streptomyces spp. Comparison of Ultra-Performance Liquid Chromatography and High-Performance Liquid Chromatography with UV detection

    Czech Academy of Sciences Publication Activity Database

    Olšovská, Jana; Jelínková, Markéta; Man, Petr; Koběrská, Markéta; Janata, Jiří; Flieger, Miroslav

    2007-01-01

    Roč. 1139, - (2007), s. 214-220 ISSN 0021-9673 R&D Projects: GA MŠk 1M06011; GA ČR GA204/05/0616 Institutional research plan: CEZ:AV0Z50200510 Keywords : hplc * uplc Subject RIV: EE - Microbiology, Virology Impact factor: 3.641, year: 2007

  1. Determination of Oxidized Phosphatidylcholines by Hydrophilic Interaction Liquid Chromatography Coupled to Fourier Transform Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Pia Sala

    2015-04-01

    Full Text Available A novel liquid chromatography-mass spectrometry (LC-MS approach for analysis of oxidized phosphatidylcholines by an Orbitrap Fourier Transform mass spectrometer in positive electrospray ionization (ESI coupled to hydrophilic interaction liquid chromatography (HILIC was developed. This method depends on three selectivity criteria for separation and identification: retention time, exact mass at a resolution of 100,000 and collision induced dissociation (CID fragment spectra in a linear ion trap. The process of chromatography development showed the best separation properties with a silica-based Kinetex column. This type of chromatography was able to separate all major lipid classes expected in mammalian samples, yielding increased sensitivity of oxidized phosphatidylcholines over reversed phase chromatography. Identification of molecular species was achieved by exact mass on intact molecular ions and CID tandem mass spectra containing characteristic fragments. Due to a lack of commercially available standards, method development was performed with copper induced oxidation products of palmitoyl-arachidonoyl-phosphatidylcholine, which resulted in a plethora of lipid species oxidized at the arachidonoyl moiety. Validation of the method was done with copper oxidized human low-density lipoprotein (LDL prepared by ultracentrifugation. In these LDL samples we could identify 46 oxidized molecular phosphatidylcholine species out of 99 possible candidates.

  2. Two-Dimensional Liquid Chromatography Analysis of Polystyrene/Polybutadiene Block Copolymers.

    Science.gov (United States)

    Lee, Sanghoon; Choi, Heejae; Chang, Taihyun; Staal, Bastiaan

    2018-05-15

    A detailed characterization of a commercial polystyrene/polybutadiene block copolymer material (Styrolux) was carried out using two-dimensional liquid chromatography (2D-LC). The Styrolux is prepared by statistical linking reaction of two different polystyrene- block-polybutadienyl anion precursors with a multivalent linking agent. Therefore, it is a mixture of a number of branched block copolymers different in molecular weight, composition, and chain architecture. While individual LC analysis, including size exclusion chromatography, interaction chromatography, or liquid chromatography at critical condition, is not good enough to resolve all the polymer species, 2D-LC separations coupling two chromatography methods were able to resolve all polymer species present in the sample; at least 13 block copolymer species and a homopolystyrene blended. Four different 2D-LC analyses combining a different pair of two LC methods provide their characteristic separation results. The separation characteristics of the 2D-LC separations are compared to elucidate the elution characteristics of the block copolymer species.

  3. The determination of antipyrine elimination in saliva by liquid chromatography.

    Science.gov (United States)

    Gartzke, J; Jäger, H

    1991-01-01

    A simple, fast and reliable liquid chromatographic method for the determination of antipyrine in saliva is described. The elimination of antipyrine is a good indicator for general evaluation of the liver function for dispositional purposes for example in occupational and environmental medicine. The described LC method was compared with a more extensive photometric procedure. The results obtained from both methods show very good correlation. Only one measurement is necessary to determine the antipyrine clearance. Furthermore the antipyrine dosage can be minimized, because of the sensitivity of the HPLC-method.

  4. Simultaneous determination of seven anticoagulant rodenticides in agricultural products by gel permeation chromatography and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Saito-Shida, Shizuka; Nemoto, Satoru; Matsuda, Rieko; Akiyama, Hiroshi

    2016-11-01

    A sensitive and reliable method for the simultaneous determination of hydroxycoumarin-type (brodifacoum, bromadiolone, coumatetralyl, and warfarin) and indandione-type (chlorophacinone, diphacinone, and pindone) rodenticides in agricultural products by gel permeation chromatography (GPC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. The procedure involved extraction of the rodenticides from samples with acetone, followed by liquid-liquid partitioning with hexane/ethyl acetate (1:1, v/v) and 10% sodium chloride aqueous solution, then cleanup using GPC, and finally, analysis using LC-MS/MS. High recoveries from the GPC column were obtained for all rodenticides tested using a mobile phase of acetone/cyclohexane/triethylamine (400:1600:1, v/v/v). An ODS column, which contains low levels of metal impurities, gave satisfactory peak shapes for both hydroxycoumarin- and indandione-type rodenticides in the LC-MS/MS separation. The average recoveries of rodenticides from eight agricultural foods (apple, eggplant, cabbage, orange, potato, tomato, brown rice, and soybean) fortified at 0.0005-0.001 mg/kg ranged from 76 to 116%, except for bromadiolone in orange (53%) and diphacinone in soybean (54%), and the relative standard deviations ranged from 1 to 16%. The proposed method effectively removed interfering components, such as pigments and lipids, and showed high selectivity. In addition, the matrix effects were negligible for most of the rodenticide/food combinations. The results suggest that the proposed method is reliable and suitable for determining hydroxycoumarin- and indandione-type rodenticides in agricultural products.

  5. Comprehensive lipidomic analysis of human plasma using multidimensional liquid- and gas-phase separations: Two-dimensional liquid chromatography-mass spectrometry vs. liquid chromatography-trapped-ion-mobility-mass spectrometry.

    Science.gov (United States)

    Baglai, Anna; Gargano, Andrea F G; Jordens, Jan; Mengerink, Ynze; Honing, Maarten; van der Wal, Sjoerd; Schoenmakers, Peter J

    2017-12-29

    Recent advancements in separation science have resulted in the commercialization of multidimensional separation systems that provide higher peak capacities and, hence, enable a more-detailed characterization of complex mixtures. In particular, two powerful analytical tools are increasingly used by analytical scientists, namely online comprehensive two-dimensional liquid chromatography (LC×LC, having a second-dimension separation in the liquid phase) and liquid chromatography-ion mobility-spectrometry (LC-IMS, second dimension separation in the gas phase). The goal of the current study was a general assessment of the liquid-chromatography-trapped-ion-mobility-mass spectrometry (LC-TIMS-MS) and comprehensive two-dimensional liquid chromatography-mass spectrometry (LC×LC-MS) platforms for untargeted lipid mapping in human plasma. For the first time trapped-ion-mobility spectrometry (TIMS) was employed for the separation of the major lipid classes and ion-mobility-derived collision-cross-section values were determined for a number of lipid standards. The general effects of a number of influencing parameters have been inspected and possible directions for improvements are discussed. We aimed to provide a general indication and practical guidelines for the analyst to choose an efficient multidimensional separation platform according to the particular requirements of the application. Analysis time, orthogonality, peak capacity, and an indicative measure for the resolving power are discussed as main characteristics for multidimensional separation systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Combined high-performance liquid chromatography/32P-postlabeling assay of N7-methyldeoxyguanosine

    International Nuclear Information System (INIS)

    Shields, P.G.; Povey, A.C.; Wilson, V.L.; Weston, A.; Harris, C.C.

    1990-01-01

    A highly sensitive and specific assay for the detection of N7-methyl-2'-deoxyguanosine (N7methyldG) has been developed by combining high-performance liquid chromatography, 32 P-postlabeling, and nucleotide chromatography. Separation of normal nucleotides and adducts by high-performance liquid chromatography and then combining a portion of 2'-deoxyguanosine to the N7methyldG allows for quantitation using an internal standard. The directly determined molar ratio is not subject to errors in digestion, variable ATP-specific activity, or assumptions in relative adduct-labeling efficiency. The detection limit was one N7methyldG adduct in 10(7) unmodified 2'-deoxyguanosine bases. N7methyldG adducts have been detected in 5 human lung samples in which O6-methyl-2'-deoxyguanosine adducts had been previously determined. The mean ratio of N7methyldG to O6-methyl-2'-deoxyguanosine was determined to be approximately 10. The current assay complements the high-performance liquid chromatography/ 32 P-postlabeling assay for O6-methyl-2'-deoxyguanosine and increases the detection sensitivity of DNA methylated by exogenous alkylating agents

  7. Liquid chromatography-tandem mass spectrometric assay for the tyrosine kinase inhibitor afatinib in mouse plasma using salting-out liquid-liquid extraction

    NARCIS (Netherlands)

    Sparidans, Rolf W; van Hoppe, Stephanie; Rood, Johannes J M; Schinkel, Alfred H; Schellens, Jan H M; Beijnen, Jos H

    2016-01-01

    A quantitative bioanalytical liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay for afatinib, an irreversible inhibitor of the ErbB (erythroblastic leukemia viral oncogene homolog) tyrosine kinase family, was developed and validated. Plasma samples were pre-treated using salting-out

  8. Sensitive determination of nitrophenol isomers by reverse-phase high-performance liquid chromatography in conjunction with liquid-liquid extraction

    Science.gov (United States)

    A method for the highly sensitive determination of 2-, 3- and 4- nitrophenols was developed using reverse-phase high-performance liquid chromatography (RP-HPLC) with a UV photodiode array detector. Using a reverse-phase column and 40% aqueous acetonitrile as an eluent (i.e. isocratic elution), the i...

  9. [Blood levels of homocysteine by high pressure liquid chromatography and comparison with two other techniques].

    Science.gov (United States)

    Ceppa, F; Drouillard, I; Chianea, D; Burnat, P; Perrier, F; Vaillant, C; El Jahiri, Y

    1999-01-01

    Cardio-vascular diseases are the most common cause of death in industrialized countries. A new marker has emerged among offending risk factors in the past few years: homocysteine. This sulphured amino-acid is an important intermediate in transsulphuration and remethylation reactions of methionine's metabolism. We proposed to evaluate a home made method of determination for this parameter by high performance liquid chromatography (HPLC) and to compare it to fluorescence polarization immunoassay technique (FPIA) and to gaz phase chromatography (CG-SM). This method associated with good sensibility and precision remain much less expensive than FPIA technique.

  10. Characterization of Extracellular Vesicles by Size-Exclusion High-Performance Liquid Chromatography (HPLC).

    Science.gov (United States)

    Huang, Tao; He, Jiang

    2017-01-01

    Extracellular vesicles (EVs) have recently attracted substantial attention due to the potential diagnostic and therapeutic relevance. Although a variety of techniques have been used to isolate and analyze EVs, it is still far away from satisfaction. Size-exclusion chromatography (SEC), which separates subjects by size, has been widely applied in protein purification and analysis. The purpose of this chapter is to show the applications of size-exclusion high-performance liquid chromatography (HPLC) as methods for EV characterization of impurities or contaminants of small size, and thus for quality assay for the purity of the samples of EVs.

  11. Nanoparticle Analysis by Online Comprehensive Two-Dimensional Liquid Chromatography combining Hydrodynamic Chromatography and Size-Exclusion Chromatography with Intermediate Sample Transformation

    Science.gov (United States)

    2017-01-01

    Polymeric nanoparticles have become indispensable in modern society with a wide array of applications ranging from waterborne coatings to drug-carrier-delivery systems. While a large range of techniques exist to determine a multitude of properties of these particles, relating physicochemical properties of the particle to the chemical structure of the intrinsic polymers is still challenging. A novel, highly orthogonal separation system based on comprehensive two-dimensional liquid chromatography (LC × LC) has been developed. The system combines hydrodynamic chromatography (HDC) in the first-dimension to separate the particles based on their size, with ultrahigh-performance size-exclusion chromatography (SEC) in the second dimension to separate the constituting polymer molecules according to their hydrodynamic radius for each of 80 to 100 separated fractions. A chip-based mixer is incorporated to transform the sample by dissolving the separated nanoparticles from the first-dimension online in tetrahydrofuran. The polymer bands are then focused using stationary-phase-assisted modulation to enhance sensitivity, and the water from the first-dimension eluent is largely eliminated to allow interaction-free SEC. Using the developed system, the combined two-dimensional distribution of the particle-size and the molecular-size of a mixture of various polystyrene (PS) and polyacrylate (PACR) nanoparticles has been obtained within 60 min. PMID:28745485

  12. Determination of pyrazinamide in human by high performance liquid chromatography.

    Directory of Open Access Journals (Sweden)

    Revankar S

    1994-01-01

    Full Text Available A facile and sensitive high performance liquid chromatographic (HPLC technique has been developed for the determination pyrazinamide (PZA in human plasma. Nicotinamide(NIA is used as internal standard(IS. Plasma is deproteinized with 0.7 M perchloric acid; clear supernatant is neutralized with 1M NaOH and injected onto HPLC. The separation of pyrazinamide and the internal standard is carried out on a Supelco LC-18 (DB column with a basic mobile phase. Pyrazinoic acid, the major metabolite, other anti-tuberculous drugs and endogenous components do not interfere with measurement of pyrazinamide. The limit of detection of pyrazinamide with this method is 0.2 mg/0.2 ml plasma (CV 8.2%.

  13. Microwave-assisted ionic liquid homogeneous liquid-liquid microextraction coupled with high performance liquid chromatography for the determination of anthraquinones in Rheum palmatum L.

    Science.gov (United States)

    Wang, Zhibing; Hu, Jianxue; Du, Hongxia; He, Shuang; Li, Qing; Zhang, Hanqi

    2016-06-05

    The microwave-assisted ionic liquid homogeneous liquid-liquid microextraction (MA-IL-HLLME) coupled with high performance liquid chromatography with diode array detection (HPLC-DAD) was developed for the determination of anthraquinones, including aloe-emodin, emodin, chrysophanol and physcion in root of Rheum palmatum L. Several experimental parameters influencing the extraction efficiency, including amount of sample, type and volume of ionic liquid, volume and pH value of extraction medium, microwave power and extraction time, concentration of NH4PF6 as well as centrifugal condition were optimized. When 140μL of ionic liquid ([C8MIM][BF4]) was used as an extraction solvent, target analytes can be extracted from sample matrix in one minute with the help of microwave irradiation. The MA-IL-HLLME is simple and quick. The calibration curves exhibited good linear relationship (r>0.9984). The limits of detection and quantification were in the range of 0.015-0.026 and 0.051-0.088μgmL(-1), respectively. The spiked recovery for each analyte was in the range of 81.13-93.07% with relative standard deviations lower than 6.89%. The present method is free of volatile organic solvents, and represents lower expenditures of sample, extraction time and solvent, compared with ultrasonic and heat reflux extraction. The results indicated that the present method can be successfully applied to the determination of anthraquinones in medicinal plant. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Development and evaluation of a liquid chromatography tandem mass spectrometry method for simultaneous determination of salivary melatonin, cortisol and testosterone

    DEFF Research Database (Denmark)

    Jensen, Marie Aarrebo; Hansen, Åse Marie; Abrahamsson, Peter

    2011-01-01

    saliva. We used liquid-liquid extraction (LLE) followed by liquid chromatography coupled to electrospray tandem mass spectrometry (LC-ESI-MS/MS) recorded in positive ion mode. Saliva samples were collected by spitting directly into tubes and 250 µL were used for analysis. The limits of detection were 4...

  15. [Separation and purification of the components in Trachelospermum jasminoides by two dimensional hydrophilic interaction liquid chromatography- reversed-phase liquid chromatography].

    Science.gov (United States)

    Jia, Youmei; Cai, Jianfeng; Xin, Huaxia; Feng, Jiatao; Fu, Yanhui; Fu, Qing; Jin, Yu

    2017-06-08

    A preparative two dimensional hydrophilic interaction liquid chromatography/reversed-phase liquid chromatography (Pre-2D-HILIC/RPLC) method was established to separate and purify the components in Trachelospermum jasminoides . The pigments and strongly polar components were removed from the crude extract after the active carbon decolorization and solid phase extraction processes. A Click XIon column (250 mm×20 mm, 10 μm) was selected as stationary phase and water-acetonitrile as mobile phases in the first dimensional HILIC. Finally, 15 fractions were collected under UV-triggered mode. In the second dimensional RPLC, a C18 column (250 mm×20 mm, 5 μm) was selected and water-acetonitrile was used as mobile phases. As a result, 14 compounds with high purity were obtained, which were further identified by mass spectrometry (MS) and nuclear magnetic resonance (NMR). Finally, 11 lignan compounds and three flavonoid compounds were obtained. The method has a good orthogonality, and can improve the resolution and the peak capacity. It is significant for the separation of complex components from Trachelospermum jasminoides .

  16. Chemical fingerprint of Ganmaoling granule by double-wavelength ultra high performance liquid chromatography and ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Lou, Qiong; Ye, Xiaolan; Zhou, Yingyi; Li, Hua; Song, Fenyun

    2015-06-01

    A method incorporating double-wavelength ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry was developed for the investigation of the chemical fingerprint of Ganmaoling granule. The chromatographic separations were performed on an ACQUITY UPLC HSS C18 column (2.1 × 50 mm, 1.8 μm) at 30°C using gradient elution with water/formic acid (1%) and acetonitrile at a flow rate of 0.4 mL/min. A total of 11 chemical constituents of Ganmaoling granule were identified from their molecular weight, UV spectra, tandem mass spectrometry data, and retention behavior by comparing the results with those of the reference standards or literature. And 25 peaks were selected as the common peaks for fingerprint analysis to evaluate the similarities among 25 batches of Ganmaoling granule. The results of principal component analysis and orthogonal projection to latent structures discriminant analysis showed that the important chemical markers that could distinguish the different batches were revealed as 4,5-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, and 4-O-caffeoylquinic acid. This is the first report of the ultra high performance liquid chromatography chemical fingerprint and component identification of Ganmaoling granule, which could lay a foundation for further studies of Ganmaoling granule. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Determination of chloroacetanilide herbicide metabolites in water using high-performance liquid chromatography-diode array detection and high-performance liquid chromatography/mass spectrometry

    Science.gov (United States)

    Hostetler, K.A.; Thurman, E.M.

    2000-01-01

    Analytical methods using high-performance liquid chromatography-diode array detection (HPLC-DAD) and high-performance liquid chromatography/mass spectrometry (HPLC/MS) were developed for the analysis of the following chloroacetanilide herbicide metabolites in water: alachlor ethanesulfonic acid (ESA); alachlor oxanilic acid; acetochlor ESA; acetochlor oxanilic acid; metolachlor ESA; and metolachlor oxanilic acid. Good precision and accuracy were demonstrated for both the HPLC-DAD and HPLC/MS methods in reagent water, surface water, and ground water. The average HPLC-DAD recoveries of the chloroacetanilide herbicide metabolites from water samples spiked at 0.25, 0.5 and 2.0 ??g/l ranged from 84 to 112%, with relative standard deviations of 18% or less. The average HPLC/MS recoveries of the metabolites from water samples spiked at 0.05, 0.2 and 2.0 ??g/l ranged from 81 to 118%, with relative standard deviations of 20% or less. The limit of quantitation (LOQ) for all metabolites using the HPLC-DAD method was 0.20 ??g/l, whereas the LOQ using the HPLC/MS method was at 0.05 ??g/l. These metabolite-determination methods are valuable for acquiring information about water quality and the fate and transport of the parent chloroacetanilide herbicides in water. Copyright (C) 2000 Elsevier Science B.V.

  18. Analyses of Indole Compounds in Sugar Cane (Saccharum officinarum L. Juice by High Performance Liquid Chromatography and Liquid Chromatography-Mass Spectrometry after Solid-Phase Extraction

    Directory of Open Access Journals (Sweden)

    Jean Wan Hong Yong

    2017-03-01

    Full Text Available Simultaneous quantitative analysis of 10 indole compounds, including indole-3-acetic acid (IAA, one of the most important naturally occurring auxins and some of its metabolites, by high performance liquid chromatography (HPLC and liquid chromatography-mass spectrometry (LC-MS after solid-phase extraction (SPE was reported for the first time. The analysis was carried out using a reverse phase HPLC gradient elution, with an aqueous mobile phase (containing 0.1% formic acid modified by methanol. Furthermore, a novel SPE procedure was developed for the pre-concentration and purification of indole compounds using C18 SPE cartridges. The combination of SPE, HPLC, and LC-MS was applied to screen for the indole compounds present in sugar cane (Saccharum officinarum L. juice, a refreshing beverage with various health benefits. Finally, four indole compounds were successfully detected and quantified in sugar cane juice by HPLC, which were further unequivocally confirmed by LC-MS/MS experiments operating in the multiple reaction monitoring (MRM mode.

  19. On-line comprehensive two-dimensional normal-phase liquid chromatography × reversed-phase liquid chromatography for preparative isolation of Peucedanum praeruptorum.

    Science.gov (United States)

    Wang, Xin-Yuan; Li, Jia-Fu; Jian, Ya-Mei; Wu, Zhen; Fang, Mei-Juan; Qiu, Ying-Kun

    2015-03-27

    A new on-line comprehensive preparative two-dimensional normal-phase liquid chromatography × reversed-phase liquid chromatography (2D NPLC × RPLC) system was developed for the separation of complicated natural products. It was based on the use of a silica gel packed medium-pressure column as the first dimension and an ODS preparative HPLC column as the second dimension. The two dimensions were connected with normal-phase (NP) and reversed-phase (RP) enrichment units, involving a newly developed airflow assisted adsorption (AAA) technique. The instrument operation and the performance of this NPLC × RPLC separation method were illustrated by gram-scale isolation of ethanol extract from the roots of Peucedanum praeruptorum. In total, 19 compounds with high purity were obtained via automated multi-step preparative separation in a short period of time using this system, and their structures were comprehensively characterized by ESI-MS, (1)H NMR, and (13)C NMR. Including two new compounds, five isomers in two groups with identical HPLC and TLC retention values were also obtained and identified by 1D NMR and 2D NMR. This is the first report of an NPLC × RPLC system successfully applied in an on-line preparative process. This system not only solved the interfacing problem of mobile-phase immiscibility caused by NP and RP separation, it also exhibited apparent advantages in separation efficiency and sample treatment capacity compared with conventional methods. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Low-level flow counting of liquid chromatography column eluates

    International Nuclear Information System (INIS)

    Harding, N.G.L.; Farid, Y.; Stewart, M.J.

    1982-01-01

    The principal parameters which determine the operation of a high-resolution, high-sensitivity radioactive flow monitor are described: a) Sample preparation to ensure adequate recovery of radiolabelled sample, metabolites and internal standard. b) The instrument background count rate, when no sample or radiolabel is present in the flow cell, is a function of shielding and a reduction in noise obtained with a coincidence time below one microsecond. c) The minimum detectable amount of label depends upon the machine background, HPLC eluent and scintillator flow, whether or not packed flow cells are used, flow cell geometry, and the scintillator used. d) Three types of flow cell have been designed to cover the majority of HPLC and isotope applications. e) The performance of solid and liquid scintillators. It is shown that an instrument has been designed taking account of these parameters. The resulting design satisfies present high sensitivity counting requirements and maintains the resolution of current HPLC procedures when detection is by simultaneous flow radioassay and by optical methods. (orig.)

  1. Determination of Finasteride in Tablets by High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    K. Basavaiah

    2007-01-01

    Full Text Available A rapid, highly sensitive high performance liquid chromatographic method has been developed for the determination of finasteride(FNS in bulk drug and in tablets. FNS was eluted from a ODS C18 reversed phase column at laboratory temperature (30 ± 2°C with a mobile phase consisting of methanol and water (80+20 at a flow rate of 1 mL min-1 with UV detection at 225 nm. The retention time was ∼ 6.1 min and each analysis took not more than 10 min. Quantitation was achieved by measurement of peak area without using any internal standard. Calibration graph was linear from 2.0 to 30 μg mL-1 with limits of detection (LOD and quantification (LOQ being 0.2 and 0.6 μg mL-1, respectively. The method was validated according to the current ICH guidelines. Within-day co efficients of variation (CV ranged from 0.31 to 0.69% and between-day CV were in the range 1.2-3.2%. Recovery of FNS from the pharmaceutical dosage forms ranged from 97.89 – 102.9 with CV of 1.41-4.13%. The developed method was compared with the official method for FNS determination in its tablet forms.

  2. Hyphenated and comprehensive liquid chromatography × gas chromatography-mass spectrometry for the identification of Mycobacterium tuberculosis.

    Science.gov (United States)

    Mourão, Marta P B; Denekamp, Ilse; Kuijper, Sjoukje; Kolk, Arend H J; Janssen, Hans-Gerd

    2016-03-25

    Tuberculosis is one of the world's most emerging public health problems, particularly in developing countries. Chromatography based methods have been used to tackle this epidemic by focusing on biomarker detection. Unfortunately, interferences from lipids in the sputum matrix, particularly cholesterol, adversely affect the identification and detection of the marker compounds. The present contribution describes the serial combination of normal phase liquid chromatography (NPLC) with thermally assisted hydrolysis and methylation followed by gas chromatography-mass spectrometry (THM-GC-MS) to overcome the difficulties of biomarker evaluation. The in-series combination consists of an LC analysis where fractions are collected and then transferred to the THM-GC-MS system. This was either done with comprehensive coupling, transferring all the fractions, or with hyphenated interfacing, i.e. off-line multi heart-cutting, transferring only selected fractions. Owing to the high sensitivity and selectivity of LC as a sample pre-treatment method, and to the high specificity of the MS as a detector, this analytical approach, NPLC × THM-GC-MS, is extremely sensitive. The results obtained indicate that this analytical set-up is able to detect down to 1 × 10(3) mycobacteria/mL of Mycobacterium tuberculosis strain 124, spiked in blank sputum samples. It is a powerful analytical tool and also has great potential for full automation. If further studies demonstrate its usefulness when applied blind in real sputum specimens, this technique could compete with the current smear microscopy in the early diagnosis of tuberculosis. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Column liquid chromatography applied to concentrating, separating, and determining platinum metals

    International Nuclear Information System (INIS)

    Alimarin, I.P.; Basova, E.M.; Bol'shova, T.A.; Ivanov, V.M.

    1986-01-01

    The present survey deals with high-performance liquid chromatography (HPLC) in relation to the chromatographic behavior of the platinum metals, including separation and determination. The data shows that HPLC is the most promising and effective method of separating metals, including platinum ones. The method provides efficient separation of microgram amoounts of mixtures with a resolving power 3-20 times that of thin-layer chromatography. It is shown that the most promising line of advance in HPLC for inorganic systems lies in the separation and determination of metals as chelates by absorption or ion-pair chromatography. Examples of using HPLC for determining noble metals in particular cases indicate that the metrological characteristics are favorable

  4. Determination of oxyfluorfen herbicide and oxyfluorfen amine residues in garbanzo beans by liquid chromatography.

    Science.gov (United States)

    Zhou, M; Miles, C J

    1991-01-01

    Oxyfluorfen and oxyfluorfen amine were determined by liquid chromatography (LC) with ultraviolet (UV) and photoconductivity detection (PCD). A simple extraction procedure acceptably recovered both analytes from garbanzo beans over a wide range of fortifications (0.05 to 20 ppm) (83 +/- 4 for oxyfluorfen; 85 +/- 4 for oxyfluorfen amine). Percent recoveries decreased slightly as the fortification level decreased. Both analytes could be determined simultaneously at a concentration greater than 0.2 ppm in garbanzo beans. Detection limits were 3 ng for oxyfluorfen and 100 ng for oxyfluorfen amine using LC/UV, and 12 ng for both oxyfluorfen and oxyfluorfen amine with LC/PCD. Different knitted reaction coils and photoreactors were evaluated. Photoproduct yields and identification were determined by ion chromatography. The LC/PCD method measures oxyfluorfen and oxyfluorfen amine separately and has a shorter analysis time, while the standard method using gas chromatography measures total residues and is more sensitive.

  5. Phytochemical Profile of Erythrina variegata by Using High-Performance Liquid Chromatography and Gas Chromatography-Mass Spectroscopy Analyses.

    Science.gov (United States)

    Muthukrishnan, Suriyavathana; Palanisamy, Subha; Subramanian, Senthilkumar; Selvaraj, Sumathi; Mari, Kavitha Rani; Kuppulingam, Ramalingam

    2016-08-01

    Natural products derived from plant sources have been utilized to treat patients with numerous diseases. The phytochemical constituents present in ethanolic leaf extract of Erythrina variegata (ELEV) were identified by using high-performance liquid chromatography (HPLC) and gas chromatography-mass spectroscopy (GC-MS) analyses. Shade dried leaves were powdered and extracted with ethanol for analyses through HPLC to identify selected flavonoids and through GC-MS to identify other molecules. The HPLC analysis of ELEV showed the presence of gallic and caffeic acids as the major components at concentrations of 2.0 ppm and 0.1 ppm, respectively, as well as other components. GC-MS analysis revealed the presence of 3-eicosyne; 3,7,11,15-tetramethyl-2-hexadecen-1-ol; butanoic acid, 3-methyl-3,7-dimethyl-6-octenyl ester; phytol; 1,2-benzenedicarboxylic acid, diundecyl ester; 1-octanol, 2-butyl-; squalene; and 2H-pyran, 2-(7-heptadecynyloxy) tetrahydro-derivative. Because pharmacopuncture is a new evolving natural mode that uses herbal extracts for treating patients with various ailments with minimum pain and maximum effect, the results of this study are particularly important and show that ELEV possesses a wide range of phytochemical constituents, as indicated above, as effective active principle molecules that can be used individually or in combination to treat patients with various diseases. Copyright © 2016. Published by Elsevier B.V.

  6. Gas chromatography-mass spectrometry and high-performance liquid chromatography-diode array detection for dating of paper ink.

    Science.gov (United States)

    Díaz-Santana, Oscar; Vega-Moreno, Daura; Conde-Hardisson, Francisco

    2017-09-15

    An extraction and determination method is shown for the analysis of dyes and solvents present in two types of ballpoint pen inks that are deposited onto paper. Ink extracts are analysed using a combination of gas chromatography with mass spectrometry (GC-MS), and high-pressure liquid chromatography with photodiode array detection (HPLC-DAD), within a single sample extraction procedure. Seventeen solvents and thirteen dyes contained in two Montblanc ® inks (black and blue) were monitored for 45 months at monthly intervals, in order to determine variations in the concentrations of the compounds over time. We also studied the relative variations between different compounds and the generation of degradation products such as phenol. The concentration data obtained from these compounds during their exposure have been analysed and a multiple regression model is developed for each ink type that allows an estimate of the exposure time of the ink on paper with a maximum error of between 4 and 7 months. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Pressurized planar electrochromatography, high-performance thin-layer chromatography and high-performance liquid chromatography--comparison of performance.

    Science.gov (United States)

    Płocharz, Paweł; Klimek-Turek, Anna; Dzido, Tadeusz H

    2010-07-16

    Kinetic performance, measured by plate height, of High-Performance Thin-Layer Chromatography (HPTLC), High-Performance Liquid Chromatography (HPLC) and Pressurized Planar Electrochromatography (PPEC) was compared for the systems with adsorbent of the HPTLC RP18W plate from Merck as the stationary phase and the mobile phase composed of acetonitrile and buffer solution. The HPLC column was packed with the adsorbent, which was scrapped from the chromatographic plate mentioned. An additional HPLC column was also packed with adsorbent of 5 microm particle diameter, C18 type silica based (LiChrosorb RP-18 from Merck). The dependence of plate height of both HPLC and PPEC separating systems on flow velocity of the mobile phase and on migration distance of the mobile phase in TLC system was presented applying test solute (prednisolone succinate). The highest performance, amongst systems investigated, was obtained for the PPEC system. The separation efficiency of the systems investigated in the paper was additionally confirmed by the separation of test component mixture composed of six hormones. 2010 Elsevier B.V. All rights reserved.

  8. Simultaneous achiral-chiral analysis of pharmaceutical compounds using two-dimensional reversed phase liquid chromatography-supercritical fluid chromatography.

    Science.gov (United States)

    Venkatramani, C J; Al-Sayah, Mohammad; Li, Guannan; Goel, Meenakshi; Girotti, James; Zang, Lisa; Wigman, Larry; Yehl, Peter; Chetwyn, Nik

    2016-02-01

    A new interface was designed to enable the coupling of reversed phase liquid chromatography (RPLC) and supercritical fluid chromatography (SFC). This online two-dimensional chromatographic system utilizing RPLC in the first dimension and SFC in the second was developed to achieve simultaneous achiral and chiral analysis of pharmaceutical compounds. The interface consists of an eight-port, dual-position switching valve with small volume C-18 trapping columns. The peaks of interest eluting from the first RPLC dimension column were effectively focused as sharp concentration pulses on small volume C-18 trapping column/s and then injected onto the second dimension SFC column. The first dimension RPLC separation provides the achiral purity result, and the second dimension SFC separation provides the chiral purity result (enantiomeric excess). The results are quantitative enabling simultaneous achiral, chiral analysis of compounds. The interface design and proof of concept demonstration are presented. Additionally, comparative studies to conventional SFC and case studies of the applications of 2D LC-SFC in pharmaceutical analysis is presented. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Rational approach to solvent system selection for liquid-liquid extraction-assisted sample pretreatment in counter-current chromatography.

    Science.gov (United States)

    Wang, Jiajia; Gu, Dongyu; Wang, Miao; Guo, Xinfeng; Li, Haoquan; Dong, Yue; Guo, Hong; Wang, Yi; Fan, Mengqi; Yang, Yi

    2017-05-15

    A rational liquid-liquid extraction approach was established to pre-treat samples for high-speed counter-current chromatography (HSCCC). n-Hexane-ethyl acetate-methanol-water (4:5:4:5, v/v) and (1:5:1:5, v/v) were selected as solvent systems for liquid-liquid extraction by systematically screening K of target compounds to remove low- and high-polarity impurities in the sample, respectively. After liquid-liquid extraction was performed, 1.4g of crude sample II was obtained from 18.5g of crude sample I which was extracted from the flowers of Robinia pseudoacacia L., and then separated with HSCCC by using a solvent system composed of n-hexane-ethyl acetate-methanol-water (1:2:1:2, v/v). As a result, 31mg of robinin and 37mg of kaempferol 7-O-α-l-rhamnopyranoside were isolated from 200mg of crude sample II in a single run of HSCCC. A scale-up separation was also performed, and 160mg of robinin with 95% purity and 188mg of kaempferol 7-O-α-l-rhamnopyranoside with 97% purity were produced from 1.2g of crude sample II. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Clinical applications of fast liquid chromatography: a review on the analysis of cardiovascular drugs and their metabolites.

    Science.gov (United States)

    Baranowska, Irena; Magiera, Sylwia; Baranowski, Jacek

    2013-05-15

    One of the major challenges facing the medicine today is developing new therapies that enhance human health. To help address these challenges the utilization of analytical technologies and high-throughput automated platforms has been employed; in order to perform more experiments in a shorter time frame with increased data quality. In the last decade various analytical strategies have been established to enhance separation speed and efficiency in liquid chromatography applications. Liquid chromatography is an increasingly important tool for monitoring drugs and their metabolites. Furthermore, liquid chromatography has played an important role in pharmacokinetics and metabolism studies at these drug development stages since its introduction. This paper provides an overview of current trends in fast chromatography for the analysis of cardiovascular drugs and their metabolites in clinical applications. Current trends in fast liquid chromatographic separations involve monolith technologies, fused-core columns, high-temperature liquid chromatography (HTLC) and ultra-high performance liquid chromatography (UHPLC). The high specificity in combination with high sensitivity makes it an attractive complementary method to traditional methodology used for routine applications. The practical aspects of, recent developments in and the present status of fast chromatography for the analysis of biological fluids for therapeutic drug and metabolite monitoring, pharmacokinetic studies and bioequivalence studies are presented. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Current practice of liquid chromatography-mass spectrometry in metabolomics and metabonomics.

    Science.gov (United States)

    Gika, Helen G; Theodoridis, Georgios A; Plumb, Robert S; Wilson, Ian D

    2014-01-01

    Based on publication and citation numbers liquid chromatography (LC-MS) has become the major analytical technology in the field of global metabolite profiling. This dominance reflects significant investments from both the research community and instrument manufacturers. Here an overview of the approaches taken for LC-MS-based metabolomics research is given, describing critical steps in the realisation of such studies: study design and its needs, specific technological problems to be addressed and major obstacles in data treatment and biomarker identification. The current state of the art for LC-MS-based analysis in metabonomics/metabolomics is described including recent developments in liquid chromatography, mass spectrometry and data treatment as these are applied in metabolomics underlining the challenges, limitations and prospects for metabolomics research. Examples of the application of metabolite profiling in the life sciences focusing on disease biomarker discovery are highlighted. In addition, new developments and future prospects are described. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Molecular differences between deuterated and protonated polystyrenes using reversed-phase high-performance liquid chromatography.

    Science.gov (United States)

    Kayillo, Sindy; Gray, Michael J; Shalliker, R Andrew; Dennis, Gary R

    2005-05-06

    Isotopic substitution is a technique used to highlight particular bonds within a molecule for kinetic, spectroscopic and structure analysis. It is presumed that although some properties such as stretching frequencies will not be the same for substituted analogues, the chemical interactions will not vary appreciably as a function of labelling. Reversed-phase liquid chromatography has been used to demonstrate that there are significant differences between the chromatographic behaviour of a sequence of deuterated and protonated oligomeric polystyrenes. Two-dimensional reversed-phase liquid chromatography was used to show that even the diasteromers of the oligomers (n = 5) have retention mechanisms that are dependent on the subtle changes to the molecular conformation and electronic structure, which are a consequence of deuteration.

  13. Controlled crosslinking of trimethylolpropane trimethacrylate for preparation of organic monolithic columns for capillary liquid chromatography.

    Science.gov (United States)

    Gama, Mariana R; Aggarwal, Pankaj; Lee, Milton L; Bottoli, Carla B G

    2017-11-01

    Organic monolithic columns based on single crosslinking of trimethylolpropane trimethacrylate (TRIM) monomer were prepared in a single step by living/controlled free-radical polymerization. Full optimization of the preparation, such as using different percentages of TRIM and different amounts of radical promoter as well as various porogen solvents were explored. The resulting monolithic columns were characterized by scanning electronic microscopy and nitrogen sorption for structure morphology studies and surface area measurements, respectively. Using capillary liquid chromatography, 150 μm i.d. columns were applied to separate a mixture of small hydrophobic molecules. The results indicated that column performance is highly sensitive to the type and the amount of porogen solvents used in the polymerization mixture composition. Good resolution factors and methylene selectivity were obtained, indicating the promising potential of this material for capillary liquid chromatography separations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Determination of diflubenzuron and chlorbenzuron in fruits by combining acetonitrile-based extraction with dispersive liquid-liquid microextraction followed by high-performance liquid chromatography.

    Science.gov (United States)

    Ruan, Chunqiang; Zhao, Xiang; Liu, Chenglan

    2015-09-01

    In this study, a simple and low-organic-solvent-consuming method combining an acetonitrile-partitioning extraction procedure followed by "quick, easy, cheap, effective, rugged and safe" cleanup with ionic-liquid-based dispersive liquid-liquid microextraction and high-performance liquid chromatography with diode array detection was developed for the determination of diflubenzuron and chlorbenzuron in grapes and pears. Ionic-liquid-based dispersive liquid-liquid microextraction was performed using the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate as the extractive solvent and acetonitrile extract as the dispersive solvent. The main factors influencing the efficiency of the dispersive liquid-liquid microextraction were evaluated, including the extractive solvent type and volume and the dispersive solvent volume. The validation parameters indicated the suitability of the method for routine analyses of benzoylurea insecticides in a large number of samples. The relative recoveries at three spiked levels ranged between 98.6 and 109.3% with relative standard deviations of less than 5.2%. The limit of detection was 0.005 mg/kg for the two insecticides. The proposed method was successfully used for the rapid determination of diflubenzuron and chlorbenzuron residues in real fruit samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Polymer Analysis by Liquid Chromatography/Electrospray Ionization Time-of-Flight Mass Spectrometry.

    Science.gov (United States)

    Nielen, M W; Buijtenhuijs, F A

    1999-05-01

    Hyphenation of liquid chromatography (LC) techniques with electrospray ionization (ESI) orthogonal acceleration time-of-flight (oa-TOF) mass spectrometry (MS) provides both MS-based structural information and LC-based quantitative data in polymer analysis. In one experimental setup, three different LC modes are interfaced with MS:  size-exclusion chromatography (SEC/MS), gradient polymer elution chromatography (GPEC/MS), and liquid chromatography at the critical point of adsorption (LCCC/MS). In SEC/MS, both absolute mass calibration of the SEC column based on the polymer itself and determination of monomers and end groups from the mass spectra are achieved. GPEC/MS shows detailed chemical heterogeneity of the polymer and the chemical composition distribution within oligomer groups. In LCCC/MS, the retention behavior is primarily governed by chemical heterogeneities, such as different end group functionalities, and quantitative end group calculations can be easily made. The potential of these methods and the benefit of time-of-flight analyzers in polymer analysis are discussed using SEC/MS of a polydisperse poly(methyl methacrylate) sample, GPEC/MS of dipropoxylated bisphenol A/adipic acid polyester resin, LCCC/MS of alkylated poly(ethylene glycol), and LCCC/MS of terephthalic acid/neopentyl glycol polyester resin.

  16. Polarity-based fractionation in proteomics: hydrophilic interaction vs reversed-phase liquid chromatography.

    Science.gov (United States)

    Jafari, M; Mirzaie, M; Khodabandeh, M; Rezadoost, H; Ghassempour, A; Aboul-Enein, H Y

    2016-07-01

    During recent decades, hydrophilic interaction liquid chromatography (HILIC) ahs been introduced to fractionate or purify especially polar solutes such as peptides and proteins while reversed-phase liquid chromatography (RPLC) is also a common strategy. RPLC is also a common dimension in multidimensional chromatography. In this study, the potential of HILIC vs RPLC chromatography was compared for proteome mapping of human peripheral blood mononuclear cell extract. In HILIC a silica-based stationary phase and for RPLC a C18 column were applied. Then separated proteins were eluted to an ion trap mass spectrometry system. Our results showed that the HILIC leads to more proteins being identified in comparison to RPLC. Among the total 181 identified proteins, 56 and 38 proteins were fractionated specifically by HILIC and RPLC, respectively. In order to demonstrate this, the physicochemical properties of identified proteins such as polarity and hydrophobicity were considered. This analysis indicated that polarity may play a major role in the HILIC separation of proteins vs RPLC. Using gene ontology enrichment analysis, it was also observed that differences in physicochemical properties conform to the cellular compartment and biological features. Finally, this study highlighted the potential of HILIC and the great orthogonality of RPLC in gel-free proteomic studies. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  17. Metabolite Extraction from Saccharomyces cerevisiae for Liquid Chromatography-Mass Spectrometry.

    Science.gov (United States)

    Rosebrock, Adam P; Caudy, Amy A

    2017-09-01

    Prior to mass spectrometric analysis, cellular small molecules must be extracted and separated from interfering components such as salts and culture medium. To ensure minimal perturbation of metabolism, yeast cells grown in liquid culture are rapidly harvested by filtration as described here. Simultaneous quenching of metabolism and extraction is afforded by immediate immersion in low-temperature organic solvent. Samples prepared using this method are suitable for a range of downstream liquid chromatography-mass spectrometry analyses and are stable in solvent for >1 yr at -80°C. © 2017 Cold Spring Harbor Laboratory Press.

  18. Determination of preservatives in cosmetics, cleaning agents and pharmaceuticals using fast liquid chromatography.

    Science.gov (United States)

    Baranowska, Irena; Wojciechowska, Iwona; Solarz, Natalia; Krutysza, Ewa

    2014-01-01

    This paper reports the development of a method for simultaneously determining five preservatives in cosmetics, cleaning agents and pharmaceuticals by fast liquid chromatography. Methylisothiazolinone, methylchloroisothiazolinone, benzyl alcohol, sodium benzoate and methylparaben were separated on a Chromolith Fast Gradient reversed-phase 18e column using gradient elution with acetonitrile and a 0.1% aqueous solution of formic acid, with a run time of 3 min. The preparation of solid and liquid samples included ultrasonic extraction with methanol with recoveries ranging from 69 to 119%. The developed method was used to analyze samples of cosmetics (66 samples), cleaning agents (five samples) and pharmaceutical industry products (17 samples).

  19. Identification and Quantitation of Asparagine and Citrulline Using High-Performance Liquid Chromatography (HPLC)

    OpenAIRE

    Bai, Cheng; Reilly, Charles C.; Wood, Bruce W.

    2007-01-01

    High-performance liquid chromatography (HPLC) analysis was used for identification of two problematic ureides, asparagine and citrulline. We report here a technique that takes advantage of the predictable delay in retention time of the co-asparagine/citrulline peak to enable both qualitative and quantitative analysis of asparagine and citrulline using the Platinum EPS reverse-phase C18 column (Alltech Associates). Asparagine alone is eluted earlier than citrulline alone, but when both of them...

  20. DETECTION AND QUANTIFICATION OF PHYTOCHEMICAL MARKERS OF Ilex paraguariensis BY LIQUID CHROMATOGRAPHY

    OpenAIRE

    Pinto,Rodrigo M. C.; Lemes,Bruna M.; Zielinski,Acácio A. F.; Klein,Traudi; Paula,Fernado de; Kist,Airton; Marques,Anna S. F.; Nogueira,Alessandro; Demiate,Ivo M.; Beltrame,Flávio L.

    2015-01-01

    Ilex paraguariensis (yerba-mate) is used as a beverage, and its extract requires adequate quality control methods in order to guarantee quality and safe use. Strategies to develop and optimize a chromatographic method to quantify theobromine, caffeine, and chlorogenic acid in I. paraguariensis extracts were evaluated by applying a quality by design (QbD) model and ultra high-performance liquid chromatography (UHPLC). The presence of these three phytochemical markers in the extracts was evalua...

  1. Simultaneous Determination of Four Preservatives in Foodstuffs by High Performance Liquid Chromatography

    OpenAIRE

    Mohammad Faraji; Farzaneh Rahbarzare

    2016-01-01

    Background and objectives:  High concentration of preservatives in food may result in gastrointestinal disturbances whereby some patients suffering from asthma, rhinitis, or urticaria. The aim of this study is the introduction and optimization a new method for simultaneous determination of four preservatives (SB, PS, MP, PP) in foodstuff by high performance liquid chromatography. Materials and methods: Important factors in extraction, separation and determination process were optimiz...

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

    Science.gov (United States)

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

    2000-09-01

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

  3. Core-Shell Columns in High-Performance Liquid Chromatography: Food Analysis Applications

    OpenAIRE

    Preti, Raffaella

    2016-01-01

    The increased separation efficiency provided by the new technology of column packed with core-shell particles in high-performance liquid chromatography (HPLC) has resulted in their widespread diffusion in several analytical fields: from pharmaceutical, biological, environmental, and toxicological. The present paper presents their most recent applications in food analysis. Their use has proved to be particularly advantageous for the determination of compounds at trace levels or when a large am...

  4. Enantioselective analysis of drugs: contributions of high-performance liquid chromatography and capillary electrophoresis

    OpenAIRE

    Bonato, Pierina Sueli; Jabor, Valquíria Aparecida Polisel; Gaitani, Cristiane Masetto de

    2005-01-01

    The demand for analytical methods suitable for accurate and reproducible determination of drug enantiomers has increased significantly in the last years. High-performance liquid chromatography (HPLC) using chiral stationary phases and capillary electrophoresis (CE) are the most important techniques used for this purpose. In this paper, the fundamental aspects of chiral separations using both techniques are presented. Some important aspects for the development of enantioselective methods, part...

  5. RECENT ADVANCES IN ULTRA-HIGH PERFORMANCE LIQUID CHROMATOGRAPHY FOR THE ANALYSIS OF TRADITIONAL CHINESE MEDICINE

    Science.gov (United States)

    Huang, Huilian; Liu, Min; Chen, Pei

    2014-01-01

    Traditional Chinese medicine has been widely used for the prevention and treatment of various diseases for thousands of years in China. Ultra-high performance liquid chromatography (UHPLC) is a relatively new technique offering new possibilities. This paper reviews recent developments in UHPLC in the separation and identification, fingerprinting, quantification, and metabolism of traditional Chinese medicine. Recently, the combination of UHPLC with MS has improved the efficiency of the analysis of these materials. PMID:25045170

  6. Toxic Compounds Analysis With High Performance Liquid Chromatography Detected By Electro Chemical Detector (Ecd)

    OpenAIRE

    Hideharu Shintaniq

    2014-01-01

    The principal area of application of high performance liquid chromatography-electrochemical detector (HPLC-ECD) has been in the analysis of naturally-occurring analytes, such as catecholamines, and pharmaceuticals in biological samples, HPLC-ECD has also applied to the analysis of pesticides and other analytes of interest to the toxicologist. In this paper, toxic area is described. In these, ammatoxins, aromatic amine, nitro-compounds, algal toxins, fungal toxins, pesticides, veterinary drug ...

  7. Resolution of the stereoisomers of baclofen by high performance liquid chromatography

    International Nuclear Information System (INIS)

    Weatherby, R.P.; Allan, R.D.; Johnston, G.A.R.

    1984-01-01

    The GABA analogue baclofen [3-(p-chlorophenyl)-4-aminobutanoic acid] has stereospecific actions on the peripheral and central nervous systems. This paper describes the resolution of tritium-labelled baclofen by high performance liquid chromatography on a reverse-phase C18 column using a chiral mobile phase. The method, which may have general application to certain other GABA analogues, affords optically pure (+)- and (-)-baclofen labelled with tritium to high specific activity suitable for ligand binding and other neurochemical studies. (Auth.)

  8. Quantitative analysis of cytokinins in plants by liquid chromatography single-quadrupole mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Novák, Ondřej; Tarkowski, Petr; Tarkowská, Danuše; Doležal, Karel; Lenobel, René; Strnad, Miroslav

    2003-01-01

    Roč. 480, č. 2 (2003), s. 207ů218 ISSN 0003-2670 R&D Projects: GA ČR GA522/01/0275 Grant - others:Volkswagen Stiftung(DE) I/76 865 Institutional research plan: CEZ:AV0Z5038910; CEZ:MSM 153100008 Keywords : Liquid chromatography mass spectrometry * Cytokinins Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.210, year: 2003

  9. Determination of Niacinamide in Lotions and Creams Using Liquid-Liquid Extraction and High-Performance Liquid Chromatography

    Science.gov (United States)

    Usher, Karyn M.; Simmons, Carolyn R.; Keating, Daniel W.; Rossi, Henry F., III

    2015-01-01

    Chemical separations are an important part of an undergraduate chemistry curriculum. Sophomore students often get experience with liquid-liquid extraction in organic chemistry classes, but liquid-liquid extraction is not as often introduced as a quantitative sample preparation method in honors general chemistry or quantitative analysis classes.…

  10. Simultaneous determination of several phytohormones in natural coconut juice by hollow fiber-based liquid-liquid-liquid microextraction-high performance liquid chromatography.

    Science.gov (United States)

    Wu, Yunli; Hu, Bin

    2009-11-06

    A simple, selective, sensitive and inexpensive method of hollow fiber-based liquid-liquid-liquid microextraction (HF-LLLME) combined with high performance liquid chromatography (HPLC)-ultraviolet (UV) detection was developed for the determination of four acidic phytohormones (salicylic acid (SA), indole-3-acetic acid (IAA), (+/-) abscisic acid (ABA) and (+/-) jasmonic acid (JA)) in natural coconut juice. To the best of our knowledge, this is the first report on the use of liquid phase microextraction (LPME) as a sample pretreatment technique for the simultaneous analysis of several phytohormones. Using phenetole to fill the pores of hollow fiber as the organic phase, 0.1molL(-1) NaOH solution in the lumen of hollow fiber as the acceptor phase and 1molL(-1) HCl as the donor phase, a simultaneous preconcentration of four target phytohormones was realized. The acceptor phase was finally withdrawn into the microsyringe and directly injected into HPLC for the separation and quantification of the target phytohormones. The factors affecting the extraction efficiency of four phytohormones by HF-LLLME were optimized with orthogonal design experiment, and the data was analyzed by Statistical Product and Service Solutions (SPSS) software. Under the optimized conditions, the enrichment factors for SA, IAA, ABA and JA were 243, 215, 52 and 48, with the detection limits (S/N=3) of 4.6, 1.3, 0.9ngmL(-1) and 8.8 microg mL(-1), respectively. The relative standard deviations (RSDs, n=7) were 7.9, 4.9, 6.8% at 50ngmL(-1) level for SA, IAA, ABA and 8.4% at 500 microg mL(-1) for JA, respectively. To evaluate the accuracy of the method, the developed method was applied for the simultaneous analysis of several phytohormones in five natural coconut juice samples, and the recoveries for the spiked samples were in the range of 88.3-119.1%.

  11. Applications of the solvation parameter model in reversed-phase liquid chromatography.

    Science.gov (United States)

    Poole, Colin F; Lenca, Nicole

    2017-02-24

    The solvation parameter model is widely used to provide insight into the retention mechanism in reversed-phase liquid chromatography, for column characterization, and in the development of surrogate chromatographic models for biopartitioning processes. The properties of the separation system are described by five system constants representing all possible intermolecular interactions for neutral molecules. The general model can be extended to include ions and enantiomers by adding new descriptors to encode the specific properties of these compounds. System maps provide a comprehensive overview of the separation system as a function of mobile phase composition and/or temperature for method development. The solvation parameter model has been applied to gradient elution separations but here theory and practice suggest a cautious approach since the interpretation of system and compound properties derived from its use are approximate. A growing application of the solvation parameter model in reversed-phase liquid chromatography is the screening of surrogate chromatographic systems for estimating biopartitioning properties. Throughout the discussion of the above topics success as well as known and likely deficiencies of the solvation parameter model are described with an emphasis on the role of the heterogeneous properties of the interphase region on the interpretation and understanding of the general retention mechanism in reversed-phase liquid chromatography for porous chemically bonded sorbents. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Characterization of the efficiency of microbore liquid chromatography columns by van Deemter and kinetic plot analysis.

    Science.gov (United States)

    Hetzel, Terence; Loeker, Denise; Teutenberg, Thorsten; Schmidt, Torsten C

    2016-10-01

    The efficiency of miniaturized liquid chromatography columns with inner diameters between 200 and 300 μm has been investigated using a dedicated micro-liquid chromatography system. Fully porous, core-shell and monolithic commercially available stationary phases were compared applying van Deemter and kinetic plot analysis. The sub-2 μm fully porous as well as the 2.7 μm core-shell particle packed columns showed superior efficiency and similar values for the minimum reduced plate heights (2.56-2.69) before correction for extra-column contribution compared to normal-bore columns. Moreover, the influence of extra-column contribution was investigated to demonstrate the difference between apparent and intrinsic efficiency by replacing the column by a zero dead volume union to determine the band spreading caused by the system. It was demonstrated that 72% of the intrinsic efficiency could be reached. The results of the kinetic plot analysis indicate the superior performance of the sub-2 μm fully porous particle packed column for ultra-fast liquid chromatography. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Separation of enantiomers of new psychoactive substances by high-performance liquid chromatography.

    Science.gov (United States)

    Kadkhodaei, Kian; Forcher, Lisa; Schmid, Martin G

    2018-03-01

    New psychoactive substances are defined as compounds with consciousness-changing effects and have been developed simultaneously with classical drugs. They arise through structural modifications of illegal substances and are mainly produced to circumvent laws. Availability is simple, since new psychoactive substances can be purchased from the Internet. Among them many chemical drug compound classes are chiral and thus the two resulting enantiomers can differ in their effects. The aim of this study is to develop a suitable chiral high-performance liquid chromatography separation method for a broad spectrum of new psychoactive substances using cellulose tris(3,5-dichlorophenylcarbamate) as a chiral selector. Experiments were performed by high-performance liquid chromatography in normal-phase mode under isocratic conditions using ultraviolet detection. Direct separation was carried out on a high-performance liquid chromatography column (Lux® i-Cellulose-5, 3.5 μm, Phenomenex®), available since 2016. Excellent separation results were obtained for cathinones. After further optimization, even 47 instead of 39 out of 52 cathinones showed baseline separation. For amphetamine derivatives, satisfactory results were not achieved. Further, new psychoactive substances from other compound classes such as benzofuranes, thiophenes, phenidines, phenidates, morpholines, and ketamines were partially resolved, depending on the polarity and degree of substitution. All analytes, which were mainly purchased from the Internet, were proven to be traded as racemates. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Determination of veterinary antibiotic residues in foods of animal origin by liquid chromatography

    Directory of Open Access Journals (Sweden)

    Pedro Enrique La Rosa Zambrano

    2018-05-01

    Full Text Available TITLE: Determination of veterinary antibiotic residues in foods of animal origin by liquid chromatography Introduction: The presence of certain infectious agents makes necessary the use of antibiotics to ensure the welfare of animals destined for human consumption; however, the withdrawal time must be considered and respected since there is the possibility of finding residues above the permitted levels, which could constitute a risk to public health. Objective: Present a collection of information based on how is performed the detection and quantification of antibiotic residues in various products of animal origin using chromatography methods. Method: Review of databases in Elsevier, SciELO, Springer, Hindawi, FAO, EFSA, Senasa and Sanipes, using keywords such as “liquid chromatography”, “mass spectrometry”, “antibiotic residues” and “products of animal origin” in Spanish and English. Results: They were selected 71 references among articles, book chapters, norms and regulations published between 2000 and 2017, which it is emphasized that chromatographic methodologies for antibiotic residues monitoring must be sensitive, reproducible, reliable and identify volumes in mg/kg; likewise, they must follow the requirements of international standards for the maximum residue limits detecction. Conclusions: Liquid chromatography coupled to a mass spectrometer is the most used technique to allow the separation of complex matrices based on the molecular weight of the compound (antibiotic or its fragments; however, It is complex, expensive and requires highly trained personnel.

  15. Characterization of pitches by liquid chromatography using cellulose 3,5-dinitrobenzoate as the packing material

    Energy Technology Data Exchange (ETDEWEB)

    Arai, K.; Judo, R.; Ota, E. [Gunma University, Gunma (Japan). Dept. of Chemistry

    1997-08-01

    Characterization of coal tar, petroleum and PVC pitches by a liquid chromatography using cellulose 3,5-dinitrobenzoate (DNB-cellulose) as the packing material was investigated. Separation mechanism based on charge-transfer interaction between the dinitrobenzoyl group and polyaromatic compounds was expected to be useful for separation of the constituents of the pitches. First, 26 model polyaromatic compounds were tested to examine the characteristic feature of the packing material by liquid chromatography. The compounds were found to be classified roughly into four groups with different retention volume, principally according to the number of condensed rings. The nonplanar structure and aliphatic side chain of the polyaromatic compounds also affected the separation behavior. Both benzene soluble-hexane soluble and benzene soluble-hexane insoluble fractions of the three pitches were separated on DNB-cellulose. It was found that coal tar pitch contains relatively large amounts of some highly condensed polyaromatic compounds with condensed rings of 4 to 5; petroleum pitch has small amounts of such specific highly condensed polyaromatic compounds, while PVC pitch has large amounts of less condensed polyaromatic compounds and there is no significant amount of highly condensed compound in it. Thus DNB-cellulose was useful as the convenient packing material for liquid chromatography to characterize pitches.

  16. Optimization of the combination micro-high-performance liquid-chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Haider, K.

    1997-03-01

    The coupling of liquid chromatography and mass spectrometry is still growing in significance. In this thesis, a particle beam interface has been investigated for combining ion chromatography with mass spectrometric detection. To introduce the eluent directly (without membrane suppressor) into the spectrometer, only methods with low flow rates like microcolumn chromatography can be used. For the preparation of the columns, reversed-phase and silica-based anion exchange materials were packed into PEEK, steel and fused-silica capillaries with i.d. from 130 to 1000 μm using different methods. The performance of the particle beam interface (modified with a new miniaturized aerosol generator) and the mass spectrometric detection has been studied for a series of inorganic anions as well as aminopolycarboxylic acids and the metal-EDTA complexes. Detection limits between 10 and 100 ng injected could be achieved in the multiple ion detection mode of the mass spectrometer for the investigated solutes. A second type of interface, the direct liquid introduction (DLI) has been used to analyze the priority pollutant phenols. This interface is based on a modified GC-interface into the MS. Separation columns used so far include packed fused-silica capillaries with inner diameter of 75 μm and polystyrene-divinylbenzene (functionalized with tert. butyl groups) as stationary phase. Aspects of instrumentation and effects of chemical ionization in the direct liquid introduction mode are discussed. (author)

  17. Determination of carbofuran on hydrophilic interaction liquid chromatography using TSK gel amide 80 as stationary phase

    International Nuclear Information System (INIS)

    A Kurnia; LW Lim; T Takeuchi

    2016-01-01

    The hydrophilic interaction liquid chromatography (HILIC) coupled to environmental friendly capillary liquid chromatography was employed to investigate retention behavior of carbofuran. Aim of this research is to investigate retention behavior of carbofuran using TSK gel amide 80 as stationary phase. Several condition was conducted to investigate retention behavior of carbofuran such as comparison study of TSK gel amide 80 with other polar column, comparison study retention behavior of carbofuran on various system wavelength, water content effect in HILIC mode, effect of buffer concentration on HILIC mode, and analytical performance. Results showed that TSK gel imidazole was superior compare to other polar stationary phase on determine carbofuran, wavelength 251 and 254 nm was resulting higher absorbance for carbofuran than others, increase of water content on mobile phase was decrease the retention time, also increase buffer salt concentration was decrease the retention time and according to analysis performance that is the accuracy was 101±10,1, the LOD 0.66 ppm while LOQ 2.22 ppm. As conclusions that TSK gel amide 80 was offering good determine on carbofuran even using capillary liquid chromatography with 10 cm length of column. (author)

  18. Simultaneous determination of niacin and pyridoxine at trace levels by using diode array high-performance liquid chromatography and liquid chromatography with quadrupole time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Sel, Sabriye; Öztürk Er, Elif; Bakırdere, Sezgin

    2017-12-01

    A highly sensitive and simple diode-array high-performance liquid chromatography and liquid chromatography with quadrupole time-of-flight tandem mass spectrometry method was developed for the simultaneous determination of niacin and pyridoxine in pharmaceutical drugs, tap water, and wastewater samples. To determine the in vivo behavior of niacin and pyridoxine, analytes were subjected to simulated gastric conditions. The calibration plots of the diode-array high-performance liquid chromatography and liquid chromatography with quadrupole time-of-flight tandem mass spectrometry method showed good linearity over a wide concentration range with close to 1.0 correlation coefficients for both analytes. The limit of detection/limit of quantitation values for liquid chromatography quadrupole time-of-flight tandem mass spectrometry analysis were 1.98/6.59 and 1.3/4.4 μg/L for niacin and pyridoxine, respectively, while limit of detection/limit of quantitation values for niacin and pyridoxine in high-performance liquid chromatography analysis were 3.7/12.3 and 5.7/18.9 μg/L, respectively. Recovery studies were also performed to show the applicability of the developed methods, and percentage recovery values were found to be 90-105% in tap water and 94-97% in wastewater for both analytes. The method was also successfully applied for the qualitative and quantitative determination of niacin and pyridoxine in drug samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Gas chromatography-mass spectrometry and high-performance liquid chromatographic analyses of thermal degradation products of common plastics

    OpenAIRE

    Pacakova, V.; Leclercq, P.A.

    1991-01-01

    The thermo-oxidation of five commonly used materials, namely low-density polyethylene, retarded polyethylene, paper with a polyethylene foil, a milk package and filled polypropylene, was studied. Capillary gas chromatography and gas chromatography-mass spectrometry were used to analyze the volatile degradation products, while high-performance liquid chromatography was employed to measure polycyclic aromatic hydrocarbons. The results are discussed from the point of view of toxicity of the prod...

  20. Multielement determination of rare earth elements in rock sample by liquid chromatography / inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Hamanaka, Tadashi; Itoh, Akihide; Itoh, Shinya; Sawatari, Hideyuki; Haraguchi, Hiroki.

    1995-01-01

    Rare earth elements in geological standard rock sample JG-1 (granodiolite)issued from the Geological Survey of Japan have been determined by a combined system of liquid chromatography and inductively coupled plasma mass spectrometry. (author)

  1. EXTRACTION AND QUANTITATIVE ANALYSIS OF ELEMENTAL SULFUR FROM SULFIDE MINERAL SURFACES BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY. (R826189)

    Science.gov (United States)

    A simple method for the quantitative determination of elemental sulfur on oxidized sulfide minerals is described. Extraction of elemental sulfur in perchloroethylene and subsequent analysis with high-performance liquid chromatography were used to ascertain the total elemental ...

  2. Overview of online two-dimensional liquid chromatography based on cell membrane chromatography for screening target components from traditional Chinese medicines.

    Science.gov (United States)

    Muhammad, Saqib; Han, Shengli; Xie, Xiaoyu; Wang, Sicen; Aziz, Muhammad Majid

    2017-01-01

    Cell membrane chromatography is a simple, specific, and time-saving technique for studying drug-receptor interactions, screening of active components from complex mixtures, and quality control of traditional Chinese medicines. However, the short column life, low sensitivity, low column efficiency (so cannot resolve satisfactorily mixture of compounds), low peak capacity, and inefficient in structure identification were bottleneck in its application. Combinations of cell membrane chromatography with multidimensional chromatography such as two-dimensional liquid chromatography and high sensitivity detectors like mass have significantly reduced many of the above-mentioned shortcomings. This paper provides an overview of the current advances in online two-dimensional-based cell membrane chromatography for screening target components from traditional Chinese medicines with particular emphasis on the instrumentation, preparation of cell membrane stationary phase, advantages, and disadvantages compared to alternative approaches. The last section of the review summarizes the applications of the online two-dimensional high-performance liquid chromatography based cell membrane chromatography reported since its emergence to date (2010-June 2016). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Direct solid-phase microextraction combined with gas and liquid chromatography for the determination of lidocaine in human urine

    NARCIS (Netherlands)

    Koster, E.H M; Hofman, N.S K; de Jong, G.J.

    Solid-phase microextraction (SPME) has been combined with gas chromatography (GC) and liquid chromatography (LC) for the determination of lidocaine in human urine. A polydimethylsiloxane (PDMS) coated fibre was directly immersed into buffered urine. Extraction conditions such as time, pH, ionic

  4. Determination of ten carbamate pesticides in aquatic and sediment samples by liquid chromatography-ionspray and thermospray mass spectrometry.

    NARCIS (Netherlands)

    Honing, M.; Riu, J.; Barceló, D.; van Baar, B.L.M.; Brinkman, U.A.T.

    1996-01-01

    Ten carbamate pesticides which exhibit large differences in polarity were determined simultaneously in various environmental samples, using both column liquid chromatography (LC)-thermospray (TSP) mass spectrometry (MS) and LC-ionspray (ISP) MS. For sample clean-up, column chromatography with three

  5. Preparation and Characterization of a Polymeric Monolithic Column for Use in High-Performance Liquid Chromatography (HPLC)

    Science.gov (United States)

    Bindis, Michael P.; Bretz, Stacey Lowery; Danielson, Neil D.

    2011-01-01

    The high-performance liquid chromatography (HPLC) experiment, most often done in the undergraduate analytical instrumentation laboratory course, generally illustrates reversed-phase chromatography using a commercial C[subscript]18 silica column. To avoid the expense of periodic column replacement and introduce a choice of columns with different…

  6. tRNA separation by high-performance liquid chromatography using an aggregate of ODS-Hypersil and trioctylmethylammonium chloride

    NARCIS (Netherlands)

    Bischoff, Rainer; Graeser, E.; Mclaughlin, L.W.

    1983-01-01

    High-performance liquid chromatography on a reversed-phase support treated with a tetraalkylammonium salt was used to separate tRNAs from baker's yeast. While resolution by this column appears to result from both anion-exchange and reversed-phase chromatography, it is the hydrophobic interactions

  7. Quantitative analysis of pharmaceuticals in biological fluids using high-performance liquid chromatography coupled to mass spectrometry: a review.

    Science.gov (United States)

    Plumb, R S; Dear, G J; Mallett, D N; Higton, D M; Pleasance, S; Biddlecombe, R A

    2001-01-01

    1. The development of bio-analysis of drug molecules over the last 10 years is reviewed, focusing on advances in sample preparation, liquid chromatography and detection. 2. Developments have led to improvements in detection sensitivity, enhancements in specificity and increased capacity. 3. Emerging technologies such as monolithic column chromatography and miniaturized chip-based systems are discussed.

  8. Investigation of forced and total degradation products of amlodipine besylate by liquid chromatography and liquid chromatography-mass spectrometry

    Directory of Open Access Journals (Sweden)

    Stoiljković Zora Ž.

    2014-01-01

    Full Text Available An isocratic, reversed-phase liquid chromatographic method was applied for the investigation of the degradation products of amlodipine besylate under the stressed conditions in solution. Amlodipine besylate stock solutions were subjected to acid and alkali hydrolysis, chemical oxidation and photodegradation as well as to the electrochemical degradation by cyclic voltammetry in 0.05 mol/L NaHCO3 on gold electrode. The total degradation of amlodipine besylate was achieved in 5 mol/L NaOH at 80°C for 6 h and the compound with molecular formula C15H16NOCl was identified as a main degradation product. Under acidic (5 mol/L HCl at 80°C for 6 h stress conditions 75.2% of amlodipine besylate degradation was recorded. Oxidative degradation in the solution of 3% H2O2-methanol 80:20 at 80°C for 6 h showed that amlodipine besylate degraded to 80.1%. After 14 days of expose in photostability chamber amlodipine besylate solution showed degradation of 32.2%. In electrochemical degradation after 9 hours of cyclization the beginning of amlodipine oxidation was shifted for 200 mV to more negative potentials, with the degradation of 66.5%. Mass spectrometry analysis confirmed the presence of dehydro amlodipine derivate with molecular formula C20H23N2O5Cl in oxidative and acidic conditions while in electrochemical degradation was detected in traces. [Projekat Ministarsva nauke Republike Srbije, br. 172013

  9. Quantitative analysis of phylloquinone (vitamin K1) in soy bean oils by high-performance liquid chromatography.

    Science.gov (United States)

    Zonta, F; Stancher, B

    1985-07-19

    A high-performance liquid chromatographic method for determining phylloquinone (vitamin K1) in soy bean oils is described. Resolution of vitamin K1 from interfering peaks of the matrix was obtained after enzymatic digestion, extraction and liquid-solid chromatography on alumina. An isocratic reversed-phase chromatography with UV detection was used in the final stage. The quantitation was carried out by the standard addition method, and the recovery of the whole procedure was 88.2%.

  10. Stationary and through-flow radiochemical detectors in cooperation with high performance liquid chromatography: Application in biochemistry

    International Nuclear Information System (INIS)

    Kehr, J.

    1986-01-01

    A review article is presented containing some original experimental data and discussing the usability of radiochemical detection of labelled compounds using high performance liquid chromatography. The stationary and through-flow types of detection are compared with respect to efficiency, chromatographic zone resolution, usability in biochemical research, and also to the current trends of development of liquid chromatography. (author). 3 figs., 1 tab., 19 refs

  11. Deformation and degradation of polymers in ultra-high-pressure liquid chromatography.

    Science.gov (United States)

    Uliyanchenko, Elena; van der Wal, Sjoerd; Schoenmakers, Peter J

    2011-09-28

    Ultra-high-pressure liquid chromatography (UHPLC) using columns packed with sub-2 μm particles has great potential for separations of many types of complex samples, including polymers. However, the application of UHPLC for the analysis of polymers meets some fundamental obstacles. Small particles and narrow bore tubing in combination with high pressures generate significant shear and extensional forces in UHPLC systems, which may affect polymer chains. At high stress conditions flexible macromolecules may become extended and eventually the chemical bonds in the molecules can break. Deformation and degradation of macromolecules will affect the peak retention and the peak shape in the chromatogram, which may cause errors in the obtained results (e.g. the calculated molecular-weight distributions). In the present work we explored the limitations of UHPLC for the analysis of polymers. Degradation and deformation of macromolecules were studied by collecting and re-injecting polymer peaks and by off-line two-dimensional liquid chromatography. Polystyrene standards with molecular weight of 4 MDa and larger were found to degrade at UHPLC conditions. However, for most polymers degradation could be avoided by using low linear velocities. No degradation of 3-MDa PS (and smaller) was observed at linear velocities up to 7 mm/s. The column frits were implicated as the main sources of polymer degradation. The extent of degradation was found to depend on the type of the column and on the column history. At high flow rates degradation was observed without a column being installed. We demonstrated that polymer deformation preceded degradation. Stretched polymers eluted from the column in slalom chromatography mode (elution order opposite to that in SEC or HDC). Under certain conditions we observed co-elution of large and small PS molecules though a convolution of slalom chromatography and hydrodynamic chromatography. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Determination of parabens in serum by liquid chromatography-tandem mass spectrometry: Correlation with lipstick use.

    Science.gov (United States)

    Tahan, Gabriella Padovani; Santos, Nayara de Kássia Souza; Albuquerque, Ana Carolina; Martins, Isarita

    2016-08-01

    Parabens are the most widely used preservative and are considered to be relatively safe compounds. However, studies have demonstrated that they may have estrogenic activity, and there is ongoing debate regarding the safety and potential cancer risk of using products containing these compounds. In the present work, liquid chromatography-tandem mass spectrometry was applied to determine methylparaben and propylparaben concentrations in serum, and the results were correlated with lipstick application. Samples were analyzed using liquid-liquid extraction, followed by liquid chromatography-tandem mass spectrometry. The validation results demonstrated the linearity of the method over a range of 1-20 ng/mL, in addition to the method's precision and accuracy. A statistically significant difference was demonstrated between serum parabens in women who used lipstick containing these substances compared with those not using this cosmetic (p = 0.0005 and 0.0016, respectively), and a strong association was observed between serum parabens and lipstick use (Spearman correlation = 0.7202). Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Quantitative analysis of benzodiazepines in vitreous humor by high-performance liquid chromatography

    Science.gov (United States)

    Bazmi, Elham; Behnoush, Behnam; Akhgari, Maryam; Bahmanabadi, Leila

    2016-01-01

    Objective: Benzodiazepines are frequently screened drugs in emergency toxicology, drugs of abuse testing, and in forensic cases. As the variations of benzodiazepines concentrations in biological samples during bleeding, postmortem changes, and redistribution could be biasing forensic medicine examinations, hence selecting a suitable sample and a validated accurate method is essential for the quantitative analysis of these main drug categories. The aim of this study was to develop a valid method for the determination of four benzodiazepines (flurazepam, lorazepam, alprazolam, and diazepam) in vitreous humor using liquid–liquid extraction and high-performance liquid chromatography. Methods: Sample preparation was carried out using liquid–liquid extraction with n-hexane: ethyl acetate and subsequent detection by high-performance liquid chromatography method coupled to diode array detector. This method was applied to quantify benzodiazepines in 21 authentic vitreous humor samples. Linear curve for each drug was obtained within the range of 30–3000 ng/mL with coefficient of correlation higher than 0.99. Results: The limit of detection and quantitation were 30 and 100 ng/mL respectively for four drugs. The method showed an appropriate intra- and inter-day precision (coefficient of variation forensic toxicology laboratory. PMID:27635251

  14. Analysis of aromatic amines in water samples by liquid-liquid-liquid microextraction with hollow fibers and high-performance liquid chromatography.

    Science.gov (United States)

    Zhao, Limian; Zhu, Lingyan; Lee, Hian Kee

    2002-07-19

    Liquid-liquid-liquid microextraction (LLLME) with hollow fibers in high-performance liquid chromatography (HPLC) has been applied as a rapid and sensitive quantitative method for the detection of four aromatic amines (3-nitroaniline, 4-chloroaniline, 4-bromoaniline and 3,4-dichloroaniline) in environmental water samples. The preconcentration procedure was induced by the pH difference inside and outside the hollow fiber. The target compounds were extracted from 4-ml aqueous sample (donor solution, pH approximately 13) through a microfilm of organic solvent (di-n-hexyl ether), immobilized in the pores of a hollow fiber (1.5 cm length x 0.6 mm I.D.), and finally into 4 microl of acid acceptor solution inside the fiber. After a prescribed period of time, the acceptor solution inside the fiber was withdrawn into the microsyringe and directly injected into the HPLC system for analysis. Factors relevant to the extraction procedure were studied. Up to 500-fold enrichment of analytes could be obtained under the optimized conditions (donor solution: 0.1 M sodium hydroxide solution with 20% sodium chloride and 2% acetone; organic phase: di-n-hexyl ether; acceptor solution: 0.5 M hydrochloric acid and 500 mM 18-crown-6 ether; extraction time of 30 min; stirring at 1,000 rev./min). The procedure also served as a sample clean-up step. The influence of humic acid on the extraction efficiency was also investigated, and more than 85% relative recoveries of the analytes at two different concentrations (20 and 100 microg/l) were achieved at various concentration of humic acid. This technique is a low cost, simple and fast approach to the analysis of polar compounds in aqueous samples.

  15. Incorporation of ionic liquid into porous polymer monoliths to enhance the separation of small molecules in reversed-phase high-performance liquid chromatography.

    Science.gov (United States)

    Wang, Jiafei; Bai, Ligai; Wei, Zhen; Qin, Junxiao; Ma, Yamin; Liu, Haiyan

    2015-06-01

    An ionic liquid was incorporated into the porous polymer monoliths to afford stationary phases with enhanced chromatographic performance for small molecules in reversed-phase high-performance liquid chromatography. The effect of the ionic liquid in the polymerization mixture on the performance of the monoliths was studied in detail. While monoliths without ionic liquid exhibited poor resolution and low efficiency, the addition of ionic liquid to the polymerization mixture provides highly increased resolution and high efficiency. The chromatographic performances of the monoliths were demonstrated by the separations of various small molecules including aromatic hydrocarbons, isomers, and homologues using a binary polar mobile phase. The present column efficiency reached 27 000 plates/m, which showed that the ionic liquid monoliths are alternative stationary phases in the separation of small molecules by high-performance liquid chromatography. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. High-performance liquid chromatography analysis methods developed for quantifying enzymatic esterification of flavonoids in ionic liquids.

    Science.gov (United States)

    Lue, Bena-Marie; Guo, Zheng; Xu, Xuebing

    2008-07-11

    Methods using reversed-phase high-performance liquid chromatography (RP-HPLC) with ELSD were investigated to quantify enzymatic reactions of flavonoids with fatty acids in the presence of diverse room temperature ionic liquids (RTILs). A buffered salt (preferably triethylamine-acetate) was found essential for separation of flavonoids from strongly polar RTILs, whereby RTILs were generally visible as two major peaks identified based on an ion-pairing/exchanging hypothesis. C8 and C12 stationary phases were optimal while mobile phase pH (3-7) had only a minor influence on separation. The method developed was successfully applied for primary screening of RTILs (>20), with in depth evaluation of substrates in 10 RTILs, for their evaluation as reaction media.

  17. Screening anti-tumor compounds from Ligusticum wallichii using cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry.

    Science.gov (United States)

    Zhang, Tao; Ding, Yuanyuan; An, Hongli; Feng, Liuxin; Wang, Sicen

    2015-07-14

    Tyrosine 367 Cysteine-fibroblast growth factor receptor 4 cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry was developed. Tyrosine 367 Cysteine-HEK293 cells were used as cell membrane stationary phase. Specificity and reproducibility of the cell membrane chromatography was evaluated using 1-tert-butyl-3-{2-[4-(diethylamino)butylamino]-6-(3,5-dimethoxyphenyl)pyrido[2,3-d]pyrimidin-7-yl}urea, Nimodipine and dexamethasone acetate. Then, anti-tumor components acting on Tyrosine 367 Cysteine-fibroblast growth factor receptor 4 were screened and identified from extracts of Ligusticum wallichii. Components from the extract were retained on the cell membrane chromatographic column. The retained fraction was directly eluted into high-performance liquid chromatography with mass spectrometry system for separation and identification. Finally, Levistolide A was identified as an active component from Ligusticum wallichii extracts. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide-formazan colorimetric assay revealed that Levistolide A inhibits proliferation of overexpressing the mutated receptor cells with dose-dependent manner. Phosphorylation of fibroblast growth factor receptor 4 was also decrease under Levistolide A treatment. Flex dock simulation verified that Levistolide A could bind with the tyrosine kinase domain of fibroblast growth factor receptor 4. Therefore, Levistolide A screened by the cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry can arrest cell growth. In conclusion, the two-dimensional high-performance liquid chromatography method can screen and identify potential anti-tumor ingredients which specifically act on the tyrosine kinase domain of the mutated fibroblast growth factor receptor 4. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  18. Determination of Alternaria mycotoxins in wine and juice using ionic liquid modified countercurrent chromatography as a pretreatment method followed by high-performance liquid chromatography.

    Science.gov (United States)

    Fan, Chen; Cao, Xueli; Liu, Man; Wang, Wei

    2016-03-04

    Alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TeA) are some of the main Alternaria mycotoxins that can be found as contaminants in food materials. The objective of this study was to develop a pretreatment method with countercurrent chromatography (CCC) for enrichment and cleanup of trace Alternaria mycotoxins in food samples prior to high-performance liquid chromatography (HPLC) analysis. An Analytical CCC instrument with a column volume 22.5mL was used, and a two-phase solvent system composed of ethyl acetate and water modified with 6% [HOOMIM][Cl] in mass to volume ratio was selected. Under the optimized CCC operation conditions, trace amounts of AOH, AME, and TeA in large volume of liquid sample were efficiently extracted and enriched in the stationary phase, and then eluted out just by reversing the stationary phase as mobile phase in the opposite flowing direction tail-to-head. The enrichment and elution strategies are unique and can be fulfilled online with high enrichment factors (87-114) and high recoveries (81.14-110.94%). The method has been successively applied to the determination of Alternaria mycotoxins in real apple juice and wine samples with the limits of detection (LOD) in the range of 0.03-0.14μgL(-1). Totally 12 wine samples and 15 apple juice samples from the local market were analyzed. The detection rate of AOH and AME in both kinds of the samples were more than 50%, while TeA was found in relatively high level of 1.75-49.61μgL(-1) in some of the apple juice samples. The proposed method is simple, rapid, and sensitive and could also be used for the analysis and monitoring of Alternaria mycotoxin in other food samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Home-made online hyphenation of pressurized liquid extraction, turbulent flow chromatography, and high performance liquid chromatography, Cistanche deserticola as a case study.

    Science.gov (United States)

    Song, Qingqing; Li, Jun; Liu, Xiao; Zhang, Yuan; Guo, Liping; Jiang, Yong; Song, Yuelin; Tu, Pengfei

    2016-03-18

    Incompatibility between the conventional pressurized liquid extraction (PLE) devices and high performance liquid chromatography (HPLC) extensively hinders direct and green chemical analysis of herbal materials. Herein, a facile PLE module was configured, and then it was online hyphenated with HPLC via a turbulent flow chromatography (TFC) column. Regarding PLE module, a long PEEK tube (0.13 × 1000 mm) was employed to generate desired pressure (approximately 13.0 MPa) when warm acidic water (70 °C) was delivered as extraction solvent at a high flow rate (2.5 mL/min), and a hollow guard column (3.0 × 4.0 mm) was implemented to hold crude materials. Effluent was collected from the outlet of PEEK tube, concentrated, and subjected onto HPLC coupled with hybrid ion trap-time of flight mass spectrometer to assess the extraction efficiency and also to profile the chemical composition of Cistanche deserticola (CD) that is honored as "Ginseng of the desert". Afterwards, a TFC column was introduced to accomplish online transmission of low molecule weight components from PLE module to HPLC coupled with diode array detection, and two electronic 6-port/2-channel valves were in charge of alternating the whole system between extraction (0-3.0 min) and elution (3.0-35.0 min) phases. Quantitative method was developed and validated for simultaneous determination of eight primary phenylethanoid glycosides in CD using online PLE-TFC-HPLC. All findings demonstrated that the home-made platform is advantageous at direct chemical analysis, as well as time-, solvent-, and material-savings, suggesting a robust tool for chemical fingerprinting of herbs. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Comprehensive two-dimensional liquid chromatography with on-line Fourier-transform-infrared-spectroscopy detection for the characterization of copolymers

    NARCIS (Netherlands)

    Kok, S.J.; Hankemeier, T.; Schoenmakers, P.J.

    2005-01-01

    The on-line coupling of comprehensive two-dimensional liquid chromatography (liquid chromatography × size-exclusion chromatography, LC × SEC) and infrared (IR) spectroscopy has been realized by means of an IR flow cell. The system has been assessed by the functional-group analysis of a series of

  1. Analysis of trace dicyandiamide in stream water using solid phase extraction and liquid chromatography UV spectrometry.

    Science.gov (United States)

    Qiu, Huidong; Sun, Dongdi; Gunatilake, Sameera R; She, Jinyan; Mlsna, Todd E

    2015-09-01

    An improved method for trace level quantification of dicyandiamide in stream water has been developed. This method includes sample pretreatment using solid phase extraction. The extraction procedure (including loading, washing, and eluting) used a flow rate of 1.0mL/min, and dicyandiamide was eluted with 20mL of a methanol/acetonitrile mixture (V/V=2:3), followed by pre-concentration using nitrogen evaporation and analysis with high performance liquid chromatography-ultraviolet spectroscopy (HPLC-UV). Sample extraction was carried out using a Waters Sep-Pak AC-2 Cartridge (with activated carbon). Separation was achieved on a ZIC(®)-Hydrophilic Interaction Liquid Chromatography (ZIC-HILIC) (50mm×2.1mm, 3.5μm) chromatography column and quantification was accomplished based on UV absorbance. A reliable linear relationship was obtained for the calibration curve using standard solutions (R(2)>0.999). Recoveries for dicyandiamide ranged from 84.6% to 96.8%, and the relative standard deviations (RSDs, n=3) were below 6.1% with a detection limit of 5.0ng/mL for stream water samples. Copyright © 2015. Published by Elsevier B.V.

  2. Miniaturized protein separation using a liquid chromatography column on a flexible substrate

    International Nuclear Information System (INIS)

    Yang Yongmo; Chae, Junseok

    2008-01-01

    We report a prototype protein separator that successfully miniaturizes existing technology for potential use in biocompatible health monitoring implants. The prototype is a liquid chromatography (LC) column (LC mini-column) fabricated on an inexpensive, flexible, biocompatible polydimethylsiloxane (PDMS) enclosure. The LC mini-column separates a mixture of proteins using size exclusion chromatography (SEC) with polydivinylbenzene beads (5–20 µm in diameter with 10 nm pore size). The LC mini-column is smaller than any commercially available LC column by a factor of ∼11 000 and successfully separates denatured and native protein mixtures at ∼71 psi of the applied fluidic pressure. Separated proteins are analyzed using NuPAGE-gel electrophoresis, high-performance liquid chromatography (HPLC) and an automated electrophoresis system. Quantitative HPLC results demonstrate successful separation based on intensity change: within 12 min, the intensity between large and small protein peaks changed by a factor of ∼20. In further evaluation using the automated electrophoresis system, the plate height of the LC mini-column is between 36 µm and 100 µm. The prototype LC mini-column shows the potential for real-time health monitoring in applications that require inexpensive, flexible implant technology that can function effectively under non-laboratory conditions

  3. MultiSimplex optimization of chromatographic separation and dansyl derivatization conditions in the ultra performance liquid chromatography-tandem mass spectrometry analysis of risperidone, 9-hydroxyrisperidone, monoamine and amino acid neurotransmitters in human urine.

    Science.gov (United States)

    Cai, Hua-Lin; Zhu, Rong-Hua; Li, Huan-De; Zhang, Jun; Li, Lan-Fang

    2011-07-01

    A pre-column dansylated ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-MS/MS) method for simultaneous determination of risperidone (RIP), 9-hydroxyrisperidone (9-OH-RIP), monoamine and amino acid neurotransmitters in human urine was developed with the aim of providing data on how neurotransmitters may influence each other or change simultaneously in response to risperidone treatment. MultiSimplex based on the simplex algorithm and the fuzzy set theory was applied to the optimization of chromatographic separation and dansyl derivatization conditions during method development. This method exhibited excellent linearity for all the analytes with regression coefficients higher than 0.997. The lower limit of quantification (LLOQ) values for 9-OH-RIP and RIP were 0.11 and 0.06 ng/ml, respectively, and for neurotrasmitters ranged from 0.31 to 12.8 nM. The mean accuracy ranged from 94.7% to 108.5%. The mean recovery varied between 81.6% and 97.5%. All the RSD of precision and stability were below 9.7%. Finally, the optimized method was applied to analyze the first morning urine samples of schizophrenic patients treated with risperidone and healthy volunteers. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. An ultra high performance liquid chromatography with tandem mass spectrometry method for plasma and cerebrospinal fluid pharmacokinetics of rhein in patients with traumatic brain injury after administration of rhubarb decoction.

    Science.gov (United States)

    Wang, Yang; Fan, Rong; Luo, Jiekun; Tang, Tao; Xing, Zhihua; Xia, Zian; Peng, Weijun; Wang, Wenzhu; Lv, Huiying; Huang, Wei; Liang, Yizeng; Yi, Lunzhao; Lu, Hongmei; Huang, Xi

    2015-04-01

    Damage of blood-brain barrier is a common result of traumatic brain injury. This damage can open the blood-brain barrier and allow drug passage. An ultraperformance liquid chromatography with tandem mass spectrometry method was established to determine the concentration of rhein in the biofluids (plasma and cerebrospinal fluid) of patients with a compromised blood-brain barrier following traumatic brain injury after rhubarb administration. Furthermore, the pharmacokinetic profiles were analyzed. A triple-quadruple tandem mass spectrometer with electrospray ionization was used for rhein detection. The mass transition followed was m/z 283.06→239.0. The calibration curve was linear in the concentration range of 10-8000 ng/mL for the biofluids. The intra- and interday precisions were less than 10%. The relative standard deviation of recovery was less than 15% in biological matrices. The pharmacokinetic data showed that rhein was rapidly transported into biofluids, and exhibited a peak concentration 1 h after rhubarb administration. The elimination rate of rhein was slow. The AUCcerebrospinal fluid /AUCplasma (AUC is area under curve) of rhein was approximately 17%, indicating that portions of rhein could pass the impaired blood-brain barrier. The method was successfully applied to quantify rhein in the biofluids of all patients. The data presented can help to guide clinical applications of rhubarb for treating traumatic brain injury. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Osteoblast cell membrane chromatography coupled with liquid chromatography and time-of-flight mass spectrometry for screening specific active components from traditional Chinese medicines.

    Science.gov (United States)

    Wang, Nani; Zhang, Qiaoyan; Xin, Hailiang; Shou, Dan; Qin, Luping

    2017-11-01

    A method using osteoblast membrane chromatography coupled with liquid chromatography and time-of-flight mass spectrometry was developed to recognize and identify the specific active components from traditional Chinese medicines. Primary rat osteoblasts were used for the preparation of the stationary phase in the cell chromatography method. Retention components from the cell chromatography were collected and analyzed by liquid chromatography with time-of-flight mass spectrometry. This method was applied in screening active components from extracts of four traditional Chinese medicines. In total, 24 potentially active components with different structures were retained by osteoblast cell chromatography. There were five phenolic glucosides and one triterpenoid saponin from Curculigo orchioides Gaertn, two organic acids and ten flavonoids from Epimedium sagittatum Maxim, one phthalide compound and one organic acid from Angelica sinensis Diels, and two flavonoids and two saponins from Anemarrhena asphodeloides Bunge. Among those, four components (icariin, curculigoside, ferulaic acid, and timosaponin BII) were used for in vitro pharmacodynamics validation. They significantly increased the osteoblast proliferation, alkaline phosphatase activity, levels of bone gla protein and collagen type 1, and promoted mineralized nodule formation. The developed method was an effective screening method for finding active components from complex medicines that act on bone diseases. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction for the separation and determination of estrogens in water samples by high-performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Zhang, Rui; Wang, Chuanliu; Yue, Qiaohong; Zhou, Tiecheng; Li, Na; Zhang, Hanqi; Hao, Xiaoke

    2014-11-01

    An ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction method was proposed for the extraction and concentration of 17-α-estradiol, 17-β-estradiol-benzoate, and quinestrol in environmental water samples by high-performance liquid chromatography with fluorescence detection. 1-Hexyl-3-methylimidazolium tetrafluoroborate was applied as foaming agent in the foam flotation process and dispersive solvent in microextraction. The introduction of the ion-pairing and salting-out agent NH4 PF6 was beneficial to the improvement of recoveries for the hydrophobic ionic liquid phase and analytes. Parameters of the proposed method including concentration of 1-hexyl-3-methylimidazolium tetrafluoroborate, flow rate of carrier gas, floatation time, types and concentration of ionic liquids, salt concentration in samples, extraction time, and centrifugation time were evaluated. The recoveries were between 98 and 105% with relative standard deviations lower than 7% for lake water and well water samples. The isolation of the target compounds from the water was found to be efficient, and the enrichment factors ranged from 4445 to 4632. This developing method is free of volatile organic solvents compared with regular extraction. Based on the unique properties of ionic liquids, the application of foam floatation, and dispersive liquid-liquid microextraction was widened. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Determination of the trace TBP in industrial feed liquid by gas chromatography

    International Nuclear Information System (INIS)

    Gao Yuehua; Jiang Junqing; Mu Ling; Yang Songtao

    2012-01-01

    The determination of the trace TBP in kerosene of the industrial feed liquid by gas chromatography is studied in the paper. It first takes the purification treatment for the kerosene containing trace TBP. The plutonium is removed by 0.2 mol/L ferrous sulfamate-1 mol/L nitric acid using the back-extraction. The uranium and the nitric acid in the organic phase are removed by the deionized water. The impurity which affect the measurement of the TBP and is harmful to the gas chromatograph are eliminated. Then the content of the TBP of the organic phase can be determined by gas chromatography. Results show that the measuring range of the content of the TBP is 0.02% ∼ 2%. The precision of the method is better than 5% and the recovery is between 95%∼106%. (authors)

  8. A method for fast determination of psoralens in oral solutions of phytomedicines using liquid chromatography.

    Science.gov (United States)

    Pires, Adriana Elias; Honda, Neli Kiko; Cardoso, Cláudia Andréa Lima

    2004-10-29

    A method for sample preparation and analysis by high performance liquid chromatography with UV detection (HPLC-UV) has been developed for routine analysis of psoralen and bergapten, photosensitizing compounds, in oral solutions of phytomedicines employed in Brazil for some illnesses. The linearity, accuracy, the inter- and intra-day precision of the procedure were evaluated. Calibration curves for psoralen and bergapten were linear in the range of 1.0-600.0 microg ml(-1) and 1.0-400.0 microg ml(-1) respectively. The recoveries of the psoralens in the oral solutions analysed were 94.43-99.97%. The percentage coefficient of variation (CV) of the quantitative analysis of the psoralens in the products analysis was within 5%. In inter-equipment study was employed gas chromatography-flame ionization (CG-FID) detection.

  9. Liquid Chromatography-Tandem Mass Spectrometry: An Emerging Technology in the Toxicology Laboratory.

    Science.gov (United States)

    Zhang, Yan Victoria; Wei, Bin; Zhu, Yu; Zhang, Yanhua; Bluth, Martin H

    2016-12-01

    In the last decade, liquid chromatography-tandem mass spectrometry (LC-MS/MS) has seen enormous growth in routine toxicology laboratories. LC-MS/MS offers significant advantages over other traditional testing, such as immunoassay and gas chromatography-mass spectrometry methodologies. Major strengths of LC-MS/MS include improvement in specificity, flexibility, and sample throughput when compared with other technologies. Here, the basic principles of LC-MS/MS technology are reviewed, followed by advantages and disadvantages of this technology compared with other traditional techniques. In addition, toxicology applications of LC-MS/MS for simultaneous detection of large panels of analytes are presented. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Greening Reversed-Phase Liquid Chromatography Methods Using Alternative Solvents for Pharmaceutical Analysis

    Directory of Open Access Journals (Sweden)

    Moussa Yabré

    2018-05-01

    Full Text Available The greening of analytical methods has gained increasing interest in the field of pharmaceutical analysis to reduce environmental impacts and improve the health safety of analysts. Reversed-phase high-performance liquid chromatography (RP-HPLC is the most widely used analytical technique involved in pharmaceutical drug development and manufacturing, such as the quality control of bulk drugs and pharmaceutical formulations, as well as the analysis of drugs in biological samples. However, RP-HPLC methods commonly use large amounts of organic solvents and generate high quantities of waste to be disposed, leading to some issues in terms of ecological impact and operator safety. In this context, greening HPLC methods is becoming highly desirable. One strategy to reduce the impact of hazardous solvents is to replace classically used organic solvents (i.e., acetonitrile and methanol with greener ones. So far, ethanol has been the most often used alternative organic solvent. Others strategies have followed, such as the use of totally aqueous mobile phases, micellar liquid chromatography, and ionic liquids. These approaches have been well developed, as they do not require equipment investments and are rather economical. This review describes and critically discusses the recent advances in greening RP-HPLC methods dedicated to pharmaceutical analysis based on the use of alternative solvents.

  11. Assessing the detectability of antioxidants in two-dimensional high-performance liquid chromatography.

    Science.gov (United States)

    Bassanese, Danielle N; Conlan, Xavier A; Barnett, Neil W; Stevenson, Paul G

    2015-05-01

    This paper explores the analytical figures of merit of two-dimensional high-performance liquid chromatography for the separation of antioxidant standards. The cumulative two-dimensional high-performance liquid chromatography peak area was calculated for 11 antioxidants by two different methods--the areas reported by the control software and by fitting the data with a Gaussian model; these methods were evaluated for precision and sensitivity. Both methods demonstrated excellent precision in regards to retention time in the second dimension (%RSD below 1.16%) and cumulative second dimension peak area (%RSD below 3.73% from the instrument software and 5.87% for the Gaussian method). Combining areas reported by the high-performance liquid chromatographic control software displayed superior limits of detection, in the order of 1 × 10(-6) M, almost an order of magnitude lower than the Gaussian method for some analytes. The introduction of the countergradient eliminated the strong solvent mismatch between dimensions, leading to a much improved peak shape and better detection limits for quantification. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Analysis of recombinant Schistosoma mansoni antigen rSmp28 by on-line liquid chromatography-mass spectrometry combined with sodium dodecyl sulfate polyacrylamide gel electrophoresis

    NARCIS (Netherlands)

    Klarskov, K.; Roecklin, D.; Bouchon, B.; Sabatie, J.; Van Dorsselaer, A.; Bischoff, Rainer

    1994-01-01

    A recombinant Schistosoma mansoni antigen produced in Saccharomyces cerevisiae and purified by glutathione-Sepharose affinity chromatography was analyzed by tryptic peptide mapping using on-line reversed-phase high-performance liquid chromatography pneumatically assisted electrospray mass

  13. Simultaneous Determination of Eight Bioactive Compounds in Dianthus superbus by High-performance Liquid Chromatography.

    Science.gov (United States)

    Yun, Bo-Ra; Yang, Hye Jin; Weon, Jin Bae; Lee, Jiwoo; Eom, Min Rye; Ma, Choong Je

    2016-05-01

    Dianthus superbus, one of traditional herbal medicine, is widely used to treat urethritis, carbuncles and carcinoma. A simultaneous determination method was established for controlling the quality of D. superbus using the eight compounds, (E)-methyl-4-hydroxy-4-(8a-methyl-3-oxodecahydronaphthalen-4a-yl) (1), diosmetin-7-O(2'',6''-di-O-α-L-rhamnopyranosyl)-β-D-glucopyranoside (2), vanillic acid (3), 4-hydroxyphenyl acetic acid (4), 4-methoxyphenyl acetic acid (5), (E)-4-methoxycinnamic acid (6), 3-methoxy-4-hydroxyphenylethanol (7), and methyl hydroferulate (8) isolated from D. superbus. This analysis method was developed using high performance liquid chromatography coupled with diode array detector with a Shishedo C18 column at a column temperature of 3°C. The mobile phase was composed of 0.1% trifluoroacetic acid in water and acetonitrile. The flow rate was 1 ml/min and detection wavelength was set at 205 nm and 280 nm. Validation was performed in order to demonstrate selectivity, accuracy and precision of the method. The calibration curves showed good linearity (R (2) > 0.99). The limits of detection and limits of quantification were within the ranges 0.0159-0.6205 μg/ml and 0.3210-1.8802 μg/ml, respectively. Moreover, the relative standard deviations of intra- and inter-day precision were both Dianthus superbus was established by high performance liquid chromatography-diode array detectorDeveloped analysis method is validated with linearity, precious and accuracyThe newly established method was successfully evaluated contents of eight compounds in 12 D. superbus samples (D.1.D.12) from various regions and compared. Abbreviations used: HPLC: High performance liquid chromatography, LOD: Limits of detection, LOQ: Limits of quantification, RSD: Relative standard deviation.

  14. Comparison of liquid and supercritical fluid chromatography mobile phases for enantioselective separations on polysaccharide stationary phases.

    Science.gov (United States)

    Khater, Syame; Lozac'h, Marie-Anne; Adam, Isabelle; Francotte, Eric; West, Caroline

    2016-10-07

    Analysis and production of enantiomerically pure compounds is a major topic of interest when active pharmaceutical ingredients are concerned. Enantioselective chromatography has become a favourite both at the analytical and preparative scales. High-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) are dominating the scene and are often seen as complementary techniques. Nowadays, for economic and ecologic reasons, SFC may be preferred over normal-phase HPLC (NPLC) as it allows significant reductions in solvent consumption. However, the transfer of NPLC methods to SFC is not always straightforward. In this study, we compare the retention of achiral molecules and separation of enantiomers under supercritical fluid (carbon dioxide with ethanol or isopropanol) and liquid normal-phase (heptane with ethanol or isopropanol) elution modes with polysaccharide stationary phases in order to explore the differences between the retention and enantioseparation properties between the two modes. Chemometric methods (namely quantitative structure-retention relationships and discriminant analysis) are employed to compare the results obtained on a large set of analytes (171 achiral probes and 97 racemates) and gain some understanding on the retention and separation mechanisms. The results indicate that, contrary to popular belief, carbon dioxide - solvent SFC mobile phases are often weaker eluents than liquid mobile phases. It appears that SFC and NPLC elution modes provide different retention mechanisms. While some enantioseparations are unaffected, facilitating the transfer between the two elution modes, other enantioseparations may be drastically different due to different types and strength of interactions contributing to enantioselectivity. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Characterization of rhamnolipids by liquid chromatography/mass spectrometry after solid-phase extraction.

    Science.gov (United States)

    Behrens, Beate; Engelen, Jeannine; Tiso, Till; Blank, Lars Mathias; Hayen, Heiko

    2016-04-01

    Rhamnolipids are surface-active agents with a broad application potential that are produced in complex mixtures by bacteria of the genus Pseudomonas. Analysis from fermentation broth is often characterized by laborious sample preparation and requires hyphenated analytical techniques like liquid chromatography coupled to mass spectrometry (LC-MS) to obtain detailed information about sample composition. In this study, an analytical procedure based on chromatographic method development and characterization of rhamnolipid sample material by LC-MS as well as a comparison of two sample preparation methods, i.e., liquid-liquid extraction and solid-phase extraction, is presented. Efficient separation was achieved under reversed-phase conditions using a mixed propylphenyl and octadecylsilyl-modified silica gel stationary phase. LC-MS/MS analysis of a supernatant from Pseudomonas putida strain KT2440 pVLT33_rhlABC grown on glucose as sole carbon source and purified by solid-phase extraction revealed a total of 20 congeners of di-rhamnolipids, mono-rhamnolipids, and their biosynthetic precursors 3-(3-hydroxyalkanoyloxy)alkanoic acids (HAAs) with different carbon chain lengths from C8 to C14, including three rhamnolipids with uncommon C9 and C11 fatty acid residues. LC-MS and the orcinol assay were used to evaluate the developed solid-phase extraction method in comparison with the established liquid-liquid extraction. Solid-phase extraction exhibited higher yields and reproducibility as well as lower experimental effort.

  16. Low Density Solvent-Based Dispersive Liquid-Liquid Microextraction for the Determination of Synthetic Antioxidants in Beverages by High-Performance Liquid Chromatography

    Science.gov (United States)

    Çabuk, Hasan; Köktürk, Mustafa

    2013-01-01

    A simple and efficient method was established for the determination of synthetic antioxidants in beverages by using dispersive liquid-liquid microextraction combined with high-performance liquid chromatography with ultraviolet detection. Butylated hydroxy toluene, butylated hydroxy anisole, and tert-butylhydroquinone were the antioxidants evaluated. Experimental parameters including extraction solvent, dispersive solvent, pH of sample solution, salt concentration, and extraction time were optimized. Under optimal conditions, the extraction recoveries ranged from 53 to 96%. Good linearity was observed by the square of correlation coefficients ranging from 0.9975 to 0.9997. The relative standard deviations ranged from 1.0 to 5.2% for all of the analytes. Limits of detection ranged from 0.85 to 2.73 ng mL−1. The method was successfully applied for determination of synthetic antioxidants in undiluted beverage samples with satisfactory recoveries. PMID:23853535

  17. Low Density Solvent-Based Dispersive Liquid-Liquid Microextraction for the Determination of Synthetic Antioxidants in Beverages by High-Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Hasan Çabuk

    2013-01-01

    Full Text Available A simple and efficient method was established for the determination of synthetic antioxidants in beverages by using dispersive liquid-liquid microextraction combined with high-performance liquid chromatography with ultraviolet detection. Butylated hydroxy toluene, butylated hydroxy anisole, and tert-butylhydroquinone were the antioxidants evaluated. Experimental parameters including extraction solvent, dispersive solvent, pH of sample solution, salt concentration, and extraction time were optimized. Under optimal conditions, the extraction recoveries ranged from 53 to 96%. Good linearity was observed by the square of correlation coefficients ranging from 0.9975 to 0.9997. The relative standard deviations ranged from 1.0 to 5.2% for all of the analytes. Limits of detection ranged from 0.85 to 2.73 ng mL−1. The method was successfully applied for determination of synthetic antioxidants in undiluted beverage samples with satisfactory recoveries.

  18. Determination of alpha-Tocopherol (vitamin E) in irradiated garlic by high performance liquid chromatography (HPLC)

    International Nuclear Information System (INIS)

    Rios, Magda Dias Goncalves; Penteado, Marilene de Vuono Camargo

    2003-01-01

    The effects of 60 Co ionizing radiations in doses of 0, 75, 100, 150, 200 and 250Gy on garlic, upon the α-tocopherol concentration were studied. The α-tocopherol contents were established by high performance liquid chromatography (HPLC), after direct hexane extraction from the garlic samples. The α-tocopherol was determined through normal phase column, and mobile phase was composed by hexane: iso-propyl alcohol (99:01 v/v), with 2mL/min flow rate and fluorescence detector. It is statistically shown that an irradiation dose of up to 150 Gy does not affect the garlic α-tocopherol content. (author)

  19. Determination of boron in uranium and aluminium by high pressure liquid chromatography (HPLC)

    International Nuclear Information System (INIS)

    Rao, Radhika M.; Aggarwal, S.K.

    2003-01-01

    Experiments were conducted for the determination of boron in U 3 O 8 powder and aluminium metal using dynamically modified reversed phase high pressure liquid chromatography (RP-HPLC) and using precolumn chromogenic agent viz. curcumin for complexing boron. The complex was separated from the excess of reagent and determined by HPLC. The boron curcumin complex (rosocyanin) was formed after extraction of boron with 2-ethyl-1,3-hexane diol (EHD). Linear calibration curves for boron amounts in the range of 0.02 μg to 0.5 μg were developed and used for the determination of boron in aluminium and uranium samples. (author)

  20. Determination of 1-hydroxypyrene in human urine by high-performance liquid chromatography

    DEFF Research Database (Denmark)

    Hansen, Åse Marie; Poulsen, O M; Christensen, J M

    1993-01-01

    A high-performance liquid chromatography (HPLC)/fluorescence method for quantitative analysis of 1-hydroxypyrene in urine was developed. The method validation analysis showed the method to be in analytical control. No significant systematical errors could be demonstrated. The entire run time....... The developed method is presently used for measurement of 1-hydroxypyrene in urine samples from workers exposed to a low airborne level of polycyclic aromatic hydrocarbons, generally less than 25 micrograms/m3. The urine samples of exposed workers (n = 122) showed a range of 1-hydroxypyrene from the limit...

  1. Increasing flexibility in two-dimensional liquid chromatography by pulsed elution of the first dimension

    DEFF Research Database (Denmark)

    Jakobsen, Simon S.; Christensen, Jan H.; Verdier, Sylvain

    2017-01-01

    This work demonstrates the development of an online two-dimensional liquid chromatography (2D-LC) method where the first dimension column is eluted by a sequence of pulses of increasing eluotropic strength generated by the LC pumps (pulsed-elution 2D-LC). Between the pulses, the first dimension...... online comprehensive 2D-LC: undersampling, difficulties in refocusing, and lack of flexibility in the selection of column dimensions and flow rates because the two dimensions constrain each other. The pulsed-elution 2D-LC was applied for the analysis of a basic fraction of vacuum gas oil. Peak capacity...

  2. Derivatization reagents in liquid chromatography/electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Santa, Tomofumi

    2011-01-01

    Liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) is one of the most prominent analytical techniques owing to its inherent selectivity and sensitivity. In LC/ESI-MS/MS, chemical derivatization is often used to enhance the detection sensitivity. Derivatization improves the chromatographic separation, and enhances the mass spectrometric ionization efficiency and MS/MS detectability. In this review, an overview of the derivatization reagents which have been applied to LC/ESI-MS/MS is presented, focusing on the applications to low molecular weight compounds. 2010 John Wiley & Sons, Ltd.

  3. Denaturing high-performance liquid chromatography mutation analysis in patients with reduced Protein S levels

    DEFF Research Database (Denmark)

    Bathum, Lise; Münster, Anna-Marie; Nybo, Mads

    2008-01-01

    diagnosis and risk estimation. The aim was to design a high-throughput genetic analysis based on denaturing high-performance liquid chromatography to identify sequence variations in the gene coding for Protein S. PATIENTS: In total, 55 patients referred to the Section of Thrombosis and Haemostasis, Odense......BACKGROUND: Patients with congenital Protein S deficiency have increased risk of venous thromboembolism. However, Protein S levels show large intra-individual variation and the biochemical assays have low accuracy and a high interlaboratory variability. Genetic analysis might aid in a more precise......, giving a precise diagnosis and subsequently a better risk estimation....

  4. Determination of limonin and nomilin contents in different citrus cultivars using high performance liquid chromatography

    International Nuclear Information System (INIS)

    Bilal, H.; Hassan, S.; Sahar, S.; Akram, W.; Sahar, S.

    2013-01-01

    High perlorrnance liquid chromatography (HPLC) analysis was done to quantify the amount of limonoids (nomilin and nomilin) in seven selected citrus cultivars. According to the HPLC analysis red blood orange (Citrus sinensis var red blood orange) had maximum amount of limonin (479.77 ug/rnl.), while rough lemon (Citrus jambhiri) had no limonin content. in case of nomonin, rough lemon (Citrus jambhir) had maximum amount of nomilin (54.23 micro g/ML)) while succari (citrus sinensis var succari) had very low amount of nomilin (0.37 micro g/Ml). (author)

  5. Determination of 90SR in food using extraction chromatography and LSC - Liquid Scintillation Counting

    International Nuclear Information System (INIS)

    Temba, Eliane S.C.; Amaral, Angela M.; Reis Junior, Aluisio S.; Monteiro, Roberto P.G.

    2013-01-01

    A methodology for the determination of 90 Sr in food is described. The procedure involved a preliminary freeze-drying of the samples followed by dry-ashing and sample digestion. The separation procedure was carried out using extraction chromatography with Sr Resin, from Eichrom, and 90 Sr was measured by liquid scintillation counting (LSC). A certified reference material, IAEA-375, was analyzed in order to evaluate the reliability of the method, and the results showed good agreement between the measured and certified values. The chemical yield was above 90% and the typical counting efficiency was 82%. The calculated limit of detection was 4.8 x 10 -3 Bq g -1 . (author)

  6. Hb A1c Separation by High Performance Liquid Chromatography in Hemoglobinopathies

    OpenAIRE

    Chandrashekar, Vani

    2016-01-01

    Hb A1c measurement is subject to interference by hemoglobin traits and this is dependent on the method used for determination. In this paper we studied the difference between Hb A1c measured by HPLC in hemoglobin traits and normal chromatograms. We also studied the correlation of Hb A1c with age. Hemoglobin analysis was carried out by high performance liquid chromatography. Spearman's rank correlation was used to study correlation between A1c levels and age. Mann-Whitney U test was used to st...

  7. Chiral separation of pharmaceutical compounds using electrochemically modulated liquid chromatography (EMLC)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S. [Iowa State Univ., Ames, IA (United States)

    1999-02-12

    This research explores the application of a new technique, termed electrochemically modulated liquid chromatography (EMLC), to the chiral separations of pharmaceutical compounds. The introduction section provides a literature review of the technique and its applications, as well as brief overview of the research described in each of the next two chapters. Chapter 2 investigates the EMLC-based enantiomeric separation of a group of chiral benzodiazepines with β-cyclodextrin as a chiral mobile phase additive. Chapter 3 demonstrates the effects of several experimental parameters on the separation efficiency of drug enantiomers. The author concludes with a general summary and possible directions for future studies. Chapters 2 and 3 are processed separately.

  8. Determination of sulfonamides in meat by liquid chromatography coupled with atmospheric pressure chemical ionization mass spectrometry

    International Nuclear Information System (INIS)

    Kim, Dal Ho; Choi, Jong Oh; Kim, Jin Seog; Lee, Dai Woon

    2002-01-01

    Liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS) has been used for the determination of sulfonamides in meat. Five typical sulfonamides were selected as target compounds, and beef meat was selected as a matrix sample. As internal standards, sulfapyridine and isotope labeled sulfamethazine ( 13 C 6 -SMZ) were used. Compared to the results of recent reports, our results have shown improved precision to a RSD of 1.8% for the determination of sulfamethazine spiked with 75 ng/g level in meat

  9. High-performance liquid chromatography of rat and mouse islet polypeptides

    DEFF Research Database (Denmark)

    Linde, S; Hansen, B; Welinder, B S

    1990-01-01

    After preparative high-performance liquid chromatography of mouse islet culture medium, concentrated on disposable C18 cartridges (Sep-Pak), an unexpected insulin immunoreactive peak eluting earlier than mouse insulin I and II was detected. Molecular mass determination by mass spectrometry...... on the buffer, the organic modifier and the procedure. In particular the use of methanol-trifluoroacetic acid resulted in extensive oxidation. The oxidation could be minimized by adding 2 mM dithiothreitol to the buffer and by degassing and/or nitrogen-bubbling of the buffer. Minimal formation of Met...

  10. Separation and identification of corticosterone metabolites by liquid chromatography--electrospray ionization mass spectrometry.

    Science.gov (United States)

    Miksík, I; Vylitová, M; Pácha, J; Deyl, Z

    1999-04-16

    High-performance liquid chromatography coupled to atmospheric pressure ionization-electrospray ionization mass spectrometry (API-ESI-MS) was investigated for the analysis of corticosterone metabolites; their characterization was obtained by combining the separation on Zorbax Eclipse XDB C18 column (eluted with a methanol-water-acetic acid gradient) with identification using positive ion mode API-ESI-MS and selected ion analysis. The applicability of this method was verified by monitoring the activity of steroid converting enzymes (20beta-hydroxysteroid dehydrogenase and 11beta-hydroxysteroid dehydrogenase) in avian intestines.

  11. Quantification of glibenclamide in cleaning samples of pharmaceutical equipment through high performance liquid chromatography

    International Nuclear Information System (INIS)

    Baeza Fonte, Alen Nils; Diaz Aguila, Elsa Eneida; Martinez Alfonso; Nancy

    2012-01-01

    to submit a selective analytical method for quantization of glibenclamide in cleaning samples of pharmaceutical equipment using high performance liquid chromatography. The mobile phase consisted of an equal mixing of acetonitrile/phosphate buffer KH 2 PO 4 ; with 0.037 mol/L concentration pH 5.25 and flow of 1.5 mL/min, in a Nucleosil 100 C8 column. Glibenclamide was injected with progesterone as internal standard and using an UV detector= 230 nm

  12. Determination of three estrogens and bisphenol A by functional ionic liquid dispersive liquid-phase microextraction coupled with ultra-high performance liquid chromatography and ultraviolet detection.

    Science.gov (United States)

    Jiang, Yuehuang; Tang, Tingting; Cao, Zhen; Shi, Guoyue; Zhou, Tianshu

    2015-06-01

    A hydroxyl-functionalized ionic liquid, 1-hydroxyethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, was employed in an improved dispersive liquid-phase microextraction method coupled with ultra high performance liquid chromatography for the enrichment and determination of three estrogens and bisphenol A in environmental water samples. The introduced hydroxyl group acted as the H-bond acceptor that dispersed the ionic liquid effectively in the aqueous phase without dispersive solvent or external force. Fourier transform infrared spectroscopy indicated that the hydroxyl group of the cation of the ionic liquid enhanced the combination of extractant and analytes through the formation of hydrogen bonds. The improvement of the extraction efficiency compared with that with the use of alkyl ionic liquid was proved by a comparison study. The main parameters including volume of extractant, temperature, pH, and extraction time were investigated. The calibration curves were linear in the range of 5.0-1000 μg/L for estrone, estradiol, and bisphenol A, and 10.0-1000 μg/L for estriol. The detection limits were in the range of 1.7-3.4 μg/L. The extraction efficiency was evaluated by enrichment factor that were between 85 and 129. The proposed method was proved to be simple, low cost, and environmentally friendly for the determination of the four endocrine disruptors in environmental water samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Systematic evaluation of matrix effects in hydrophilic interaction chromatography versus reversed phase liquid chromatography coupled to mass spectrometry.

    Science.gov (United States)

    Periat, Aurélie; Kohler, Isabelle; Thomas, Aurélien; Nicoli, Raul; Boccard, Julien; Veuthey, Jean-Luc; Schappler, Julie; Guillarme, Davy

    2016-03-25

    Reversed phase liquid chromatography (RPLC) coupled to mass spectrometry (MS) is the gold standard technique in bioanalysis. However, hydrophilic interaction chromatography (HILIC) could represent a viable alternative to RPLC for the analysis of polar and/or ionizable compounds, as it often provides higher MS sensitivity and alternative selectivity. Nevertheless, this technique can be also prone to matrix effects (ME). ME are one of the major issues in quantitative LC-MS bioanalysis. To ensure acceptable method performance (i.e., trueness and precision), a careful evaluation and minimization of ME is required. In the present study, the incidence of ME in HILIC-MS/MS and RPLC-MS/MS was compared for plasma and urine samples using two representative sets of 38 pharmaceutical compounds and 40 doping agents, respectively. The optimal generic chromatographic conditions in terms of selectivity with respect to interfering compounds were established in both chromatographic modes by testing three different stationary phases in each mode with different mobile phase pH. A second step involved the assessment of ME in RPLC and HILIC under the best generic conditions, using the post-extraction addition method. Biological samples were prepared using two different sample pre-treatments, i.e., a non-selective sample clean-up procedure (protein precipitation and simple dilution for plasma and urine samples, respectively) and a selective sample preparation, i.e., solid phase extraction for both matrices. The non-selective pretreatments led to significantly less ME in RPLC vs. HILIC conditions regardless of the matrix. On the contrary, HILIC appeared as a valuable alternative to RPLC for plasma and urine samples treated by a selective sample preparation. Indeed, in the case of selective sample preparation, the compounds influenced by ME were different in HILIC and RPLC, and lower and similar ME occurrence was generally observed in RPLC vs. HILIC for urine and plasma samples

  14. Quantitative Analysis of Tetramethylenedisulfotetramine ("Tetramine") Spiked into Beverages by Liquid Chromatography Tandem Mass Spectrometry with Validation by Gas Chromatography Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Owens, J; Hok, S; Alcaraz, A; Koester, C

    2008-11-13

    Tetramethylenedisulfotetramine, commonly known as tetramine, is a highly neurotoxic rodenticide (human oral LD{sub 50} = 0.1 mg/kg) used in hundreds of deliberate food poisoning events in China. Here we describe a method for quantitation of tetramine spiked into beverages, including milk, juice, tea, cola, and water and cleaned up by C8 solid phase extraction and liquid-liquid extraction. Quantitation by high performance liquid chromatography tandem mass spectrometry (LC/MS/MS) was based upon fragmentation of m/z 347 to m/z 268. The method was validated by gas chromatography mass spectrometry (GC/MS) operated in SIM mode for ions m/z 212, 240, and 360. The limit of quantitation was 0.10 {micro}g/mL by LC/MS/MS versus 0.15 {micro}g/mL for GC/MS. Fortifications of the beverages at 2.5 {micro}g/mL and 0.25 {micro}g/mL were recovered ranging from 73-128% by liquid-liquid extraction for GC/MS analysis, 13-96% by SPE and 10-101% by liquid-liquid extraction for LC/MS/MS analysis.

  15. Quantitative Analysis of Tetramethylenedisulfotetramine ('Tetramine') Spiked into Beverages by Liquid Chromatography Tandem Mass Spectrometry with Validation by Gas Chromatography Mass Spectrometry

    International Nuclear Information System (INIS)

    Owens, J.; Hok, S.; Alcaraz, A.; Koester, C.

    2008-01-01

    Tetramethylenedisulfotetramine, commonly known as tetramine, is a highly neurotoxic rodenticide (human oral LD 50 = 0.1 mg/kg) used in hundreds of deliberate food poisoning events in China. Here we describe a method for quantitation of tetramine spiked into beverages, including milk, juice, tea, cola, and water and cleaned up by C8 solid phase extraction and liquid-liquid extraction. Quantitation by high performance liquid chromatography tandem mass spectrometry (LC/MS/MS) was based upon fragmentation of m/z 347 to m/z 268. The method was validated by gas chromatography mass spectrometry (GC/MS) operated in SIM mode for ions m/z 212, 240, and 360. The limit of quantitation was 0.10 (micro)g/mL by LC/MS/MS versus 0.15 (micro)g/mL for GC/MS. Fortifications of the beverages at 2.5 (micro)g/mL and 0.25 (micro)g/mL were recovered ranging from 73-128% by liquid-liquid extraction for GC/MS analysis, 13-96% by SPE and 10-101% by liquid-liquid extraction for LC/MS/MS analysis.

  16. Use of liquid chromatography for measuring atmospheric sulfur dioxide and nitrogen oxide

    Energy Technology Data Exchange (ETDEWEB)

    Benova, E

    1973-02-01

    A literature search to ascertain the applicability of liquid chromatography to the analysis of atmospheric sulfur dioxide and various oxides of nitrogen is reported. Simple or enriched samples can be analyzed. Plastic bags are recommended for preparation of simple samples; and a table of 18 plastic materials, their manufacturers, and pollutants to which they are inert is provided. Enriched samples can be prepared in chromatographic columns by adsorption methods. Tables are provided listing carriers, stationary phase materials, temperatures, carrier liquids (helium or nitrogen), column dimensions, and other data recommended for chromatographic tests of SO/sub 2/ and NOx. Because of its reactivity and tendency to polymerize, sulfur trioxide should be reduced to SO/sub 2/ prior to analysis.

  17. A simple high performance liquid chromatography method for analyzing paraquat in soil solution samples.

    Science.gov (United States)

    Ouyang, Ying; Mansell, Robert S; Nkedi-Kizza, Peter

    2004-01-01

    A high performance liquid chromatography (HPLC) method with UV detection was developed to analyze paraquat (1,1'-dimethyl-4,4'-dipyridinium dichloride) herbicide content in soil solution samples. The analytical method was compared with the liquid scintillation counting (LSC) method using 14C-paraquat. Agreement obtained between the two methods was reasonable. However, the detection limit for paraquat analysis was 0.5 mg L(-1) by the HPLC method and 0.05 mg L(-1) by the LSC method. The LSC method was, therefore, 10 times more precise than the HPLC method for solution concentrations less than 1 mg L(-1). In spite of the high detection limit, the UC (nonradioactive) HPLC method provides an inexpensive and environmentally safe means for determining paraquat concentration in soil solution compared with the 14C-LSC method.

  18. Novel materials and methods for solid-phase extraction and liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Ambrose, Diana [Iowa State Univ., Ames, IA (United States)

    1997-06-24

    This report contains a general introduction which discusses solid-phase extraction and solid-phase micro-extraction as sample preparation techniques for high-performance liquid chromatography, which is also evaluated in the study. This report also contains the Conclusions section. Four sections have been removed and processed separately: silicalite as a sorbent for solid-phase extraction; a new, high-capacity carboxylic acid functionalized resin for solid-phase extraction; semi-micro solid-phase extraction of organic compounds from aqueous and biological samples; and the high-performance liquid chromatographic determination of drugs and metabolites in human serum and urine using direct injection and a unique molecular sieve.

  19. Screening antiallergic components from Carthamus tinctorius using rat basophilic leukemia 2H3 cell membrane chromatography combined with high-performance liquid chromatography and tandem mass spectrometry.

    Science.gov (United States)

    Han, Shengli; Huang, Jing; Cui, Ronghua; Zhang, Tao

    2015-02-01

    Carthamus tinctorius, used in traditional Chinese medicine, has many pharmacological effects, such as anticoagulant effects, antioxidant effects, antiaging effects, regulation of gene expression, and antitumor effects. However, there is no report on the antiallergic effects of the components in C. tinctorius. In the present study, we investigated the antiallergic components of C. tinctorius and its mechanism of action. A rat basophilic leukemia 2H3/cell membrane chromatography coupled online with high-performance liquid chromatography and tandem mass spectrometry method was developed to screen antiallergic components from C. tinctorius. The screening results showed that Hydroxysafflor yellow A, from C. tinctorius, was the targeted component that retained on the rat basophilic leukemia 2H3/cell membrane chromatography column. We measured the amount of β-hexosaminidase and histamine released in mast cells and the key markers of degranulation. The release assays showed that Hydroxysafflor yellow A could attenuate the immunoglobulin E induced release of allergic cytokines without affecting cell viability from 1.0 to 50.0 μM. In conclusion, the established rat basophilic leukemia 2H3 cell membrane chromatography coupled with online high-performance liquid chromatography and tandem mass spectrometry method successfully screened and identified Hydroxysafflor yellow A from C. tinctorius as a potential antiallergic component. Pharmacological analysis elucidated that Hydroxysafflor yellow A is an effective natural component for inhibiting immunoglobulin E-antigen-mediated degranulation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Analysis of lignans in Magnoliae Flos by turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Zhou, Xuan; Chen, Cen; Ye, Xiaolan; Song, Fenyun; Fan, Guorong; Wu, Fuhai

    2016-04-01

    In this study, a method coupling turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry was developed for analyzing the lignans in Magnoliae Flos. By the online pretreatment of turbulent flow chromatography solid-phase extraction, the impurities removal and analytes concentration were automatically processed, and the lignans were separated rapidly and well. Seven lignans of Magnoliae Flos including epieudesmin, magnolin, 1-irioresinol-B-dimethyl ether, epi-magnolin, fargesin aschantin, and demethoxyaschantin were identified by comparing their retention behavior, UV spectra, and mass spectra with those of reference substances or literature data. The developed method was validated, and the good results showed that the method was not only automatic and rapid, but also accurate and reliable. The turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry method holds a high potential to become an effective method for the quality control of lignans in Magnoliae Flos and a useful tool for the analysis of other complex mixtures. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Purification of lignans from Fructus Arctii using off-line two-dimensional supercritical fluid chromatography/reversed-phase liquid chromatography.

    Science.gov (United States)

    Yang, Bichao; Xin, Huaxia; Wang, Feier; Cai, Jianfeng; Liu, Yanfang; Fu, Qing; Jin, Yu; Liang, Xinmiao

    2017-08-01

    As a common traditional Chinese medicine, Fructus Arctii has important clinical medical values. Its main components are lignans, which are difficult to separate and analyze because of the complex composition, similar chemical structures, and close properties. In this study, an off-line two-dimensional supercritical fluid chromatography/reversed-phase liquid chromatography method, as well as an effective sample pretreatment method based on hydrophilic interaction chromatography material, was developed to enrich the minor lignan fractions and obtain high-purity compounds. In total, 12 high-purity compounds were isolated from Fructus Arctii. Their structures were identified by using high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy, which showed that all were lignans and that most of them were isomers. The results demonstrated the effective off-line two-dimensional supercritical fluid chromatography/reversed-phase liquid chromatography method for the purification of lignans from Fructus Arctii. The separation protocol established here will be beneficial for the separation of complex samples from other kinds of natural products. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Quantification of steroid hormones in human serum by liquid chromatography-high resolution tandem mass spectrometry.

    Science.gov (United States)

    Matysik, Silke; Liebisch, Gerhard

    2017-12-01

    A limited specificity is inherent to immunoassays for steroid hormone analysis. To improve selectivity mass spectrometric analysis of steroid hormones by liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been introduced in the clinical laboratory over the past years usually with low mass resolution triple-quadrupole instruments or more recently by high resolution mass spectrometry (HR-MS). Here we introduce liquid chromatography-high resolution tandem mass spectrometry (LC-MS/HR-MS) to further increase selectivity of steroid hormone quantification. Application of HR-MS demonstrates an enhanced selectivity compared to low mass resolution. Separation of isobaric interferences reduces background noise and avoids overestimation. Samples were prepared by automated liquid-liquid extraction with MTBE. The LC-MS/HR-MS method using a quadrupole-Orbitrap analyzer includes eight steroid hormones i.e. androstenedione, corticosterone, cortisol, cortisone, 11-deoxycortisol, 17-hydroxyprogesterone, progesterone, and testosterone. It has a run-time of 5.3min and was validated according to the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) guidelines. For most of the analytes coefficient of variation were 10% or lower and LOQs were determined significantly below 1ng/ml. Full product ion spectra including accurate masses substantiate compound identification by matching their masses and ratios with authentic standards. In summary, quantification of steroid hormones by LC-MS/HR-MS is applicable for clinical diagnostics and holds also promise for highly selective quantification of other small molecules. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Simultaneous drug identification in urine of sexual assault victims by using liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Lee, Hei Hwa; Chen, Suen Chi; Lee, Jong Feng; Lin, Hsin Yu; Chen, Bai Hsiun

    2018-01-01

    According to domestic and international epidemiological investigation, the proportion of substance involved sexual assault has the trend of ascent. In the past, laboratory methods that investigated urine sample of the sexual assault victims was to screen with enzyme immunoassay and then confirmed with mass spectrometry. The objective of the study is to simultaneously identify abused drugs in 126 decoded urine samples of sexual assault victims by liquid chromatography tandem mass spectrometry. The instrument was operated in multiple-reaction monitoring with an electro-spray positive ionization mode. Chromatograms were separated with ACE5 C18 column on a gradient of acetonitrile. After liquid-liquid extraction, samples were passed through a 0.22μm PVDF filter before injection into the system. The limits of quantitation ranged from 0.2 to 10ng/mL. The precision (CV) results were below 12.9% (intraday) and 15.0% (interday). The intraday accuracy ranged from 84.8 to 121.0%, interday accuracy ranged from 72.0 to 117.3%. We found that 29 (23.0%) were positive for drugs. The most common drug identified is flunitrazepam (11.1%), followed by nimetazepam and ketamine (7.9%), some new psychoactive substances, such as 2C-B, mephedrone, methylone, PMA and PMMA were also identified. We identified abused drugs, benzodiazepines, and new psychoactive substances in urine of sexual assault victims by using liquid chromatography tandem mass spectrometry. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Carbon nanoparticles from corn stalk soot and its novel application as stationary phase of hydrophilic interaction chromatography and per aqueous liquid chromatography

    International Nuclear Information System (INIS)

    Li Yuanyuan; Xu Luan; Chen Tong; Liu Xiaoyan; Xu Zhigang; Zhang Haixia

    2012-01-01

    Highlights: ► Carbon nanoparticles (6–18 nm in size) were prepared from corn stalk soot. ► CNPs-based silica were used as novel chromatography stationary phase. ► The new phase shows good separation selectivity for polar compounds. ► The new phase had the similar retention for polar probes in HILIC and PALC modes. ► In contrast to PALC, under HILIC conditions high efficiencies were achieved. - Abstract: Carbon nanoparticles (CNPs) (6–18 nm in size) were prepared by refluxing corn stalk soot in nitric acid. The obtained acid-oxidized CNPs are soluble in water due to the existence of carboxylic and hydroxyl groups. 13 C NMR measurement shows the CNPs are mainly of sp 2 and sp 3 carbon structure different from CNPs obtained from candle soot and natural gas soot. Furthermore, these CNPs exhibit unique photoluminescence properties. Interestingly, the CNPs might be exploited to immobilize on the surface of porous silica particles as chromatographic stationary phase. The resultant packing material was evaluated by high-performance liquid chromatography, indicating that the new stationary phase could be used in hydrophilic interaction liquid chromatography (HILIC) and per aqueous liquid chromatography (PALC) modes. The separation of five nucleosides, four sulfa compounds and safflower injection was achieved by using the new column in the HILIC and PALC modes, respectively.

  5. Quantification of Quercetin and Rutin from Benincasa hispida Seeds and Carissa Congesta Roots by High-performance Thin Layer Chromatography and High-performance Liquid Chromatography.

    Science.gov (United States)

    Doshi, Gaurav Mahesh; Une, Hemant Devidas

    2016-01-01

    In Indian Ayurvedic system, Benincasa hispida (BH) and Carissa congesta (CC) are well-known plants used for major and minor ailments. BH has been regarded as Kushmanda, whereas CC has been used in immune-related disorders of the human system. Quercetin and rutin identified from the vast plethora of plant extracts have proved to possess ethnopharmacological relevance. In present studies, we have determined quercetin and rutin in terms of percentage in BH seeds and CC roots by high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). After extraction and phytochemical screening, the extracts were subjected to quantification for the presence of quercetin and rutin by HPTLC and HPLC. HPTLC showed quercetin as 44.60, 27.13% and rutin as 32.00, 36.31% w/w, whereas HPLC revealed quercetin as 34.00, 35.00% and rutin as 21.99, 45.03% w/v in BH and CC extracts, respectively. The BH and CC extracts have elucidated peaks that were corresponding with standard peaks on undertaking chromatographic studies. Quercetin and rutin are isolated from BH seeds and CC roots by High Performance. Thin Layer Chromatography and High Performance Liquid Chromatography. HPTLC revealed presence of quercetin as 44.60, 27.13 % and rutin as 32.00, 36.31 % w/w. HPLC revealed presence of quercetin as 34.00, 35.00 % and rutin as 21.99, 45.03 % w/v. Abbreviation Used: HPTLC: High Performance Thin Layer Chromatography; HPLC: High Pressure Liquid Chromatography, UV: Ultraviolet, CC: Carissa congesta, BH: Benincasa hispida.

  6. Quantification of Quercetin and Rutin from Benincasa hispida Seeds and Carissa Congesta Roots by High-performance Thin Layer Chromatography and High-performance Liquid Chromatography

    Science.gov (United States)

    Doshi, Gaurav Mahesh; Une, Hemant Devidas

    2016-01-01

    Objective: In Indian Ayurvedic system, Benincasa hispida (BH) and Carissa congesta (CC) are well-known plants used for major and minor ailments. BH has been regarded as Kushmanda, whereas CC has been used in immune-related disorders of the human system. Quercetin and rutin identified from the vast plethora of plant extracts have proved to possess ethnopharmacological relevance. Materials and Methods: In present studies, we have determined quercetin and rutin in terms of percentage in BH seeds and CC roots by high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). After extraction and phytochemical screening, the extracts were subjected to quantification for the presence of quercetin and rutin by HPTLC and HPLC. Results: HPTLC showed quercetin as 44.60, 27.13% and rutin as 32.00, 36.31% w/w, whereas HPLC revealed quercetin as 34.00, 35.00% and rutin as 21.99, 45.03% w/v in BH and CC extracts, respectively. Conclusion: The BH and CC extracts have elucidated peaks that were corresponding with standard peaks on undertaking chromatographic studies. SUMMARY Quercetin and rutin are isolated from BH seeds and CC roots by High Performance. Thin Layer Chromatography and High Performance Liquid Chromatography. HPTLC revealed presence of quercetin as 44.60, 27.13 % and rutin as 32.00, 36.31 % w/w. HPLC revealed presence of quercetin as 34.00, 35.00 % and rutin as 21.99, 45.03 % w/v. Abbreviation Used: HPTLC: High Performance Thin Layer Chromatography; HPLC: High Pressure Liquid Chromatography, UV: Ultraviolet, CC: Carissa congesta, BH: Benincasa hispida PMID:26941534

  7. Salting-out homogenous extraction followed by ionic liquid/ionic liquid liquid-liquid micro-extraction for determination of sulfonamides in blood by high performance liquid chromatography.

    Science.gov (United States)

    Liu, Zhongling; Yu, Wei; Zhang, Hanqi; Gu, Fanbin; Jin, Xiangqun

    2016-12-01

    Salting-out homogenous extraction followed by ionic liquid/ionic liquid dispersive liquid-liquid micro-extraction system was developed and applied to the extraction of sulfonamides in blood. High-performance liquid chromatography was applied to the determination of the analytes. The blood sample was centrifuged to obtain the serum. After the proteins in the serum were removed in the presence of acetonitrile, ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, dipotassium hydrogen phosphate, ionic liquid 1-Hexyl-3-methylimidazolium hexafluorophosphate were added into the resulting solution. After the resulting mixture was ultrasonically shaken and centrifuged, the precipitate was separated. The acetonitrile was added in the precipitate and the analytes were extracted into the acetonitrile phase. The parameters affecting the extraction efficiency, such as volume of ionic liquid, amount of dipotassium hydrogen phosphate, volume of dispersant, extraction time and temperature were investigated. The limits of detection of sulfamethizole (STZ), sulfachlorpyridazine (SCP), sulfamethoxazole (SMX) and Sulfisoxazole (SSZ) were 4.78, 3.99, 5.21 and 3.77μgL -1 , respectively. When the present method was applied to the analysis of real blood samples, the recoveries of analytes ranged from 90.0% to 113.0% and relative standard deviations were lower than 7.2%. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. A high pressure liquid chromatography method for separation of prolactin forms.

    Science.gov (United States)

    Bell, Damon A; Hoad, Kirsten; Leong, Lillian; Bakar, Juwaini Abu; Sheehan, Paul; Vasikaran, Samuel D

    2012-05-01

    Prolactin has multiple forms and macroprolactin, which is thought not to be bioavailable, can cause a raised serum prolactin concentration. Gel filtration chromatography (GFC) is currently the gold standard method for separating macroprolactin, but is labour-intensive. Polyethylene glycol (PEG) precipitation is suitable for routine use but may not always be accurate. We developed a high pressure liquid chromatography (HPLC) assay for macroprolactin measurement. Chromatography was carried out using an Agilent Zorbax GF-250 (9.4 × 250 mm, 4 μm) size exclusion column and 50 mmol/L Tris buffer with 0.15 mmol/L NaCl at pH 7.2 as mobile phase, with a flow rate of 1 mL/min. Serum or plasma was diluted 1:1 with mobile phase and filtered and 100 μL injected. Fractions of 155 μL were collected for prolactin measurement and elution profile plotted. The area under the curve of each prolactin peak was calculated to quantify each prolactin form, and compared with GFC. Clear separation of monomeric-, big- and macroprolactin forms was achieved. Quantification was comparable to GFC and precision was acceptable. Total time from injection to collection of the final fraction was 16 min. We have developed an HPLC method for quantification of macroprolactin, which is rapid and easy to perform and therefore can be used for routine measurement.

  9. Enhanced fluidity liquid chromatography of inulin fructans using ternary solvent strength and selectivity gradients.

    Science.gov (United States)

    Bennett, Raffeal; Olesik, Susan V

    2018-01-25

    The value of exploring selectivity and solvent strength ternary gradients in enhanced fluidity liquid chromatography (EFLC) is demonstrated for the separation of inulin-type fructans from chicory. Commercial binary pump systems for supercritical fluid chromatography only allow for the implementation of ternary solvent strength gradients which can be restrictive for the separation of polar polymeric analytes. In this work, a custom system was designed to extend the capability of EFLC to allow tuning of selectivity or solvent strength in ternary gradients. Gradient profiles were evaluated using the Berridge function (RF 1 ), normalized resolution product (NRP), and gradient peak capacity (P c ). Selectivity gradients provided the separation of more analytes over time. The RF 1 function showed favor to selectivity gradients with comparable P c to that of solvent strength gradients. NRP did not strongly correlate with P c or RF 1 score. EFLC with the hydrophilic interaction chromatography, HILIC, separation mode was successfully employed to separate up to 47 fructan analytes in less than 25 min using a selectivity gradient. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Simultaneous determination of ramipril, ramiprilat and telmisartan in human plasma using liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Gupta, V K; Jain, Rajeev; Lukram, Ojitkumar; Agarwal, Shilpi; Dwivedi, Ashish

    2011-01-15

    A rapid and sensitive liquid chromatography tandem mass spectrometry method has been developed and validated for the simultaneous determination of ramipril, ramiprilat and telmisartan in human plasma. The solid-phase extraction technique was used for the extraction of ramipril, ramiprilat and telmisartan from human plasma. Trandolaprilat and hydrochlorothiazide were used as the internal standards (ISs). Chromatography was performed on a Hypurity C18, 5 μm, 50 mm × 4.6mm column, with the mobile phase consisting of ammonium acetate and acetonitrile (in a 20:80 ratio), followed by detection using mass spectrometry. The method involves a simple reversed isocratic chromatography condition and mass spectrometry detection, which enables detection at sub-nanogram levels. The method was validated and the lower limit of quantification for ramipril, ramiprilat and telmisartan was found to be 0.1 ng mL(-1), 0.1 ng mL(-1) and 2 ng mL(-1), respectively. The mean recovery for ramipril, ramiprilat and telmisartan ranged from 90.1 to 104.1%. This method increased the sensitivity and selectivity; resulting in high-throughput analysis of ramipril, ramiprilat and telmisartan using two different ISs in a single experiment for bioequivalence studies, with a chromatographic run time of 1.5 min only. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. State-of-the art of selective detection and identification of I-, Br-, Cl-, and F-containing compounds in gas chromatography and liquid chromatography.

    Science.gov (United States)

    Brede, Cato; Pedersen-Bjergaard, Stig

    2004-09-24

    This review article presents an overview of halogen-specific detection in gas chromatography (GC) and liquid chromatography (LC). Attention is primarily focused on the use of plasma emission spectroscopy and plasma mass spectrometry as detectors, but other halogen-selective detection principles are also mentioned. Different instrumental configurations are discussed both with respect to technical set-up and performance, the principal reasons for halogen-selective detection are highlighted, and recent applications are reviewed from areas such as environmental chemistry, petroleum characterization, and drug analysis.

  12. Development and application of liquid chromatography coupled to isotope ratio mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lijun

    2014-02-19

    Stable isotope analysis has found widespread applications in various disciplines such as archaeology, geochemistry, biology, food authenticity, and forensic science. Coupling chromatography to isotope ratio mass spectrometry for compound-specific isotope analysis (CSIA) is a trend, as it provides several advantages over bulk isotope analysis, e.g., relatively simple sample preparation, the ability to measure individual compounds in a complex mixture in one run, and the reduced sample size required for precise isotope analysis. Gas chromatography coupled to isotope ratio mass spectrometry (GC/IRMS) has been well-established for compound-specific isotope analysis of volatile organic compounds within the last two decades. However, an interface combining liquid chromatography with isotope ratio mass spectrometry (LC/IRMS) was not commercially available until 2004. The current design of the interface requires using a carbon-free eluent in chromatographic separation. This requirement limits the application of the most frequently used reversed-phase liquid chromatography in CSIA, because the elution strength of water at room temperature is too low to serve as mobile phase in reversed-phase separations. In order to increase the elution strength of water, we propose using high temperature water for chromatographic elution. The polarity of water decreases with an increase of temperature, yielding increased elution strength in reversed-phase columns. Therefore, high temperature water can be used as eluent instead of organic solvent for combining reversed-phase liquid chromatography with isotope ratio mass spectrometry (RPLC/IRMS). Additionally, temperature gradients can replace organic solvent gradients to increase chromatographic resolution. This is very important for LC/IRMS analysis, as precise isotope analysis requires baseline separation of analytes. In this thesis, high-temperature reversed-phase liquid chromatography was coupled to, and for the first time carefully

  13. Development and application of liquid chromatography coupled to isotope ratio mass spectrometry

    International Nuclear Information System (INIS)

    Zhang, Lijun

    2014-01-01

    Stable isotope analysis has found widespread applications in various disciplines such as archaeology, geochemistry, biology, food authenticity, and forensic science. Coupling chromatography to isotope ratio mass spectrometry for compound-specific isotope analysis (CSIA) is a trend, as it provides several advantages over bulk isotope analysis, e.g., relatively simple sample preparation, the ability to measure individual compounds in a complex mixture in one run, and the reduced sample size required for precise isotope analysis. Gas chromatography coupled to isotope ratio mass spectrometry (GC/IRMS) has been well-established for compound-specific isotope analysis of volatile organic compounds within the last two decades. However, an interface combining liquid chromatography with isotope ratio mass spectrometry (LC/IRMS) was not commercially available until 2004. The current design of the interface requires using a carbon-free eluent in chromatographic separation. This requirement limits the application of the most frequently used reversed-phase liquid chromatography in CSIA, because the elution strength of water at room temperature is too low to serve as mobile phase in reversed-phase separations. In order to increase the elution strength of water, we propose using high temperature water for chromatographic elution. The polarity of water decreases with an increase of temperature, yielding increased elution strength in reversed-phase columns. Therefore, high temperature water can be used as eluent instead of organic solvent for combining reversed-phase liquid chromatography with isotope ratio mass spectrometry (RPLC/IRMS). Additionally, temperature gradients can replace organic solvent gradients to increase chromatographic resolution. This is very important for LC/IRMS analysis, as precise isotope analysis requires baseline separation of analytes. In this thesis, high-temperature reversed-phase liquid chromatography was coupled to, and for the first time carefully

  14. Determination of thiopurine S-methyltransferase activity by hydrophilic interaction liquid chromatography hyphenated with mass spectrometry.

    Science.gov (United States)

    Pecher, Daniel; Dokupilová, Svetlana; Zelinková, Zuzana; Peppelenbosch, Maikel; Mikušová, Veronika; Mikuš, Peter

    2017-08-05

    Thiopurine S-methyltransferase (TPMT) plays an important role in the metabolism of thiopurines used in the therapy of inflammatory bowel diseases (IBD). In this work a new progressive method for the determination of TPMT activity in red blood cells lysates was developed. Analysis was carried out by means of hydrophilic interaction liquid chromatography (HILIC) hyphenated with mass spectrometry (MS). In comparison with reversed-phase high-performance liquid chromatography (RP-HPLC), that has been typically applied in determination of TPMT activity, the HILIC significantly improved the analytical signal provided by MS, shortened analysis time, and improved chromatographic resolution. The HILIC-HPLC-MS method was optimized and validated, providing favorable parameters of detection and quantitation limits (5.5 and 16.5pmol/mL, respectively), linearity (coefficient of determination 0.9999 in the range of 0.01-1.0nmol/mL), recovery and precision (93.25-100.37% with RSD 1.06-1.32% in the whole concentration range of QC samples). Moreover, in contrast to the conventional RP-HPLC-UV approach, the complex phenotype TPMT profiles can be reliably and without interferences monitored using the HILIC-HPLC-MS method. Such advanced monitoring can provide valuable detail information on the thiopurines (e.g. evaluating ratio of methylated and non-methylated 6-mercaptopurine) and, by that, TPMT action in biological systems before and during the therapy of IBD. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. DETECTION AND QUANTIFICATION OF PHYTOCHEMICAL MARKERS OF Ilex paraguariensis BY LIQUID CHROMATOGRAPHY

    Directory of Open Access Journals (Sweden)

    Rodrigo M. C. Pinto

    2015-11-01

    Full Text Available Ilex paraguariensis (yerba-mate is used as a beverage, and its extract requires adequate quality control methods in order to guarantee quality and safe use. Strategies to develop and optimize a chromatographic method to quantify theobromine, caffeine, and chlorogenic acid in I. paraguariensis extracts were evaluated by applying a quality by design (QbD model and ultra high-performance liquid chromatography (UHPLC. The presence of these three phytochemical markers in the extracts was evaluated using UHPLC-MS and was confirmed by the chromatographic bands in the total ion current traces (m/z of 181.1 [M+H]+, 195.0 [M+H]+, and 353.0 [M−H]−, respectively. The developed method was then transferred to a high-performance liquid chromatography (HPLC platform, and the three phytochemical markers were used as external standards in the validation of a method for analyses of these compounds in extracts using a diode array detector (DAD. The validated method was applied to quantify the chlorogenic acid, caffeine, and theobromine in the samples. HPLC-DAD chromatographic fingerprinting was also used in a multivariate approach to process the entire data and to separate the I. paraguariensis extracts into two groups. The developed method is very useful for qualifying and quantifying I. paraguariensis extracts.

  16. Core-shell microspheres with porous nanostructured shells for liquid chromatography.

    Science.gov (United States)

    Ahmed, Adham; Skinley, Kevin; Herodotou, Stephanie; Zhang, Haifei

    2018-01-01

    The development of new stationary phases has been the key aspect for fast and efficient high-performance liquid chromatography separation with relatively low backpressure. Core-shell particles, with a solid core and porous shell, have been extensively investigated and commercially manufactured in the last decade. The excellent performance of core-shell particles columns has been recorded for a wide range of analytes, covering small and large molecules, neutral and ionic (acidic and basic), biomolecules and metabolites. In this review, we first introduce the advance and advantages of core-shell particles (or more widely known as superficially porous particles) against non-porous particles and fully porous particles. This is followed by the detailed description of various methods used to fabricate core-shell particles. We then discuss the applications of common silica core-shell particles (mostly commercially manufactured), spheres-on-sphere particles and core-shell particles with a non-silica shell. This review concludes with a summary and perspective on the development of stationary phase materials for high-performance liquid chromatography applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Analysis of glyphosate residues in cereals using liquid chromatography-mass spectrometry (LC-MS/MS)

    DEFF Research Database (Denmark)

    Granby, Kit; Johannesen, S.; Gabrielsen, Martin Vahl

    2003-01-01

    A fast and specific method for the determination of glyphosate in cereals is described. The method is based on extraction with water by ultrasonication. The samples are cleaned up and separated by high-performance liquid chromatography on a polystyrene-based reverse-phase column (clean-up) in ser......A fast and specific method for the determination of glyphosate in cereals is described. The method is based on extraction with water by ultrasonication. The samples are cleaned up and separated by high-performance liquid chromatography on a polystyrene-based reverse-phase column (clean...... monitored m/z 168--> 150 (glyphosate) and 170-->152 (internal standard 2- 13 (CN)-N-15-glyphosate) for quantification. The mean recovery was 85% ( n =32) at spiking levels from 0.03 to 0.33 mg kg(-1) . From 1998 to 2001, from the analysis of about 50 samples per annum, a reduction in the glyphosate residues...... was observed owing to a Danish trade decision not to use grain with glyphosate residues for milling or bread production....

  18. [Rapid determination of 8 urinary carbamate pesticides by liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Liu, Hualiang; Wang, Yuan; Zhu, Baoli

    2015-11-01

    To establish a method for simultaneously determining the urinary concentrations of 8 carbamate pesticides. After being purified by acetonitrile precipitation, urine samples were transferred to a liquid chromatography-tandem mass spectrometry system, and the concentrations of 8 carbamate pesticides were determined by external standard method. A C18 column was used for ultra-high-performance liquid chromatography; methanol/ammonium acetate solution was used as the mobile phase for gradient elution; the mass spectrometer was operated in a multi-reaction monitoring mode. The calibration curves were linear when the urinary concentrations of these carbamate pesticides were 20~800 µg/L, and the recovery rates were 61.0%~121% at spiked levels of 20, 200 and 800 µg/L, with a relative standard deviation of 1.7%~5.5%. This determination method meets the Guide for establishing occupational health standards-part 5: Determination methods of chemicals in biological materials, and can be used for simultaneous determination of 8 carbamate pesticides in the urine of poisoning patients.

  19. High-throughput, Highly Sensitive Analyses of Bacterial Morphogenesis Using Ultra Performance Liquid Chromatography*

    Science.gov (United States)

    Desmarais, Samantha M.; Tropini, Carolina; Miguel, Amanda; Cava, Felipe; Monds, Russell D.; de Pedro, Miguel A.; Huang, Kerwyn Casey

    2015-01-01

    The bacterial cell wall is a network of glycan strands cross-linked by short peptides (peptidoglycan); it is responsible for the mechanical integrity of the cell and shape determination. Liquid chromatography can be used to measure the abundance of the muropeptide subunits composing the cell wall. Characteristics such as the degree of cross-linking and average glycan strand length are known to vary across species. However, a systematic comparison among strains of a given species has yet to be undertaken, making it difficult to assess the origins of variability in peptidoglycan composition. We present a protocol for muropeptide analysis using ultra performance liquid chromatography (UPLC) and demonstrate that UPLC achieves resolution comparable with that of HPLC while requiring orders of magnitude less injection volume and a fraction of the elution time. We also developed a software platform to automate the identification and quantification of chromatographic peaks, which we demonstrate has improved accuracy relative to other software. This combined experimental and computational methodology revealed that peptidoglycan composition was approximately maintained across strains from three Gram-negative species despite taxonomical and morphological differences. Peptidoglycan composition and density were maintained after we systematically altered cell size in Escherichia coli using the antibiotic A22, indicating that cell shape is largely decoupled from the biochemistry of peptidoglycan synthesis. High-throughput, sensitive UPLC combined with our automated software for chromatographic analysis will accelerate the discovery of peptidoglycan composition and the molecular mechanisms of cell wall structure determination. PMID:26468288

  20. Determination of Urine Albumin by New Simple High-Performance Liquid Chromatography Method.

    Science.gov (United States)

    Klapkova, Eva; Fortova, Magdalena; Prusa, Richard; Moravcova, Libuse; Kotaska, Karel

    2016-11-01

    A simple high-performance liquid chromatography (HPLC) method was developed for the determination of albumin in patients' urine samples without coeluting proteins and was compared with the immunoturbidimetric determination of albumin. Urine albumin is important biomarker in diabetic patients, but part of it is immuno-nonreactive. Albumin was determined by high-performance liquid chromatography (HPLC), UV detection at 280 nm, Zorbax 300SB-C3 column. Immunoturbidimetric analysis was performed using commercial kit on automatic biochemistry analyzer COBAS INTEGRA ® 400, Roche Diagnostics GmbH, Manheim, Germany. The HLPC method was fully validated. No significant interference with other proteins (transferrin, α-1-acid glycoprotein, α-1-antichymotrypsin, antitrypsin, hemopexin) was found. The results from 301 urine samples were compared with immunochemical determination. We found a statistically significant difference between these methods (P = 0.0001, Mann-Whitney test). New simple HPLC method was developed for the determination of urine albumin without coeluting proteins. Our data indicate that the HPLC method is highly specific and more sensitive than immunoturbidimetry. © 2016 Wiley Periodicals, Inc.