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Sample records for chromatography electrospray mass

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

    NARCIS (Netherlands)

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

    1999-01-01

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

  2. 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.

  3. 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,

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    A tiered approach is proposed for the discovery of unknown anionic and nonionic polyfluorinated alkyl surfactants (PFASs) by reversed phase ultra high performance liquid chromatography (UHPLC) – negative electrospray ionisation – quadrupole time of flight mass spectrometry (UHPLC–ESI−–QTOF–MS). T......A tiered approach is proposed for the discovery of unknown anionic and nonionic polyfluorinated alkyl surfactants (PFASs) by reversed phase ultra high performance liquid chromatography (UHPLC) – negative electrospray ionisation – quadrupole time of flight mass spectrometry (UHPLC...... such as [M−H+solvent]− and [(M−H)(M−H+Na)n]− were used to confirm the identity of the precursor ions. In relation to quantification of PFASs, we discuss how their surfactancy influence the ESI processes, challenge their handling in solution and choices of precursor-to-product ions for MSMS of e...

  5. Determination of clarithromycin in human plasma by liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Jiang, Yao; Wang, Jiang; Li, Hao; Wang, Yingwu; Gu, Jingkai

    2007-03-12

    A rapid and sensitive method has been developed for the determination of clarithromycin in human plasma with liquid chromatography-tandem mass spectrometry. Clarithromycin and the internal standard, telmisartan were precipitated from the matrix (50 microl) with 200 microl acetonitrile and separated by HPLC using formic acid:10 mM ammonium acetate:methanol (1:99:400, v/v/v) as the mobile phase. The assay based on detection by electrospray positive ionization mass spectrometry in the multiple-reaction monitoring mode was finished within 2.4 min. Linearity was over the concentration range 10-5000 ng/ml with a limit of detection of 0.50 ng/ml. Intra- and inter-day precision measured as relative standard deviation were bioequivalence study of two tablet formulations of clarithromycin.

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

    NARCIS (Netherlands)

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

    2006-01-01

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

  7. Separation and characterisation of five polar herbicides using countercurrent chromatography with detection by negative ion electrospray ionisation mass spectrometry.

    Science.gov (United States)

    Kidwell, H; Jones, J J; Games, D E

    2001-01-01

    Five polar herbicides were separated and characterised using high-speed analytical countercurrent chromatography (HSACCC) in conjunction with online electrospray mass spectrometry (ESI-MS). The countercurrent chromatography used a standard isocratic biphasic solvent system of hexane/ethyl acetate/methanol/water in reverse phase to effect the separation of these five environmentally important compounds. The chromatograph was coupled to a triple quadrupole mass spectrometer via a standard electrospray liquid chromatography interface that was able to give mass spectra in negative ion mode of each compound. Limits of detection are reported for this series of compounds along with representative negative ion ESI-MS data and calibrations for the separation. Copyright 2001 John Wiley & Sons, Ltd.

  8. Determination of strychnine and brucine in rat plasma using liquid chromatography electrospray ionization mass spectrometry.

    Science.gov (United States)

    Xu, Yanyan; Si, Duanyun; Liu, Changxiao

    2009-02-20

    A simple, sensitive and selective liquid chromatography-electrospray mass spectrometric (LC-ESI-MS) method was developed and validated for simultaneous determination of strychnine and brucine in rat plasma, using tacrine as the internal standard (IS). Sample preparation involved a liquid-liquid extraction of the analytes with n-hexane, dichloromethane and isopropanol (65:30:5, v/v/v) from 0.1mL of plasma. Chromatographic separation was carried out on a Waters C(18) column using a mobile phase of methanol-20mM ammonium formate-formic acid (32:68:0.68, v/v/v). Positive selected ion monitoring mode was used for detection of strychnine, brucine and the IS at m/z 335.2, m/z 395.2 and m/z 199.2, respectively. Linearity was obtained over the concentration range of 0.5-500ng/mL for strychnine and 0.1-100ng/mL for brucine. The lower limit of quantification was 0.5ng/mL and 0.1ng/mL for strychnine and brucine, respectively. The intra- and inter-day precision for both strychnine and brucine was less than 7.74%, and accuracy ranged from -4.38% to 2.21% at all QC levels. The method has been successfully applied to a pharmacokinetic study of processed Semen Strychni after oral administration to rats.

  9. Determination of pyrrolizidine alkaloids in comfrey by liquid chromatography-electrospray ionization mass spectrometry.

    Science.gov (United States)

    Liu, Feng; Wan, Sow Yin; Jiang, Zhangjian; Li, Sam Fong Yau; Ong, Eng Shi; Osorio, Jhon Carlos Castaño

    2009-12-15

    Symphytum officinale L. (comfrey) is a medicinal plant commonly used in decoctions and aliments. Besides therapeutic bioactive compounds present in the herb, it is found to contain hepatotoxic pyrrolizidine alkaloids (PAs), such as lycopsamine and others. In the present study, PAs such as lycopsamine, echimidine and lasiocarpine were determined using electrospray liquid chromatography-mass spectrometry (LC-MS) with the method precision (relative standard deviation, RSD) comfrey followed by the comparison with heating under reflux with the RSD ranging from 2.49% to 19.32%. Our results showed a higher extraction efficiency for heating under reflux compared with PHWE. It was proposed that the lower extraction efficiency for PHWE was attributable to dissolved nitrogen from air which caused the reduction in the solubility of lycopsamine in the compressed hot solvent. In this study, quantitative analysis of PAs in comfrey was demonstrated. In addition, it was found that the use of subcritical water for extractions depended on the physical properties of the dissolved solutes and their tendency to degrade under the chosen extraction conditions.

  10. METHOD 332.0: DETERMINATION OF PERCHLORATE IN DRINKING WATER BY ION CHROMATOGRAPHY WITH SUPPRESSED CONDUCTIVITY AND ELECTROSPRAY IONIZATION MASS SPECTROMETRY

    Science.gov (United States)

    This method is applicable to the identification and quantitation of perchlorate in raw and finished drinking waters. The approach used is ion chromatography with suppressed conductivity and electrospray ionization mass spectrometry (IC-ESI/MS)

  11. Identification and Quantification of Glucosinolates in Kimchi by Liquid Chromatography-Electrospray Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Ho Jin Kim

    2017-01-01

    Full Text Available A novel and simple method for detecting five glucosinolates (glucoalyssin, gluconapin, glucobrassicanapin, glucobrassicin, and 4-methoxyglucobrassicin in kimchi was developed using liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS. The chromatographic peaks of the five glucosinolates were successfully identified by comparing their retention times, mass spectra. The mobile phase was composed of A (acetonitrile and B (water. As for glucosinolate, the relative quantities were found through sinigrin, and five different compounds that have not been previously discovered in kimchi were observed. Monitoring was carried out on the glucosinolate in 20 kimchis distributed in markets, and this study examined the various quality and quantity compositions of the five components. The glucoalyssin content ranged from 0.00 to 7.07 μmol/g of day weight (DW, with an average content of 0.86 μmol/g of DW, whereas the gluconapin content ranged from 0.00 to 5.85 μmol/g of DW, with an average of 1.17 μmol/g of DW. The content of glucobrassicanapin varied between 0.00 and 11.87 μmol/g of DW (average = 3.03 μmol/g of DW, whereas that of glucobrassicin varied between 0.00 and 0.42 μmol/g of DW (average = 0.06 μmol/g of DW. The 4-methoxyglucobrassicin content ranged from 0.12 to 9.36 μmol/g of DW (average = 3.52 μmol/g of DW. A comparison of the contents revealed that, in most cases, the content of 4-methoxyglucobrassicin was the highest.

  12. Ion-exchange chromatography/electrospray mass spectrometry for the identification of organic and inorganic species in topiramate tablets.

    Science.gov (United States)

    Xiang, X; Ko, C Y; Guh, H Y

    1996-11-01

    An ion-exchange chromatograph/electrospray ionization mass spectrometer (IC/ESI-MS) was used successfully to identify organic and inorganic species present in topiramate tablets. An ion suppressor is placed between the column and detectors to replace sodium ions in the mobile phase with hydrogen ions supplied by the suppressor. The ensuing combination of the hydrogen ions with the mobile phase hydroxide ions produces water and thus allows simultaneous ion detection by an ion conductivity detector and a mass spectrometer. Analytes, including lactate, glycolate, chloride, formate, sulfate, and oxalate, were unambiguously identified by matching the mass spectra and retention times with those of the authentic compounds. Due to its capability of detecting positive and negative as well as neutral species, ESI-MS provides valuable information which is not available with ion conductivity detection alone. Though the coupling of ion-exchange chromatography to mass spectrometry has been reported previously, this is the first demonstration of IC/ESI-MS for the identification of unknown species in real samples. Finally, with the use of deuterium/carbon-13 labeling and MS/MS techniques, we have confirmed that oxalic acid (HOOC-COOH) is formed from formic acid (HCOOH) at the electrospray interface in the presence of the electric field. This observation not only confirms the identity of an unknown peak, but it also provides new insight into chemistry that can take place during electrospray ionization.

  13. Comparison of three buffer solutions for amino acid derivatization and following analysis by liquid chromatography electrospray mass spectrometry.

    Science.gov (United States)

    Rebane, Riin; Herodes, Koit

    2012-07-06

    For reversed phase separation amino acids are usually derivatized. Several derivatization reactions are carried out at basic pH. In the present work, influence of three basic buffer solutions on liquid chromatography electrospray ionization mass-spectrometric (LC-ESI-MS) analysis of amino acid derivatives was studied. Borate buffer--the most common derivatization buffer--was found to influence ESI ionization up to 23 min retention time. For 9-fluorenylmethylmethoxycarbonyl chloride (Fmoc-Cl derivatization) carbonate buffer should be preferred as it provides higher responses. Hexafluoroisopropanol (HFIP) buffer improves chromatographic peak shapes and responses for diethyl ethoxymethylenemalonate (DEEMM) derivatives. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Quantitative profiling method for oxylipin metabolome by liquid chromatography electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Yang, Jun; Schmelzer, Kara; Georgi, Katrin; Hammock, Bruce D

    2009-10-01

    Cyclooxygenase, lipoxygenase, and epoxygenase derived oxylipins, especially eicosanoids, play important roles in many physiological processes. Assessment of oxidized fatty acid levels is important for understanding their homeostatic and pathophysiological roles. Most reported methods examine these pathways in isolation. The work described here employed a solid phase extraction-liquid chromatography-electrospray ionization MS/MS (SPE-LC-ESI MS/MS) method to monitor these metabolites. In 21 min, 39 oxylipins were quantified along with eight corresponding internal standards. The limits of quantification were between 0.07 and 32 pg (20 pM-10 nM). Finally, the validated method was used to evaluate oxylipin profiles in lipopolysaccharide-exposed mice, an established septic inflammatory model. The method described here offers a useful tool for the evaluation of complex regulatory oxylipin responses in in vitro or in vivo studies.

  15. 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

  16. Quantification of cow milk adulteration in goat milk using high-performance liquid chromatography with electrospray ionization mass spectrometry.

    Science.gov (United States)

    Chen, Ren-Kun; Chang, Li-Wen; Chung, Ya-Yun; Lee, Ming-Hsung; Ling, Yong-Chien

    2004-01-01

    A method was developed for the quantification of cow milk adulteration in goat milk, based on solvent separation of whey proteins followed by high-performance liquid chromatography with electrospray ionization mass spectrometry (HPLC/ESI-MS). The presence of cow milk was determined using beta-lactoglobulin whey protein as the molecular marker. The adulterants were identified using both retention time and molecular mass derived from multiply charged molecular ions. Standard solutions containing cow and goat milk in different volume ratios were prepared and analyzed. Good linearity covering cow milk content from 5% and above was obtained. The proposed method identifies the adulterants using accurate molecular masses for protein identification and detects the addition of cow milk to goat milk at levels as low as 5%. Copyright 2004 John Wiley & Sons, Ltd.

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

    OpenAIRE

    Owis, Asmaa Ibrahim; El-Naggar, El-Motaz Bellah

    2016-01-01

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

  18. Preparation and structural elucidation of the picolinyl ester of aldosterone for liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Yamashita, Kouwa; Tadokoro, Yumiko; Takahashi, Madoka; Numazawa, Mitsuteru

    2008-06-01

    Treatment of aldosterone with 35% HCl in EtOH or in MeOH followed by the picolinyl derivatization gave the picolinyl derivative of aldosterone-ethyl ether, 8, or methyl ether, 9, as a single and well-shaped liquid chromatographic peak. Picolinyl derivatization of aldosterone produced 21-picolinyl derivative of 18,20-anhydro-hemiacetal derivatives, 6, with poor chromatographic peak with wide half-width. Further conversion of 6 to 8 required long reaction time (>4 h). Structure of each picolinyl or alkyl ether-picolinyl derivative, was carefully elucidated by nuclear magnetic resonance spectroscopy, electron ionization mass spectrometry and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Enhancement of sensitivity (approximately 10-fold) in positive-LC-ESI-MS/MS of aldosterone was confirmed by the use of the alkyl ether-picolinyl derivatization when compared to the underivatized molecule.

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

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2014-01-01

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

  20. Gas chromatography-electron ionization mass spectrometry and liquid chromatography-electrospray tandem mass spectrometry for determination of impurities in the anti-cancer drug isophosphoramide mustard

    Science.gov (United States)

    Cole, Richard B.; Chou, Chau-Wen; Boué, Stephen M.; Leblanc, Blaise W.; Rodgers, Andrew H.; Struck, Robert F.; Morgan, Lee Roy

    2004-02-01

    Isophosphoramide mustard (IPM) is known to have substantial anti-cancer activities in various animal models. Liquid chromatography-electrospray mass spectrometry (LC-ES-MS) and LC-ES-MS/MS methodologies have been developed and applied to the analysis of synthesized preparations of IPM. Our studies reveal that the principal impurity in IPM is N-(2-chloroethyl)-N'-ethylphosphorodiamidic acid (MC-IPM) formed by dehydrochlorination of IPM with subsequent hydrogenation during synthesis. This impurity is present at levels in the range of 2-5% depending upon synthesis conditions. In addition, a second IPM derivative has been characterized by LC-ES-MS/MS and has been shown to be the product of a reaction of IPM with the dilute perchloric acid mobile phase used for liquid chromatography separations. The LC-ES-MS/MS method has been successfully employed to detect IPM spiked into a blood plasma sample. This work establishes that LC-ES-MS/MS is a viable tool for the detailed characterization of IPM and related products.

  1. An improved thin-layer chromatography/mass spectrometry coupling using a surface sampling probe electrospray ion trap system

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Michael J [ORNL; Van Berkel, Gary J [ORNL

    2004-01-01

    A combined surface sampling probe/electrospray emitter coupled with an ion trap mass spectrometer was used for the direct read out of unmodified reversed-phase C18 thin-layer chromatography (TLC) plates. The operation of the surface sampling electrospray ionization interface in positive and negative ionization modes was demonstrated through the direct analysis of TLC plates on which a commercial test mix comprised of four dye compounds viz., rhodamine B, fluorescein, naphthol blue black, and fast green FCF, and an extract of the caffeine-containing plant Ilex vomitoria, were spotted and developed. Acquisition of full-scan mass spectra and automated collection of MS/MS product ion spectra while scanning a development lane along the surface of a TLC plate demonstrated the advantages of using an ion trap in this combination. Details of the sampling system, benefits of analyzing a developed lane in both positive ion and negative ion modes, levels of detection while surface scanning, surface scan speed effects, and the utility of three-dimensional data display, are also discussed.

  2. Identification and quantitation of auxins in plants by liquid chromatography/electrospray ionization ion trap mass spectrometry.

    Science.gov (United States)

    Lu, Qiaomei; Zhang, Lan; Chen, Tianwen; Lu, Minghua; Ping, Tong; Chen, Guonan

    2008-08-01

    Auxin is an important phylohormone, which regulates specific physiological responses such as division, elongation and differentiation of cells. A new method using liquid chromatography/electrospray ionization ion trap mass spectrometry (LC/ESI-ITMS) has been developed for identification and quantitation of four auxins. Under the optimum conditions, four auxins (indole-3-acetic acid, indole-3-propionic acid, indole-3-butyric acid and 1-naphthylacetic acid) were completely separated and quantitated within 7 min with a minimum detection limit of 8.0 ng mL(-1) with relative standard deviations lower than 5.0%. This method also has been applied to analysis of auxins in Chinese cabbage where, even with a complicated serious background perturbation due to the natural biological matrix, the mean recoveries ranged from 77.5% to 99.8%. Finally, we discuss the MS-relevant properties of the identified auxins in detail. Copyright (c) 2008 John Wiley & Sons, Ltd.

  3. Liquid chromatography/electrospray ionization tandem mass spectrometry profiling of compounds from the infusion of Byrsonima fagifolia Niedenzu.

    Science.gov (United States)

    Sannomiya, Miriam; dos Santos, Lourdes Campaner; Carbone, Virginia; Napolitano, Assunta; Piacente, Sonia; Pizza, Cosimo; Souza-Brito, Alba R M; Vilegas, Wagner

    2007-01-01

    A rapid analytical approach suitable to achieve a comprehensive characterization of the compounds present in the infusion prepared from the leaves of Byrsonima fagifolia Niedenzu (Malpighiaceae), a Brazilian plant used as an infusion to treat gastric disorders, was developed. The method was based on high-performance liquid chromatography coupled to electrospray negative ionisation multistage ion trap mass spectrometry (HPLC/ESI-ITMSn). The main ions in the ESI-ITMS spectra were attributed to a quinic acid core containing from one to five galloyl units. Quercetin derivatives containing one and two sugar moieties as well as galloyl esterification were also detected. These results indicated that HPLC/ESI-ITMSn is easily applicable to infusions of this plant and allows the rapid and direct identification of these compounds in crude plant extracts. Copyright (c) 2007 John Wiley & Sons, Ltd.

  4. Determination of trinexapac in wheat by liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Hiemstra, Maurice; de Kok, André

    2003-09-24

    A quantitative and confirmatory method for the analysis of trinexapac (free acid metabolite of trinexapac-ethyl) in wheat is described. Residues were extracted from wheat with acetonitrile in aqueous phosphate buffer (pH 7) overnight. The extract was directly injected into the HPLC system. Chromatographic separation was achieved on an octadecylsilica column, and detection was performed by negative ion electrospray ionization tandem mass spectrometry. The precursor ion of trinexapac [M - H](-) at m/z 223 was subjected to collisional fragmentation with argon to yield two intense diagnostic product ions at m/z 135 and 179, respectively. Accuracy and specificity for routine analysis of trinexapac were demonstrated. The validated concentration range was 10-200 microg/kg based on a 0.10 g/mL wheat sample extract. Recoveries were within the range of 71-94%, with associated relative standard deviations better than 10%. The limit of detection for trinexapac in wheat was estimated at 5 microg/kg. The method has been applied to a survey of 100 samples of wheat. In 46% of the samples analyzed, a quantifiable amount of trinexapac was detected, ranging from 10 to 110 microg/kg. It has been demonstrated that analyses of trinexapac accurately reflect the total amount of residues of the plant growth regulator, trinexapac-ethyl, in the wheat samples following field application. No residues of the parent compound, trinexapac-ethyl, in wheat were detected.

  5. Liquid chromatography/electrospray ionisation tandem mass spectrometric study of sitagliptin and its stressed degradation products.

    Science.gov (United States)

    Vishnuvardhan, C; Radhakrishnanand, P; Navalgund, S G; Satheeshkumar, N

    2014-12-01

    A sensitive UPLC positive ion electrospray tandem mass spectrometry method was developed and validated for identification of degradation products of sitagliptin formed during stress study. Six of the major degradants were identi-fied with the proposed method. The separation of sitagliptin and its degradation products was achieved on a Acquity BEH C-18 column (50×2.1 mm, 1.7 µm) using a gradient programme. The mobile phase consists of solvent A (10 mM ammonium formate, pH 6.4 adjusted with formic acid) and solvent B (acetonitrile) and quantitative evaluation was performed at 267 nm with a flow rate of 0.15 mL min(-1). Suitability of this method for the quantitative determination of the drugs was proved by validation in accordance with International Conference on Harmonization (ICH) guidelines and can be used for routine analysis of sitagliptin formulations in quality control. © Georg Thieme Verlag KG Stuttgart · New York.

  6. Synthesis of pyridine-carboxylate derivatives of hydroxysteroids for liquid chromatography-electrospray ionization-mass spectrometry.

    Science.gov (United States)

    Yamashita, Kouwa; Kobayashi, Sayuri; Tsukamoto, Satoshi; Numazawa, Mitsuteru

    2007-01-01

    Synthesis and liquid chromatography-electrospray ionization-mass spectrometric (LC-ESI-MS) behaviors of the picolinoyl, 6-methylpicolinoyl, nicotinoyl, 2-methoxynicotinoyl and isonicotinoyl derivatives of the hydroxysteroids estrone, estradiol, 3beta-hydroxyandrost-5-en-17-one (dehydroepiandrosterone) and testosterone in positive mode were investigated. Each steroid was converted to the corresponding pyridine-carboxylate derivative by the acyl chloride method or the mixed anhydride method using the corresponding free acids and 2-methyl-6-nitrobenzoic anhydride; in each case, the latter method principally gave a better yield. The pyridine-carboxylate derivative of each steroid exhibited a clear single peak in liquid chromatography with a reversed phase column and CH(3)CN-0.1% CH(3)COOH as a mobile phase. The positive-ESI-mass spectra of the picolinoyl, 6-methylpicolinoyl and 2-methoxynicotinoyl derivatives showed a predominance of [M+H](+), whereas [M+H+CH(3)CN](+) was observed with high intensity in the nicotinoyl and isonicotinoyl derivatives. Even in the case of estradiol, with its two hydroxyl groups, a single charged ion of [M+H](+) or [M+H+CH(3)CN](+) was observed in the positive-ESI-mass spectrum of each derivative. The results revealed that picolinoyl derivatization is a simple and versatile method suitable for the sensitive and specific determination of hydroxysteroids by LC-ESI-MS (selected reaction monitoring).

  7. Characterisation of chemical components for identifying historical Chinese textile dyes by ultra high performance liquid chromatography – photodiode array – electrospray ionisation mass spectrometer

    NARCIS (Netherlands)

    Han, J.; Wanrooij, J.; van Bommel, M.; Quye, A.

    2017-01-01

    This research makes the first attempt to apply Ultra High Performance Liquid Chromatography (UHPLC) coupled to both Photodiode Array detection (PDA) and Electrospray Ionisation Mass Spectrometer (ESI–MS) to the chemical characterisation of common textile dyes in ancient China. Three different

  8. Quantitative Thin-Layer Chromatography/Mass Spectrometry Analysis of Caffeine Using a Surface Sampling Probe Electrospray Ionization Tandem Mass Spectrometry System

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Michael J [ORNL; Deibel, Michael A. [Earlham College; Tomkins, Bruce A [ORNL; Van Berkel, Gary J [ORNL

    2005-01-01

    Quantitative determination of caffeine on reversed-phase C8 thin-layer chromatography plates using a surface sampling electrospray ionization system with tandem mass spectrometry detection is reported. The thin-layer chromatography/electrospray tandem mass spectrometry method employed a deuterium-labeled caffeine internal standard and selected reaction monitoring detection. Up to nine parallel caffeine bands on a single plate were sampled in a single surface scanning experiment requiring 35 min at a surface scan rate of 44 {mu}m/s. A reversed-phase HPLC/UV caffeine assay was developed in parallel to assess the mass spectrometry method performance. Limits of detection for the HPLC/UV and thin-layer chromatography/electrospray tandem mass spectrometry methods determined from the calibration curve statistics were 0.20 ng injected (0.50 {mu}L) and 1.0 ng spotted on the plate, respectively. Spike recoveries with standards and real samples ranged between 97 and 106% for both methods. The caffeine content of three diet soft drinks (Diet Coke, Diet Cherry Coke, Diet Pepsi) and three diet sport drinks (Diet Turbo Tea, Speed Stack Grape, Speed Stack Fruit Punch) was measured. The HPLC/UV and mass spectrometry determinations were in general agreement, and these values were consistent with the quoted values for two of the three diet colas. In the case of Diet Cherry Coke and the diet sports drinks, the determined caffeine amounts using both methods were consistently higher (by 8% or more) than the literature values.

  9. Analysis of perchlorate, thiocyanate, nitrate and iodide in human amniotic fluid using ion chromatography and electrospray tandem mass spectrometry

    International Nuclear Information System (INIS)

    Blount, Benjamin C.; Valentin-Blasini, Liza

    2006-01-01

    Because of health concerns surrounding in utero exposure to perchlorate, we developed a sensitive and selective method for quantifying iodide, as well as perchlorate and other sodium-iodide symporter (NIS) inhibitors in human amniotic fluid using ion chromatography coupled with electrospray ionization tandem mass spectrometry. Iodide and NIS inhibitors were quantified using a stable isotope-labeled internal standards (Cl 18 O 4 - , S 13 CN - and 15 NO 3 - with excellent assay accuracy of 100%, 98%, 99%, 95% for perchlorate, thiocyanate, nitrate and iodide, respectively, in triplicate analysis of spiked amniotic fluid sample). Excellent analytical precision (<5.2% RSD for all analytes) was found when amniotic fluid quality control pools were repetitively analyzed for iodide and NIS-inhibitors. Selective chromatography and tandem mass spectrometry reduced the need for sample cleanup, resulting in a rugged and rapid method capable of routinely analyzing 75 samples/day. Analytical response was linear across the physiologically relevant concentration range for the analytes. Analysis of a set of 48 amniotic fluid samples identified the range and median levels for perchlorate (0.057-0.71, 0.18 μg/L), thiocyanate (<10-5860, 89 μg/L), nitrate (650-8900, 1620 μg/L) and iodide (1.7-170, 8.1 μg/L). This selective, sensitive, and rapid method will help assess exposure of the developing fetus to low levels of NIS-inhibitors and their potential to inhibit thyroid function

  10. Simultaneous determination of water-soluble vitamins in selected food matrices by liquid chromatography/electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Gentili, Alessandra; Caretti, Fulvia; D'Ascenzo, Giuseppe; Marchese, Stefano; Perret, Daniela; Di Corcia, Daniele; Rocca, Lucia Mainero

    2008-07-01

    A rapid, simple and sensitive method based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) with an electrospray ionization (ESI) source for the simultaneous analysis of fourteen water-soluble vitamins (B1, B2, two B3 vitamers, B5, five B6 vitamers, B8, B9, B12 and C) in various food matrices, i.e. maize flour, green and golden kiwi and tomato pulp, is presented here. Analytes were separated by ion-suppression reversed-phase liquid chromatography in less than 10 min and detected in positive ion mode. Sensitivity and specificity of this method allowed two important results to be achieved: (i) limits of detection of the analytes at ng g(-1) levels (except for vitamin C); (ii) development of a rapid sample treatment that minimizes analyte exposition to light, air and heat, eliminating any step of extract concentration. Analyte recovery depended on the type of matrix. In particular, recovery of the analytes in maize flour was > or =70%, with the exception of vitamin C, pyridoxal-5'-phosphate and vitamin B9 (ca 40%); with tomato pulp, recovery was > or =64%, except for vitamin C (41%); with kiwi, recovery was > or =73%, except for nicotinamide (ca. 30%).

  11. Determination of sarin, soman and their hydrolysis products in soil by packed capillary liquid chromatography-electrospray mass spectrometry.

    Science.gov (United States)

    D'Agostino, P A; Hancock, J R; Provost, L R

    2001-04-06

    An analytical method based on aqueous ultrasonic extraction and packed capillary liquid chromatography-electrospray mass spectrometry (LC-ESI-MS) analysis was developed and compared to an existing gas chromatography(GC)-MS based method for the determination of sarin, soman and their hydrolysis products in contaminated soil. Three soils, a red clay, a tan sandy clay and a brown sandy clay loam, were spiked with sarin and soman and their initial hydrolysis products, isopropyl methylphosphonic acid and pinacolyl methylphosphonic acid, at the 10 microg/g level to assess recovery efficiency. Recovery of sarin and soman from the aqueous soil extracts was comparable to the existing analytical method, with a significant improvement in recovery being demonstrated for the chemical warfare agent hydrolysis products. Sarin and soman were recovered in the 20-90% range from the three soil types with aqueous extraction, while the hydrolysis products of these chemical warfare agents were extracted with recoveries in excess of 80%. The developed soil extraction and analysis method appears to be an attractive alternative to the GC-MS based method, since aqueous extracts containing chemical warfare agent hydrolysis products may be analysed directly, eliminating the need for additional sample handling and derivatization steps.

  12. Simultaneous analysis of strychnine and brucine and their major metabolites by liquid chromatography-electrospray ion trap mass spectrometry.

    Science.gov (United States)

    Chen, Xueguo; Lai, Yongquan; Cai, Zongwei

    2012-04-01

    A liquid chromatography-electrospray ionization-ion trap mass spectrometry (LC-ESI-ITMS) method was developed for the simultaneous analysis of strychnine, brucine and their major metabolites. Strychnine and brucine were individually incubated with rat liver S9 fraction. The incubation samples were pooled together and analyzed with LC-ESI-ITMS in positive ion and full-scan detection mode. The calibration curves of strychnine and brucine in rat liver showed good linearity in ranges of 0.020 to 8.0 µg/mL for strychnine and 0.020 to 8.5 µg/mL for brucine. The limits of detections were both 0.008 µg/mL and the recoveries were 88.3 and 83.2% for strychnine and brucine, respectively. Two metabolites were identified as strychnine N-oxide and brucine N-oxide by comparing the molecular mass, retention time, full-scan mass spectra, tandem MS and MS(3) spectra with those of strychnine and brucine. The developed method provided high sensitivity and selectivity for the determination of poisonous alkaloids and their major metabolites and can be applied in the determination of samples in forensic and clinically toxicological cases.

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

    Science.gov (United States)

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

    2016-06-10

    Reversed-phase ultrahigh-performance liquid chromatography (RP-UHPLC) method using two 15cm sub-2μm particles octadecylsilica gel columns is developed with the goal to separate and unambiguously identify a large number of lipid species in biological samples. The identification is performed by the coupling with high-resolution tandem mass spectrometry (MS/MS) using quadrupole - time-of-flight (QTOF) instrument. Electrospray ionization (ESI) full scan and tandem mass spectra are measured in both polarity modes with the mass accuracy better than 5ppm, which provides a high confidence of lipid identification. Over 400 lipid species covering 14 polar and nonpolar lipid classes from 5 lipid categories are identified in total lipid extracts of human plasma, human urine and porcine brain. The general dependences of relative retention times on relative carbon number or relative double bond number are constructed and fit with the second degree polynomial regression. The regular retention patterns in homologous lipid series provide additional identification point for UHPLC/MS lipidomic analysis, which increases the confidence of lipid identification. The reprocessing of previously published data by our and other groups measured in the RP mode and ultrahigh-performance supercritical fluid chromatography on the silica column shows more generic applicability of the polynomial regression for the description of retention behavior and the prediction of retention times. The novelty of this work is the characterization of general trends in the retention behavior of lipids within logical series with constant fatty acyl length or double bond number, which may be used as an additional criterion to increase the confidence of lipid identification. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Simultaneous determination of monosaccharides and oligosaccharides in dates using liquid chromatography-electrospray ionization mass spectrometry.

    Science.gov (United States)

    Ghfar, Ayman A; Wabaidur, Saikh M; Ahmed, A Yacine Badjah Hadj; Alothman, Zeid A; Khan, Mohammad R; Al-Shaalan, Nora H

    2015-06-01

    Ultra performance liquid chromatography coupled to mass spectrometry was used for the simultaneous separation and determination of reducing monosaccharides (fructose and glucose), a non-reducing disaccharide (sucrose) and oligosaccharides (kestose and nystose) in HILIC mode. The chromatographic separation of all saccharides was performed on a BEH amide column using an acetonitrile-water gradient elution. The detection was carried out using selected ion recording (SIR) acquisition mode. The validation of the proposed method showed that the limit of detection and limit of quantification values for the five analyzed compounds were in the range of 0.25-0.69μg/mL and 0.82-3.58μg/mL, respectively; while the response was linear in the range of 1-50μg/mL. The developed method showed potential usefulness for a rapid and sensitive analysis of underivatized saccharides and was used for determination of sugars in three date samples (Sefri, Mabroom, Ghassab) which were soxhlet extracted by ethanol. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Absolute Quantification of Choline-Related Biomarkers in Breast Cancer Biopsies by Liquid Chromatography Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Mimmi, Maria Chiara; Finato, Nicoletta; Pizzolato, Gloria; Beltrami, Carlo Alberto; Fogolari, Federico; Corazza, Alessandra; Esposito, Gennaro

    2013-01-01

    It has been repeatedly demonstrated that choline metabolism is altered in a wide variety of cancers. In breast tumours, the choline metabolite profile is characterized by an elevation of phosphocholine and total choline-compounds. This pattern is increasingly being exploited as biomarker in cancer diagnosis. The majority of in vitro metabolomics studies, for biomarkers quantification in cell cultures or tissues, entail proton NMR spectroscopy. Although many “targeted” approaches have been proposed to quantify metabolites from standard one-dimensional (1D) NMR experiments, the task is often made difficult by the high degree of overlap characterizing 1H NMR spectra of biological samples. Here we present an optimized protocol for tissue extraction and absolute quantification of choline, phosphocholine and glycerophosphocholine by means of liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS). The selected chromatographic separation system with a HILIC (hydrophilic interaction chromatography) amide column effectively separates free choline and its phopshorylated derivatives, contrary to failure observed using standard reversed-phase chromatography. The metabolite absolute quantification is based on external calibration with commercial standards, and is validated by a parallel 1D proton NMR analysis. The LC-MS/NMR analysis is applied to three breast carcinoma specimens obtained by surgical excision, each one accompanied by a control tissue sample taken outside the tumor margin. The metabolite concentrations measured are in good agreement with previous results on metabolic profile changes of breast cancer. Each of the three cancerous biopsies, when compared with the control tissue, exhibit a highly increased levels phosphocholine, total choline and phosphocholine/glycerophosphocholine ratio. PMID:24036926

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

    Science.gov (United States)

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

    2009-08-14

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

  17. Application of liquid chromatography-electrospray ionization tandem mass spectrometry to the detection of 10 sulfonamides in honey.

    Science.gov (United States)

    Verzegnassi, L; Savoy-Perroud, M C; Stadler, R H

    2002-11-15

    Liquid chromatography (LC) in combination with tandem mass spectrometry (MS-MS) has been applied to the separation and detection of 10 different sulfonamides in honey. The methodology encompasses a simple hydrolysis of the honey sample to liberate sugar-bound sulfonamides followed by liquid-liquid extraction of the 10 analytes, filtration, and analysis by LC-MS-MS. Conditions for reversed-phase LC and electrospray ionization (ESI) MS-MS in the positive ion mode were optimized for the 10 compounds under study, monitoring two characteristic mass transitions simultaneously for each analyte. The procedure is a qualitative confirmatory method for 10 sulfonamides at the low microg/kg level in honey. Typical recoveries of the analytes in honey ranged from 44 to 73% at a fortification level of 50 microg/kg. This study also addresses the issue of matrix-induced suppression of ionization, an effect often encountered in trace residue analysis of food matrices using LC-ESI-MS-MS based methods.

  18. Development of sensitive derivatization method for aldosterone in liquid chromatography-electrospray ionization tandem mass spectrometry of corticosteroids.

    Science.gov (United States)

    Yamashita, Kouwa; Okuyama, Mitsunobu; Nakagawa, Risa; Honma, Seijiro; Satoh, Fumitoshi; Morimoto, Ryo; Ito, Sadayoshi; Takahashi, Madoka; Numazawa, Mitsuteru

    2008-07-25

    A highly sensitive quantification method of aldosterone by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) was investigated in a positive mode using recently developed picolinyl derivatization. Aldosterone was smoothly and quantitatively converted to the ethyl ether-picolinyl derivative by treatment with HCl-ethanol followed by the esterification with picolinic acid in the presence of 2-methyl-6-nitrobenzoic anhydride and 4-dimethylaminopyridine. The positive ion-ESI mass spectrum of the ethyl ether-picolinyl derivative was characterized by an appearance of protonated molecule ([M+H](+)) as a base peak. The ethyl ether-picolinyl derivatization gave a successful result in a separation of aldosterone from corticosterone, dehydrocorticosterone and cortexolone, and also provided an approximately 10-fold higher ESI response in the positive-LC-ESI-MS/MS (selected reaction monitoring; SRM) when compared to that of underivatized molecule (negative mode). The limit of quantification of aldosterone by SRM using ethyl ether-picolinyl derivatization (m/z 494-->m/z 448) was 1 pg/0.2 ml serum with accuracy and precision of 92.6% and 5.6%, respectively.

  19. Highly sensitive determination of estrone and estradiol in human serum by liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Yamashita, Kouwa; Okuyama, Mitsunobu; Watanabe, Yoko; Honma, Seijiro; Kobayashi, Sayuri; Numazawa, Mitsuteru

    2007-10-01

    A highly sensitive and specific quantification method of estrone and estradiol in human serum was described based upon the use of picolinoyl derivatization and liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) in a positive mode. Estrogens were treated with picolinoyl chloride hydrochloride or picolinic acid and 2-methyl-6-nitrobenzoic anhydride followed by a solid-phase extraction with ODS cartridge. Picolinoyl derivatization proceeded quantitatively even in a microscale, and the picolinoyl esters provided simple positive ESI-mass spectra showing [M+H](+) as base peaks for these estrogens. The picolinoyl derivatives of these estrogens showed 100-fold higher detection response compared to underivatized intact molecules by LC-ESI-MS (selected reaction monitoring). Using this derivatization, estrogens spiked in the charcoal treated human serum samples were analyzed with limit of quantification (LOQ), intra-day accuracy and precision of 1.0pg/ml, 96.0% and 9.9% for estrone, and 0.5pg/ml, 84.4% and 12.8% for estradiol, respectively. Estrone and estradiol added to the crude serum samples were recovered with comparable LOQ and accuracy obtained for the charcoal treated serum samples as well.

  20. Simultaneous determination of tetrahydrocortisol, allotetrahydrocortisol and tetrahydrocortisone in human urine by liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Yamashita, Kouwa; Nakagawa, Risa; Okuyama, Mitsunobu; Honma, Seijiro; Takahashi, Madoka; Numazawa, Mitsuteru

    2008-08-01

    Simultaneous quantification method of three major metabolites of cortisone and cortisol, tetrahydrocortisol, allotetrahydrocortisol and tetrahydrocortisone by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) was investigated in a positive mode using a recently developed picolinyl derivatization. Conversion of each steroid into the corresponding picolinyl derivatives (1b, 2b or 3b) was performed by mixed anhydride method using picolinic acids and 2-methyl-6-nitrobenzoic anhydride. Derivatization proceeded smoothly to afford the corresponding 3, 21-dipicolinyl derivatives. Positive ion-ESI mass spectra of the picolinyl derivatives were dominated by an appearance of [M+H](+) as base peaks in all cases. The picolinyl derivatives provided 15 to 80-fold higher ESI response in the LC-ESI-MS/MS (selected reaction monitoring: SRM) when compared to those of underivatized molecules in a positive LC-ESI mode. The use of the picolinyl ester, solid-phase extraction, and deuterium labeled internal standards enabled the concentrations of these metabolites in human urine to be determined simultaneously by LC-ESI-MS/MS (SRM) with a small sample volume of less than 1microl urine.

  1. Simultaneous quantification of phytohormones in fermentation extracts of Botryodiplodia theobromae by liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Castillo, Grolamys; Torrecillas, Alejandro; Nogueiras, Clara; Michelena, Georgina; Sánchez-Bravo, José; Acosta, Manuel

    2014-07-01

    Fermentation broth and biomass from three strains of Botryodiplodia theobromae were characterized by high performance liquid chromatography-electrospray tandem mass spectrometry (HPLC-ESI-MS/MS) method, in order to quantify different phytohormones and to identify amino acid conjugates of jasmonic acid (JA) present in fermentation broths. A liquid-liquid extraction with ethyl acetate was used as sample preparation. The separation was carried out on a C18 reversed-phase HPLC column followed by analysis via ESI-MS/MS. The multiple reaction monitoring mode was used for quantitative measurement. For the first time, indole-3-acetic acid, indole-3-propionic acid, indole-3-butyric acid and JA were identified and quantified in the ethyl acetate extracts from the biomass, after the separation of mycelium from supernatant. The fermentation broths showed significantly higher levels of JA in relation to the other phytohormones. This is the first report of the presence of gibberellic acid, abscisic acid, salicylic acid and the cytokinins zeatin, and zeatin riboside in fermentation broths of Botryodiplodia sp. The presence of JA-serine and JA-threonine conjugates in fermentation broth was confirmed using HPLC-ESI tandem mass spectrometry in negative ionization mode, while the occurrence of JA-glycine and JA-isoleucine conjugates was evidenced with the same technique but with positive ionization. The results demonstrated that the used HPLC-ESI-MS/MS method was effective for analysing phytohormones in fermentation samples.

  2. Comparison of negative and positive ion electrospray tandem mass spectrometry for the liquid chromatography tandem mass spectrometry analysis of oxidized deoxynucleosides.

    Science.gov (United States)

    Hua, Y; Wainhaus, S B; Yang, Y; Shen, L; Xiong, Y; Xu, X; Zhang, F; Bolton, J L; van Breemen, R B

    2001-01-01

    Oxidized deoxynucleosides are widely used as biomarkers for DNA oxidation and oxidative stress assessment. Although gas chromatography mass spectrometry is widely used for the measurement of multiple DNA lesions, this approach requires complex sample preparation contributing to possible artifactual oxidation. To address these issues, a high performance liquid chromatography (HPLC)-tandem mass spectrometric (LC-MS/MS) method was developed to measure 8-hydroxy-2'-deoxyguanosine (8-OH-dG), 8-hydroxy-2'-deoxyadenosine (8-OH-dA), 2-hydroxy-2'-deoxyadenosine (2-OH-dA), thymidine glycol (TG), and 5-hydroxy-methyl-2'-deoxyuridine (HMDU) in DNA samples with fast sample preparation. In order to selectively monitor the product ions of these precursors with optimum sensitivity for use during quantitative LC-MS/MS analysis, unique and abundant fragment ions had to be identified during MS/MS with collision-induced dissociation (CID). Positive and negative ion electrospray tandem mass spectra with CID were compared for the analysis of these five oxidized deoxynucleosides. The most abundant fragment ions were usually formed by cleavage of the glycosidic bond in both positive and negative ion modes. However, in the negative ion electrospray tandem mass spectra of 8-OH-dG, 2-OH-dA, and 8-OH-dA, cleavage of two bonds within the sugar ring produced abundant S1 type ions with loss of a neutral molecule weighing 90 u, [M - H - 90]-. The signal-to-noise ratio was similar for negative and positive ion electrospray MS/MS except in the case of thymidine glycol where the signal-to-noise was 100 times greater in negative ionization mode. Therefore, negative ion electrospray tandem mass spectrometry with CID would be preferred to positive ion mode for the analysis of sets of oxidized deoxynucleosides that include thymidine glycol. Investigation of the fragmentation pathways indicated some new general rules for the fragmentation of negatively charged oxidized nucleosides. When purine

  3. Simultaneous determination of mono- and disubstituted polyfluoroalkyl phosphates in drinking water by liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Ding, Huanhuan; Peng, Hui; Yang, Min; Hu, Jianying

    2012-03-02

    A sensitive liquid chromatography-electrospray tandem mass spectrometry method was established for the simultaneous determination of five monosubstituted polyfluoroalkyl phosphates (monoPAPs) and eight disubstituted polyfluoroalkyl phosphates (diPAPs) in drinking water. Complete separation and good retention for 13 polyfluoroalkyls phosphates (PAPs) were achieved with a Waters ACUITY UPLC BEH C8 column using a mixture of methanol/water containing 0.1% NH₄OH as the mobile phases. Extraction of drinking water samples was performed on weak anion exchange (WAX) cartridges, and the recoveries of target compounds were from 65 to 110%. The limits of quantization (LOQs) for 13 analytes were in the range of 0.4-40 ng/L. This method was applied to analyze the PAPs in drinking water samples from three cities in China. Of the 13 PAPs, six PAPs including 6:2 monoPAP (13.0 ng/L), 8:2 monoPAP (3.6 ng/L), 10:1 monoPAP (4.3-70.3 ng/L), 10:2 monoPAP (1.4-5.6 ng/L), 8:2 diPAP (0.10 ng/L), and 10:1 diPAP (0.8-3.8 ng/L) were detected. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Extraction and Characterization of Phenolic Compounds from Rose Hip (Rosa canina L.) Using Liquid Chromatography Coupled with Electrospray Ionization - Mass Spectrometry

    OpenAIRE

    Andreea STĂNILĂ; Zoriţa DIACONEASA; Ioana ROMAN; Nicușor SIMA; Dănuț MĂNIUȚIU; Alin ROMAN; Rodica SIMA

    2015-01-01

    Wild berry are a rich of natural compounds which provide them high antioxidant potential. The compounds which provide them these proprieties are known to be vitamins, flavonoids, anthocyanins and phenolic acids. The aim of this study was to extract and characterize bioactive compounds from rose hip (Rosa canina L.) currently found in Romania. A qualitative high-performance liquid chromatography coupled with electrospray ionization mass spectrometric (ESI-MS) detection in positive ion mode has...

  5. Preparative purification of gentamicin components using high-speed counter-current chromatography coupled with electrospray mass spectrometry.

    Science.gov (United States)

    Inoue, Koichi; Hattori, Yasuko; Horie, Masakazu; Hino, Tomoaki; Oka, Hisao

    2011-06-01

    We developed a useful and preparative method based on high-speed counter-current chromatography with mass spectrometry (HSCCC/MS) to purify gentamicin C1a, C2/2a and C1 from standard powder. The analytes were purified on the HSCCC model CCC-1000 (multi-layer coil planet centrifuge) with a volatile two-phase solvent system composed of n-butanol/10% aqueous ammonia solution (50:50, v/v) and detected on an LCMS-2020EV quadrupole mass spectrometer fitted with an electrospray ionization (ESI) source system in positive ionization following scan mode (m/z 100-500). The HSCCC/ESI-MS peaks indicated that gentamicin C1a (m/z 450: [M+H](+)), C2/2a (m/z 464: [M+H](+)) and C1 (m/z 478: [M+H](+)) have the peak resolution values of 1.3 and 1.7 from 30 mg of loaded gentamicin powder. The HSCCC yielded 3.9 mg of gentamicin C1a, 12.6 mg of gentamicin C2/2a and 12.0 mg of gentamicin C1. These purified substances were analyzed by LC/MS with scan positive-mode. Based on the LC/MS chromatograms and spectra of the fractions, analytes were estimated to be over 95% pure. These gentamicin isomers of C1a, C2/2a and C1 were evaluated for their antibacterial activities. The overall results indicate that this approach of HSCCC/MS is a powerful technique for the purification of gentamicin components. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Fragment profiling of low molecular weight heparins using reversed phase ion pair liquid chromatography-electrospray mass spectrometry.

    Science.gov (United States)

    Xu, Xiaohui; Li, Daoyuan; Chi, Lequan; Du, Xuzhao; Bai, Xue; Chi, Lianli

    2015-04-30

    Low molecular weight heparins (LMWHs) are linear and highly charged carbohydrate polymers prepared by chemical or enzymatic depolymerization of heparin. Compared to unfractionated heparin (UFH), LMWHs are prevalently used as clinical anticoagulant drugs due to their lower side effects and better bioavailability. The work presented herein provides a rapid and powerful fragment mapping method for structural characterization of LMWHs. The chain fragments of two types of LMWHs, enoxaparin and nadroparin, were generated by controlled enzymatic digestion with each of heparinase I (Hep I, Enzyme Commission (EC) # 4.2.2.7), heparinase II (Hep II, no EC # assigned) and heparinase III (Hep III, EC # 4.2.2.8). Reversed phase ion pair high performance liquid chromatography (RPIP-HPLC) coupled with electrospray ion trap time-of-flight mass spectrometry (ESI-IT-TOF-MS) was used to profile the oligosaccharide chains ranging from disaccharides to decasaccharides. A database containing all theoretical structural compositions was established to assist the mass spectra interpretation. The six digests derived by three enzymes from two types of LMWHs exhibited distinguishable fingerprinting patterns. And a total of 94 enoxaparin fragments and 109 nadroparin fragments were detected and identified. Besides the common LMWH oligosaccharides, many components containing characteristic LMWH structures such as saturated L-idopyranosuronic acid, 2,5-anhydro-D-mannitol, 1,6-anhydro-D-aminopyranose, as well as odd number oligosaccharides were also revealed. Quantitative comparison of major components derived from innovator and generic nadroparin products was presented. This approach to profile LMWHs' fragments offers a highly reproducible, high resolution and information-rich tool for evaluating the quality of this category of anticoagulant drugs or comparing structural similarities among samples from various sources. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Ultra-pressure liquid chromatography-electrospray tandem mass spectrometry for multiresidue determination of pesticides in water.

    Science.gov (United States)

    Gervais, G; Brosillon, S; Laplanche, A; Helen, C

    2008-08-22

    A multiresidue analysis method has been developed for the determination of pesticides in water by ultra-performance liquid chromatography (UPLC) combined with tandem mass spectrometry (MS/MS). The selected pesticides represent a broad range of polarity and volatility [benzoylcyclohexanedione (mesotrione and sulcotrione); chloroacetamide (acetochlor, alachlor, dimethenamide, and metolachlor); phenoxyacetic acid (2,4-D and MCPA); phenoxypropionic (dichloprop and mecoprop); phenylurea (chlortoluron, diuron, isoproturon, linuron, and metoxuron); sulfonylurea (foramsulfuron, iodosulfuron, and nicolsulfuron); triazine (atrazine, cyanazine, desethylatrazine (DEA), desisopropylatrazine (DIA), simazine, and terbutylazine)]. The analytes were extracted using solid-phase extraction (SPE). The separation was carried out on an acquity UPLC BEH C18 column (1.7 microm, 50 mm x 1 mm ID) using a gradient elution profile and mobile phase consisting of 0.1% formic acid in water and acetonitrile. The pesticides were detected with a tandem mass spectrometer after being ionised positively or negatively (depending on the molecule) using an electrospray ionisation (ESI) source. To achieve the suitable extraction conditions for sample preparation, several parameters affecting the efficiency of SPE such as the nature of the sorbent and the eluent, extractant volume and pH were studied. The best recovery was obtained by the extraction with an Oasis HLB cartridge and 3 mL of a solution of acetonitrile/dichloromethane (1:1, v/v) at pH 2. The average recoveries of the pesticides in different samples ranged from 82 to 109%. The weight least squares (WLS) linear regression was used to calculate the limits of detection and quantification (LOD and LOQ) because the dispersion was heteroskedastic. All the pesticides could be correctly quantified at a concentration level of 50 ng L(-1) and most of them could be detected at a concentration inferior or equal to 8 ng L(-1). Efficiency and robustness of

  8. Determination of ethylenediaminetetraacetic acid in nuclear waste by high-performance liquid chromatography coupled with electrospray mass spectrometry.

    Science.gov (United States)

    du Bois de Maquillé, Laurence; Renaudin, Laetitia; Goutelard, Florence; Jardy, Alain; Vial, Jérôme; Thiébaut, Didier

    2013-02-08

    EDTA is a chelating agent that has been used in decontamination processes. Its quantification is required for nuclear waste management because it affects the mobility of radionuclides and metals in environment and, thus, can harm the safety of the storage. Ion-pair chromatography coupled with electrospray mass spectrometry detection is a convenient method for quantitative analysis of EDTA but EDTA should be present as a single anionic chelate form. However, radioactive liquid wastes contain high concentrations of heavy metals and salts and consequently, EDTA is present as several chelates. Speciation studies were carried out to choose a metal cation to be added in excess to the solution to obtain a major chelate form. Fe is the predominant cation and Fe(III)-EDTA is thermodynamically favored but these speciation studies showed that ferric hydroxide precipitated above pH 2. Consequently, it was not possible to quantify EDTA as Fe(III)-EDTA complex. Therefore, Ni(2+) was chosen but its use implied pretreatment with a base of the solution to eliminate Fe. Deuterated EDTA was used as tracer in order to validate the whole procedure, from the treatment with a base to the final analysis by HPLC-ESI-MS. This analytical method was successfully applied for EDTA quantification in two real effluents resulting from a nuclear liquid waste process. A recovery rate between 60 and 80% was obtained. The limit of detection of this method was determined at 34×10(-9)mol L(-1). Copyright © 2012 Elsevier B.V. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-08-18

    A method using an immunoaffinity column (IAC) and liquid chromatography-electrospray ionization mass spectrometry (LC/MS) for on-line detecting the presence of MA in the effluent was developed for the quantitative and enantiomeric determination of (S)-(+)-methamphetamine (D-MA) in urine. The IAC was made in our laboratory and utilized in the LC/MS to simultaneously extract and separate enantiomers of MA from urine samples. An aqueous ammonium acetate buffer was used as the mobile phase. Urine samples were spiked with racemic deuterated methamphetamine (MA-d{sub 14}) as internal standard (IS), filtered through a membrane, and injected into the LC/MS without any further pre-treatment. Protonated molecular ion of MA and MA-d{sub 14} (m/z 150 and 164) were isolated and further fragmented, the respective product ions, m/z 119 and 130, were collected for quantitative determination. This is an improvement of our previous method (A.C. Lua, Tsong-Yung Chou, J. Chromatogr. A 967 (2002) 191). In the previous method, MA was separated with HPLC, the efflux was fractionated and each fraction was either determined with an immunoassay or GC/MS. Monitoring of MA in the efflux is tedious and time consuming. Urine samples spiked with different concentrations of D-MA were measured by this method. A linear relationship exists in the 150-1050 ng/mL range, and the detection limit (defined as signal-to-noise ratio 3) of D-MA was determined to be 18 ng/mL. The linearity of the method for D-MA can be described by the equation (Y = 1.415 x 10{sup -3} X + 0.034, correlation coefficient: r {sup 2} = 0.999). Within run, accuracy and precision (n = 6, relative error: -7.2 to +4.0% and relative standard deviation: 3.8-9.3%) of the method are fairly good.

  10. Development of a liquid chromatography-electrospray-tandem mass spectrometry method for the quantitative determination of benzoxazinone derivatives in plants.

    Science.gov (United States)

    Bonnington, Lea; Eljarrat, Ethel; Guillamón, Miriam; Eichhorn, Peter; Taberner, Andreu; Barceló, Damià

    2003-07-01

    A new method for the quantification of benzoxazinone derivatives in extracts of wheat foliage and root samples using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS-MS) is described. Using this method, the characterization, separation, and quantitative detection of a mixture of six naturally occurring 1,4-benzoxazin-3(4H)-one derivatives, including the hydroxamic acids (DIMBOA, DIBOA), lactams (HBOA, and HMBOA), benzoxazilinones (BOA, MBOA), and two synthetic methoxylated variations of DIBOA and HBOA, was achieved. The application of a novel, highly modified reversed-phase LC column, the dodecyl (C12) TMS end-capped Synergi MAX-RP, enhanced the on-line chromatographic separation through improvements to component resolution, analyte stability and peak shape and also to the column lifetime. The complete ESI-MS-MS precursor-product ion fragmentation pathways for the benzoxazinone derivatives are described for the first time and used to deduce a generic fragmentation pattern for the compound class. Characteristic transitions for the benzoxazinones were thus used in the developed analytical method enabling reliable quantification with simultaneous screening for other potentially present derivatives, while eliminating interferences from other coeluting contaminants from the complex plant extract matrix. Quantitative analysis was done in the multiple reaction monitoring mode, using two specific combinations of a precursor-product ion transitions for each compound. The ESI-MS-MS detection method offered improvements to the sensitivity and selectivity, as compared with previously applied LC methods, with detection limits down to 0.002-0.023 ng/microL. The developed method was demonstrated by analyzing foliages and roots of six different wheat cultivars using pressurized liquid extraction-solid-phase extraction cleanup-LC-ESI-MS-MS. The analytes were detected in the range of 0.7-207 microg/g of dry weight.

  11. Highly informative multiclass profiling of lipids by ultra-high performance liquid chromatography - Low resolution (quadrupole) mass spectrometry by using electrospray ionization and atmospheric pressure chemical ionization interfaces.

    Science.gov (United States)

    Beccaria, Marco; Inferrera, Veronica; Rigano, Francesca; Gorynski, Krzysztof; Purcaro, Giorgia; Pawliszyn, Janusz; Dugo, Paola; Mondello, Luigi

    2017-08-04

    A simple, fast, and versatile method, using an ultra-high performance liquid chromatography system coupled with a low resolution (single quadrupole) mass spectrometer was optimized to perform multiclass lipid profiling of human plasma. Particular attention was made to develop a method suitable for both electrospray ionization and atmospheric pressure chemical ionization interfaces (sequentially in positive- and negative-ion mode), without any modification of the chromatographic conditions (mobile phase, flow-rate, gradient, etc.). Emphasis was given to the extrapolation of the structural information based on the fragmentation pattern obtained using atmospheric pressure chemical ionization interface, under each different ionization condition, highlighting the complementary information obtained using the electrospray ionization interface, of support for related molecule ions identification. Furthermore, mass spectra of phosphatidylserine and phosphatidylinositol obtained using the atmospheric pressure chemical ionization interface are reported and discussed for the first time. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Quantitative characterization of solid epoxy resins using comprehensive two dimensional liquid chromatography coupled with electrospray ionization-time of flight mass spectrometry.

    Science.gov (United States)

    Julka, Samir; Cortes, Hernan; Harfmann, Robert; Bell, Bruce; Schweizer-Theobaldt, Andreas; Pursch, Matthias; Mondello, Luigi; Maynard, Shawn; West, David

    2009-06-01

    A comprehensive multidimensional liquid chromatography system coupled to Electrospray Ionization-Mass Spectrometry (LCxLC-ESI-MS) was developed for detailed characterization and quantitation of solid epoxy resin components. The two orthogonal modes of separation selected were size exclusion chromatography (SEC) in the first dimension and liquid chromatography at critical conditions (LCCC) in the second dimension. Different components present in the solid epoxy resins were separated and quantitated for the first time based on the functional groups and molecular weight heterogeneity. Coupling LCxLC separations with mass spectrometry enabled the identification of components resolved in the two-dimensional space. Several different functional group families of compounds were separated and identified, including epoxy-epoxy and epoxy-alpha-glycol functional oligomers, and their individual molecular weight ranges were determined. Repeatability obtained ranged from 0.5% for the main product to 21% for oligomers at the 0.4% concentration level.

  13. Liquid chromatography/tandem mass spectrometric confirmatory method for determining aflatoxin M1 in cow milk: comparison between electrospray and atmospheric pressure photoionization sources.

    Science.gov (United States)

    Cavaliere, Chiara; Foglia, Patrizia; Pastorini, Elisabetta; Samperi, Roberto; Laganà, Aldo

    2006-01-06

    A liquid chromatography/electrospray (ESI)-tandem mass spectrometric method for the measurement of aflatoxin M1 (AFM1) in milk is described. Milk sample after protein precipitation with acetone was cleaned-up with a Carbograph-4 cartridge. Performances of the ESI source were compared with those of the atmospheric pressure photoionization source (APPI). Although a method quantification limit (MQL) of 6 ng/kg could be achieved operating with APPI source with respect to an MQL of 12 ng/kg with ESI, all the other performances being similar, then ESI was preferred as being more robust and widespread at present.

  14. Low-molecular weight protein profiling of genetically modified maize using fast liquid chromatography electrospray ionization and time-of-flight mass spectrometry.

    Science.gov (United States)

    Koc, Anna; Cañuelo, Ana; Garcia-Reyes, Juan F; Molina-Diaz, Antonio; Trojanowicz, Marek

    2012-06-01

    In this work, the use of liquid chromatography coupled to electrospray time-of-flight mass spectrometry (LC-TOFMS) has been evaluated for the profiling of relatively low-molecular weight protein species in both genetically modified (GM) and non-GM maize. The proposed approach consisted of a straightforward sample fractionation with different water and ethanol-based buffer solutions followed by separation and detection of the protein species using liquid chromatography with a small particle size (1.8 μm) C(18) column and electrospray-time-of-flight mass spectrometry detection in the positive ionization mode. The fractionation of maize reference material containing different content of transgenic material (from 0 to 5% GM) led to five different fractions (albumins, globulins, zeins, zein-like glutelins, and glutelins), all of them containing different protein species (from 2 to 52 different species in each fraction). Some relevant differences in the quantity and types of protein species were observed in the different fractions of the reference material (with different GM contents) tested, thus revealing the potential use of the proposed approach for fast protein profiling and to detect tentative GMO markers in maize. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. High-performance thin-layer chromatography/desorption electrospray ionization mass spectrometry imaging of the crude extract from the peels of Citrus aurantium L. (Rutaceae).

    Science.gov (United States)

    Bagatela, Bianca S; Lopes, Andrey P; Cabral, Elaine C; Perazzo, Fábio F; Ifa, Demian R

    2015-08-30

    Citrus aurantium L. is a plant belonging to the Rutaceae family, whose extracts are extensively used in weight management products and as thermogenic agents. Here we present two methodologies to analyse the extracts obtained from the peels of Citrus aurantium L. that usually require multiple sample preparation and detection steps. Polar compounds of the crude extract from the peels of Citrus aurantium L. (Rutaceae) were investigated by direct infusion electrospray ionization mass spectrometry (ESI-MS) and high-performance thin-layer chromatography (HPTLC) coupled to desorption electrospray ionization mass spectrometry (DESI-MS). ESI-MS was performed in both positive and negative ion modes. Molecular imaging of the HPTLC plates was used for the direct analysis of the phytocompounds present in the crude extract from the peels of Citrus aurantium L. by DESI-MS imaging. Characteristic mass spectra with many diagnostic ions were obtained from the extract analysis, allowing a fast and reliable identification of these species. Tandem mass spectrometry (MS/MS) was employed to confirm the identity of specific metabolites. HPTLC/DESI-MS imaging is a relatively fast, versatile, and efficient technique for natural product analysis, since many more ions are observed than with the direct infusion ESI-MS. The MS/MS technique provided information about the component structures, revealing the presence of important bioactive components. The application of DESI-MS imaging may contribute to the improvement identification and characterization of pharmacologically active compounds in phytochemistry. Copyright © 2015 John Wiley & Sons, Ltd.

  16. Use of novel picolinoyl derivatization for simultaneous quantification of six corticosteroids by liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Yamashita, Kouwa; Takahashi, Madoka; Tsukamoto, Satoshi; Numazawa, Mitsuteru; Okuyama, Mitsunobu; Honma, Seijiro

    2007-11-30

    Simultaneous quantification method of six corticosteroids, cortisone, cortisol, cortexolone, corticosterone, dehydrocorticosterone and deoxycorticosterone, by LC-electrospray ionization (ESI)-MS in a positive mode using novel picolinoyl derivatization was investigated. Conversion of each corticosteroid into the corresponding picolinoyl derivative was performed by mixed anhydride method using picolinic acids and 2-methyl-6-nitrobenzoic anhydride. Derivatization proceeded smoothly to afford the corresponding 21-monopicolinoyl derivatives. Positive ion-ESI mass spectra of the picolinoyl derivatives were dominated by the appearance of [M+H](+) as base peaks. The picolinoyl derivatives provided 5-10 times higher ESI response in the LC-ESI-MS-selected reaction monitoring (SRM) when compared to those of underivatized molecules in a positive LC-ESI-MS mode. The use of the picolinoyl ester, solid-phase extraction, and deuterium labeled internal standards enabled to determine the concentrations of these corticosteroids in human saliva simultaneously by LC-ESI-MS-SRM.

  17. Quantitative analysis of paraquat in vegetation by stable isotope dilution and liquid chromatography/electrospray ionization-mass spectrometry.

    Science.gov (United States)

    Schaner, Angela; Hickes, Heidi

    2015-01-01

    The method presented is a suitable approach for routine testing of paraquat in difficult sample types, such as winter wheat and alfalfa plant tissue, typically found with accidental spray drift. Hydrophilic interaction chromatography and ultra-performance LC is utilized with tandem quadrupole MS in the positive electrospray ionization mode. Three precursor-product ion transitions are measured in the multiple reaction monitoring mode, and paraquat d8 is added as an internal standard at the beginning of the extraction procedure to correct for losses in recovery and/or matrix effects in instrument response. A 5 g portion is digested with 6 M HCl in a 100°C water bath for 1 h. An aliquot is removed and adjusted to pH 7-8 prior to loading on a mixed mode weak cation-exchange SPE cartridge, and paraquat is eluted with formic acid-acetonitrile (10 + 90, v/v). Average recoveries of paraquat fortified at 0.020-0.080 ppm in winter wheat and alfalfa ranged from 80 to 114% (RSD 12-30%). Result data from naturally incurred paraquat (0.027-0.51 ppm) in composite garden plants, potato leaves, tree leaves, and alfalfa are presented. The LOQ is 0.020 ppm.

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

    Science.gov (United States)

    Zhou, Yan; Liu, Xin; Yang, Jing; Han, Quan-Bin; Song, Jing-Zheng; Li, Song-Lin; Qiao, Chun-Feng; Ding, Li-Sheng; Xu, Hong-Xi

    2008-11-23

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-11-23

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

  20. Characterization of phenolic acids and flavonoids in dandelion (Taraxacum officinale WEB. ex WIGG.) root and herb by high-performance liquid chromatography/electrospray ionization mass spectrometry.

    Science.gov (United States)

    Schütz, Katrin; Kammerer, Dietmar R; Carle, Reinhold; Schieber, Andreas

    2005-01-01

    Phenolic acids and flavonoids were extracted from a dandelion (Taraxacum officinale WEB. ex WIGG.) root and herb juice and characterized by high-performance liquid chromatography/electrospray ionization mass spectrometry. Among the 43 compounds detected, 5 mono- and dicaffeoylquinic acids, 5 tartaric acid derivatives, 8 flavone and 8 flavonol glycosides were characterized based on their UV spectra and their fragmentation patterns in collision-induced dissociation experiments. The predominant compound was chicoric acid (dicaffeoyltartaric acid). Furthermore, several caffeoylquinic acid isomers were distinguished in dandelion extracts for the first time by their specific mass spectral data. The present study reveals that even more quercetin glycosides were found in dandelion than hitherto assumed. The occurrence of di- and triglycosylated flavonoids in particular has not yet been described. This paper marks the first report on HPLC-DAD/ESI-MSn investigations of phenolic compounds in dandelion.

  1. Structural characterisation of degradation products formed upon di-n-butyl phthalate radiolysis by high-performance liquid chromatography electro-spray tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tintaru, A.; Charles, L. [Univ Aix Marseille 1, CNRS, Lab Chim Provence Spectrometries Appl Chim Struct, UMR 6264, F-13397 Marseille (France); Univ Aix Marseille 2, CNRS, Lab Chim Provence Spectrometries Appl Chim Struct, UMR 6264, F-13397 Marseille (France); Labed, V. [CEA Marcoule, DTCD SPDE L2ED, F-30207 Bagnols Sur Ceze (France)

    2010-07-01

    Complete text of publication follows: Structural characterisation of 15 degradation products, formed upon di-n-butyl phthalate (DBP) radiolysis, has been achieved using a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) coupling. The dissociation behaviour of protonated DBP was first established to be further used to characterise structural deviation in the degradation products. Based on accurate mass measurements, compounds shown by HPLC-MS analysis were all found to be DBP oxidation products, amongst which various sets of isomers could be distinguished. Collision-induced dissociation experiments performed on each electro-sprayed molecule first allowed unambiguous definition of the location of the additional oxygen atoms; that is, in the alkyl branch or on the aromatic ring. Although location of the oxygen atom in the alkyl branches could not always be precisely determined, relative abundances of some product ions allowed oxygenated functions to be identified

  2. Coupling of gas chromatography and electrospray ionization high resolution mass spectrometry for the analysis of anabolic steroids as trimethylsilyl derivatives in human urine.

    Science.gov (United States)

    Cha, Eunju; Jeong, Eun Sook; Cha, Sangwon; Lee, Jaeick

    2017-04-29

    In this study, gas chromatography (GC) was interfaced with high resolution mass spectrometry (HRMS) with electrospray ionization source (ESI) and the relevant parameters were investigated to enhance the ionization efficiency. In GC-ESI, the distances (x-, y- and z) and angle between the ESI needle, GC capillary column and MS orifice were set to 7 (x-distance), 4 (y-distance), and 1 mm (z-distance). The ESI spray solvent, acid modifier and nebulizer gas flow were methanol, 0.1% formic acid and 5 arbitrary units, respectively. Based on these results, analytical conditions for GC-ESI/HRMS were established. In particular, the results of spray solvent flow indicated a concentration-dependent mechanism (peak dilution effect), and other parameters also greatly influenced the ionization performance. The developed GC-ESI/HRMS was then applied to the analysis of anabolic steroids as trimethylsilyl (TMS) derivatives in human urine to demonstrate its application. The ionization profiles of TMS-derivatized steroids were investigated and compared with those of underivatized steroids obtained from gas chromatography-electrospray ionization/mass spectrometry (GC-ESI/MS) and liquid chromatography-electrospray ionization/mass spectrometry (LC-ESI/MS). The steroids exhibited ionization profiles based on their structural characteristics, regardless of the analyte phase or derivatization. Groups I and II with conjugated or unconjugated keto functional groups at C3 generated the [M+H] + and [M+H-TMS] + ions, respectively. On the other hand, Groups III and IV gave rise to the characteristic fragment ions [M+H-TMS-H 2 O] + and [M+H-2TMS-H 2 O] + , corresponding to loss of a neutral TMS·H 2 O moiety from the protonated molecular ion by in-source dissociation. To the best of our knowledge, this is the first study to successfully ionize and analyze steroids as TMS derivatives using ESI coupled with GC. The present system has enabled the ionization of TMS derivatives under ESI conditions

  3. An approach based on liquid chromatography/electrospray ionization–mass spectrometry to detect diol metabolites as biomarkers of exposure to styrene and 1,3-butadiene

    Science.gov (United States)

    Shen, Shuijie; Zhang, Fan; Zeng, Su; Zheng, Jiang

    2012-01-01

    Styrene and 1,3-butadiene are important intermediates used extensively in the plastics industry. They are metabolized mainly through cytochrome P450-mediated oxidation to the corresponding epoxides, which are subsequently converted to diols by epoxide hydrolase or through spontaneous hydration. The resulting styrene glycol and 3-butene-1,2-diol have been suggested as biomarkers of exposure to styrene and 1,3-butadiene, respectively. Unfortunately, poor ionization of the diols within electrospray mass spectrometers becomes an obstacle to the detection of the two diols by liquid chromatography/electrospray ionization–mass spectrometry (LC/ESI–MS). We developed an LC/ESI–MS approach to analyze styrene glycol and 3-butene-1,2-diol by means of derivatization with 2-bromopyridine-5-boronic acid (BPBA), which not only dramatically increases the sensitivity of diol detection but also facilitates the identification of the diols. The analytical approach developed was simple, quick, and convincing without the need for complicated chemical derivatization. To evaluate the feasibility of BPBA as a derivatizing reagent of diols, we investigated the impact of diol configuration on the affinity of a selection of diols to BPBA using the established LC/ESI–MS approach. We found that both cis and trans diols can be derivatized by BPBA. In conclusion, BPBA may be used as a general derivatizing reagent for the detection of vicinal diols by LC/MS. PMID:19111668

  4. Capillary column switching restricted-access media-liquid chromatography-electrospray ionization-tandem mass spectrometry system for simultaneous and direct analysis of drugs in biofluids.

    Science.gov (United States)

    Santos-Neto, Alvaro J; Markides, Karin E; Sjöberg, Per J R; Bergquist, Jonas; Lancas, Fernando M

    2007-08-15

    Capillary online restricted-access media-liquid chromatography-electrospray ionization-tandem mass spectrometry (RAM-LC-ESI-MS/MS) for direct analysis of drugs and metabolites spiked in biological fluids was developed. Using a column switching setup it was possible to perform effective sample preparation and analysis of raw biological fluids (plasma and urine) without matrix effects in the electrospray mass spectrometric detection step. The peak focusing efficiency of the extraction column was more effective in backflush compared to foreflush mode. The system was able to concentrate diminished samples of polar drugs and their metabolites reaching quantifiable results as low as 1 ng/mL utilizing a sample volume of only 333 nL of biofluids. New column hardware was developed to circumvent clogging problems experienced with plasma injections. The glass fiber filter frit, which is commonly used, was replaced with a short piece of 20 microm i.d. fused silica capillary. The extraction columns were able to handle up to 60 injections and showed a high loading capacity, making the saturation of the MS detector the limiting factor on the linear dynamic range. The simultaneous separation and detection of 10 drugs and metabolites was obtained in 8 min of analysis, including the online sample preparation and enrichment step.

  5. Liquid chromatography/electrospray ionization tandem mass spectrometry analysis of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX).

    Science.gov (United States)

    Pan, Xiaoping; Zhang, Baohong; Tian, Kang; Jones, Lindsey E; Liu, Jun; Anderson, Todd A; Wang, Jia-Sheng; Cobb, George P

    2006-01-01

    A quantitative liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method was developed for the analysis of the explosive, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). In negative ionization mode, HMX forms an acetate adduct ion [M + CH(3)COO](-), m/z 355, in the presence of a small amount of acetic acid in the mobile phase. The ESI collision-induced dissociation (CID) spectrum of m/z 355 was acquired and the transitions m/z 355 --> 147 and m/z 355 --> 174 were chosen for the determination of HMX in samples. Using this quantification technique, the method detection limit was 1.57 microg/L and good linearity was achieved in the range 5-500 microg/L. This method will help to unambiguously analyze environmentally relevant concentrations of HMX. Copyright (c) 2006 John Wiley & Sons, Ltd.

  6. Biodegradation and removal of 3,4-dichloroaniline by Chlorella pyrenoidosa based on liquid chromatography-electrospray ionization-mass spectrometry.

    Science.gov (United States)

    Wang, Shujuan; Poon, Karen; Cai, Zongwei

    2013-01-01

    3,4-Dichloroaniline (3,4-DCA), widely used in the synthesis of dyes, textile and herbicides, is toxic to living organisms. The purpose of this study was to investigate the capability of green algae in degrading and removing 3,4-DCA in water. An environmentally ubiquitous green alga Chlorella pyrenoidosa was isolated from fresh aquatic environment. Then unicellular alga was incubated with 3,4-DCA at a concentration of 4.6 μg/ mL in water. The residual concentration of 3,4-DCA in the medium and the metabolites were analyzed. A removal percentage of 78.4 % was obtained over a 7-day period. Two major metabolites with less toxicity were identified as 3,4-dichloroformanilide and 3,4-dichloroacetanilide from the liquid chromatography-electrospray ionization-mass spectrometry analysis. The application of microalga C. pyrenoidosa may have potential for removing the environmental pollutant in aquatic environment.

  7. Development of highly sensitive quantification method for testosterone and dihydrotestosterone in human serum and prostate tissue by liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Yamashita, Kouwa; Miyashiro, Yoshimichi; Maekubo, Hitoe; Okuyama, Mitsunobu; Honma, Seijiro; Takahashi, Madoka; Numazawa, Mitsuteru

    2009-11-01

    We developed highly sensitive detection of testosterone (T) and 5alpha-dihydrotestosterone (DHT) by liquid chromatography-electrospray ionization tandem mass spectrometry using high proton affinitive derivatization of 17beta-hydroxyl group of T and DHT with picolinic acid, mobile phase consisting of MeCN-MeOH-H(2)O-formic acid and conventional octadecylsilica (ODS) column. Purification of the derivatives was carried out using solid-phase extraction with ODS cartridge. By this method, T and DHT were determined simultaneously with limits of quantification (LOQs) of 1 pg/0.2 ml in serum, and T and DHT with LOQs of 0.5 pg and 1 pg/3mg in prostate tissue, respectively, under acceptable assay performance (intra-assay and inter-assay accuracy and precision). The present method provides reliable and reproducible results for quantification of T and DHT in small volumes of serum and prostate samples for diagnosis in prostatic disorders and male climacteric.

  8. Structural elucidation of metabolites of ginkgolic acid in rat liver microsomes by ultra-performance liquid chromatography/electrospray ionization tandem mass spectrometry and hydrogen/deuterium exchange.

    Science.gov (United States)

    Liu, Z H; Chen, J; Yu, L S; Jiang, H D; Yao, T W; Zeng, S

    2009-07-01

    Ginkgolic acids have been shown to possess allergenic as well as genotoxic and cytotoxic properties. The question arises whether the metabolism of ginkgolic acids in the liver could decrease or increase their toxicity. In this study, the in vitro metabolism of ginkgolic acid (15:1, GA), one component of ginkgo acids, was investigated as a model compound in Sprague-Dawley rat liver microsomes. The metabolites were analyzed by ultra-performance liquid chromatography coupled with photodiode array detector/negative-ion electrospray ionization tandem mass spectrometry (UPLC-PDA/ESI-MS/MS) and hydrogen/deuterium (H/D) exchange. The result showed that the benzene ring remained unchanged and the oxidations occurred at the side alkyl chain in rat liver microsomes. At least eight metabolites were found. Among them, six phase I metabolites were tentatively identified. This study might be useful for the investigation of toxicological mechanism of ginkgolic acids. Copyright (c) 2009 John Wiley & Sons, Ltd.

  9. Application of liquid chromatography/electrospray ionization tandem mass spectrometry to the analysis of polyphenolic compounds from an infusion of Byrsonima crassa Niedenzu.

    Science.gov (United States)

    Sannomiya, Miriam; Montoro, Paola; Piacente, Sonia; Pizza, Cosimo; Brito, Alba R M S; Vilegas, Wagner

    2005-01-01

    A fast and reliable method, based on high-performance liquid chromatography coupled to electrospray ionization ion trap tandem mass spectrometry (HPLC/ESI-ITMS), was developed to investigate the infusion prepared from the leaves of Byrsonima crassa Niedenzu (Malpighiaceae), a native plant used in Brazil against gastric disorders. The use of on-line reverse-phase HPLC/ESI-ITMS allowed separation of three major classes of compounds and identification of over 20 very polar compounds characterized as galloylquinic acids, proanthocyanidins, and flavonoid glycosides, as well as the dimeric flavonoid amentoflavone and minor amounts of galloyl hexose and galloyl saccharose. This approach provided data that will allow establishment of a method for a future standardization of the infusion. Copyright (c) 2005 John Wiley & Sons, Ltd.

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

    DEFF Research Database (Denmark)

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

    2001-01-01

    A reversed-phase high-performance liquid chromatography (HPLC) method with on-line electrospray ionization/collision-induced dissociation/mass spectrometry (ESI/CID/MS) is presented for the regiospecific analysis of synthetic reference compounds of neutral ether lipids. The reference compounds were....... The diagnostic ions of directly analyzed 1-O-alkyl-2,3-diacyl-sn- glycerols were the [M - alkyl](+), [M - sn-2-acyl](+) and [M - sn-3-acyl](+) ions. Regiospecific characterization of the fatty acid identity and position was evident from the relative ion intensities, as fragmentation of the sn-2 fatty acids...... for each neutral ether lipid class. The present study demonstrates that reversed-phase HPLC and positive ion ESI/CID/MS provide direct and unambiguous information about the configuration and identity of molecular species in neutral 1-O-alkyl-sn-glycerol classes....

  11. Investigation of pyrrolizidine alkaloids and their N-oxides in commercial comfrey-containing products and botanical materials by liquid chromatography electrospray ionization mass spectrometry.

    Science.gov (United States)

    Altamirano, Jorgelina C; Gratz, Samuel R; Wolnik, Karen A

    2005-01-01

    Pyrrolizidine alkaloids (PAs) and their N-oxides are found in several plant families throughout the world. PAs are potentially toxic to the liver and/or lungs in humans and may cause acute liver failure, cirrhosis, pneumonitis, or pulmonary hypertension. PAs are also carcinogenic to animals, and they have been linked to the development of hepatocellular and skin squamous cell carcinomas as well as liver angiosarcomas. According to experimental studies, the quantity of PAs in some herbal teas and dietary supplements is sufficient to be carcinogenic in exposed individuals. A method for the extraction and identification of PAs and their N-oxides in botanical materials and commercial comfrey-containing products has been developed using liquid chromatography electrospray ionization mass spectrometry. Following optimization of the extraction procedure and the chromatographic conditions, the method was applied to the analysis of 10 herbal remedies. All of the products that were labeled to contain comfrey were found to contain measurable quantities of PAs.

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

    Science.gov (United States)

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

    2016-01-08

    A new high pressure liquid chromatography-electrospray ionization-tandem mass spectrometry method for the simultaneous determination of glucosinolates, as glucoraphanin and glucoerucin, and the corresponding isothiocyanates, as sulforaphane and erucin, was developed and applied to quantify these compounds in Eruca sativa defatted seed meals and enriched functional foods. The method involved solvent extraction, separation was achieved in gradient mode using water with 0.5% formic acid and acetonitrile with 0.5% formic acid and using a reverse phase C18 column. The electrospray ion source operated in negative and positive mode for the detection of glucosinolates and isothiocyanates, respectively, and the multiple reaction monitoring (MRM) was selected as acquisition mode. The method was validated following the ICH guidelines. Replicate experiments demonstrated a good accuracy (bias%food products enriched with glucosinolates, or nutraceutical bakery products. In addition, the developed method was applied to the simultaneous determination of glucosinolates and isothiocyanates in bakery product enriched with glucosinolates, to evaluate their thermal stability after different industrial processes from cultivation phases to consumer processing. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2015-12-04

    Cloud-point extraction (CPE) draws increasing interest in a number of analytical fields including bioanalysis, but combining CPE and LC-MS with electrospray ionization (ESI) in the determination of drugs in biological fluids such as plasma, serum or blood has not been reported so far. Bisoprolol was determined in human plasma by CPE using Trition X-114 as a surfactant and metoprolol as the internal standard. NaOH concentration, temperature and Trition X-114 concentration were optimized. All analyses were performed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). All validation experiments met international acceptance criteria and no significant matrix effect was observed. The compatibility of CPE and LC-ESI-MS/MS was confirmed using clinical plasma samples and appropriate statistical tests. The determination of bisoprolol concentration in human plasma in the range 1.0-70ngmL(-1) by the CPE method leads to the results which are equivalent to those obtained by the widely used liquid-liquid extraction method. The results revealed that a structural analogue may be an appropriate internal standard when CPE is used as the extraction technique. CPE offers significant practical advantages over the classical extraction methods, including a positive impact on the environment, therefore its wider application in future pharmacokinetic studies is justifiable. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2007-01-01

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

  15. Hyphenating size-exclusion chromatography with electrospray mass spectrometry; using on-line liquid-liquid extraction to study the lipid composition of lipoprotein particles.

    Science.gov (United States)

    Osei, Michael; Griffin, Julian L; Koulman, Albert

    2015-11-15

    Lipoproteins belong to the most commonly measured clinical biochemical parameters. Lipidomics is an orthogonal approach and aims to profile the individual lipid molecules that jointly form the lipoprotein particles. However, in the first step of the extraction of lipid molecules from serum, an organic solvent is used leading to dissociation of the lipoproteins. Thus far it has been impossible to combine lipidomics and lipoprotein analysis in one analytical system. Human plasma was diluted in phosphate-buffered saline (PBS) and injected onto a Superose 6 PC 3.2 column with PBS as a mobile phase to separate lipoproteins. The eluent was led to a Syrris FLLEX module, which also received CHCl3 /MeOH (3:1). The two phases were mixed and subsequently separated using a Teflon membrane in an especially designed pressurized flow chamber. The organic phase was led to a standard electrospray source of an Orbitrap mass spectrometer. Size-exclusion chromatography (SEC) has been commonly applied to separate lipoproteins and is considered a practical alternative to ultracentrifugation. Through the on-line liquid-liquid extraction method it becomes possible to obtained detailed mass spectra of lipids across different lipoprotein fractions. The extracted ion chromatograms of specific lipid signals showed their distribution against the size of lipoprotein particles. The application of on-line liquid-liquid extraction allows for the continuous electrospray-based mass spectral analysis of SEC eluent, providing the detailed lipid composition of lipoprotein particles separated by size. This approach provides new possibilities for the study of the biochemistry of lipoproteins. © 2015 The Authors. Rapid Communications in Mass Spectrometry Published by John Wiley & Sons Ltd.

  16. Confirmatory analysis method for zeranol, its metabolites and related mycotoxins in urine by liquid chromatography-negative ion electrospray tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-11-25

    The determination of the banned anabolic substance zeranol and the metabolites taleranol and zearalanone in bovine urine is complicated by the occurrence of the structurally-related mycotoxin zearalenone and the corresponding {alpha}- and {beta}-zearalenol metabolites which possess similar estrogenic properties. A liquid chromatography-negative ion electrospray tandem mass spectrometric method is presented for the confirmatory analysis of all six resorcylic acid lactones ('zeranols') in urine samples using deuterium-labelled internal standards. The method was validated as a confirmatory method for bovine urine samples according to new draft EU guidelines and showed good precision and linearity, and CC{alpha} and CC{beta} values of 0.02-0.30 and <1.0 ng ml{sup -1}, respectively. The applicability was demonstrated by comparing the results of an incurred sample with previous results on the same sample obtained by gas chromatography high resolution mass spectrometry. Preliminary data show that following a simple matrix solid phase dispersion clean-up, liver samples from poultry will be amenable to this method as well.

  17. Supercritical fluid chromatography-photodiode array detection-electrospray ionization mass spectrometry as a framework for impurity fate mapping in the development and manufacture of drug substances.

    Science.gov (United States)

    Pirrone, Gregory F; Mathew, Rose M; Makarov, Alexey A; Bernardoni, Frank; Klapars, Artis; Hartman, Robert; Limanto, John; Regalado, Erik L

    2018-03-30

    Impurity fate and purge studies are critical in order to establish an effective impurity control strategy for approval of the commercial filing application of new medicines. Reversed phase liquid chromatography-diode array-mass spectrometry (RPLC-DAD-MS) has traditionally been the preferred tool for impurity fate mapping. However, separation of some reaction mixtures by LC can be very problematic requiring combination LC-UV for area % analysis and a different LC-MS method for peak identification. In addition, some synthetic intermediates might be chemically susceptible to the aqueous conditions used in RPLC separations. In this study, the use of supercritical fluid chromatography-photodiode array-electrospray ionization mass spectrometry (SFC-PDA-ESIMS) for fate and purge of two specified impurities in the 1-uridine starting material from the synthesis of a bis-piv 2'keto-uridine, an intermediate in the synthesis of uprifosbuvir, a treatment under investigation for chronic hepatitis C infection. Readily available SFC instrumentation with a Chiralpak IC column (4.6 × 150 mm, 3 μm) and ethanol: carbon dioxide based mobile phase eluent enabled the separation of closely related components from complex reaction mixtures where RLPC failed to deliver optimal chromatographic performance. These results illustrate how SFC combined with PDA and ESI-MS detection can become a powerful tool for direct impurity fate mapping across multiple reaction steps. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Enhanced detection of amino acids in hydrophilic interaction chromatography electrospray tandem mass spectrometry with carboxylic acids as mobile phase additives.

    Science.gov (United States)

    Yin, Dengyang; Hu, Xunxiu; Liu, Dantong; Du, Wencheng; Wang, Haibo; Guo, Mengzhe; Tang, Daoquan

    2017-06-01

    Liquid chromatography coupled with mass spectrometry technique has been widely used in the analysis of biological targets such as amino acids, peptides, and proteins. In this work, eight common single carboxylic acids or diacids, which contain different pKa have been investigated as the additives to the analysis of amino acids. As the results, carboxylic acid additive can improve the signal intensity of acidity amino acids such as Asp and Glu and the chromatographic separation of basic amino acids such as Arg, His, and Lys. In particular, the diacids have better performance than single acids. The proposed mechanism is that the diacid has hydrogen bond interaction with amino acids to reduce their polarity/amphiprotic characteristics. Besides, oxalic acid has been found having better enhancement than phthalic acid by overall consideration. Therefore, we successfully quantified the 15 amino acids in Sepia bulk pharmaceutical chemical by using oxalic acid as the additive.

  19. Ultrahigh-performance liquid chromatography/electrospray ionization linear ion trap Orbitrap mass spectrometry of antioxidants (amines and phenols) applied in lubricant engineering.

    Science.gov (United States)

    Kassler, Alexander; Pittenauer, Ernst; Doerr, Nicole; Allmaier, Guenter

    2014-01-15

    For the qualification and quantification of antioxidants (aromatic amines and sterically hindered phenols), most of them applied as lubricant additives, two ultrahigh-performance liquid chromatography (UHPLC) electrospray ionization mass spectrometric methods applying the positive and negative ion mode have been developed for lubricant design and engineering thus allowing e.g. the study of the degradation of lubricants. Based on the different chemical properties of the two groups of antioxidants, two methods offering a fast separation (10 min) without prior derivatization were developed. In order to reach these requirements, UHPLC was coupled with an LTQ Orbitrap hybrid tandem mass spectrometer with positive and negative ion electrospray ionization for simultaneous detection of spectra from UHPLC-high-resolution (HR)-MS (full scan mode) and UHPLC-low-resolution linear ion trap MS(2) (LITMS(2)), which we term UHPLC/HRMS-LITMS(2). All 20 analytes investigated could be qualified by an UHPLC/HRMS-LITMS(2) approach consisting of simultaneous UHPLC/HRMS (elemental composition) and UHPLC/LITMS(2) (diagnostic product ions) according to EC guidelines. Quantification was based on an UHPLC/LITMS(2) approach due to increased sensitivity and selectivity compared to UHPLC/HRMS. Absolute quantification was only feasible for seven analytes with well-specified purity of references whereas relative quantification was obtainable for another nine antioxidants. All of them showed good standard deviation and repeatability. The combined methods allow qualitative and quantitative determination of a wide variety of different antioxidants including aminic/phenolic compounds applied in lubricant engineering. These data show that the developed methods will be versatile tools for further research on identification and characterization of the thermo-oxidative degradation products of antioxidants in lubricants. Copyright © 2013 John Wiley & Sons, Ltd.

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

    Directory of Open Access Journals (Sweden)

    Lin Zhang

    2016-04-01

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

  1. Simultaneous Quantification of Antioxidant Compounds in Phellinus igniarius Using Ultra Performance Liquid Chromatography-Photodiode Array Detection-Electrospray Ionization Tandem Mass Spectrometry.

    Directory of Open Access Journals (Sweden)

    Dan Shou

    Full Text Available Natural antioxidants are widely used in the life sciences. Phellinus igniarius is a historically used natural antioxidant containing a variety of active compounds. Phenols, particularly Inoscavin A and Hypholomine B, are found in the high concentrations. Better quantitative methods are needed to perform quality control in order to support further research of this mushroom. An ultra-performance liquid chromatography method coupled to photodiode-array detection and an electrospray ionization tandem mass spectrometry method (UPLC-PAD-MS was developed to simultaneously quantify Inoscavin A and Hypholomine B levels in the medicinal fungus Phellinus igniarius. The two compounds were quantified using UPLC-PAD and UPLC-MS. The methods were accurate (mean accuracy for spiked matrix ranged from 101.5% to 105.8%, sensitive (limit of detection ranged from 0.28 to 1.14 mg L-1 and precise (the relative standard deviations ranged from 0.13 to 2.8%. Inoscavin A and Hypholomine B were purified using high-speed counter-current chromatography (HSCCC, structural evaluated to meet the request of standard substances. UPLC separation was performed on a reversed-phase C18 column using gradient elution with acetonitrile and 0.1% formic acid over 10 min. The developed method was successfully applied to determine Inoscavin A and Hypholomine B in twelve Phellinus igniarius samples of different origins and the results showed that it was suitable for the analysis of these active components in Phellinus igniarius samples.

  2. Simultaneous determination of 13 phytohormones in oilseed rape tissues by liquid chromatography-electrospray tandem mass spectrometry and the evaluation of the matrix effect.

    Science.gov (United States)

    Fan, Sufang; Wang, Xiupin; Li, Peiwu; Zhang, Qi; Zhang, Wen

    2011-03-01

    In the experiment, a high-performance liquid chromatography and electrospray ionization-tandem mass spectrometry with selected reaction monitoring was used to simultaneously determine various classes of phytohormones, including indole-3-acetic acid, α-naphthaleneacetic acid, 2-chlorobenzoic acid, 4-chlorobenzoic acid, indole-3-butyric acid, gibberellic acid, 2,4-dichlorophenoxyacetic acid, 2-naphthoxyacetic acid, abscisic acid, 2,3,5-triiodobenzoic acid, uniconazole, paclobutrazol and 2,4-epibassinolide in rape tissues. The analyses were separated by an HPLC equipped with a reversed-phase column using a binary solvent system composed of methanol and water, both containing 0.1% of formic acid. The matrix effect was also considered and determined. The technology was applied to analyze rape tissues, including roots, stems, leaves, flowers, immature pods and rape seeds. The rape tissues were subjected to ultrasound-assisted extraction and purified by dispersive solid-phase extraction, and then transferred into the liquid chromatography system. The detection limit for each plant hormone was defined by the ratio of signal/background noise (S/N) of 3. The results showed perfect linearity (R(2) values of 0.9987-1.0000) and reproducibility of elution times (relative standard deviations, RSDs,<1%) and peak areas (RSDs,<7%) for all target compounds. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. A framework to estimate concentrations of potentially unknown substances by semi-quantification in liquid chromatography electrospray ionization mass spectrometry

    DEFF Research Database (Denmark)

    Pieke, Eelco Nicolaas; Granby, Kit; Trier, Xenia

    2017-01-01

    . Positive electrospray (ESI+) was found to have more complex source interactions than negative electrospray (ESI-). Choice of quantification marker resulted in better quantification if the retention time difference was minimized (12 out of 12 cases error factor ...Risk assessment of exposure to chemicals from food and other sources rely on quantitative information of the occurrence of these chemicals. As screening analysis is increasingly used, a strategy to semi-quantify unknown or untargeted analytes is required. A proof of concept strategy to semi...... selected analytes were semi-quantified using a different analyte to assess the quantification performance under various conditions. It was found that source conditions had strong effects on the responses, with the range of low-response signals varying from −80% to over +300% compared to centerpoints...

  4. Determination of mazindol in human oral fluid by high performance liquid chromatography-electrospray ionization mass spectrometry.

    Science.gov (United States)

    de Oliveira, Marcella Herbstrith; Carlos, Graciela; Bergold, Ana Maria; Pechansky, Flavio; Limberger, Renata Pereira; Fröehlich, Pedro Eduardo

    2014-08-01

    Brazil is one of the countries most affected by abuse of stimulant medications by professional drivers, especially fenproporex, amfepramone and mazindol. Even though their sale is banned, they can be found in illegal markets, such as those located on the country's borders. The use of oral fluid to monitor drug levels has many advantages over plasma and urine because it is noninvasive, easier to collect and more difficult to adulterate. The aim of this study was to develop and validate a sensitive and specific method to quantify mazindol in human oral fluid by liquid chromatography-mass spectrometry (LC-MS). The LC system consisted of an LC-MS system operated in selected ion monitoring mode. The mobile phase was composed of water at pH 4.0, acetonitrile and methanol (60:15:25 v/v/v) at a flow rate of 1.0 mL/min and propranolol was used as internal standard. Total running time was 10 min. The lower limit of quantification was 0.2 ng/mL and the method exhibited good linearity within the 0.2-20 ng/mL range (r = 0.9987). A rapid, specific, sensitive, linear, precise and accurate method was developed for determination of mazindol in human oral fluid according to European Medicines Agency guidelines, and is suitable for monitoring mazindol levels in oral fluid of professional drivers. Copyright © 2014 John Wiley & Sons, Ltd.

  5. Qualitative and semi-quantitative analysis of phenolics in Eucalyptus globulus leaves by high-performance liquid chromatography coupled with diode array detection and electrospray ionisation mass spectrometry.

    Science.gov (United States)

    Boulekbache-Makhlouf, Lila; Meudec, Emmanuelle; Mazauric, Jean-Paul; Madani, Khodir; Cheynier, Véronique

    2013-02-01

    Eucalyptus species are widely cultivated in Mediterranean regions. Moreover, plants of this family have been utilized for medicinal purposes. A number of studies have been devoted to the identification of eucalypt phenolics, all of them have focused on specific families of compounds, and no exhaustive profiling has been reported in leaves of this plant. To develop methods that allows the identification and quantification of different classes of phenolics in Eucalyptus globulus leaf. Acetonic extract was fractionated by chromatography on a Sephadex LH-20 column using consecutive elution with ethanol, methanol and aqueous acetone (60%). High-performance liquid chromatography coupled with diode array detection and electrospray ionization mass spectrometry (HPLC-DAD-ESI/MS) were applied to determine the structure of different compounds. Quantities were evaluated from peak areas in the HPLC profile, using external calibration curves. Fractionation of acetonic extract yielded three fractions: F1, F2 and F3. In total 39 phenolic compounds are detected. Among them: 16 hydrolyzable tannins, 3 terpenyl derivatives, 12 ellagic acid derivatives, 5 flavonols, 2 hydroxybenzoic acids and 1 formylated phloroglucinol. 26 compounds described in this study have not previously detected in leaves of this plant and this is the first report of quercetin 3-O-β-galactoside-6"-O-gallate and cypellogin A and B, in E. globulus plant. Quantitatively, ellagic acid derivatives and sideroxylonal A or B are largely predominant. Fractionation of crude extract by chromatography on Sephadex LH-20 was efficient to separate different molecular weight compounds. HPLC-DAD-ESI/MS enabled detection of gallotannin, ellagitannin and flavonol derivatives, in leaves of E. globulus. Copyright © 2012 John Wiley & Sons, Ltd.

  6. Ultra pressure liquid chromatography-negative electrospray ionization mass spectrometry determination of twelve halobenzoquinones at ng/L levels in drinking water.

    Science.gov (United States)

    Huang, Rongfu; Wang, Wei; Qian, Yichao; Boyd, Jessica M; Zhao, Yuli; Li, Xing-Fang

    2013-05-07

    We report here the characterization of twelve halobenzoquinones (HBQs) using electrospray ionization (ESI) high resolution quadrupole time-of-flight mass spectrometry. The high resolution negative ESI spectra of the twelve HBQs formed two parent ions, [M + H(+) + 2e(-)], and the radical M(-•). The intensities of these two parent ions are dependent on their chemical structures and on instrumental parameters such as the source temperature and flow rate. The characteristic ions of the HBQs were used to develop an ultra pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. At the UPLC flow rate (400 μL/min) and under the optimized ESI conditions, eleven HBQs showed the stable and abundant transitions [M + H(+) + 2e(-)] → X(-) (X(-) representing Cl(-), Br(-), or I(-)), while dibromo-dimethyl-benzoquinone (DBDMBQ) showed only the transition of M(-•) → Br(-). The UPLC efficiently separates all HBQs including some HBQ isomers, while the MS/MS offers exquisite limits of detection (LODs) at subng/mL levels for all HBQs except DBDMBQ. Combined with solid phase extraction (SPE), the method LOD is down to ng/L. The results from analysis of authentic samples demonstrated that the SPE-UPLC-MS/MS method is reliable, fast, and sensitive for the identification and quantification of the twelve HBQs in drinking water.

  7. Fully automated determination of 74 pharmaceuticals in environmental and waste waters by online solid phase extraction-liquid chromatography-electrospray-tandem mass spectrometry.

    Science.gov (United States)

    López-Serna, Rebeca; Pérez, Sandra; Ginebreda, Antoni; Petrović, Mira; Barceló, Damià

    2010-12-15

    The present work describes the development of a fully automated method, based on on-line solid-phase extraction (SPE)-liquid chromatography-electrospray-tandem mass spectrometry (LC-MS-MS), for the determination of 74 pharmaceuticals in environmental waters (superficial water and groundwater) as well as sewage waters. On-line SPE is performed by passing 2.5 mL of the water sample through a HySphere Resin GP cartridge. For unequivocal identification and confirmation two selected reaction monitoring (SRM) transitions are monitored per compound, thus four identification points are achieved. Quantification is performed by the internal standard approach, indispensable to correct the losses during the solid phase extraction, as well as the matrix effects. The main advantages of the method developed are high sensitivity (limits of detection in the low ng L(-1) range), selectivity due the use of tandem mass spectrometry and reliability due the use of 51 surrogates and minimum sample manipulation. As a part of the validation procedure, the method developed has been applied to the analysis of various environmental and sewage samples from a Spanish river and a sewage treatment plant. Copyright © 2010 Elsevier B.V. All rights reserved.

  8. Application of high performance liquid chromatography coupled with ultraviolet spectroscopy and electrospray mass spectrometry to the characterisation of ellagitannins from Terminalia macroptera roots.

    Science.gov (United States)

    Silva, O; Gomes, E T; Wolfender, J L; Marston, A; Hostettmann, K

    2000-11-01

    Terminalia macroptera roots are used in Guinea-Bissau and other West African countries to treat infectious diseases like gonorrhoea. Previous work showed an ethanol extract of T. macroptera roots (T) to have an in vitro antimicrobial profile against Neisseria gonorrhoae (including resistant strains) and enteropathogenic agents. The most active fractions of this extract were identified as the diethyl ether (T2) and water (T5) fractions. The aim of the present study was the identification of major compounds present in T and simultaneously in T2 or T5. The T extract and T2 and T5 fractions were analysed by high performance liquid chromatography coupled with ultraviolet photodiode array (LC-UV) spectroscopy and electrospray ionization mass spectrometry (ES-MS). These analyses indicated the presence of ellagitannin derivatives. In order to confirm the identities of the detected compounds, they were isolated from T2 and T5 by preparative chromatographic techniques and identified by spectroscopic methods including tandem mass spectrometry. By using LC-UV-ES-MS, four major compounds (ellagic acid, gallic acid, punicalagin, terchebulin) could be identified in the T extract. Three other compounds (3,3'di-O-methylellagic acid, 3,4,3',4'-tetra-O-methylellagic acid, terflavin A) were also isolated and identified. LC-UV-ES-MS is a useful technique for the analysis of mixtures containing ellagitannins.

  9. High-performance thin-layer chromatography screening of multi class antibiotics in animal food by bioluminescent bioautography and electrospray ionization mass spectrometry.

    Science.gov (United States)

    Chen, Yisheng; Schwack, Wolfgang

    2014-08-22

    The world-wide usage and partly abuse of veterinary antibiotics resulted in a pressing need to control residues in animal-derived foods. Large-scale screening for residues of antibiotics is typically performed by microbial agar diffusion tests. This work employing high-performance thin-layer chromatography (HPTLC) combined with bioautography and electrospray ionization mass spectrometry introduces a rapid and efficient method for a multi-class screening of antibiotic residues. The viability of the bioluminescent bacterium Aliivibrio fischeri to the studied antibiotics (16 species of 5 groups) was optimized on amino plates, enabling detection sensitivity down to the strictest maximum residue limits. The HPTLC method was developed not to separate the individual antibiotics, but for cleanup of sample extracts. The studied antibiotics either remained at the start zones (tetracyclines, aminoglycosides, fluoroquinolones, and macrolides) or migrated into the front (amphenicols), while interfering co-extracted matrix compounds were dispersed at hRf 20-80. Only after a few hours, the multi-sample plate image clearly revealed the presence or absence of antibiotic residues. Moreover, molecular information as to the suspected findings was rapidly achieved by HPTLC-mass spectrometry. Showing remarkable sensitivity and matrix-tolerance, the established method was successfully applied to milk and kidney samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Determination of toosendanin in rat plasma by ultra-performance liquid chromatography-electrospray ionization-mass spectrometry and its application in a pharmacokinetic study.

    Science.gov (United States)

    Wang, Xintang; Wang, Changhong; Wang, Zhengtao

    2013-02-01

    Toosendanin (TSN) is a major triterpenoid existing in Melia toosendan, which has been used as a digestive tract parasiticide and insecticide but with serious hepatotoxicity. An ultra-performance liquid chromatography-electrospray ionization-mass spectrometry method was developed for determination of TSN in rat plasma. Plasma samples were separated on Acquity UPLC(TM) BEH C(18) column with acetonitrile and water as flow phase by gradient elution and determined by quadrupole mass spectrometer in negative selective ion monitoring mode. Usolic acid was used as internal standard. The calibration curves were linear over 0.02-3.0 µg/mL for TSN with a lower limit of quantification (LLOQ) of 20 ng/mL in rat plasma. The extraction recoveries of TSN were within 74.3-80.7% with an accuracy of 94.5-108.9%. The intra- and inter-day precision values of the assay at three quality control levels were 8.8-13.8% and TSN in rats after a single intravenous and oral administration of 2 and 60 mg/kg. The shorter T(max) , higher V(d) and Cl of TSN after oral administration indicated that TSN could be absorbed, distributed and eliminated quickly in rats in vivo. The absolute bioavailability of TSN after oral administration was 9.9%. Copyright © 2012 John Wiley & Sons, Ltd.

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

    Directory of Open Access Journals (Sweden)

    Daniel O. Carvalho

    2015-08-01

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

  12. Comparison and characterization of soybean and sunflower lecithins used for chocolate production by high-performance thin-layer chromatography with fluorescence detection and electrospray mass spectrometry.

    Science.gov (United States)

    Krüger, Stephanie; Bürmann, Laura; Morlock, Gertrud E

    2015-03-25

    The scarce availability of nongenetically modified soybeans on the world market represents a growing problem for food manufacturers. Hence, in this study the effects of substituting soybean with sunflower lecithin were investigated with regard to chocolate production. The glycerophospholipid pattern of the different lecithin samples was investigated by high-performance thin-layer chromatography fluorescence detection (HPTLC-FLD) and by HPTLC-positive ion electrospray ionization mass spectrometry (ESI(+)-MS) via the TLC-MS Interface and by scanning HPTLC-matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOFMS). Especially, the contents of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were of interest due to the influencing effects of these two glycerophospholipids on the rheological parameters of chocolate production. The lecithin substitution led to only slight differences in the rheological parameters of milk and dark chocolate. Limits of detection (LODs) and limits of quantification (LOQs) of seven glycerophospholipids were studied for three detection modes. Mean LODs ranged from 8 to 40 mg/kg for HPTLC-FLD and, using a single-quadrupole MS, from 10 to 280 mg/kg for HPTLC-ESI(+)-MS as well as from 15 to 310 mg/kg for HPTLC-FLD-ESI(+)-MS recorded after derivatization with the primuline reagent.

  13. Determination of benzoxazinone derivatives in plants by combining pressurized liquid extraction-solid-phase extraction followed by liquid chromatography-electrospray mass spectrometry.

    Science.gov (United States)

    Villagrasa, Marta; Guillamón, Miriam; Eljarrat, Ethel; Barceló, Damià

    2006-02-22

    A new analytical method based on the use of pressurized liquid extraction (PLE) followed by solid-phase extraction with LiChrolut RP C18 cartridges was evaluated for the sample preparation, extraction, and cleanup of eight naturally occurring benzoxazinone derivatives, 2-beta-D-glucopyranosyloxy-4-hydroxy-1,4-benzoxazin-3-one, 2-beta-D-glucopyranosyloxy-4-hydroxy-7-methoxy-1,4-benzoxazin-3-one, 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA), 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one, 2-hydroxy-1,4-benzoxazin-3-one, 2-hydroxy-7-methoxy-1,4-benzoxazin-3-one, benzoxazolin-2-one, and 6-methoxybenzoxazolin-2-one in plant samples. Afterward, liquid chromatography-electrospray mass spectrometry, using the selected ion monitoring mode and internal standard (2-MeO-DIBOA, indoxyl-beta-D-glucoside, and quercetin-3-O-rutinoside) quantification method was performed. This paper demonstrates the effectiveness of the PLE method, in conjunction with sensitive and specific mass spectrometric detection, for the quantitative recovery of compounds of the benzoxazinone class from plants. The recoveries of the analytes ranged from 66 to 110% with coefficients of variation ranging from 1 to 14%. This method gave detection limits between 1 and 27 microg/g. The method was applied to foliage and roots of three different wheat cultivars, and the analytes were detected in the range of 11-3261 microg/g of dry weight.

  14. Multi-residue analysis of drugs of abuse in wastewater and surface water by solid-phase extraction and liquid chromatography-positive electrospray ionisation tandem mass spectrometry.

    Science.gov (United States)

    Baker, David R; Kasprzyk-Hordern, Barbara

    2011-03-25

    A new-multi residue method was developed for the environmental monitoring of 65 stimulants, opiod and morphine derivatives, benzodiazepines, antidepressants, dissociative anaesthetics, drug precursors, human urine indicators and their metabolites in wastewater and surface water. The proposed analytical methodology offers rapid analysis for a large number of compounds, with low limits of quantification and utilises only one solid-phase extraction-ultra performance liquid chromatography-positive electrospray ionisation tandem mass spectrometry (SPE-LC-MS/MS) method, thus overcoming the drawbacks of previously published procedures. The method employed solid phase extraction with the usage of Oasis MCX sorbent and subsequent ultra performance liquid chromatography-positive electrospray ionisation tandem mass spectrometry. The usage of a 1.7 μm particle size column (1 mm×150 mm) resulted in very low flow rates (0.04 mLmin(-1)), and as a consequence gave good sensitivity, low mobile phase consumption and short retention times for all compounds (from 2.9 to 23.1 min). High SPE recoveries (>60%) were obtained for the majority of compounds. The mean correlation coefficients of the calibration curves were typically higher than 0.997 and showed good linearity in the range 0-1000 μgL(-1). The method limits of detection ranged from 0.1 ngL(-1) for compounds including cocaine, benzoylecgonine, norbenzoylecgonine and 2-oxo-3-hydroxy-LSD to 100 ngL(-1) for caffeine. Method quantification limits ranged from 0.5 to 154.2 ngL(-1). Intra- and inter-day repeatabilities were on average less than 10%. The method accuracy range was within -33.1 to 30.1%. The new multi-residue method was used to analyse drugs of abuse in wastewater and river water in the UK environment. Of the targeted 65 compounds, 46 analytes were detected at levels above the method quantification limit (MQL) in wastewater treatment plant (WWTP) influent, 43 in WWTP effluent and 36 compounds in river water. Copyright

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Bert Lagrain

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

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

    International Nuclear Information System (INIS)

    Xu Weihai; Zhang Gan; Zou Shichun; Li Xiangdong; Liu Yuchun

    2007-01-01

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

  18. Pharmacokinetic Study of a Diclofenac Sodium Capsule Filled with Enteric-coated Pellets in Healthy Chinese Volunteers by Liquid Chromatography-electrospray Ionization-tandem Mass Spectrometry.

    Science.gov (United States)

    Ma, J-Y; Liu, M; Yang, M; Zhao, H; Tong, Y; Zhang, Y; Deng, M; Liu, H

    2016-05-01

    The pharmacokinetic study of a diclofenac sodium capsule filled with enteric-coated pellets (abbreviated as CAPSULE) in healthy Chinese subjects was evaluated using liquid chromatography-electrospray ionization-tandem mass spectrometry with simple sample preparation. In a cross-over study, 12 healthy male volunteers were given 50 mg CAPSULE and diclofenac sodium enteric-coated tablet (abbreviated as TABLET, used as a control dosage form) at fasting. The Cmax, AUC0-t, and Tmax of CAPSULE were 1.01±0.52 μg/mL, 1.54±0.18 μg·h/mL, and 1.50±1.31 h, respectively. When compared with TABLET, the pharmacokinetic study showed that although this CAPSULE exhibited similar AUC (only 10% lower), it presented lower maximum plasma concentration, faster absorption and shorter time to reach maximum concentration. When compared with the previous study in Germany, obvious variations on Tmax were found in Chinese subjects taking CAPSULE, but not TABLET. The results indicated that individual difference should be paid attention when prescribing CAPSULE to Chinese patients. © Georg Thieme Verlag KG Stuttgart · New York.

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

    Directory of Open Access Journals (Sweden)

    Chi Wang

    2016-01-01

    Full Text Available Corn peptides (CPs are reported to have many biological functions, such as facilitating alcohol metabolism, antioxidation, antitumor, antihypertension, and hepatoprotection. To develop a method for quality control, the high-performance liquid chromatography (HPLC system was applied. Twenty-eight common peaks were found in all the CPs of corn samples from Enshi, China, based on which, a fingerprinting chromatogram was established for use in quality control in future research. Subsequently, the major chemical constituents of these common peaks were identified respectively using the HPLC-diode-array detection electrospray ionization tandem mass spectrometry (DAD-ESI-MS/MS system, and 48 peptide fractions were determined ultimately. This was the first time for the majority of these peptides to be reported, and many of them contained amino acids of glutamine (Q, L and A, which might play an important role in the exhibition of the bioactivities of CPs. Many peptides had a similar primary structure to the peptides which had been proven to be bioactive such as facilitating alcohol metabolism, scavenging free radicals, and inhibiting lipid peroxidation. This systematical analysis of the primary structure of CPs facilitated subsequent studies on the relationship between the structures and functions, and could accelerate holistic research on CPs.

  20. High-performance liquid chromatography electrospray ionization tandem mass spectrometry for the detection and quantitation of pyrrolizidine alkaloid-derived DNA adducts in vitro and in vivo.

    Science.gov (United States)

    Fu, Peter P; Chou, Ming W; Churchwell, Mona; Wang, Yuping; Zhao, Yuewei; Xia, Qingsu; Gamboa da Costa, Gonçalo; Marques, M Matilde; Beland, Frederick A; Doerge, Daniel R

    2010-03-15

    Pyrrolizidine alkaloid-containing plants are widespread in the world and are probably the most common poisonous plants affecting livestock, wildlife, and humans. Pyrrolizidine alkaloids require metabolism to exert their genotoxicity and tumorigenicity. We have determined that the metabolism of a series of tumorigenic pyrrolizidine alkaloids in vitro or in vivo generates a common set of (+/-)-6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine (DHP)-derived DNA adducts that are responsible for tumor induction. The identification and quantitation of the DHP-derived DNA adducts formed in vivo and in vitro were accomplished previously by (32)P-postlabeling/HPLC methodology. In this article, we report the development of a sensitive and specific liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ES-MS/MS) method to detect DHP-derived DNA adducts formed in vitro and in vivo. The method is used to quantify the levels of DHP-2'-deoxyguanosine (dG) and DHP-2'-deoxyadenosine (dA) adducts by multiple reaction monitoring (MRM) analysis in the presence of known quantities of isotopically labeled DHP-dG and DHP-dA internal standards. This HPLC-ES-MS/MS method is accurate and precise. When applied to liver samples from rats treated with the pyrrolizidine alkaloids riddelliine and monocrotaline, the method provided significant new information regarding the mechanism of DNA adduct formation.

  1. A low-makeup beveled tip capillary electrophoresis /electrospray ionization mass spectrometry interface for micellar electrokinetic chromatography and nonvolatile buffer capillary electrophoresis.

    Science.gov (United States)

    Tseng, Mei-Chun; Chen, Yet-Ran; Her, Guor-Rong

    2004-11-01

    A robust interface has been developed for interfacing micellar electrokinetic chromatography (MEKC) and nonvolatile buffer capillary electrophoresis (CE) to electrospray ionization mass spectrometry (ESI-MS). The interface consists of two parallel capillaries for separation (50 microm i.d. x 155 microm o.d.) and makeup (50 microm i.d. x 155 microm o.d.) housed within a larger capillary (530 microm i.d. x 690 microm o.d.). The capillaries terminate in a single tapered tip having a beveled edge. The use of a tapered beveled edge results in a greater tip orifice diameter (75 microm) than in a previous design from our laboratory (25 microm) that used a flat tip. While maintaining a similar optimum flow rate and consequently similar sample dilution, a 75-microm beveled emitter is more rugged than a 25-microm flat tip. Furthermore, the incorporation of a sheath liquid capillary allows the compositions of the final spray solution to be controlled. The application of this novel CE/ESI-MS interface was demonstrated for MEKC using mixtures of triazines (positive ion mode) and phenols (negative ion mode). The ability to perform CE/ESI-MS using a nonvolatile buffer was demonstrated by the analysis of gangliosides with a buffer consisting of 40 mM borate and 20 mM alpha-cyclodextrin.

  2. Factorial design optimization of experimental variables in preconcentration of carbamates pesticides in water samples using solid phase extraction and liquid chromatography-electrospray-mass spectrometry determination.

    Science.gov (United States)

    Latrous El Atrache, Latifa; Ben Sghaier, Rafika; Bejaoui Kefi, Bochra; Haldys, Violette; Dachraoui, Mohamed; Tortajada, Jeanine

    2013-12-15

    An experimental design was applied for the optimization of extraction process of carbamates pesticides from surface water samples. Solid phase extraction (SPE) of carbamates compounds and their determination by liquid chromatography coupled to electrospray mass spectrometry detector were considered. A two level full factorial design 2(k) was used for selecting the variables which affected the extraction procedure. Eluent and sample volumes were statistically the most significant parameters. These significant variables were optimized using Doehlert matrix. The developed SPE method included 200mg of C-18 sorbent, 143.5 mL of water sample and 5.5 mL of acetonitrile in the elution step. For validation of the technique, accuracy, precision, detection and quantification limits, linearity, sensibility and selectivity were evaluated. Extraction recovery percentages of all the carbamates were above 90% with relative standard deviations (R.S.D.) in the range of 3-11%. The extraction method was selective and the detection and quantification limits were between 0.1 and 0.5 µg L(-1), and 1 and 3 µg L(-1), respectively. © 2013 Elsevier B.V. All rights reserved.

  3. Chemical analysis of raw and processed Fructus arctii by high-performance liquid chromatography/diode array detection-electrospray ionization-mass spectrometry

    Science.gov (United States)

    Qin, Kunming; Liu, Qidi; Cai, Hao; Cao, Gang; Lu, Tulin; Shen, Baojia; Shu, Yachun; Cai, Baochang

    2014-01-01

    Background: In traditional Chinese medicine (TCM), raw and processed herbs are used to treat the different diseases. Fructus Arctii, the dried fruits of Arctium lappa l. (Compositae), is widely used in the TCM. Stir-frying is the most common processing method, which might modify the chemical compositions in Fructus Arctii. Materials and Methods: To test this hypothesis, we focused on analysis and identification of the main chemical constituents in raw and processed Fructus Arctii (PFA) by high-performance liquid chromatography/diode array detection-electrospray ionization-mass spectrometry. Results: The results indicated that there was less arctiin in stir-fried materials than in raw materials. however, there were higher levels of arctigenin in stir-fried materials than in raw materials. Conclusion: We suggest that arctiin reduced significantly following the thermal conversion of arctiin to arctigenin. In conclusion, this finding may shed some light on understanding the differences in the therapeutic values of raw versus PFA in TCM. PMID:25422559

  4. Direct analysis of psychoactive tryptamine and harmala alkaloids in the Amazonian botanical medicine ayahuasca by liquid chromatography-electrospray ionization-tandem mass spectrometry.

    Science.gov (United States)

    McIlhenny, Ethan H; Pipkin, Kelly E; Standish, Leanna J; Wechkin, Hope A; Strassman, Rick; Barker, Steven A

    2009-12-18

    A direct injection/liquid chromatography-electrospray ionization-tandem mass spectrometry procedure has been developed for the simultaneous quantitation of 11 compounds potentially found in the increasingly popular Amazonian botanical medicine and religious sacrament ayahuasca. The method utilizes a deuterated internal standard for quantitation and affords rapid detection of the alkaloids by a simple dilution assay, requiring no extraction procedures. Further, the method demonstrates a high degree of specificity for the compounds in question, as well as low limits of detection and quantitation despite using samples for analysis that had been diluted up to 200:1. This approach also appears to eliminate potential matrix effects. Method bias for each compound, examined over a range of concentrations, was also determined as was inter- and intra-assay variation. Its application to the analysis of three different ayahuasca preparations is also described. This method should prove useful in the study of ayahuasca in clinical and ethnobotanical research as well as in forensic examinations of ayahuasca preparations.

  5. Identification of acteoside and its major metabolites in rat urine by ultra-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Qi, Meng; Xiong, Aizhen; Li, Pengfei; Yang, Qiming; Yang, Li; Wang, Zhengtao

    2013-12-01

    In this study, metabolites in the urine samples of rats orally administered with acteoside, a phenylethanoid glycoside compound, were detected and identified using ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC/ESI-QTOF-MS) combined with an automated MS(E) technique. Up to 35 metabolites (19 metabolites of the parent drug and 16 metabolites of the degradation products) were observed, including processes of oxidization, glucuronidation, sulfation, and methyl conjugation. According to the metabolic pathways, acteoside mainly functioned as a prodrug and underwent hydrolysis before being absorbed into the blood. The degradation products, especially caffeic acid and hydroxytyrosol, were involved in further metabolism which was responsible for the low oral bioavailability but obvious pharmacological activities of acteoside. In summary, this work provided valuable information on acteoside metabolism through the rapid and reliable UPLC/ESI-QTOF-MS technique, which could be widely used for the investigation of natural product metabolites. Copyright © 2013 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2016-09-05

    Cloud-point extraction (CPE) is attracting increasing interest in a number of analytical fields, including bioanalysis, as it provides a simple, safe and environmentally-friendly sample preparation technique. However, there are only few reports on the application of this extraction technique in liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) analysis. In this study, CPE was used for the isolation of antazoline from human plasma. To date, only one method of antazoline isolation from plasma exists-liquid-liquid extraction (LLE). The aim of this study was to prove the compatibility of CPE and LC-ESI-MS/MS and the applicability of CPE to the determination of antazoline in spiked human plasma and clinical samples. Antazoline was isolated from human plasma using Triton X-114 as a surfactant. Xylometazoline was used as an internal standard. NaOH concentration, temperature and Triton X-114 concentration were optimized. The absolute matrix effect was carefully investigated. All validation experiments met international acceptance criteria and no significant relative matrix effect was observed. The compatibility of CPE and LC-ESI-MS/MS was confirmed using clinical plasma samples. The determination of antazoline concentration in human plasma in the range 10-2500ngmL(-1) by the CPE method led to results which are equivalent to those obtained by the widely used liquid-liquid extraction method. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-02-15

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

  8. Identification of heat-induced degradation products from purified betanin, phyllocactin and hylocerenin by high-performance liquid chromatography/electrospray ionization mass spectrometry.

    Science.gov (United States)

    Herbach, Kirsten M; Stintzing, Florian C; Carle, Reinhold

    2005-01-01

    Betanin, phyllocactin (malonylbetanin) and hylocerenin (3-hydroxy-3-methylglutarylbetanin) were isolated from purple pitaya (Hylocereus polyrhizus [Weber] Britton and Rose) juice, and their degradation products generated by heating at 85 degrees C were subsequently monitored by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry. Thermal degradation of phyllocactin and hylocerenin in purified solution excluding the alleged protective effects by the juice matrix is reported for the first time. Betanin was predominantly degraded by hydrolytic cleavage, while decarboxylation and dehydrogenation were of minor relevance. In contrast, hylocerenin showed a strong tendency to decarboxylation and dehydrogenation, hydrolytic cleavage of the aldimine bond occurring secondarily. Phyllocactin degradation was most complex because of additional decarboxylation of the malonic acid moiety as well as generation and subsequent degradation of betanin due to phyllocactin demalonylation. Upon prolonged heating, all betacyanins under observation formed degradation products characterized by an additional double bond at C2-C3. Hydrolytic cleavage of the aldimine bond of phyllocactin and hylocerenin yielded previously unknown acylated cyclo-dopa derivatives traceable by positive ionization, while application of ESI(-) facilitated the detection of a glycosylated aminopropanal derivative and dopamine, which have never been described before as betanin degradation products. Copyright (c) 2005 John Wiley & Sons, Ltd.

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

    Directory of Open Access Journals (Sweden)

    Pankaj Partani

    2014-02-01

    Full Text Available A sensitive, accurate and selective liquid chromatography–tandem mass spectrometry method (LC–MS/MS was developed and validated for the simultaneous quantitation of atorvastatin (AT and its equipotent hydroxyl metabolites, 2-hydroxy atorvastatin (2-AT and 4-hydroxy atorvastatin (4-AT, in human plasma. Electrospray ionization (ESI interface in negative ion mode was selected to improve the selectivity and the sensitivity required for this application. Additionally, a solid phase extraction (SPE step was performed to reduce any ion-suppression and/or enhancement effects. The separation of all compounds was achieved in less than 6 min using a C18 reverse-phase fused-core® column and a mobile phase, composed of a mixture of 0.005% formic acid in water:acetonitrile:methanol (35:25:40, v/v/v, in isocratic mode at a flow rate of 0.6 mL/min. The method has lower limit of quantitation (LLOQ of 0.050 ng/mL for all analytes. The method has shown tremendous reproducibility, with intra- and inter-day precision less than 6.6%, and intra- and inter-day accuracy within ±4.3% of nominal values, for all analytes, and has proved to be highly reliable for the analysis of clinical samples. Keywords: Atorvastatin, LC–MS/MS, Solid phase extraction, Pharmacokinetics, Method validation

  10. Ultra high performance liquid chromatography-electrospray ionization-tandem mass spectrometry screening method for direct analysis of designer drugs, "spice" and stimulants in oral fluid.

    Science.gov (United States)

    Strano-Rossi, Sabina; Anzillotti, Luca; Castrignanò, Erika; Romolo, Francesco Saverio; Chiarotti, Marcello

    2012-10-05

    An ultra high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS) screening method for the direct analysis in oral fluid (OF) of 24 drugs, including new synthetic cannabinoids and so-called "smart" designer drugs, in a single chromatographic run was set up. Benzylpiperazine, methylone, 5,6-methylenedioxy-2-aminoindane (MDAI), fenproporex, 4-fluoroamphetamine (4-FA), 4-methyl-N-ethylcathinone (4-MEC), 4-methylamphetamine (4-MA), methylbenzodioxolylbutanamine (MBDB), mephedrone, methylthioamphetamine (MTA), methylenedioxypyrovalerone (MDPV), mefenorex, nabilone, furfenorex, clobenzorex, JWH-200, AM 694, JWH-250, JWH-073, JWH-018, JWH-019, JWH-122, HU 210 and CP 47497 were determined in a chromatographic run of 9 min only with no sample pre-treatment, after addition of ISs and dilution in mobile phase A. This method is designed to be applied to 250 μL of OF sample, anyway is suitable to be used on smaller volumes (till 100 μL). LODs vary from 1ng/mL to 20 ng/mL. No interfering peaks were observed due to similar analytes, common therapeutic drugs or endogenous compounds. Matrix effect, although present especially for mephedrone, is acceptable, allowing the detection of the compounds at the LODs described. The developed method was applied on 400 real OF samples from on-site tests performed by police officers. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Rapid separation and identification of major constituents in Pseudolarix kaempferi by ultra-performance liquid chromatography coupled with electrospray and quadrupole time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Ye, Xia; Tang, Minghai; Chen, Lijuan; Peng, Aihua; Ma, Liang; Ye, Haoyu

    2009-12-01

    A rapid and reliable method based on ultra-performance liquid chromatography (UPLC) coupled with photodiode-array detection (PDA) and electrospray ionization quadrupole time-of-flight tandem mass spectrometry (ESI-Q-TOF-MS/MS) has been developed for separation and identification of major constituents in extracts of root bark of Pseudolarix kaempferi Gordon (PKG). Identification of the constituents was carried out by interpretation of their retention times, UV absorption spectra, MS and MS/MS spectra, as well as the data provided by authentic standards and literatures. A total of 20 components were separated in only 8.0 min on a small particle size C18 column (1.7 microm). These components included nine diterpene acids, seven glycosides and four triterpenoids, among which pseudolaric acid C-O-beta-D-glucopyranoside and pseudolaric acid C2-O-beta-D-glucopyranoside were separated and identified for the first time in this study. Furthermore, the fragmentation patterns of the three types of compounds were elucidated for the first time. This established UPLC-PDA/Q-TOF-MS/MS method is reliable and effective for the separation and identification of the 20 compounds and will be useful for quality control of the crude materials of Pseudolarix kaempferi Gordon and their related preparations. Copyright 2009 John Wiley & Sons, Ltd.

  12. An ultrahigh-performance liquid chromatography method with electrospray ionization tandem mass spectrometry for simultaneous quantification of five phytohormones in medicinal plant Glycyrrhiza uralensis under abscisic acid stress.

    Science.gov (United States)

    Xiang, Yu; Song, Xiaona; Qiao, Jing; Zang, Yimei; Li, Yanpeng; Liu, Yong; Liu, Chunsheng

    2015-07-01

    An efficient simplified method was developed to determine multiple classes of phytohormones simultaneously in the medicinal plant Glycyrrhiza uralensis. Ultrahigh-performance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC/ESI-MS/MS) with multiple reaction monitoring (MRM) in negative mode was used for quantification. The five studied phytohormones are gibberellic acid (GA3), abscisic acid (ABA), jasmonic acid (JA), indole-3-acetic acid, and salicylic acid (SA). Only 100 mg of fresh leaves was needed, with one purification step based on C18 solid-phase extraction. Cinnamic acid was chosen as the internal standard instead of isotope-labeled internal standards. Under the optimized conditions, the five phytohormones with internal standard were separated within 4 min, with good linearities and high sensitivity. The validated method was applied to monitor the spatial and temporal changes of the five phytohormones in G. uralensis under ABA stress. The levels of GA3, ABA, JA, and SA in leaves of G. uralensis were increased at different times and with different tendencies in the reported stress mode. These changes in phytohormone levels are discussed in the context of a possible feedback regulation mechanism. Understanding this mechanism will provide a good chance of revealing the mutual interplay between different biosynthetic routes, which could further help elucidate the mechanisms of effective composition accumulation in medicinal plants.

  13. Comparison of Electrospray Ionization and Atmospheric Chemical Ionization Coupled with the Liquid Chromatography-Tandem Mass Spectrometry for the Analysis of Cholesteryl Esters

    Directory of Open Access Journals (Sweden)

    Hae-Rim Lee

    2015-01-01

    Full Text Available The approach of two different ionization techniques including electrospray ionization (ESI and atmospheric pressure chemical ionization (APCI coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS was tested for the analysis of cholesteryl esters (CEs. The retention time (RT, signal intensity, protonated ion, and product ion of CEs were compared between ESI and APCI. RT of CEs from both ionizations decreased with increasing double bonds, while it increased with longer carbon chain length. The ESI process generated strong signal intensity of precursor ions corresponding to [M+Na]+ and [M+NH4]+ regardless of the number of carbon chains and double bonds in CEs. On the other hand, the APCI process produced a protonated ion of CEs [M+H]+ with a weak signal intensity, and it is selectively sensitive to detect precursor ions of CEs with unsaturated fatty acids. The ESI technique proved to be effective in ionizing more kinds of CEs than the APCI technique.

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

    Science.gov (United States)

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

    2016-04-01

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

  15. Simultaneous determination of antiretroviral drugs in human hair with liquid chromatography-electrospray ionization-tandem mass spectrometry.

    Science.gov (United States)

    Wu, Yan; Yang, Jin; Duan, Cailing; Chu, Liuxi; Chen, Shenghuo; Qiao, Shan; Li, Xiaoming; Deng, Huihua

    2018-04-15

    The determination of the concentrations of antiretroviral drugs in hair is believed to be an important means for the assessment of the long-term adherence to highly active antiretroviral therapy. At present, the combination of tenofovir, lamivudine and nevirapine is widely used in China. However, there was no research reporting simultaneous determination of the three drugs in hair. The present study aimed to develop a sensitive method for simultaneous determination of the three drugs in 2-mg and 10-mg natural hair (Method 1 and Method 2). Hair samples were incubated in methanol at 37 °C for 16 h after being rinsed with methanol twice. The analysis was performed on high performance liquid chromatography tandem mass spectrometry with electronic spray ionization in positive mode and multiple reactions monitoring. Method 1 and Method 2 showed the limits of detection at 160 and 30 pg/mg for tenofovir, at 5 and 6 pg/mg for lamivudine and at 15 and 3 pg/mg for nevirapine. The two methods showed good linearity with the square of correlation coefficient >0.99 at the ranges of 416-5000 and 77-5000 pg/mg for tenofovir, 12-5000 and 15-5000 pg/mg for lamivudine and 39-50,000 and 6-50,000 pg/mg for nevirapine. They gave intra-day and inter-day coefficient of variation <15% and the recoveries ranging from 80.6 to 122.3% and from 83.1 to 114.4%. Method 2 showed LOD and LOQ better than Method 1 for tenofovir and nevirapine and matched Method 1 for lamivudine, but there was high consistency between them in the determination of the three drugs in hair. The population analysis with Method 2 revealed that the concentrations in hair were decreased with the distance of hair segment away from the scalp for the three antiretroviral drugs. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Seasonal variations in the profile of main phospholipids in Mytilus galloprovincialis mussels: A study by hydrophilic interaction liquid chromatography-electrospray ionization Fourier transform mass spectrometry.

    Science.gov (United States)

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

    2018-01-01

    A systematic characterization of phosphatidylcholines and phosphatidylethanolamines in mussels of sp Mytilus galloprovincialis was performed by high-efficiency hydrophilic interaction liquid chromatography combined with electrospray ionization and Fourier transform mass spectrometry (FTMS), based on a quadrupole-Orbitrap hybrid spectrometer. The FTMS/MS experiments under high collisional energy dissociation conditions, complemented by low-energy collisionally induced dissociation MS n (n = 2,3) experiments, performed in a linear ion trap mass spectrometer, were exploited for structural elucidation purposes. The described approach led to an unprecedented characterization of the mussel phospholipidome, with 185 phosphatidylcholines and 131 phosphatidylethanolamines species recognized, distributed among diacylic, plasmanylic, and plasmenylic forms. This was the starting point for the evaluation of the effects of season (in particular, of sea temperature) on the profile of those phospholipids. To this aim, a set of mussel samples retrieved from commercial sources in different periods of the year was considered. Principal component analysis revealed a clear separation between samples collected in periods characterized by cold, intermediate, or warm sea temperatures, respectively. In particular, an enrichment in phospholipids containing unsaturated side chains was observed in mussels collected from cold seawaters (winter-early spring), thus confirming the general model previously elaborated to explain the adaptation of marine invertebrates, including some bivalve molluscs, to low temperatures. On the other hand, relevant levels of plasma(e)nylic and acylic phospholipids bearing either saturated or non-methylene-interrupted side chains were found in mussels collected in warm seawaters (typical of summer and early autumn, at Italian latitudes). This finding opened interesting perspectives towards the development of strategies able to prevent global warming-related mussel

  17. Determination of vitamin B5 in a range of fortified food products by reversed-phase liquid chromatography-mass spectrometry with electrospray ionisation.

    Science.gov (United States)

    Mittermayr, Ruth; Kalman, Andras; Trisconi, Marie-José; Heudi, Olivier

    2004-04-02

    Methods for Vitamin B5 determination in food products remain limited by their low sensitivity and poor selectivity. Here, we have developed a liquid chromatography-mass spectrometry (LC-MS) method for Vitamin B5 determination in wide range of fortified food products. Vitamin B5 was extracted from food samples by heat treatment and analysed by LC-MS in the positive mode using electrospray ionisation (ESI). Vitamin B5 was quantified using hopantenic acid (HOPA) as internal standard after their separation on a C18 narrow-bore column with a gradient of mobile phase made of water/acetonitrile and trifluoroacetic acid (TFA) 0.025%. MS with single ion monitoring mode at mass m/z 220 was used for Vitamin B5 quantification. Calibration curve between 0.5 and 10 microg/ml of Vitamin B5 was linear (r2=0.9993) and the detection limit was determined to be 800 pg. The overall quantitative efficiency of the method was evaluated using Nestle reference sample (infant formula). The intra-assay RSD was 4.8% (n=8), the inter-assay RSD 6.4% (n=4) and the recoveries of the spiked samples were above 95%. Application of the LC-MS method to Vitamin B5 determination in wide range of fortified food products including three US National Institute of Standards and Technology (NIST) reference samples (RM 8435, RM 8415 and SRM 1546) shows consistent results with those obtained by microbiology and recoveries of Vitamin B5 between 93 and 104% for the spiked samples.

  18. Assay of labile estrogen o-quinones, potent carcinogenic molecular species, by high performance liquid chromatography-electrospray ionization tandem mass spectrometry with phenazine derivatization.

    Science.gov (United States)

    Yamashita, Kouwa; Masuda, Akina; Hoshino, Yuka; Komatsu, Sachiko; Numazawa, Mitsuteru

    2010-04-01

    A sensitive and selective assay method for labile estrogen o-quinones, estrone (E(1))-2,3-quinone (Q), E(1)-3,4-Q, estradiol (E(2))-2,3-Q and E(2)-3,4-Q, based on the use of phenazine (Phz) derivatization with o-phenylenediamine and high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) was described. The Phz derivatives of four estrogen o-quinones were purified by solid phase extraction and analyzed by HPLC-ESI-MS/MS. The protonated molecule was observed as a base peak for all Phz derivatives in their ESI-mass spectra (positive mode). In multiple reaction monitoring, the transition from [M+H]+ to m/z 231 was chosen for quantification. Calibration curves for the o-quinones were obtained using standard catechol estrogens after sodium metaperiodate treatment and Phz derivatization. Using this method, these four estrogen o-quinones were analyzed with the limit of quantification of 5 ng/ml in acetonitrile (MeCN)-blank matrix (1:4, v/v), respectively, on a basis of the weight of catechol estrogens. Assay accuracy and precision for four estrogen o-quinones were 89.6-113.0% and 3.1-12.6% (5, 125 and 2000 ng/ml in MeCN-blank matrix). Applications of this method enabled to determine the catalytic activities on hydroxylation and subsequent oxidation of E(1) and E(2) of Mushroom tyrosinase and rat liver microsomal fraction. It was confirmed by this method that tyrosinase exhibited 2- and 4-hydroxylation and further oxidation activities for catechols in the ring-A of estrogens. Whereas rat liver microsomal fraction possessed only 2- and 4-hydroxylation activities, and further oxidation activity for catechol estrogens was low. 2010 Elsevier Ltd. All rights reserved.

  19. Analysis of trichloroethylene-induced global DNA hypomethylation in hepatic L-02 cells by liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Zhang, Hang; Hong, Wen-Xu; Ye, Jinbo; Yang, Xifei; Ren, Xiaohu; Huang, Aibo; Yang, Linqing; Zhou, Li; Huang, Haiyan; Wu, Desheng; Huang, Xinfeng; Zhuang, Zhixiong; Liu, Jianjun

    2014-04-04

    Trichloroethylene (TCE), a major occupational and environmental pollutant, has been recently associated with aberrant epigenetic changes in experimental animals and cultured cells. TCE is known to cause severe hepatotoxicity; however, the association between epigenetic alterations and TCE-induced hepatotoxicity are not yet well explored. DNA methylation, catalyzed by enzymes known as DNA methyltransferases (DNMT), is a major epigenetic modification that plays a critical role in regulating many cellular processes. In this study, we analyzed the TCE-induced effect on global DNA methylation and DNMT enzymatic activity in human hepatic L-02 cells. A sensitive and quantitative method combined with liquid chromatography and electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) was validated and utilized for assessing the altered DNA methylation in TCE-induced L-02 cells. Quantification was accomplished in multiple reaction monitoring (MRM) mode by monitoring a transition pair of m/z 242.1 (molecular ion)/126.3 (fragment ion) for 5-mdC and m/z 268.1/152.3 for dG. The correlation coefficient of calibration curves between 5-mdC and dG was higher than 0.9990. The intra-day and inter-day relative standard derivation values (RSD) were on the range of 0.53-7.09% and 0.40-2.83%, respectively. We found that TCE exposure was able to significantly decrease the DNA methylation and inhibit DNMT activity in L-02 cells. Our results not only reveal the association between TCE exposure and epigenetic alterations, but also provide an alternative mass spectrometry-based method for rapid and accurate assessment of chemical-induced altered DNA methylation in mammal cells. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Solvent system selectivities in countercurrent chromatography using Salicornia gaudichaudiana metabolites as practical example with off-line electrospray mass-spectrometry injection profiling.

    Science.gov (United States)

    Costa, Fernanda das Neves; Jerz, Gerold; Figueiredo, Fabiana de Souza; Winterhalter, Peter; Leitão, Gilda Guimarães

    2015-03-13

    For the development of an efficient two-stage isolation process for high-speed countercurrent chromatography (HSCCC) with focus on principal metabolites from the ethyl acetate extract of the halophyte plant Salicornia gaudichaudiana, separation selectivities of two different biphasic solvent systems with similar polarities were evaluated using the elution and extrusion approach. Efficiency in isolation of target compounds is determined by the solvent system selectivity and their chronological use in multiple separation steps. The system n-hexane-ethyl acetate-methanol-water (0.5:6:0.5:6, v/v/v/v) resulted in a comprehensive separation of polyphenolic glycosides. The system n-hexane-n-butanol-water (1:1:2, v/v/v) was less universal but was highly efficient in the fractionation of positional isomers such as di-substituted cinnamic acid quinic acid derivatives. Multiple metabolite detection performed on recovered HSCCC tube fractions was done with rapid mass-spectrometry profiling by sequential off-line injections to electrospray mass-spectrometry (ESI-MS/MS). Selective ion traces of metabolites delivered reconstituted preparative HSCCC runs. Molecular weight distribution of target compounds in single HSCCC tube fractions and MS/MS fragment data were available. Chromatographic areas with strong co-elution effects and fractions of pure recoverable compounds were visualized. In total 11 metabolites have been identified and monitored. Result of this approach was a fast isolation protocol for S. gaudichaudiana metabolites using two solvent systems in a strategic sequence. The process could easily be scaled-up to larger lab-scale or industrial recovery. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2015-07-01

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

  2. 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.)

  3. Multi-mycotoxin Analysis of Finished Grain and Nut Products Using Ultrahigh-Performance Liquid Chromatography and Positive Electrospray Ionization-Quadrupole Orbital Ion Trap High-Resolution Mass Spectrometry.

    Science.gov (United States)

    Liao, Chia-Ding; Wong, Jon W; Zhang, Kai; Yang, Paul; Wittenberg, James B; Trucksess, Mary W; Hayward, Douglas G; Lee, Nathaniel S; Chang, James S

    2015-09-23

    Ultrahigh-performance liquid chromatography using positive electrospray ionization and quadrupole orbital ion trap high-resolution mass spectrometry was evaluated for analyzing mycotoxins in finished cereal and nut products. Optimizing the orbital ion trap mass analyzer in full-scan mode using mycotoxin-fortified matrix extracts gave mass accuracies, δM, of aflatoxin B1 in peanut and almond) to 1175 μg/kg (fumonisin B1 in corn flour) were found in 35 of the 70 commercial grain and nut samples surveyed. Mycotoxins could be identified at δM nut products.

  4. Ultrahigh-performance liquid chromatography electrospray ionization Q-Orbitrap mass spectrometry for the analysis of 451 pesticide residues in fruits and vegetables: method development and validation.

    Science.gov (United States)

    Wang, Jian; Chow, Willis; Chang, James; Wong, Jon W

    2014-10-22

    This paper presents an application of ultrahigh-performance liquid chromatography electrospray ionization quadrupole Orbitrap high-resolution mass spectrometry (UHPLC/ESI Q-Orbitrap MS) for the determination of 451 pesticide residues in fruits and vegetables. Pesticides were extracted from samples using the QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure. UHPLC/ESI Q-Orbitrap MS in full MS scan mode acquired full MS data for quantification, and UHPLC/ESI Q-Orbitrap Full MS/dd-MS(2) (i.e., data-dependent scan mode) obtained product ion spectra for identification. UHPLC/ESI Q-Orbitrap MS quantification was achieved using matrix-matched standard calibration curves along with the use of isotopically labeled standards or a chemical analogue as internal standards to achieve optimal method accuracy. The method performance characteristics include overall recovery, intermediate precision, and measurement uncertainty evaluated according to a nested experimental design. For the 10 matrices studied, 94.5% of the pesticides in fruits and 90.7% in vegetables had recoveries between 81 and 110%; 99.3% of the pesticides in fruits and 99.1% of the pesticides in vegetables had an intermediate precision of ≤20%; and 97.8% of the pesticides in fruits and 96.4% of the pesticides in vegetables showed measurement uncertainty of ≤50%. Overall, the UHPLC/ESI Q-Orbitrap MS demonstrated acceptable performance for the quantification of pesticide residues in fruits and vegetables. The UHPLC/ESI Q-Orbitrap Full MS/dd-MS(2) along with library matching showed great potential for identification and is being investigated further for routine practice.

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

    Science.gov (United States)

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

    2008-06-15

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

  6. Direct and simultaneous determination of 5-aminolaevulinic acid and porphobilinogen in urine by hydrophilic interaction liquid chromatography-electrospray ionisation/tandem mass spectrometry.

    Science.gov (United States)

    Benton, Christopher M; Couchman, Lewis; Marsden, Joanne T; Rees, David C; Moniz, Caje; Lim, Chang Kee

    2012-08-01

    Urinary concentrations of 5-aminolaevulinic acid (ALA) and porphobilinogen (PBG) are elevated in patients with acute hepatic porphyrias, especially during acute attacks. Current assays require lengthy sample pre-treatment and derivatisation steps. We report here a rapid, sensitive and specific hydrophilic interaction liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, for the direct and simultaneous quantitation of ALA and PBG in urine following simple dilution with acetonitrile and centrifugation prior to injection. ALA and PBG were detected using selected reaction monitoring mode, following positive electrospray ionisation. Urine samples (N = 46) from active and latent mutation-confirmed acute hepatic porphyria patients and normal subjects (N = 45) were analysed and the results compared with those of a commercially available spectrophotometric method. The validated calibration range was 3-3000 µmol/L for ALA and 2-2000 µmol/L for PBG. For both analytes, imprecision (relative standard deviation) was less than 5% and accuracy (percentage nominal concentrations) was between 88 and 109%. The lower limit of quantitation was 0.1 μmol/L for both analytes. The calculated LC-MS/MS and spectrophotometric results from patient samples compared well [Pearson correlation (r²) of 0.99 and 0.95, for ALA and PBG, respectively]. The method was successfully applied to the measurement of ALA and PBG in urine samples for the screening, biochemical diagnosis and treatment monitoring of patients with acute hepatic porphyrias. Copyright © 2012 John Wiley & Sons, Ltd.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-08-26

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

  8. Analysis of selected sugars and sugar phosphates in mouse heart tissue by reductive amination and liquid chromatography-electrospray ionization mass spectrometry.

    Science.gov (United States)

    Han, Jun; Tschernutter, Vera; Yang, Juncong; Eckle, Tobias; Borchers, Christoph H

    2013-06-18

    Sensitive and reliable analysis of sugars and sugar phosphates in tissues and cells is essential for many biological and cell engineering studies. However, the successful analysis of these endogenous compounds in biological samples by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) is often difficult because of their poor chromatographic retention properties in reversed-phase LC, the complex biological matrices, and the ionization suppression in ESI. This situation is further complicated by the existence of their multiple structural isomers in vivo. This work describes the combination of reductive amination using 3-amino-9-ethylcarbazole, with a new LC approach using a pentafluorophenyl core-shell ultrahigh performance (UP) LC column and methylphosphonic acid as an efficient tail-sweeping reagent for improved chromatographic separation. This new method was used for selected detection and accurate quantitation of the major free and phosphorylated reducing sugars in mouse heart tissue. Among the detected compounds, accurate quantitation of glyceraldehyde, ribose, glucose, glycerylaldehyde-3-phosphate, ribose-5-phosphate, glucose-6-phosphate, and mannose-6-phosphate was achieved by UPLC/multiple-reaction monitoring (MRM)-MS, with analytical accuracies ranging from 87.4% to 109.4% and CVs of ≤8.5% (n = 6). To demonstrate isotope-resolved metabolic profiling, we used UPLC/quadrupole time-of-flight (QTOF)-MS to analyze the isotope distribution patterns of C3 to C6 free and phosphorylated reducing sugars in heart tissues from (13)C-labeled wild type and knockout mice. In conclusion, the preanalytical derivatization-LC/ESI-MS method has resulted in selective determination of free and phosphorylated reducing sugars without the interferences from their nonreducing structural isomers in mouse heart tissue, with analytical sensitivities in the femtomole to low picomole range.

  9. Screening of lake sediments for emerging contaminants by liquid chromatography atmospheric pressure photoionization and electrospray ionization coupled to high resolution mass spectrometry.

    Science.gov (United States)

    Chiaia-Hernandez, Aurea C; Krauss, Martin; Hollender, Juliane

    2013-01-15

    We developed a multiresidue method for the target and suspect screening of more than 180 pharmaceuticals, personal care products, pesticides, biocides, additives, corrosion inhibitors, musk fragrances, UV light stabilizers, and industrial chemicals in sediments. Sediment samples were freeze-dried, extracted by pressurized liquid extraction, and cleaned up by liquid-liquid partitioning. The quantification and identification of target compounds with a broad range of physicochemical properties (log K(ow) 0-12) was carried out by liquid chromatography followed by electrospray ionization (ESI) and atmospheric pressure photoionization (APPI) coupled to high resolution Orbitrap mass spectrometry (HRMS/MS). The overall method average recoveries and precision are 103% and 9% (RSD), respectively. The method detection limits range from 0.010 to 4 ng/g(dw), while limits of quantification range from 0.030 to 14 ng/g(dw). The use of APPI as an alternative ionization source helped to distinguish two isomeric musk fragrances by means of different ionization behavior. The method was demonstrated on sediment cores from Lake Greifensee located in northeastern Switzerland. The results show that biocides, musk fragrances, and other personal care products were the most frequently detected compounds with concentrations ranging from pg/g(dw) to ng/g(dw), whereas none of the targeted pharmaceuticals were found. The concentrations of many urban contaminants originating from wastewater correlate with the highest phosphorus input into the lake as a proxy for treatment efficiency. HRMS enabled a retrospective analysis of the full-scan data acquisition allowing the detection of suspected compounds like quaternary ammonium surfactants, the biocide triclocarban, and the tentative identification of further compounds without reference standards, among others transformation products of triclosan and triclocarban.

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

    Science.gov (United States)

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

    2013-11-01

    Microcystins (MCs) are toxins produced by cyanobacteria which are common organisms in the phytoplankton of eutrophic lakes, rivers and freshwater reservoirs. In the present work, a novel method of liquid chromatography-electrospray ion trap tandem mass spectrometry (LC/ESI/Ion trap-MS/MS), operated in the negative ionization mode, was developed for the analysis of these cyanotoxins. The method was applied to determine the amounts of total microcystins-LR, -YR and -RR in two water reservoirs in Southern Portugal, namely Alqueva and Beliche. A total of 30 water samples were analysed along 2011. Solid phase extraction (SPE) was used for sample cleaning-up and analyte enrichment. The extracted toxins were separated on a C18 column with a gradient of acetonitrile/water with 0.1% formic acid. Detection of microcystins was carried out using multiple reaction monitoring (MRM) in the negative polarity mode, as this method gave a higher selectivity. The MC-RR, YR and LR quantification limits were 17.9, 31.7 and 15.8 ng/L, respectively; quite below the limits recommended by WHO guidelines for drinking water (1 μg/L). Total MC highest concentrations were found in the warm months of June, July and September in Alqueva sampling sites, with concentrations of MC LR and RR ranging 17-344 and 25-212 ng/L, respectively, showing comparable results for MC-RR and LR and slightly lower concentration of MC-YR. Detected values for Beliche reservoir were below quantification limits. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Benzylic rearrangement stable isotope labeling for quantitation of guanidino and ureido compounds in thyroid tissues by liquid chromatography-electrospray ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Ruo-Jing [State Key Laboratory of Organmetallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032 (China); Guan, Qing [Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032 (China); Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032 (China); Zhang, Fang, E-mail: fzhang@sioc.ac.cn [State Key Laboratory of Organmetallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032 (China); Leng, Jia-Peng [State Key Laboratory of Organmetallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032 (China); Sun, Tuan-Qi, E-mail: tuanqisun@163.com [Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032 (China); Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032 (China); Guo, Yin-Long, E-mail: ylguo@sioc.ac.cn [State Key Laboratory of Organmetallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032 (China)

    2016-02-18

    Benzylic rearrangement stable isotope labeling (BRSIL) was explored to quantify the guanidino and ureido compounds (GCs and UCs). This method employed a common reagent, benzil, to label the guanidino and ureido groups through nucleophilic attacking then benzylic migrating. The use of BRSIL was investigated in the analysis of five GCs (creatine, L-arginine, homoarginine, 4-guanidinobutyric acid, and methylguanidine) and two UCs (urea and citrulline). The labeling was found simple and specific. The introduction of bi-phenyl group and the generation of nitrogen heterocyclic ring in the benzil-d0/d5 labeled GCs and UCs improved the retention behaviors in liquid chromatography (LC) and increased the sensitivity of electrospray ionization mass spectrometry (ESI MS) detection. The fragment ion pairs of m/z 182/187 and m/z 210/215 from the benzil-d0/d5 tags facilitated the discovery of potential GCs and UCs candidates residing in biological matrices. The use of BRSIL combined with LC-ESI MS was applied for simultaneously quantitation of GCs and UCs in thyroid tissues. It was demonstrated that nine GCs and UCs were detected, six of which were further quantified based on corresponding standards. It was concluded that five GCs and UCs (L-arginine, homoarginine, 4-guanidinobutyric acid, methylguanidine, and citrulline) were statistically significantly different (p < 0.05) between the para-carcinoma and carcinoma thyroid tissue samples. - Highlights: • A common reagent, benzil-d0/d5 was employed to label the GCs and UCs through BRSIL. • The benzil-d0/d5 labeling improved the retention behavior in RPLC and increased the sensitivity by ESI MS detection. • BRSIL coupled with LC-ESI MS was applied to the qualitation and quantitation of GCs and UCs in thyroid tissues.

  12. Online Simultaneous Hydrogen/Deuterium Exchange of Multitarget Gas-Phase Molecules by Electrospray Ionization Mass Spectrometry Coupled with Gas Chromatography.

    Science.gov (United States)

    Jeong, Eun Sook; Cha, Eunju; Cha, Sangwon; Kim, Sunghwan; Oh, Han Bin; Kwon, Oh-Seung; Lee, Jaeick

    2017-11-21

    In this study, a hydrogen/deuterium (H/D) exchange method using gas chromatography-electrospray ionization/mass spectrometry (GC-ESI/MS) was first investigated as a novel tool for online H/D exchange of multitarget analytes. The GC and ESI source were combined with a homemade heated column transfer line. GC-ESI/MS-based H/D exchange occurs in an atmospheric pressure ion source as a result of reacting the gas-phase analyte eluted from GC with charged droplets of deuterium oxide infused as the ESI spray solvent. The consumption of the deuterated solvent at a flow rate of 2 μL min -1 was more economical than that in online H/D exchange methods reported to date. In-ESI-source H/D exchange by GC-ESI/MS was applied to 11 stimulants with secondary amino or hydroxyl groups. After H/D exchange, the spectra of the stimulants showed unexchanged, partially exchanged, and fully exchanged ions showing various degrees of exchange. The relative abundances corrected for naturally occurring isotopes of the fully exchanged ions of stimulants, except for etamivan, were in the range 24.3-85.5%. Methylephedrine and cyclazodone showed low H/D exchange efficiency under acidic, neutral, and basic spray solvent conditions and nonexchange for etamivan with an acidic phenolic OH group. The in-ESI-source H/D exchange efficiency by GC-ESI/MS was sufficient to determine the number of hydrogen by elucidation of fragmentation from the spectrum. Therefore, this online H/D exchange technique using GC-ESI/MS has potential as an alternative method for simultaneous H/D exchange of multitarget analytes.

  13. Investigation of pyrrolizidine alkaloids including their respective N-oxides in selected food products available in Hong Kong by liquid chromatography electrospray ionisation mass spectrometry.

    Science.gov (United States)

    Chung, Stephen W C; Lam, Aaron C H

    2017-07-01

    This study determined the levels of pyrrolizidine alkaloids (PAs), including their respective N-oxides, in foodstuffs available in Hong Kong by liquid chromatography-electrospray ionisation tandem mass spectrometry. A total of 234 samples (48 food items) were collected randomly from a local market and analysed. About 50% of samples were found to contain detectable amount of PAs. Amongst the 48 food items, PAs were not detected in 11 food items, including barley flour, beef, cattle liver, pork, pig liver, chicken meat, chicken liver, milk, non-fermented tea, Melissa tea and linden tea. For those found to contain detectable PAs, the summed PA content ranged up to 11,000 µg kg -1 . The highest sum of PA content among the 37 food items calculated with lower bound was cumin seed, then followed by oregano, tarragon and herbs de Provence with ranges of 2.5-11,000, 1.5-5100, 8.0-3300 and 18-1300 µg kg -1 respectively. Among the samples, the highest sum of PA content was detected in a cumin seed sample (11,000 µg kg -1 ), followed by an oregano (5100 µg kg -1 ), a tarragon (3300 µg kg -1 ) and a herbs de Provence (1300 µg kg -1 ). In general, the results of this study agreed well with other published results in peer-reviewed journals, except that the total PAs in honey and specific tea infusion in this study were comparatively lower.

  14. Development of multi-residue analysis of herbicides in cereal grain by ultra-performance liquid chromatography-electrospray ionization-mass spectrometry.

    Science.gov (United States)

    Dong, Xinfeng; Liang, Shuxuan; Shi, Zhihong; Sun, Hanwen

    2016-02-01

    A rapid and sensitive method was developed for the determination of 50 herbicides in cereal grain by ultra-performance liquid chromatography-electrospray ionization-mass spectrometry (UPLC-ESI-MS). Using acetonitrile effectively extracted 22 kinds of triazine and other basic herbicides, and using 90:10 v/v acetonitrile-phosphate buffer (pH = 7.5) effectively extracted other 28 herbicides. Chromatographic separation was achieved using gradient elution with acetonitrile-water as a mobile phase for 22 triazine and phenylurea herbicides and with 5mM ammonium acetate aqueous solution containing 0.1% formic acid-acetonitrile as a mobile phase for other 28 herbicides. Using matrix-matched standard calibration curve effectively reduced the indirect matrix effects, ensured accurate quantification for these herbicides. The response was linear over two orders of magnitude with a correlation coefficients (r(2)) higher than 0.992. The limits of quantification for the herbicides varied from 0.2 to 25.6 μg kg(-1). The intra- and inter-day precisions (relative standard deviation, RSD) were 2.2-9.3% and 5.7-17.1%, respectively. The recovery varied from 61.6% to 110% with the RSD of 1.6-11.8%. Analyzing soybean, corn and wheat samples from 17 counties evaluated this method. The developed and validated method has high sensitivity, satisfactory recovery and precision, can ensure the multi-class multi-residue analysis at low μg kg(-1) level for the most herbicides in cereal grain. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Metabolite fingerprinting of Punica granatum L. (pomegranate) polyphenols by means of high-performance liquid chromatography with diode array and electrospray ionization-mass spectrometry detection.

    Science.gov (United States)

    Brighenti, Virginia; Groothuis, Sebastiaan Frearick; Prencipe, Francesco Pio; Amir, Rachel; Benvenuti, Stefania; Pellati, Federica

    2017-01-13

    The present study was aimed at the development of a new analytical method for the comprehensive multi-component analysis of polyphenols in Punica granatum L. (pomegranate) juice and peel. While pomegranate juice was directly analysed after simple centrifugation, different extraction techniques, including maceration, heat reflux extraction, ultrasound-assisted extraction and microwave-assisted extraction, were compared in order to obtain a high yield of the target analytes from pomegranate peel. Dynamic maceration with a mixture of water and ethanol 80:20 (v/v) with 0.1% of hydrochloric acid as the extraction solvent provided the best result in terms of recovery of pomegranate secondary metabolites. The quali- and quantitative analysis of pomegranate polyphenols was performed by high-performance liquid chromatography with diode array and electrospray ionization-mass spectrometry detection. The application of fused-core column technology allowed us to obtain an improvement of the chromatographic performance in comparison with that of conventional particulate stationary phases, thus enabling a good separation of all constituents in a shorter time and with low solvent usage. The analytical method was completely validated to show compliance with the International Conference on Harmonization of Technical Requirements for the Registration of Pharmaceuticals for Human Use guidelines and successfully applied to the characterisation of commercial and experimental pomegranate samples, thus demonstrating its efficiency as a tool for the fingerprinting of this plant material. The quantitative data collected were submitted to principal component analysis, in order to highlight the possible presence of pomegranate samples with high content of secondary metabolites. From the statistical analysis, four experimental samples showed a notable content of bioactive compounds in the peels, while commercial ones still represent the best source of healthy juice. Copyright © 2016 Elsevier

  16. Monolithic silica-based capillary reversed-phase liquid chromatography/electrospray mass spectrometry for plant metabolomics

    NARCIS (Netherlands)

    Tolstikov, V.V.; Lommen, A.; Nakanishi, K.; Tanaka, N.; Fiehn, O.

    2003-01-01

    Application of C18 monolithic silica capillary columns in HPLC coupled to ion trap mass spectrometry detection was studied for probing the metabolome of the model plant Arabidopsis thaliana. It could be shown that the use of a long capillary column is an easy and effective approach to reduce

  17. Identification of forced degradation products of tedizolid phosphate by liquid chromatography/electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Lei, Yinping; Jin, Bo; Ma, Chen; Zhang, Tingting; Li, Tong

    2017-05-30

    In this study, stress degradation behavior of tedizolid phosphate was investigated and structural characterization of its degradation products were performed with the use of the UPLC-MS n and LC-HRMS. The toxicity prediction of the degradation products was performed with web-based prediction system. Tedizolid phosphate was subjected to forced degradation under hydrolytic (acid, base and neutral), oxidative, photolytic and thermal conditions in accordance with ICH guidelines Q1A(R2). The drug was degraded significantly under acid, base and oxidative conditions, while it was relatively stable to neutral, thermal and photolytic conditions. A total of four degradation products were formed. All of them have been identified and characterized based on QTRAP MS n and accurate mass measurements. To the best of our knowledge, three of these impurities were identified for the first time and two of them further synthesized and characterized by NMR spectroscopy. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Isolation and identification of phenolic compounds from rum aged in oak barrels by high-speed countercurrent chromatography/high-performance liquid chromatography-diode array detection-electrospray ionization mass spectrometry and screening for antioxidant activity.

    Science.gov (United States)

    Regalado, Erik L; Tolle, Sebastian; Pino, Jorge A; Winterhalter, Peter; Menendez, Roberto; Morales, Ana R; Rodríguez, José L

    2011-10-14

    Beverages, especially wines are well-known to contain a variety of health-beneficial bioactive substances, mainly of phenolic nature which frequently exhibit antioxidant activity. Significant information is available about the separation and identification of polyphenols from some beverages by chromatographic and spectroscopic techniques, but considerably poor is chemical data related to the polyphenolic content in rums. In this paper, a method involving the all-liquid chromatographic technique of high-speed countercurrent chromatography (HSCCC) combined with high-performance liquid chromatography coupled with diode-array detection and electrospray ionization mass spectrometry (HPLC-DAD-ESI-MS(n)) has been successfully applied for separation and identification of phenolic compounds in an aged rum. Besides, the phenolic fraction (PF) was assayed for its antioxidant effects using three different free radical in vitro assays (DPPH·, RO(2)· and spontaneous lipid peroxidation (LPO) on brain homogenates) and on ferric reducing antioxidant power (FRAP). Results showed that PF potently scavenged DPPH and strongly scavenged peroxyl radicals compared to ascorbic acid and butylated hydroxytoluene (BHT); and almost equally inhibited LPO on brain homogenates subjected to spontaneous LPO when compared to quercetin. Moreover, PF also exhibited strong reducing power. This chemical analysis illustrates the rich array of phenols in the aged rum and represents a rapid and suitable method for the isolation and identification of phenolic compounds from mixtures of considerable complexity, achieving high purity and reproducibility with the use of two separation steps. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Characteristics of glycation and glycation sites of lysozyme by matrix-assisted laser desorption/ionization time of flight/time-of-flight mass spectrometry and Liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Ruan, Eric Dongliang; Wang, Hui; Ruan, Yuanyuan; Juáreza, Manuel

    2014-01-01

    Protein glycation with reducing sugars through the Maillard reaction is regarded as one of the most important reactions in food chem- istry. Amadori rearrangement products [ARPs] are produced at the initial stage of the Maillard reaction and then advanced glycation products may be formed. We report here that using matrix-assisted laser desorption/ionization mass spectrometry with time-of-flight detection [MALDI-TOF-MS] and electrospray ionization mass spectrometry (ESI-MSJ to monitor the glycation process in lysozyme and the D-glucose model system. MALDI-TOF-MS displayed a heterogeneous distribution of glycation via a total mass shift in spectra. However electrospray ionization mass spectrometry [ESI-MS] data showed that a total of four molecules of glucose reacted with Lysozyme at an increase in molecular weight by a 162 Da unit. Further, we identified the glycation sites of lysozyme by using MALDI-TOF/TOF-MS and Liquid chromatography [LC]-ESI-MS/MS. Besides the two glycation sites of Lys1 and Lys97 identified by MALDI-TOF/TOF-MS, the other two glycation sites of Lys13 and Lys116 were characterized unambiguously by LC-ESI-MS/MS. Both MALDI-TOF/TOF-MS and LC-ESI-MS/ MS provided confidence in the study of the glycation by restricting the number of possible residues through (un]modified ions. The study is useful to monitor and characterize glycation in protein systems based on both MALDI-TOF-MS and ESI-MS. Comparatively, LC-ESI-MS/MS provides more fragments with better recovery for the identification of glycation than MALDI-TOF/TOF-MS.

  20. 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

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

    Science.gov (United States)

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

    2016-05-13

    A novel, rapid and simple analytical method was developed for the quantitative determination of crocin, crocetin and geniposide in soft drink, pastry and instant noodles. The solid samples were relatively homogenized into powders and fragments. The gardenia yellow colorants were successively extracted with methanol using ultrasound-assisted extraction. The analytes were quantitatively measured in the extracts by liquid chromatography coupled with electrospray ionization tandem mass spectrometry. High correlation coefficients (r(2)>0.995) of crocin, crocetin and geniposide were obtained within their linear ranges respectively (50-1000ng/mL, 50-1000ng/mL, 15-240ng/mL) by external standard method. The limits of detection (LODs) were 0.02μg/g for crocin, 0.01μg/g for crocetin and 0.002μg/g for geniposide. And the limits of quantitation (LOQs) were in the ranges of 0.05-0.45μg/g for crocin, and in the ranges of 0.042-0.32μg/g for crocetin, and in the ranges of 0.02-0.15μg/g for geniposide in soft drink, pastry and instant noodles samples. The average recoveries of crocin, crocetin and geniposide ranged from 81.3% to 117.6% in soft drink, pastry and instant noodles. The intra- and inter-day precisions were respectively in the range of 1.3-4.8% and 1.7-11.8% in soft drink, pastry and instant noodle. The developed methods were successfully validated and applied to the soft drink, pastry, and instant noodles collected from the located market in Beijing from China. Crocin, crocetin and geniposide were detected in the collected samples. The average concentrations ranged from 0.84 to 4.20mg/g for crocin, and from 0.62 to 3.11mg/g for crocetin, and from 0.18 to 0.79mg/g for gardenia in various food samples. The method can provide evidences for government to determine gardenia yellow pigments and geniposide in food. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Determination of acrylamide in Chinese traditional carbohydrate-rich foods using gas chromatography with micro-electron capture detector and isotope dilution liquid chromatography combined with electrospray ionization tandem mass spectrometry

    International Nuclear Information System (INIS)

    Zhang Yu; Ren Yiping; Zhao Hangmei; Zhang Ying

    2007-01-01

    The present study developed two analytical methods for quantification of acrylamide in complex food matrixes, such as Chinese traditional carbohydrate-rich foods. One is based on derivatization with potassium bromate and potassium bromide without clean-up prior to gas chromatography with micro-electron capture detector (GC-MECD). Alternatively, the underivatized acrylamide was detected by high-performance liquid chromatography coupled to quadrupole tandem mass spectrometry (HPLC-MS/MS) in the positive electrospray ionization mode. For both methods, the Chinese carbohydrate-rich samples were homogenized, defatted with petroleum ether and extracted with aqueous solution of sodium chloride. Recovery rates for acrylamide from spiked Chinese style foods with the spiking level of 50, 500 and 1000 μg kg -1 were in the range of 79-93% for the GC-MECD including derivatization and 84-97% for the HPLC-MS/MS method. Typical quantification limits of the HPLC-MSMS method were 4 μg kg -1 for acrylamide. The GC-MECD method achieved quantification limits of 10 μg kg -1 in Chinese style foods. Thirty-eight Chinese traditional foods purchased from different manufacturers were analyzed and compared with four Western style foods. Acrylamide contaminant was found in all of samples at the concentration up to 771.1 and 734.5 μg kg -1 detected by the GC and HPLC method, respectively. The concentrations determined with the two different quantitative methods corresponded well with each other. A convenient and fast pretreatment procedure will be optimized in order to satisfy further investigation of hundreds of samples

  3. Reversed-phase liquid chromatography with electrospray mass detection and 1H and 13C NMR characterization of new process-related impurities, including forced degradants of efavirenz: related substances correlated to the synthetic pathway.

    Science.gov (United States)

    Gadapayale, Kamalesh; Kakde, Rajendra; Sarma, V U M

    2015-01-01

    In this study, a stability-indicating reversed-phase liquid chromatographic electrospray mass spectrometric method was developed and validated for the determination of process-related impurities and forced degradants of Efavirenz in bulk drugs. Efavirenz was subjected to acid, alkaline hydrolysis, H2O2 oxidation, photolysis, and thermal stress. Significant degradation was observed during alkaline hydrolysis, and the degradants were isolated on a mass-based purification system and characterized by high-resolution mass spectrometry, positive electrospray ionization tandem mass spectrometry, and (1)H and (13)C NMR spectroscopy. Accurate mass measurement and NMR spectroscopy revealed the possible structure of process-related impurities and degradant under stress conditions. The acceptable separation was accomplished on Waters bondapak C18 column (250 mm × 4.6 mm; 5 μm), using 5 mM ammonium acetate and acetonitrile as a mobile phase in a gradient elution mode at a flow rate of 1.0 mL/min. The eluents were monitored by diode array detector at 247 nm and quantitation limits were obtained in the range of 0.1-2.5 μg/mL for Efavirenz, degradants, and process-related impurities. The liquid chromatography method was validated with respect to accuracy, precision, linearity, robustness, and limits of detection and quantification as per International Conference on Harmonization guidelines. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Liquid chromatography-electrospray ionization mass spectrometry analysis of limonoids and flavanois in seeds of grapefruits, other citrus species, and dietary supplements

    Science.gov (United States)

    A selective ultra-high performance liquid chromatography-didode array detector-quadrapole time of flight-mass spectrometry (UHPLC-DAD-QToF-MS) method has been developed to screen grapefruit seeds, and other citrus seed samples for limonoid aglycones, limonoid acids, limonoid glucosides and flavonoid...

  5. Systematic fragmentation patterns of archaeal intact polar lipids by high-performance liquid chromatography/electrospray ionization ion-trap mass spectrometry

    OpenAIRE

    Yoshinaga, Marcos Y.; Kellermann, Matthias Y.; Rossel, Pamela E.; Schubotz, Florence; Lipp, Julius S.; Hinrichs, Kai-Uwe

    2011-01-01

    Archaea are ubiquitous and abundant microorganisms on Earth that mediate key global biogeochemical cycles. The headgroup attached to the sn-1 position in the glycerol backbone and the ether-linked isoprenoid lipids are among the diagnostic traits that distinguish Archaea from Bacteria and Eukarya. Over the last 30 years, numerous archaeal lipids were purified and described in pure cultures. Coupled high performance liquid chromatography (HPLC) ion trap mass spectrometry (ITMS) now enables the...

  6. Identification and determination of coumateralyl and coumafuryl in animal tissues by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Jin, Mi-cong; Xu, Guo-zhang; Ren, Yi-ping; Chen, Xiao-hong; Xu, Xiao-ming

    2008-07-01

    A high-performance liquid chromatographic-tandem mass spectrometric (HPLC-MS-MS) method was developed and validated to determine simultaneously coumafuryl and coumateralyl in animal tissues using warfarin as an internal standard (IS). Animal tissue samples were extracted with ethyl acetate and cleaned by Oasis HLB solid-phase extraction (SPE) cartridges. After pretreatment, the separation was performed on a XDB C18 column with an isocratic mobile phase of acetic acid-ammonium acetate (5 mmol l(-1), pH = 4.5)/methanol (30:70, v/v). Detection was carried out on a mass spectrometer by negative electrospray ionization (ESI) in multiple reaction monitoring (MRM) mode. The calibration curves were linear (r(2) > 0.998) in the concentration range 0.75-100.0 ng g(-1) with a lower limit of quantification of 0.75 ng g(-1) for coumafuryl, and 0.5 ng g(-1) for coumateralyl in liver and kidney samples. Intra-day and inter-day relative standard deviations (RSDs) were less than 8.6% and 10.9%, respectively. Recoveries of coumafuryl and coumateralyl were in the range 81.5-89.5%. The developed assay has been applied to the determination of trace residues of coumafuryl and coumateralyl in animal tissues to investigate suspected poisoning of human and animals. 2008 John Wiley & Sons, Ltd

  7. Polar organic chemical integrative sampling and liquid chromatography- electrospray/ion-trap mass spectrometry for assessing selected prescription and illicit drugs in treated sewage effluents

    Science.gov (United States)

    Jones-Lepp, T. L.; Alvarez, D.A.; Petty, J.D.; Huckins, J.N.

    2004-01-01

    The purpose of the research presented in this paper was twofold: (1) to demonstrate the coupling of two state-of-the-art techniques: a time-weighted polar organic chemical integrative sampler (POCIS) and microliquid chromatography–electrospray/ion-trap mass spectrometry and (2) to assess the ability of these methodologies to detect six drugs (azithromycin, fluoxetine, omeprazole, levothyroxine, methamphetamine, methylenedioxymethamphetamine [MDMA]) in a real-world environment, e.g., waste water effluent. In the effluent from three wastewater treatment plants (WWTPs), azithromycin was detected at concentrations ranging from 15 to 66 ng/L, which is equivalent to a total annual release of 1 to 4 kg into receiving waters. Detected and confirmed in the effluent from two WWTPs were two illicit drugs, methamphetamine and MDMA, at 2 and 0.5 ng/L, respectively. Although the ecotoxicologic significance of drugs in environmental matrices, particularly water, has not been closely examined, it can only be surmised that these substances have the potential to adversely affect biota that are continuously exposed to them even at very low levels. The potential for chronic effects on human health is also unknown but of increasing concern because of the multiuse character of water, particularly in densely populated, arid areas.

  8. Quantification of anandamide, oleoylethanolamide and palmitoylethanolamide in rodent brain tissue using high performance liquid chromatography–electrospray mass spectroscopy

    Directory of Open Access Journals (Sweden)

    Daniel J. Liput

    2014-08-01

    Full Text Available Reported concentrations for endocannabinoids and related lipids in biological tissues can vary greatly; therefore, methods used to quantify these compounds need to be validated. This report describes a method to quantify anandamide (AEA, oleoylethanolamide (OEA and palmitoylethanolamide (PEA from rodent brain tissue. Analytes were extracted using acetonitrile without further sample clean up, resolved on a C18 reverse-phase column using a gradient mobile phase and detected using electrospray ionization in positive selected ion monitoring mode on a single quadrupole mass spectrometer. The method produced high recovery rates for AEA, OEA and PEA, ranging from 98.1% to 106.2%, 98.5% to 102.2% and 85.4% to 89.5%, respectively. The method resulted in adequate sensitivity with a lower limit of quantification for AEA, OEA and PEA of 1.4 ng/mL, 0.6 ng/mL and 0.5 ng/mL, respectively. The method was reproducible as intraday and interday accuracies and precisions were under 15%. This method was suitable for quantifying AEA, OEA and PEA from rat brain following pharmacological inhibition of fatty acid amide hydrolase. Keywords: Endocannabinoids, Acylethanolamides, Anandamide, OEA, PEA, LC–MS

  9. Development and validation of an ultra-performance liquid chromatography/electrospray ionization-tandem mass spectrometry bioanalytical method for quantifying clonazepam in human plasma.

    Science.gov (United States)

    Favreto, Wagner Alex Jann; Pinto, Ana Maria Pugens; Manfio, Josélia Larger; Hoss, Ivonete; Pristch, Mariely Camila; Bordignon, Solange Fátima

    2013-01-01

    A sensitive, selective, and rapid ultra-performance LC (UPLC)/MSIMS method was validated for the confirmation and quantification of clonazepam in human plasma. The analyte was extracted from human plasma with diethyl ether, reaching an average recovery of 64.02 and 66.48% for clonazepam and the internal standard, respectively. The separation was performed on a Waters ACQUITY UPLC BEH C18 column (50 x 2.1 mm id, 1.7 microm particle size) with gradient elution at a flow rate of 0.25 mL/min using a 0.5% formic acid solution (mobile phase A) and acetonitrile-methanol-formic acid (75+25 + 0.5, v/v/v; mobile phase B). Detection was performed on a triple-quadruple tandem mass spectrometer in the multiple reaction monitoring mode via electrospray ionization. Linear calibration curves were obtained in the concentration range of 0.3-50.0 ng/mL, with an LOQ of 0.3 ng/mL. The intraday and interday precision (CV) values were below 10%, and accuracy (relative error) ranged from -2.6 to 6.6% at all QC levels. The suggested method was successfully applied for the determination of clonazepam in human plasma in a bioequivalence study.

  10. Simultaneous determination of carboprost methylate and its active metabolite carboprost in dog plasma by liquid chromatography-tandem mass spectrometry with positive/negative ion-switching electrospray ionization and its application to a pharmacokinetic study.

    Science.gov (United States)

    Yin, Lei; Meng, Xiangjun; Zhou, Xiaotong; Zhang, Tinglan; Sun, Heping; Yang, Zhichao; Yang, Bo; Xiao, Ning; Fawcett, J Paul; Yang, Yan; Gu, Jingkai

    2015-08-15

    A liquid chromatography-tandem mass spectrometric (LC-MS/MS) method using positive/negative electrospray ionization (ESI) switching for the simultaneous quantitation of carboprost methylate and carboprost in dog plasma has been developed and validated. After screening, the esterase inhibitor, dichlorvos was added to the whole blood at a ratio of 1:99 (v/v) to stabilize carboprost methylate during blood collection, sample storage and LLE. Indomethacin was added to plasma to inhibit prostaglandins synthesis after sampling. After liquid-liquid extraction of 500μL plasma with ethyl ether-dichloromethane (75:25, v/v), analytes and internal standard (IS), alprostadil-d4, were chromatographed on a CAPCELL PAK Phenyl column (150×2.0mm, 5μm) using acetonitrile-5mM ammonium acetate as mobile phase. Carboprost methylate was detected by positive ion electrospray ionization followed by multiple reaction monitoring (MRM) of the transition at m/z 400.5→329.3; the carboprost and IS were detected by negative ion electrospray ionization followed by MRM of the transitions at m/z 367.2→323.2, and 357.1→321.2, respectively. The method was linear for both analytes in the concentration range 0.05-30ng/mL with intra- and inter-day precisions (as relative standard deviation) of ≤6.75% and accuracy (as relative error) of ≤7.21% and limit of detection (LOD) values were 10 and 20pg/mL, respectively. The method was successfully applied to a pharmacokinetic study of the analytes in beagle dogs after intravaginal administration of a suppository containing 0.5mg carboprost methylate. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Use of liquid chromatography/electrospray ionization tandem mass spectrometry to study the degradation pathways of terbuthylazine (TER) by Typha latifolia in constructed wetlands: identification of a new TER metabolite.

    Science.gov (United States)

    Gikas, Evagelos; Papadopoulos, Nikolaos G; Bazoti, Fotini N; Zalidis, Georgios; Tsarbopoulos, Anthony

    2012-01-30

    S-Triazines are used worldwide as herbicides for agricultural and non-agricultural purposes. Although terbuthylazine (TER) is the second most frequently used S-triazine, there is limited information on its metabolism. For this reason, an analytical method based on liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI MS/MS) has been developed aiming at the identification of TER and its five major metabolites (desisopropyl-hydroxy-atrazine, desethyl-hydroxy-terbuthylazine, desisopropyl-atrazine, hydroxy-terbuthylazine and desethyl-terbuthylazine) in constructed wetland water samples. The separation of TER and its major metabolites was performed by reversed-phase high-performance liquid chromatography (HPLC) on a C(8) column using a gradient elution of aqueous acetic acid 1% (solvent A) and acetonitrile (solvent B), followed by MS/MS analysis on a triple quadrupole mass spectrometer. The data-depended analysis (DDA) scan approach has been employed and the main degradation pathways of both hydroxyl and chloro (dealkylated and alkylated) metabolites are elucidated through the tandem mass spectral (MS/MS) interpretation of triazine fragments under CID conditions. In addition, another major metabolite of TER, namely N2-tert-butyl-N4-ethyl-6-methoxy-1,3,5-triazine-2,4-diamine, has been identified. This methodology can be further employed in biodegradation studies of TER, thus assisting the assessment of its environmental impact. Copyright © 2011 John Wiley & Sons, Ltd.

  12. Fingerprint analysis and quality consistency evaluation of flavonoid compounds for fermented Guava leaf by combining high-performance liquid chromatography time-of-flight electrospray ionization mass spectrometry and chemometric methods.

    Science.gov (United States)

    Wang, Lu; Tian, Xiaofei; Wei, Wenhao; Chen, Gong; Wu, Zhenqiang

    2016-10-01

    Guava leaves are used in traditional herbal teas as antidiabetic therapies. Flavonoids are the main active of Guava leaves and have many physiological functions. However, the flavonoid compositions and activities of Guava leaves could change due to microbial fermentation. A high-performance liquid chromatography time-of-flight electrospray ionization mass spectrometry method was applied to identify the varieties of the flavonoids in Guava leaves before and after fermentation. High-performance liquid chromatography, hierarchical cluster analysis and principal component analysis were used to quantitatively determine the changes in flavonoid compositions and evaluate the consistency and quality of Guava leaves. Monascus anka Saccharomyces cerevisiae fermented Guava leaves contained 2.32- and 4.06-fold more total flavonoids and quercetin, respectively, than natural Guava leaves. The flavonoid compounds of the natural Guava leaves had similarities ranging from 0.837 to 0.927. The flavonoid compounds from the Monascus anka S. cerevisiae fermented Guava leaves had similarities higher than 0.993. This indicated that the quality consistency of the fermented Guava leaves was better than that of the natural Guava leaves. High-performance liquid chromatography fingerprinting and chemometric analysis are promising methods for evaluating the degree of fermentation of Guava leaves based on quality consistency, which could be used in assessing flavonoid compounds for the production of fermented Guava leaves. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Using precursor ion scan of 184 with liquid chromatography-electrospray ionization-tandem mass spectrometry for concentration normalization in cellular lipidomic studies.

    Science.gov (United States)

    Chao, Hsi-Chun; Chen, Guan-Yuan; Hsu, Lih-Ching; Liao, Hsiao-Wei; Yang, Sin-Yu; Wang, San-Yuan; Li, Yu-Liang; Tang, Sung-Chun; Tseng, Yufeng Jane; Kuo, Ching-Hua

    2017-06-08

    Cellular lipidomic studies have been favored approaches in many biomedical research areas. To provide fair comparisons of the studied cells, it is essential to perform normalization of the determined concentration before lipidomic analysis. This study proposed a cellular lipidomic normalization method by measuring the phosphatidylcholine (PC) and sphingomyelin (SM) contents in cell extracts. To provide efficient analysis of PC and SM in cell extracts, flow injection analysis-electrospray ionization-tandem mass spectrometry (FIA-ESI-MS/MS) with a precursor ion scan (PIS) of m/z 184 was used, and the parameters affecting the performance of the method were optimized. Good linearity could be observed between the cell extract dilution factor and the reciprocal of the total ion chromatogram (TIC) area in the PIS of m/z 184 within the dilution range of 1- to 16-fold (R 2  = 0.998). The calibration curve could be used for concentration adjustment of the unknown concentration of a cell extract. The intraday and intermediate precisions were below 10%. The accuracy ranged from 93.0% to 105.6%. The performance of the new normalization method was evaluated using different numbers of HCT-116 cells. Sphingosine, ceramide (d18:1/18:0), SM (d18:1/18:0) and PC (16:1/18:0) were selected as the representative test lipid species, and the results showed that the peak areas of each lipid species obtained from different cell numbers were within a 20% variation after normalization. Finally, the PIS of 184 normalization method was applied to study ischemia-induced neuron injury using oxygen and glucose deprivation (OGD) on primary neuronal cultured cells. Our results showed that the PIS of 184 normalization method is an efficient and effective approach for concentration normalization in cellular lipidomic studies. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Direct injection liquid chromatography/electrospray ionization mass spectrometric horse urine analysis for the quantification and confirmation of threshold substances for doping control. II. Determination of theobromine.

    Science.gov (United States)

    Vonaparti, A; Lyris, E; Panderi, I; Koupparis, M; Georgakopoulos, C

    2009-04-01

    In equine sport, theobromine is prohibited with a threshold level of 2 microg mL(-1) in urine, hence doping control laboratories have to establish quantitative and qualitative methods for its determination. Two simple liquid chromatography/mass spectrometry (LC/MS) methods for the identification and quantification of theobromine were developed and validated using the same sample preparation procedure but different mass spectrometric systems: ion trap mass spectrometry (ITMS) and time-of-flight mass spectrometry (TOFMS). Particle-free diluted urine samples were directly injected into the LC/MS systems, avoiding the time-consuming extraction step. 3-Propylxanthine was used as the internal standard. The tested linear range was 0.75-15 microg mL(-1). Matrix effects were evaluated analyzing calibration curves in water and different fortified horse urine samples. A great variation in the signal of theobromine and the internal standard was observed in different matrices. To overcome matrix effects, a standard additions calibration method was applied. The relative standard deviations of intra- and inter-day analysis were lower than 8.6 and 7.2%, respectively, for the LC/ITMS method and lower than 5.7 and 5.8%, respectively, for the LC/TOFMS method. The bias was less than 8.7% for both methods. The methods were applied to two case samples, demonstrating simplicity, accuracy and selectivity. Copyright (c) 2009 John Wiley & Sons, Ltd.

  15. Simultaneous metabolite fingerprinting of hydrophilic and lipophilic compounds in Echinacea pallida by high-performance liquid chromatography with diode array and electrospray ionization-mass spectrometry detection.

    Science.gov (United States)

    Pellati, Federica; Orlandini, Giulia; Benvenuti, Stefania

    2012-06-15

    In this study, a detailed phytochemical characterization of Echinacea pallida (Nutt.) Nutt. root extracts and dietary supplements was carried out for the first time by developing advanced chromatographic techniques, based on HPLC with diode array (DAD) and electrospray ionization-mass spectrometry (ESI-MS) detection (with ion trap and triple quadrupole mass analyzers), for the simultaneous analysis of hydrophilic and lipophilic secondary metabolites. The HPLC analyses were carried out on an Ascentis C(18) column (250 mm × 4.6 mm I.D., 5 μm), with a mobile phase composed by H(2)O and ACN both containing 0.1% formic acid, under gradient elution. The UV spectra, in combination with MS and MS/MS data, allowed the identification of fourteen compounds, including caffeic acid derivatives, polyacetylenes and polyenes, in the analyzed samples. MS and MS/MS data were discussed in detail and the typical fragmentation patterns of each class of secondary metabolites were identified. For the first time, a hydroperoxide intermediate was characterized as an oxidation product of one of E. pallida monocarbonylic acetylenes, providing a confirmation of the mechanism that leads to the generation of hydroxylated derivatives. The HPLC method was fully validated in agreement with ICH guidelines and then applied to real samples. The quantitative analysis indicated that there was a great variability in the amount of the active compounds in the dietary supplements containing E. pallida root extracts: the content of total caffeic acid derivatives ranged from 2.31 to 11.45 mg/g and the amount of total polyacetylenes and polyenes from 6.38 to 30.54 mg/g. In the analyzed samples, the most abundant caffeic acid derivative was found to be echinacoside. Regarding polyacetylenes and polyenes, the most representative compounds were found to be tetradec-(8Z)-ene-11,13-diyn-2-one, pentedeca-(8Z,11Z)-dien-2-one and pentadec-(8Z)-en-2-one. The developed method can be considered suitable for metabolite

  16. Liquid Chromatography with Electrospray Ionization and Tandem Mass Spectrometry Applied in the Quantitative Analysis of Chitin-Derived Glucosamine for a Rapid Estimation of Fungal Biomass in Soil

    Directory of Open Access Journals (Sweden)

    Madelen A. Olofsson

    2016-01-01

    Full Text Available This method employs liquid chromatography-tandem mass spectrometry to rapidly quantify chitin-derived glucosamine for estimating fungal biomass. Analyte retention was achieved using hydrophilic interaction liquid chromatography, with a zwitter-ionic stationary phase (ZIC-HILIC, and isocratic elution using 60% 5 mM ammonium formate buffer (pH 3.0 and 40% ACN. Inclusion of muramic acid and its chromatographic separation from glucosamine enabled calculation of the bacterial contribution to the latter. Galactosamine, an isobaric isomer to glucosamine, found in significant amounts in soil samples, was also investigated. The two isomers form the same precursor and product ions and could not be chromatographically separated using this rapid method. Instead, glucosamine and galactosamine were distinguished mathematically, using the linear relationships describing the differences in product ion intensities for the two analytes. The m/z transitions of 180 → 72 and 180 → 84 were applied for the detection of glucosamine and galactosamine and that of 252 → 126 for muramic acid. Limits of detection were in the nanomolar range for all included analytes. The total analysis time was 6 min, providing a high sample throughput method.

  17. Detection of previously unknown fumonisin P analogue mycotoxins in a Fusarium verticillioides culture by high-performance liquid chromatography-electrospray ionization time-of-flight and ion trap mass spectrometry.

    Science.gov (United States)

    Bartók, Tibor; Tölgyesi, László; Szécsi, Árpád; Mesterházy, Ákos; Bartók, Mihály; Gyimes, Ernő; Véha, Antal

    2014-07-01

    Five previously unknown fumonisin mycotoxins (iso-FP1, iso-FP(2,3a), iso-FP(2,3b), FP4 and iso-FP4) and three previously described FP analogues (FP(1-3)) were detected in a solid rice culture inoculated with Fusarium verticillioides. The fumonisins were characterized by high-performance liquid chromatography-electrospray ionization time-of-flight mass spectrometry (HPLC-ESI-TOFMS) and ion trap mass spectrometry (ITMS). The FP isomers were separated by using a flat gradient on a special, high-coverage C18, narrow-bore HPLC column (YMC-Pack J'sphere ODS H80), which was suggested for the separation of structural isomers. The verified structures of the FP(1-3) mycotoxins, the relative retention times (by HPLC-ESI-TOFMS and ITMS), the exact masses of the molecular ions (by TOFMS) and the masses of the product ions, including the hydrocarbon backbones (by ITMS) of the new compounds, strongly suggested their structures. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

    Directory of Open Access Journals (Sweden)

    K Conceição

    2009-01-01

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

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

    Science.gov (United States)

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

    2016-04-01

    This study aimed to validate a method developed for the determination of six antibiotics from the polyether ionophore class (lasalocid, maduramicin, monensin, narasin, salinomycin and semduramicin) at residue levels in raw, UHT, pasteurized and powdered milk using QuEChERS extraction and high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). The validation was conducted under an in-house laboratory protocol that is primarily based on 2002/657/EC Decision, but takes in account the variability of matrix sources. Overall recoveries between 93% and 113% with relative standard deviations up to 16% were obtained under intermediate precision conditions. CCα calculated values did not exceed 20% the Maximum Residue Limit for monensin and 25% the Maximum Levels for all other substances. The method showed to be simple, fast and suitable for verifying the compliance of raw and processed milk samples regarding the limits recommended by Codex Alimentarius and those adopted in European Community for polyether ionophores. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Cuban and Brazilian red propolis: botanical origin and comparative analysis by high-performance liquid chromatography-photodiode array detection/electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Piccinelli, Anna Lisa; Lotti, Cinzia; Campone, Luca; Cuesta-Rubio, Osmany; Campo Fernandez, Mercedes; Rastrelli, Luca

    2011-06-22

    Chemical composition of propolis depends on the specificity of the local flora at the site of collection and thus on the geographic and climatic characteristics of this place. This paper describes a comparative analysis of Cuban red propolis (CRP), Brazilian red propolis (BRP), and Dalbergia ecastophyllum exudates (DEE) by high-performance liquid chromatography with diode-array detection and tandem mass spectrometry. The aim of this study was to investigate the overall chemical profile and the botanical origin of red propolis and to suggest similarities and differences between samples collected in different tropical regions. Isoliquiritigenin (1), liquiritigenin and naringenin (2 and 17), isoflavones (3-4 and 16), isoflavans (5-7 and 18), and pterocarpans (8-13) were detected in CRP, BRP, and DEE, whereas polyisoprenylated benzophenones (PPBs) guttiferone E/xanthochymol (14a,b) and oblongifolin A (15) were detected only in BRP. Pigments responsible for the red color of DEE and red propolis were also identified as two C30 isoflavans, the new retusapurpurin B (19) and retusapurpurin A (20). PPBs and pigments were isolated and unambiguously characterized by 1D and 2D NMR analysis. These results show that red propolis samples from different tropical zones have a similar chemical composition. DEE is the main red propolis source, but the presence of PPBs in BRP suggests the contribution of different botanical sources for Brazilian samples. This chemical information is important for quality control of red propolis and its commercial products and for biological study.

  1. Quantitative analysis of amoxicillin, its major metabolites and ampicillin in eggs by liquid chromatography combined with electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Sun, Lirui; Jia, Longfei; Xie, Xing; Xie, Kaizhou; Wang, Jianfeng; Liu, Jianyu; Cui, Lulu; Zhang, Genxi; Dai, Guojun; Wang, Jinyu

    2016-02-01

    In this present study, we developed a simple, rapid and specific method for the quantitative analysis of the contents of amoxicillin (AMO), AMO metabolites and ampicillin (AMP) in eggs. This method uses a simple liquid-liquid extraction with acetonitrile followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The optimized method has been validated according to requirements defined by the European Union and Food and Drug Administration. Extraction recoveries of the target compounds from the egg at 5, 10 and 25 μg/kg were all higher than 80%, with relative standard deviations not exceeding 10.00%. The limits of quantification in eggs were below the maximum residue limits (MRLs). The decision limits (CCα) ranged between 11.1 and 11.5 μg/kg, while detection capabilities (CCβ) from 12.1 to 13.0 μg/kg. These values were very close to the corresponding MRLs. Finally, the new approach was successfully verified for the quantitative determination of these analytes in 40 commercial eggs from local supermarkets. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Quantitative determination of antidepressants and their select degradates by liquid chromatography/electrospray ionization tandem mass spectrometry in biosolids destined for land application.

    Science.gov (United States)

    Niemi, Lydia M; Stencel, Katherine A; Murphy, Madigan J; Schultz, Melissa M

    2013-08-06

    Antidepressants are one of the most widely dispensed classes of pharmaceuticals in the United States. As wastewater treatment plants are a primary source of pharmaceuticals in the environment, the use of biosolids as fertilizer is a potential route for antidepressants to enter the terrestrial environment. A microsolvent extraction method, utilizing green chemistry, was developed for extraction of the target antidepressants and degradation products from biosolids, or more specifically lagoon biosolids. Liquid chromatography/tandem mass spectrometry was used for quantitative determination of antidepressants in the lagoon biosolid extracts. Recoveries from matrix spiking experiments for the individual antidepressants had an average of 96%. The limits of detection for antidepressant pharmaceuticals and degradates ranged from 0.36 to 8.0 ng/kg wet weight. The method was applied to biosolids destined for land application. A suite of antidepressants was consistently detected in the lagoon biosolid samples, and thus antidepressants are being introduced to terrestrial environments through the land application of these biosolids. Sertraline and norsertraline were the most abundant antidepressant and degradation product detected in the biosolid samples. Detected, individual antidepressant concentrations ranged from 8.5 ng/kg (norfluoxetine) to 420 ng/kg wet weight (norsertraline).

  3. 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 MS(E mode.

    Directory of Open Access Journals (Sweden)

    Haibo Li

    Full Text Available 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 MS(E ((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 MS(E, 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.

  4. 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

  5. Quantitative analysis of tylosin in eggs by high performance liquid chromatography with electrospray ionization tandem mass spectrometry: residue depletion kinetics after administration via feed and drinking water in laying hens.

    Science.gov (United States)

    Hamscher, Gerd; Limsuwan, Sasithorn; Tansakul, Natthasit; Kietzmann, Manfred

    2006-11-29

    Maximum residue limits (MRLs) have been established by the European Union when tylosin is used therapeutically. They are fixed at 200 microg/kg for eggs. A highly sensitive and selective quantitative liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI/MS/MS) method suitable for monitoring tylosin residues in eggs to determine its depletion kinetics was developed and validated. For sample pretreatment all samples were liquid-liquid extracted with citrate buffer (pH 5.0) and acetonitrile. Liquid chromatographic separation was carried out on a reversed phase C18 column employing a 0.5% formic acid/acetonitrile gradient system. The tylosin recovery in eggs at a concentration range from 1.0-400 microg/kg was >82% with relative standard deviations between 1.5 and 11.0%. In two experimental studies administrating tylosin via feed (final dosage: 1.5 g/kg) or drinking water (final dosage: 0.5 g/L), no residues above the MRL were found during and after treatment. Moreover, all samples were well below the actual MRL of 200 microg/kg. Therefore, our residue data suggest that a withholding period for eggs is not required when laying hens are treated with tylosin in recommended dosages via feed or drinking water. Tylosin; residue; depletion; laying hen; withholding period; mass spectrometry.

  6. Determination of interglycosidic linkages in O-glycosyl flavones by high-performance liquid chromatography/photodiode-array detection coupled to electrospray ionization ion trap mass spectrometry. Its application to Tetragonula carbonaria honey from Australia.

    Science.gov (United States)

    Truchado, Pilar; Vit, Patricia; Heard, Tim A; Tomás-Barberán, Francisco A; Ferreres, Federico

    2015-05-30

    Tetragonula carbonaria pot-honeys are highly valued as a food source and for their biological activities in Australia, and there is a growing interest to know its composition. Phenolic metabolites, which could be related to their beneficial properties, have not been studied in depth yet. Mass spectrometry (MS) coupled to liquid chromatography (LC) is an advanced technique for the study of complex flavonoids present in difficult food matrices that hampers their isolation and purification. This allows the tentative characterization of diglycosides/triglycosides establishing the position of the O-glycosylation on the sugar moiety by the study of the MS data in T. carbonaria pot-honeys from Australia. Their spectra obtained by high-performance liquid chromatography/photodiode-array detection/electrospray ionization ion trap mass spectrometry (HPLC/DAD/ESI-MS(n) ) revealed for the first time 19 quercetin, kaempferol and isorhamnetin O-glycosides. These compounds were clustered in flavonoid triglycosides, diglycosides and monoglycosides. The first cluster contained one flavonoid trihexoside, two -3-O-(2-hexosyl, 6-rhamnosyl)hexosides and their isomers and two -3-O-(2,6-di-rhamnosyl)hexosides. In the second cluster, eleven flavonoid diglycosides such as three -3-O-(2-hexosyl)hexosides, four -3-O-(2-rhamnosyl)hexosides and one -3-O-(6-rhamnosyl)hexoside as well as two -3-O-(2-pentosyl)hexosides and one tentative -3-O-(3-pentosyl)hexoside were detected. In the monoglycoside group, only one flavonoid -3-O-hexoside was identified. The occurrence of this large number of flavonoid glycosides could be due to the low glucosidase activity previously reported in stingless bee honey. Copyright © 2015 John Wiley & Sons, Ltd.

  7. Simultaneous determination of phentermine and topiramate in human plasma by liquid chromatography-tandem mass spectrometry with positive/negative ion-switching electrospray ionization and its application in pharmacokinetic study.

    Science.gov (United States)

    Ni, Yang; Zhou, Ying; Xu, Mingzhen; He, Xiaomeng; Li, Huqun; Haseeb, Satter; Chen, Hui; Li, Weiyong

    2015-03-25

    A new method for simultaneous determination of phentermine and topiramate by liquid chromatography/electrospray tandem mass spectrometry (LC/MS/MS) operated in positive and negative ionization switching modes was developed and validated. Protein precipitation with acetonitrile was selected for sample preparation. Analyses were performed on a liquid chromatography system employing a Kromasil 60-5CN column (2.1 mm × 100 mm, 5 μm) and an isocratic elution with mixed solution of acetonitrile-20mM ammonium formate containing 0.3% formic acid (40:60, v/v), at a flow rate of 0.35 mL/min. Doxazosin mesylate and pioglitazone were used as the internal standard (IS) respectively for quantification. The determination was carried out on an API 4000 triple-quadrupole mass spectrometer operated in multiple reaction monitoring (MRM) mode using the following transitions monitored simultaneously: positive m/z 150.0/91.0 for phentermine, m/z 452.1/344.3 for doxazosin, and negative m/z 338.3/77.9 for topiramate, m/z 355.0/41.9 for pioglitazone. The method was validated to be linear over the concentration range of 1-800 ng mL(-1) for phentermine, 1-1000 ng mL(-1) for topiramate. Within- and between-day accuracy and precision of the validated method at three different concentration levels were within the acceptable limits of <15% at all concentrations. Blood samples were collected into heparinized tubes before and after administration. The simple and robust LC/MS/MS method was successfully applied for the simultaneous determination of phentermine and topiramate in a pharmacokinetic study in healthy male Chinese volunteers. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Qualitative and quantitative analysis of an alkaloid fraction from Piper longum L. using ultra-high performance liquid chromatography-diode array detector-electrospray ionization mass spectrometry.

    Science.gov (United States)

    Li, Kuiyong; Fan, Yunpeng; Wang, Hui; Fu, Qing; Jin, Yu; Liang, Xinmiao

    2015-05-10

    In a previous research, an alkaloid fraction and 18 alkaloid compounds were prepared from Piper longum L. by series of purification process. In this paper, a qualitative and quantitative analysis method using ultra-high performance liquid chromatography-diode array detector-mass spectrometry (UHPLC-DAD-MS) was developed to evaluate the alkaloid fraction. Qualitative analysis of the alkaloid fraction was firstly completed by UHPLC-DAD method and 18 amide alkaloid compounds were identified. A further qualitative analysis of the alkaloid fraction was accomplished by UHPLC-MS/MS method. Another 25 amide alkaloids were identified according to their characteristic ions and neutral losses. At last, a quantitative method for the alkaloid fraction was established using four marker compounds including piperine, pipernonatine, guineensine and N-isobutyl-2E,4E-octadecadienamide. After the validation of this method, the contents of above four marker compounds in the alkaloid fraction were 57.5mg/g, 65.6mg/g, 17.7mg/g and 23.9mg/g, respectively. Moreover, the relative response factors of other three compounds to piperine were calculated. A comparative study between external standard quantification and relative response factor quantification proved no remarkable difference. UHPLC-DAD-MS method was demonstrated to be a powerful tool for the characterization of the alkaloid fraction from P. longum L. and the result proved that the quality of alkaloid fraction was efficiently improved after appropriate purification. Copyright © 2015. Published by Elsevier B.V.

  9. Fast profiling of anthocyanins in wine by desorption nano-electrospray ionization mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Hartmanová, L.; Ranc, V.; Papoušková, B.; Bednář, P.; Havlíček, Vladimír; Lemr, Karel

    2010-01-01

    Roč. 1217, č. 25 (2010), s. 4223-4228 ISSN 0021-9673 R&D Projects: GA ČR GA203/07/0765 Institutional research plan: CEZ:AV0Z50200510 Keywords : Mass spectrometry * Desorption nano-electrospray * Liquid chromatography Subject RIV: CE - Biochemistry Impact factor: 4.194, year: 2010

  10. Reversed-phase ultra-high-performance liquid chromatography coupled to electrospray ionization-quadrupole-time-of-flight mass spectrometry as a powerful tool for metabolic profiling of vegetables: Lactuca sativa as an example of its application.

    Science.gov (United States)

    Abu-Reidah, I M; Contreras, M M; Arráez-Román, D; Segura-Carretero, A; Fernández-Gutiérrez, A

    2013-10-25

    Lettuce (Lactuca sativa), a leafy vegetal widely consumed worldwide, fresh cut or minimally processed, constitutes a major dietary source of natural antioxidants and bioactive compounds. In this study, reversed-phase ultra-high-performance liquid chromatography (RP-UHPLC) coupled to electrospray ionization-quadrupole-time-of-flight mass spectrometry (ESI-QTOF-MS) was applied for the comprehensive profiling of polar and semi-polar metabolites from three lettuce cultivars (baby, romaine, and iceberg). The UHPLC systems allowed the use of a small-particle-size C18 column (1.8 μm), with very fine resolution for the separation of up to seven isomers, and the QTOF mass analyzer enabled sensitive detection with high mass resolution and accuracy in full scan. Thus, a total of 171 compounds were tentatively identified by matching their accurate mass signals and suggested molecular formula with those previously reported in family Asteraceae. Afterwards, their structures were also corroborated by the MS/MS data provided by the QTOF analyzer. Well-known amino acids, organic acids, sesquiterpene lactones, phenolic acids and flavonoids were characterized, e.g. lactucin, lactucopicrin, caftaric acid, chlorogenic acid, caffeoylmalic acid, chicoric acid, isochlorogenic acid A, luteolin, and quercetin glycosides. For this plant species, this is the first available report of several isomeric forms of the latter polyphenols and other types of components such as nucleosides, peptides, and tryptophan-derived alkaloids. Remarkably, 10 novel structures formed by the conjugation of known amino acids and sesquiterpene lactones were also proposed. Thus, the methodology applied is a useful option to develop an exhaustive metabolic profiling of plants that helps to explain their potential biological activities and folk uses. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Quantitative determination of juvenile hormone III and 20-hydroxyecdysone in queen larvae and drone pupae of Apis mellifera by ultrasonic-assisted extraction and liquid chromatography with electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Zhou, Jinhui; Qi, Yitao; Hou, Yali; Zhao, Jing; Li, Yi; Xue, Xiaofeng; Wu, Liming; Zhang, Jinzhen; Chen, Fang

    2011-09-01

    In this paper, a method for the rapid and sensitive analysis of juvenile hormone III (JH III) and 20-hydroxyecdysone (20E) in queen larvae and drone pupae samples was presented. Ultrasound-assisted extraction provided a significant shortening of the leaching time for the extraction of JH III and 20E and satisfactory sensitivity as compared to the conventional shake extraction procedure. After extraction, determination was carried out by liquid chromatography-tandem mass spectrometry (LC-MS/MS) operating in electrospray ionization positive ion mode via multiple reaction monitoring (MRM) without any clean-up step prior to analysis. A linear gradient consisting of (A) water containing 0.1% formic acid and (B) acetonitrile containing 0.1% formic acid, and a ZORBAX SB-Aq column (100 mm × 2.1 mm, 3.5 μm) were employed to obtain the best resolution of the target analytes. The method was validated for linearity, limit of quantification, recovery, matrix effects, precision and stability. Drone pupae samples were found to contain 20E at concentrations of 18.0 ± 0.1 ng/g (mean ± SD) and JH III was detected at concentrations of 0.20 ± 0.06 ng/g (mean ± SD) in queen larvae samples. This validated method provided some practical information for the actual content of JH III and 20E in queen larvae and drone pupae samples. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Multi-responses extraction optimization combined with high-performance liquid chromatography-diode array detection-electrospray ionization-tandem mass spectrometry and chemometrics techniques for the fingerprint analysis of Aloe barbadensis Miller.

    Science.gov (United States)

    Zhong, Jia-Sheng; Wan, Jin-Zhi; Ding, Wen-Jing; Wu, Xiao-Fang; Xie, Zhi-Yong

    2015-03-25

    A quality control strategy using high-performance liquid chromatography-diode array detector-electrospray ionization-tandem mass spectrometry (HPLC-DAD-ESI-MS/MS) coupled with chemometrics analysis was proposed for Aloe barbadensis Miller. Firstly, the extraction conditions including methanol concentration, extraction time and solvent-to-material ratio were optimized by multi-responses optimization based on response surface methodology (RSM). The optimum conditions were achieved by Derringer's desirability function and experimental validation implied that the established model exhibited favorable prediction ability. Then, HPLC fingerprint consisting of 27 common peaks was developed among 15 batches of A. barbadensis samples. 25 common peaks were identified using HPLC-DAD-ESI-MS/MS method by their spectral characteristics or comparison with the authentic standards. Chemometrics techniques including similarity analysis (SA), principal components analysis (PCA) and hierarchical clustering analysis (HCA) were implemented to classify A. barbadensis samples. The results demonstrated that all A. barbadensis samples shared similar chromatographic patterns as well as differences. These achievements provided an effective, reliable and comprehensive quality control method for A. barbadensis. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    Belmonte, M. A.

    2015-12-01

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

  14. Modification of human serum albumin by the nerve agent VX: microbore liquid chromatography/electrospray ionization high-resolution time-of-flight tandem mass spectrometry method for detection of phosphonylated tyrosine and novel cysteine containing disulfide adducts.

    Science.gov (United States)

    Kranawetvogl, Andreas; Worek, Franz; Thiermann, Horst; John, Harald

    2016-10-15

    Organophosphorus nerve agents still constitute a considerable threat to the health of military personnel and the civilian population. Long-term biomarkers are crucial for reliable verification of exposure to banned substances. Therefore, current research focuses on identification of endogenous protein targets showing covalent modifications by organophosphorus nerve agents (adducts). Purified human serum albumin and human plasma were incubated with the nerve agent VX followed by enzymatic proteolysis with pronase. Resulting peptide cleavage products were separated by microbore liquid chromatography (μLC) online coupled to positive electrospray ionization (ESI) with subsequent high-resolution time-of-flight tandem mass spectrometry (HR MS/MS) allowing identification of known and novel adducts. In addition to known phosphonylation of various tyrosine residues, albumin was found to be modified at diverse cysteine residues by covalent attachment of the leaving group of VX. These novel disulfide adducts were cleaved from at least two regions of the intact protein as dipeptides containing cysteine and proline either as CP or PC. A rapid and sensitive method was developed for simultaneous detection of the diverse covalent modifications of human albumin by VX. Identification of the novel leaving group adducts with human albumin expands the basic knowledge on molecular toxicology of the nerve agent VX. Furthermore, the presented μLC/ESI HR MS/MS method might be of relevance for verification of VX poisoning. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  15. Simultaneous quantification of eight bioactive components of Houttuynia cordata and related Saururaceae medicinal plants by on-line high performance liquid chromatography-diode array detector-electrospray mass spectrometry.

    Science.gov (United States)

    Meng, Jiang; Leung, Kelvin Sze-Yin; Dong, Xiao-Ping; Zhou, Yi-Sheng; Jiang, Zhi-Hong; Zhao, Zhong-Zhen

    2009-12-01

    An on-line high performance liquid chromatography (HPLC)-diode array detector (DAD)-electrospray ionization mass spectrometry (ESI-MS) method has been developed to quantify simultaneously eight bioactive chemical components in Houttuynia cordata Thunb and related Saururaceae medicinal plants. Simultaneous separation of these eight compounds was achieved on a C(18) analytical column with gradient elution of acetonitrile and 0.2% acetic acid (v/v) at a flow rate of 0.6 mL/min and being detected at 280 nm. These eight compounds were completely separated within 90 min. Good linear regression relationship (r(2)>0.9978) within test ranges was shown in all calibration curves. Good repeatabilty for the quantification of these eight compounds in H.cordata was also demonstrated in this method, with intra- and inter-day variations less than 3.0%. The method established was successfully applied to quantify eight bioactive compounds in closely related species of H.cordata, which provides a new basis for quality assessment of H.cordata.

  16. Profile of phenolic compounds of Brazilian virgin olive oils by rapid resolution liquid chromatography coupled to electrospray ionisation time-of-flight mass spectrometry (RRLC-ESI-TOF-MS).

    Science.gov (United States)

    Ballus, Cristiano Augusto; Quirantes-Piné, Rosa; Bakhouche, Abdelhakim; da Silva, Luiz Fernando de Oliveira; de Oliveira, Adelson Francisco; Coutinho, Enilton Fick; da Croce, Dorli Mario; Segura-Carretero, Antonio; Godoy, Helena Teixeira

    2015-03-01

    In recent years, agronomical researchers began to cultivate several olive varieties in different regions of Brazil to produce virgin olive oil (VOO). Because there has been no reported data regarding the phenolic profile of the first Brazilian VOO, the aim of this work was to determine phenolic contents of these samples using rapid-resolution liquid chromatography coupled to electrospray ionisation time-of-flight mass spectrometry. 25 VOO samples from Arbequina, Koroneiki, Arbosana, Grappolo, Manzanilla, Coratina, Frantoio and MGS Mariense varieties from three different Brazilian states and two crops were analysed. It was possible to quantify 19 phenolic compounds belonging to different classes. The results indicated that Brazilian VOOs have high total phenolic content because the values were comparable with those from high-quality VOOs produced in other countries. VOOs from Coratina, Arbosana and Grappolo presented the highest total phenolic content. These data will be useful in the development and improvement of Brazilian VOO. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Rapid characterisation and comparison of saponin profiles in the seeds of Korean Leguminous species using ultra performance liquid chromatography with photodiode array detector and electrospray ionisation/mass spectrometry (UPLC-PDA-ESI/MS) analysis.

    Science.gov (United States)

    Ha, Tae Joung; Lee, Byong Won; Park, Ki Hun; Jeong, Seong Hun; Kim, Hyun-Tae; Ko, Jong-Min; Baek, In-Youl; Lee, Jin Hwan

    2014-03-01

    The present work was reported on investigation of saponin profiles in nine different legume seeds, including soybean, adzuki bean, cowpea, common bean, scarlet runner bean, lentil, chick pea, hyacinth bean, and broad bean using ultra performance liquid chromatography with photodiode array detector and electrospray ionisation/mass spectrometry (UPLC-PDA-ESI/MS) technique. A total of twenty saponins were characterised under rapid and simple conditions within 15min by the 80% methanol extracts of all species. Their chemical structures were elucidated as soyasaponin Ab (1), soyasaponin Ba (2), soyasaponin Bb (3), soyasaponin Bc (4), soyasaponin Bd (5), soyasaponin αg (6), soyasaponin βg (7), soyasaponin βa (8), soyasaponin γg (9), soyasaponin γa (10), azukisaponin VI (11), azukisaponin IV (12), azukisaponin II (13), AzII (14), AzIV (15), lablaboside E (16), lablaboside F (17), lablaboside D (18), chikusetusaponin IVa (19), and lablab saponin I (20). The individual and total saponin compositions exhibited remarkable differences in all legume seeds. In particular, soyasaponin βa (8) was detected the predominant composition in soybean, cowpea, and lentil with various concentrations. Interestingly, soybean, adzuki bean, common bean, and scarlet runner bean had high saponin contents, while chick pea and broad bean showed low contents. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. High-throughput method for macrolides and lincosamides antibiotics residues analysis in milk and muscle using a simple liquid-liquid extraction technique and liquid chromatography-electrospray-tandem mass spectrometry analysis (LC-MS/MS).

    Science.gov (United States)

    Jank, Louise; Martins, Magda Targa; Arsand, Juliana Bazzan; Campos Motta, Tanara Magalhães; Hoff, Rodrigo Barcellos; Barreto, Fabiano; Pizzolato, Tânia Mara

    2015-11-01

    A fast and simple method for residue analysis of the antibiotics classes of macrolides (erythromycin, azithromycin, tylosin, tilmicosin and spiramycin) and lincosamides (lincomycin and clindamycin) was developed and validated for cattle, swine and chicken muscle and for bovine milk. Sample preparation consists in a liquid-liquid extraction (LLE) with acetonitrile, followed by liquid chromatography-electrospray-tandem mass spectrometry analysis (LC-ESI-MS/MS), without the need of any additional clean-up steps. Chromatographic separation was achieved using a C18 column and a mobile phase composed by acidified acetonitrile and water. The method was fully validated according the criteria of the Commission Decision 2002/657/EC. Validation parameters such as limit of detection, limit of quantification, linearity, accuracy, repeatability, specificity, reproducibility, decision limit (CCα) and detection capability (CCβ) were evaluated. All calculated values met the established criteria. Reproducibility values, expressed as coefficient of variation, were all lower than 19.1%. Recoveries range from 60% to 107%. Limits of detection were from 5 to 25 µg kg(-1).The present method is able to be applied in routine analysis, with adequate time of analysis, low cost and a simple sample preparation protocol. Copyright © 2015. Published by Elsevier B.V.

  19. Robust method for investigating nitrogen metabolism of 15N labeled amino acids using AccQ•Tag ultra performance liquid chromatography-photodiode array-electrospray ionization-mass spectrometry: application to a parasitic plant-plant interaction.

    Science.gov (United States)

    Gaudin, Zachary; Cerveau, Delphine; Marnet, Nathalie; Bouchereau, Alain; Delavault, Philippe; Simier, Philippe; Pouvreau, Jean-Bernard

    2014-01-21

    An AccQ•Tag ultra performance liquid chromatography-photodiode array-electrospray ionization-mass spectrometry (AccQ•Tag-UPLC-PDA-ESI-MS) method is presented here for the fast, robust, and sensitive quantification of (15)N isotopologue enrichment of amino acids in biological samples, as for example in the special biotic interaction between the cultivated specie Brassica napus (rapeseed) and the parasitic weed Phelipanche ramosa (broomrape). This method was developed and validated using amino acid standard solutions containing (15)N amino acid isotopologues and/or biological unlabeled extracts. Apparatus optimization, limits of detection and quantification, quantification reproducibility, and calculation method of (15)N isotopologue enrichment are presented. Using this method, we could demonstrate that young parasite tubercles assimilate inorganic nitrogen as (15)N-ammonium when supplied directly through batch incubation but not when supplied by translocation from host root phloem, contrary to (15)N2-glutamine. (15)N2-glutamine mobility from host roots to parasite tubercles followed by its low metabolism in tubercles suggests that the host-derived glutamine acts as an important nitrogen containing storage compound in the young tubercle of Phelipanche ramosa.

  20. One-pot polymerization of monolith coated stir bar for high efficient sorptive extraction of perfluoroalkyl acids from environmental water samples followed by high performance liquid chromatography-electrospray tandem mass spectrometry detection.

    Science.gov (United States)

    Yao, Xuezi; Zhou, Zhen; He, Man; Chen, Beibei; Liang, Yong; Hu, Bin

    2018-04-06

    In this work, poly(1-vinylimidazole-ethyleneglycol dimethacrylate) (poly(VI-EDMA)) monolith coated stir bars were synthesized by one-pot polymerization, and they exhibited higher extraction efficiency and faster extraction dynamics for selected PFAAs than commercial ethylene glycol modified silicone (EG-silicone) and polydimethylsiloxane (PDMS) coated stir bars. Taking eleven PFAAs as target analytes, including C4-C12 perfluoroalkyl carboxylates (PFCAs) and C6, C8 perfluoroalkane sulfonates (PFSAs), a method combining monolith-based stir bar sorptive extraction (SBSE) with high performance liquid chromatography (HPLC) - electrospray tandem mass spectrometry (ESI-MS/MS) was proposed for the determination of multiplex PFAAs in environmental water samples. Under the optimized conditions, low limits of detection (0.06-0.40 ng/L) and wide linear range (0.6-400 ng/L) were obtained for target PFAAs with. The developed method was then applied for the analysis of target PFAAs in environmental water samples, and recoveries of 80.1-117% and 80.3-122% were obtained for target PFAAs in spiked Yangtze River and East Lake water samples respectively. Copyright © 2018 Elsevier B.V. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Michele L. Etter

    2010-02-01

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

  2. Identification of unsaturated N-acylhomoserine lactones in bacterial isolates of Rhodobacter sphaeroides by liquid chromatography coupled to electrospray ionization-hybrid linear ion trap-Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Cataldi, Tommaso R I; Bianco, Giuliana; Abate, Salvatore; Losito, Ilario

    2011-07-15

    The identification of two unsaturated N-acylhomoserine lactones (AHLs) produced by Rhodobacter sphaeroides bacteria, based on liquid chromatography (LC) coupled to a hybrid quadrupole linear ion trap (LTQ)-Fourier transform ion cyclotron resonance (FTICR) mass spectrometer upon electrospray ionization (ESI), is presented. Besides the confirmation of the signaling molecule already described in the literature, i.e. (Z)-N-tetradec-7-enoyl-homoserine lactone (C(14:1)-HSL), we have discovered the occurrence, at low, yet significant levels, of another monounsaturated compound, C(12:1) -HSL, which may extend the number of small diffusible chemical signals known for R. sphaeroides. Both unsaturated AHLs were identified by high-resolution FTICR mass spectrometry in extracts of bacterial culture media and the occurrence of a C=C bond was assessed upon their conversion into bromohydrins. Collision-induced dissociation (CID) spectra were then collected on the LTQ mass analyzer. A careful comparison of tandem MS spectra of monounsaturated (i.e., C(12:1)-HSL and C(14:1)-HSL) and saturated AHLs (i.e. C(12)-HSL and C(14)-HSL) led to the emphasis of two series of product ions, exhibiting 14 Da spaced m/z ratios. Both series were referred to progressive fragmentations at the aliphatic end of the AHL acyl chains, followed by neutral losses of terminal alkenes (i.e. CH(2)=CH(CH(2))(n)H). In particular, the series located at the higher end of the explored m/z range (>200 Da), observed only for monounsaturated species, enabled the location of the C=C bond between carbons 7 and 8 of the acyl chain. Copyright © 2011 John Wiley & Sons, Ltd.

  3. Relationships between structure, ionization profile and sensitivity of exogenous anabolic steroids under electrospray ionization and analysis in human urine using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Cha, Eunju; Kim, Sohee; Kim, Hee Won; Lee, Kang Mi; Kim, Ho Jun; Kwon, Oh-Seung; Lee, Jaeick

    2016-04-01

    The relationships between the ionization profile, sensitivity, and structures of 64 exogenous anabolic steroids (groups I-IV) was investigated under electrospray ionization (ESI) conditions. The target analytes were ionized as [M + H](+) or [M + H-nH2 O](+) in the positive mode, and these ions were used as precursor ions for selected reaction monitoring analysis. The collision energy and Q3 ions were optimized based on the sensitivity and selectivity. The limits of detection (LODs) were 0.05-20 ng/mL for the 64 steroids. The LODs for 38 compounds, 14 compounds and 12 compounds were in the range of 0.05-1, 2-5 and 10-20 ng/mL, respectively. Steroids including the conjugated keto-functional group at C3 showed good proton affinity and stability, and generated the [M + H](+) ion as the most abundant precursor ion. In addition, the LODs of steroids using the [M + H](+) ion as the precursor ion were mostly distributed at low concentrations. In contrast, steroids containing conjugated/unconjugated hydroxyl functional groups at C3 generated [M + H - H2 O](+) or [M + H - 2H2 O](+) ions, and these steroids showed relatively high LODs owing to poor stability and multiple ion formation. An LC-MS/MS method based on the present ionization profile was developed and validated for the determination of 78 steroids (groups I-V) in human urine. Copyright © 2015 John Wiley & Sons, Ltd.

  4. DMSO Assisted Electrospray Ionization for the Detection of Small Peptide Hormones in Urine by Dilute-and-Shoot-Liquid-Chromatography-High Resolution Mass Spectrometry

    Science.gov (United States)

    Judák, Péter; Grainger, Janelle; Goebel, Catrin; Van Eenoo, Peter; Deventer, Koen

    2017-08-01

    The mobile phase additive (DMSO) has been described as a useful tool to enhance electrospray ionization (ESI) of peptides and proteins. So far, this technique has mainly been used in proteomic/peptide research, and its applicability in a routine clinical laboratory setting (i.e., doping control analysis) has not been described yet. This work provides a simple, easy to implement screening method for the detection of doping relevant small peptides (GHRPs, GnRHs, GHS, and vasopressin-analogues) with molecular weight less than 2 kDa applying DMSO in the mobile phase. The gain in sensitivity was sufficient to inject the urine samples after a 2-fold dilution step omitting a time consuming sample preparation. The employed analytical procedure was validated for the qualitative determination of 36 compounds, including 13 metabolites. The detection limits (LODs) ranged between 50 and 1000 pg/mL and were compliant with the 2 ng/mL minimum detection level required by the World Anti-Doping Agency (WADA) for all the target peptides. To demonstrate the feasibility of the work, urine samples obtained from patients who have been treated with desmopressin or leuprolide and urine samples that have been declared as adverse analytical findings were analyzed.

  5. Reversed phase liquid chromatography hyphenated to continuous flow-extractive desorption electrospray ionization-mass spectrometry for analysis and charge state manipulation of undigested proteins

    Czech Academy of Sciences Publication Activity Database

    Li, L.; Yang, S.; Vidová, Veronika; Rice, E. M.; Wijeratne, A.; Havlíček, Vladimír; Schug, K. A.

    2015-01-01

    Roč. 21, č. 3 (2015), s. 361-368 ISSN 1469-0667 R&D Projects: GA ČR(CZ) GAP206/12/1150; GA MŠk(CZ) LH14064; GA MŠk LO1509 Institutional support: RVO:61388971 Keywords : protein chromatography * ambient ionization * charge-state manipulation Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.011, year: 2015

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

    International Nuclear Information System (INIS)

    Dumont, Emmie; Ogra, Yasumitsu; Suzuki, Kazuo T.; Vanhaecke, Frank; Cornelis, Rita

    2006-01-01

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

  7. Evaluation of immobilized metal-ion affinity chromatography and electrospray ionization tandem mass spectrometry for recovery and identification of copper(II-binding ligands in seawater using the model ligand 8-hydroxyquinoline

    Directory of Open Access Journals (Sweden)

    Richard L Nixon

    2016-11-01

    Full Text Available Complexation by organic ligands dominates the speciation of iron (Fe, copper (Cu, and other bioactive trace metals in seawater, controlling their bioavailability and distribution in the marine environment. Several classes of high-affinity Fe-binding ligands (siderophores have been identified in seawater but the chemical structures of marine Cu-complexing ligands remain unknown. Immobilized metal-ion affinity chromatography (IMAC allows Cu ligands to be isolated from bulk dissolved organic matter (DOM in seawater and separated into fractions which can be characterized independently using electrochemical and spectroscopic techniques. Attempts have been made to combine IMAC with electrospray ionization mass spectrometry (ESI-MS to characterize marine Cu ligands, but results have proven inconclusive due to the lack of tandem mass spectrometry (MS/MS data to confirm ligand recovery. We used 8-hydroxyquinoline (8-HQ, a well-characterized model ligand that forms strong 1:2 metal:ligand complexes with Cu2+ at pH 8 (log β2 = 18.3, to evaluate Cu(II-IMAC and ESI-MS/MS for recovery and identification of copper(II-complexing ligands in seawater. One-litre samples of 0.45µm-filtered surface seawater were spiked with 8-HQ at low concentrations (up to 100 nM and fractionated by IMAC. Fractions eluted with acidified artificial seawater were desalted and re-suspended in methanol via solid-phase extraction (SPE to obtain extracts suitable for ESI-MS analysis. Recovery of 8-HQ by Cu(II-IMAC was confirmed unambiguously by MS/MS and found to average 81% based upon accurate quantitation via multiple reaction monitoring (MRM. Cu(II-IMAC fractionation of unspiked seawater using multiple UV detection wavelengths suggests an optimal fraction size of 2 mL for isolating and analyzing Cu ligands with similar properties.

  8. Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometric (LC/ESI-MS/MS Study for the Identification and Characterization of In Vivo Metabolites of Cisplatin in Rat Kidney Cancer Tissues: Online Hydrogen/Deuterium (H/D Exchange Study.

    Directory of Open Access Journals (Sweden)

    Raju Bandu

    Full Text Available In vivo rat kidney tissue metabolites of an anticancer drug, cisplatin (cis-diamminedichloroplatinum [II] (CP which is used for the treatment of testicular, ovarian, bladder, cervical, esophageal, small cell lung, head and neck cancers, have been identified and characterized by using liquid chromatography positive ion electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS in combination with on line hydrogen/deuterium exchange (HDX experiments. To identify in vivo metabolites, kidney tissues were collected after intravenous administration of CP to adult male Sprague-Dawley rats (n = 3 per group. The tissue samples were homogenized and extracted using newly optimized metabolite extraction procedure which involves liquid extraction with phosphate buffer containing ethyl acetate and protein precipitation with mixed solvents of methanol-water-chloroform followed by solid-phase clean-up procedure on Oasis HLB 3cc cartridges and then subjected to LC/ESI-HRMS analysis. A total of thirty one unknown in vivo metabolites have been identified and the structures of metabolites were elucidated using LC-MS/MS experiments combined with accurate mass measurements. Online HDX experiments have been used to further support the structural characterization of metabolites. The results showed that CP undergoes a series of ligand exchange biotransformation reactions with water and other nucleophiles like thio groups of methionine, cysteine, acetylcysteine, glutathione and thioether. This is the first research approach focused on the structure elucidation of biotransformation products of CP in rats, and the identification of metabolites provides essential information for further pharmacological and clinical studies of CP, and may also be useful to develop various effective new anticancer agents.

  9. Simultaneous determination of phenolic compounds and saponins in quinoa (Chenopodium quinoa Willd) by a liquid chromatography-diode array detection-electrospray ionization-time-of-flight mass spectrometry methodology.

    Science.gov (United States)

    Gómez-Caravaca, Ana María; Segura-Carretero, Antonio; Fernández-Gutiérrez, Alberto; Caboni, Maria Fiorenza

    2011-10-26

    A new liquid chromatography methodology coupled to a diode array detector and a time-of-flight mass spectrometer has been developed for the simultaneous determination of phenolic compounds and saponins in quinoa (Chenopodium quinoa Willd). This method has allowed the simultaneous determination of these two families of compounds with the same analytical method for the first time. A fused-core column C18 has been used, and the analysis has been performed in less than 27 min. Both chromatographic and electrospray ionization time-of-flight mass spectrometry parameters have been optimized to improve the sensitivity and to maximize the number of compounds detected. A validation of the method has also been carried out, and free and bound polar fractions of quinoa have been studied. Twenty-five compounds have been tentatively identified and quantified in the free polar fraction, while five compounds have been tentatively identified and quantified in the bound polar fraction. It is important to highlight that 1-O-galloyl-β-D-glucoside, acacetin, protocatechuic acid 4-O-glucoside, penstebioside, ethyl-m-digallate, (epi)-gallocatechin, and canthoside have been tentatively identified for the first time in quinoa. Free phenolic compounds have been found to be in the range of 2.746-3.803 g/kg of quinoa, while bound phenolic compounds were present in a concentration that varies from 0.139 and 0.164 g/kg. Indeed, saponins have been found to be in a concentration that ranged from 5.6 to 7.5% of the total composition of whole quinoa flour.

  10. Simultaneous Determination of Celecoxib, Erlotinib, and its Metabolite Desmethyl-Erlotinib (OSI-420) in Rat Plasma by Liquid chromatography/Tandem Mass Spectrometry with Positive/Negative Ion-Switching Electrospray Ionisation.

    Science.gov (United States)

    Thappali, Satheeshmanikandan R S; Varanasi, Kanthikiran; Veeraraghavan, Sridhar; Arla, Rambabu; Chennupati, Sandhya; Rajamanickam, Madheswaran; Vakkalanka, Swaroop; Khagga, Mukkanti

    2012-01-01

    A new method for the simultaneous determination of celecoxib, erlotinib, and its active metabolite desmethyl-erlotinib (OSI-420) in rat plasma, by liquid chromatography/tandem mass spectrometry with positive/negative ion-switching electrospray ionization mode, was developed and validated. Protein precipitation with methanol was selected as the method for preparing the samples. The analytes were separated on a reverse-phase C(18) column (50mm×4.6mm i.d., 3μ) using methanol: 2 mM ammonium acetate buffer, and pH 4.0 as the mobile phase at a flow rate 0.8 mL/min. Sitagliptin and Efervirenz were used as the internal standards for quantification. The determination was carried out on a Theremo Finnigan Quantam ultra triple-quadrupole mass spectrometer, operated in selected reaction monitoring (SRM) mode using the following transitions monitored simultaneously: positive m/z 394.5→278.1 for erlotinib, m/z 380.3→278.1 for desmethyl erlotinib (OSI-420), and negative m/z -380.1→ -316.3 for celecoxib. The limits of quantification (LOQs) were 1.5 ng/mL for Celecoxib, erlotinib, and OSI-420. Within- and between-day accuracy and precision of the validated method were within the acceptable limits of < 15% at all concentrations. The quantitation method was successfully applied for the simultaneous estimation of celecoxib, erlotinib, and desmethyl erlotinib in a pharmacokinetic study in Wistar rats.

  11. Dehydrodimerization of pterostilbene during electrospray ionization mass spectrometry

    KAUST Repository

    Raji, Misjudeen

    2013-04-30

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

  12. Subcellular analysis by laser ablation electrospray ionization mass spectrometry

    Science.gov (United States)

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

    2014-12-02

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

  13. Analysis and occurrence of selected medium to highly polar pesticides in groundwater of Catalonia (NE Spain): An approach based on on-line solid phase extraction-liquid chromatography-electrospray-tandem mass spectrometry detection

    Science.gov (United States)

    Postigo, Cristina; López de Alda, Maria José; Barceló, Damià; Ginebreda, Antoni; Garrido, Teresa; Fraile, Josep

    2010-03-01

    SummaryThe present work describes an automated methodology based on on-line solid phase extraction-liquid chromatography-electrospray-tandem mass spectrometry (on-line SPE-LC-ESI-MS/MS) for the determination of 22 medium to highly polar pesticides in groundwater, and its application to the analysis of 133 samples collected from different aquifers of Catalonia (NE Spain), in areas where agricultural practice is significant. Sample preconcentration was performed by passing 5 mL of the sample through PLRPs cartridges (for analysis of 16 pesticides measured in the positive ionization mode) and through Hysphere-Resin GP cartridges (for analysis of six pesticides measured in the negative ionization mode). Further LC-MS/MS determination was performed in the selected reaction monitoring (SRM) mode, by recording two SRM transitions per compound, thus obtaining four identification points. The methodology developed allows the determination of the target compounds at the pg or low ng L -1 level with satisfactory precision (relative standard deviations lower than 16%) and accuracy (recovery percentages higher than 75%) and is well suited for routine monitoring. Its application to various groundwater samples from Catalonia has revealed simazine, diuron and atrazine (present in more than 70% of the samples) as the most ubiquitous compounds. Approximately 16% of the samples investigated had individual pesticides levels above 100 ng L -1 and 7% presented total pesticides levels above 500 ng L -1. Concentrations higher than 100 ng L -1 were found for all triazines studied but cyanazine, the phenylureas diuron, linuron and chlortoluron, the target chloroacetanilides alachlor and metolachlor, and the organophosphate dimethoate in a few samples. Three and eight out of the 16 investigated groundwater bodies presented total pesticide levels exceeding the EU quality standards in terms of individual and total pesticide concentrations, 100 and 500 ng L -1, respectively.

  14. Biotransformation of the high-molecular weight polycyclic aromatic hydrocarbon (PAH) benzo[k]fluoranthene by Sphingobium sp. strain KK22 and identification of new products of non-alternant PAH biodegradation by liquid chromatography electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Maeda, Allyn H; Nishi, Shinro; Hatada, Yuji; Ozeki, Yasuhiro; Kanaly, Robert A

    2014-03-01

    A pathway for the biotransformation of the environmental pollutant and high-molecular weight polycyclic aromatic hydrocarbon (PAH) benzo[k]fluoranthene by a soil bacterium was constructed through analyses of results from liquid chromatography negative electrospray ionization tandem mass spectrometry (LC/ESI(-)-MS/MS). Exposure of Sphingobium sp. strain KK22 to benzo[k]fluoranthene resulted in transformation to four-, three- and two-aromatic ring products. The structurally similar four- and three-ring non-alternant PAHs fluoranthene and acenaphthylene were also biotransformed by strain KK22, and LC/ESI(-)-MS/MS analyses of these products confirmed the lower biotransformation pathway proposed for benzo[k]fluoranthene. In all, seven products from benzo[k]fluoranthene and seven products from fluoranthene were revealed and included previously unreported products from both PAHs. Benzo[k]fluoranthene biotransformation proceeded through ortho-cleavage of 8,9-dihydroxy-benzo[k]fluoranthene to 8-carboxyfluoranthenyl-9-propenic acid and 9-hydroxy-fluoranthene-8-carboxylic acid, and was followed by meta-cleavage to produce 3-(2-formylacenaphthylen-1-yl)-2-hydroxy-prop-2-enoic acid. The fluoranthene pathway converged with the benzo[k]fluoranthene pathway through detection of the three-ring product, 2-formylacenaphthylene-1-carboxylic acid. Production of key downstream metabolites, 1,8-naphthalic anhydride and 1-naphthoic acid from benzo[k]fluoranthene, fluoranthene and acenaphthylene biotransformations provided evidence for a common pathway by strain KK22 for all three PAHs through acenaphthoquinone. Quantitative analysis of benzo[k]fluoranthene biotransformation by strain KK22 confirmed biodegradation. This is the first pathway proposed for the biotransformation of benzo[k]fluoranthene by a bacterium. © 2013 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  15. Biotransformation of the high-molecular weight polycyclic aromatic hydrocarbon (PAH) benzo[k]fluoranthene by Sphingobium sp. strain KK22 and identification of new products of non-alternant PAH biodegradation by liquid chromatography electrospray ionization tandem mass spectrometry

    Science.gov (United States)

    Maeda, Allyn H; Nishi, Shinro; Hatada, Yuji; Ozeki, Yasuhiro; Kanaly, Robert A

    2014-01-01

    A pathway for the biotransformation of the environmental pollutant and high-molecular weight polycyclic aromatic hydrocarbon (PAH) benzo[k]fluoranthene by a soil bacterium was constructed through analyses of results from liquid chromatography negative electrospray ionization tandem mass spectrometry (LC/ESI(–)-MS/MS). Exposure of Sphingobium sp. strain KK22 to benzo[k]fluoranthene resulted in transformation to four-, three-and two-aromatic ring products. The structurally similar four-and three-ring non-alternant PAHs fluoranthene and acenaphthylene were also biotransformed by strain KK22, and LC/ESI(–)-MS/MS analyses of these products confirmed the lower biotransformation pathway proposed for benzo[k]fluoranthene. In all, seven products from benzo[k]fluoranthene and seven products from fluoranthene were revealed and included previously unreported products from both PAHs. Benzo[k]fluoranthene biotransformation proceeded through ortho-cleavage of 8,9-dihydroxy-benzo[k]fluoranthene to 8-carboxyfluoranthenyl-9-propenic acid and 9-hydroxy-fluoranthene-8-carboxylic acid, and was followed by meta-cleavage to produce 3-(2-formylacenaphthylen-1-yl)-2-hydroxy-prop-2-enoic acid. The fluoranthene pathway converged with the benzo[k]fluoranthene pathway through detection of the three-ring product, 2-formylacenaphthylene-1-carboxylic acid. Production of key downstream metabolites, 1,8-naphthalic anhydride and 1-naphthoic acid from benzo[k]fluoranthene, fluoranthene and acenaphthylene biotransformations provided evidence for a common pathway by strain KK22 for all three PAHs through acenaphthoquinone. Quantitative analysis of benzo[k]fluoranthene biotransformation by strain KK22 confirmed biodegradation. This is the first pathway proposed for the biotransformation of benzo[k]fluoranthene by a bacterium. PMID:24325265

  16. Characterization of metabolite profiles from the leaves of green perilla (Perilla frutescens by ultra high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry and screening for their antioxidant properties

    Directory of Open Access Journals (Sweden)

    Yeon Hee Lee

    2017-10-01

    Full Text Available The objective of this research was to access the determination of metabolite profiles and antioxidant properties in the leaves of green perilla (Perilla frutescens, where these are considered functional and nutraceutical substances in Korea. A total of 25 compositions were confirmed as six phenolic acids, two triterpenoids, eight flavonoids, seven fatty acids, and two glucosides using an ultra high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-ESI-Q-TOF-MS/MS technique from the methanol extract of this species. The individual and total compositions exhibited significant differences, especially rosmarinic acid (10, and linolenic acids (22 and 23 were detected as the predominant metabolites. Interestingly, rosmarinic acid (10 was observed to have considerable differences with various concentrations in three samples (Doryong, 6.38 μg/g; Sinseong, 317.60 μg/g; Bongmyeong, 903.53 μg/g by UPLC analysis at 330 nm. The scavenging properties against 2,2-diphenyl-1-picrylhydrazyl (DPPH and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid (ABTS radicals also showed potent effects with remarkable differences at a concentration of 100 μg/mL, and their abilities were as follows: Sinseong (DPPH, 86%; ABTS, 90% > Bongmyeong (71% and 84%, respectively > Doryong (63% and 73%, respectively. Our results suggest that the antioxidant activities of green perilla leaves are correlated with metabolite contents, especially the five major compositions 10 and 22–25. Moreover, this study may be useful in evaluating the relationship between metabolite composition and antioxidant activity.

  17. Quantification of perifosine, an alkylphosphocholine anti-tumour agent, in plasma by pneumatically assisted electrospray tandem mass spectrometry coupled with high-performance liquid chromatography

    NARCIS (Netherlands)

    Knebel, N.G.; Grieb, S.; Winkler, M.; Locher, M.; Vlis, E. van der; Verheij, E.R.

    1999-01-01

    An HPLC assay with tandem mass spectrometric detection in the positive-ion Turbo-Ion-Spray((TM)) (TISP) mode for the fast and sensitive determination of perifosine ((I), D-21266) in human plasma was developed, utilising the structural analogue, miltefosine ((II), D-18506), as internal standard.

  18. High Performance Liquid Chromatography-Electrochemistry-Electrospray Ionization Mass Spectrometry (HPLC/EC/ESI-MS) for Detection and Characterization of Roscovitine Oxidation Products

    Czech Academy of Sciences Publication Activity Database

    Karady, Michal; Novák, Ondřej; Horna, A.; Strnad, Miroslav; Doležal, Karel

    2011-01-01

    Roč. 23, č. 12 (2011), s. 2898-2905 ISSN 1040-0397 R&D Projects: GA MŠk ED0007/01/01; GA ČR GA301/08/1649 Keywords : Electrochemistry * Mass spectrometry * R-roscovitine Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.872, year: 2011

  19. Stability and Degradation of Caffeoylquinic Acids under Different Storage Conditions Studied by High-Performance Liquid Chromatography with Photo Diode Array Detection and High-Performance Liquid Chromatography with Electrospray Ionization Collision-Induced Dissociation Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Meng Xue

    2016-07-01

    Full Text Available Caffeoylquinic acids (CQAs are main constituents in many herbal medicines with various biological and pharmacological effects. However, CQAs will degrade or isomerize when affected by temperature, pH, light, etc. In this study, high-performance liquid chromatography with photodiode array detection (HPLC-PDA and high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS was utilized to study the stability and degradation of CQAs (three mono-acyl CQAs and four di-acyl CQAs under various ordinary storage conditions (involving different temperatures, solvents, and light irradiation. The results indicated that the stability of CQAs was mainly affected by temperature and light irradiation, while solvents did not affect it in any obvious way under the conditions studied. Mono-acyl CQAs were generally much more stable than di-acyl CQAs under the same conditions. Meanwhile, the chemical structures of 30 degradation products were also characterized by HPLC-MSn, inferring that isomerization, methylation, and hydrolysis were three major degradation pathways. The result provides a meaningful clue for the storage conditions of CQAs standard substances and samples.

  20. Simultaneous determination of phenolic compounds in Cynthiana grape (Vitis aestivalis) by high performance liquid chromatography-electrospray ionisation-mass spectrometry.

    Science.gov (United States)

    Ramirez-Lopez, L M; McGlynn, W; Goad, C L; Mireles Dewitt, C A

    2014-04-15

    Phenolic acids, flavanols, flavonols and stilbenes (PAFFS) were isolated from whole grapes, juice, or pomace and purified using enzymatic hydrolysis. Only anthocyanin mono-glucosides and a few of the oligomers from Cynthiana grape (Vitis aestivalis) were analysed. Flavonoid-anthocyanin mono-glucosides (FA) were isolated using methanol/0.1% hydrochloric acid extraction. In addition, crude extractions of phenolic compounds from Cynthiana grape using 50% methanol, 70% methanol, 50% acetone, 0.01% pectinase, or petroleum ether were also evaluated. Reverse phase high performance liquid chromatography (RP-HPLC) with photodiode array (PDA) detector was used to identify phenolic compounds. A method was developed for simultaneous separation, identification and quantification of both PAFFS and FA. Quantification was performed by the internal standard method using a five points regression graph of the UV-visible absorption data collected at the wavelength of maximum absorbance for each analyte. From whole grape samples nine phenolic compounds were tentatively identified and quantified. The individual phenolic compounds content varied from 3 to 875 mg kg⁻¹ dry weight. For juice, twelve phenolic compounds were identified and quantified. The content varied from 0.07 to 910 mg kg⁻¹ dry weight. For pomace, a total of fifteen phenolic compounds were tentatively identified and quantified. The content varied from 2 mg kg⁻¹ to 198 mg kg⁻¹ dry matter. Results from HPLC analysis of the samples showed that gallic acid and (+)-catechin hydrate were the major phenolic compounds in both whole grapes and pomace. Cyanidin and petunidin 3-O-glucoside were the major anthocyanin glucosides in the juice. Published by Elsevier Ltd.

  1. Simultaneous determination of asperosaponin VI and its active metabolite hederagenin in rat plasma by liquid chromatography-tandem mass spectrometry with positive/negative ion-switching electrospray ionization and its application in pharmacokinetic study.

    Science.gov (United States)

    Zhu, He; Ding, Li; Shakya, Shailendra; Qi, Xiemin; Hu, Linlin; Yang, Xiaolin; Yang, Zhonglin

    2011-11-15

    A new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method operated in the positive/negative electrospray ionization (ESI) switching mode has been developed and validated for the simultaneous determination of asperosaponin VI and its active metabolite hederagenin in rat plasma. After addition of internal standards diazepam (for asperosaponin VI) and glycyrrhetic acid (for hederagenin), the plasma sample was deproteinized with acetonitrile, and separated on a reversed phase C18 column with a mobile phase of methanol (solvent A)-0.05% glacial acetic acid containing 10 mM ammonium acetate and 30 μM sodium acetate (solvent B) using gradient elution. The detection of target compounds was done in multiple reaction monitoring (MRM) mode using a tandem mass spectrometry equipped with positive/negative ion-switching ESI source. At the first segment, the MRM detection was operated in the positive ESI mode using the transitions of m/z 951.5 ([M+Na](+))→347.1 for asperosaponin VI and m/z 285.1 ([M+H](+))→193.1 for diazepam for 4 min, then switched to the negative ESI mode using the transitions of m/z 471.3 ([M-H](-))→471.3 for hederagenin and m/z 469.4 ([M-H](-))→425.4 for glycyrrhetic acid, respectively. The sodiated molecular ion [M+Na](+) at m/z 951.5 was selected as the precursor ion for asperosaponin VI, since it provided better sensitivity compared to the deprotonated and protonated molecular ions. Sodium acetate was added to the mobile phase to make sure that abundant amount of the sodiated molecular ion of asperosaponin VI could be produced, and more stable and intensive mass response of the product ion could be obtained. For the detection of hederagenin, since all of the mass responses of the fragment ions were very weak, the deprotonated molecular ion [M-H](-)m/z 471.3 was employed as both the precursor ion and the product ion. But the collision energy was still used for the MRM, in order to eliminate the influences induced by the interference

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-03-25

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

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

    International Nuclear Information System (INIS)

    Giménez, Estela; Balmaña, Meritxell; Figueras, Joan; Fort, Esther; Bolós, Carme de; Sanz-Nebot, Victòria; Peracaula, Rosa; Rizzi, Andreas

    2015-01-01

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

  4. Application of liquid chromatography/electrospray ionization ion trap tandem mass spectrometry for the evaluation of global nucleic acids: methylation in garden cress under exposure to CuO nanoparticles.

    Science.gov (United States)

    Alcazar Magana, Armando; Wrobel, Kazimierz; Corrales Escobosa, Alma Rosa; Wrobel, Katarzyna

    2016-01-15

    A full understanding of the biological impact of nanomaterials demands analytical procedures suitable for the detection/quantification of epigenetic changes that occur in the exposed organisms. Here, the effect of CuO nanoparticles (NPs) on global methylation of nucleic acids in Lepidium sativum was evaluated by liquid chromatography/ion trap mass spectrometry. Enhanced selectivity toward cytosine-containing nucleosides was achieved by using their proton-bound dimers formed in positive electrospray ionization (ESI(+)) as precursor ions for multiple reaction monitoring (MRM) quantification based on one or two ion transitions. Plants were exposed to CuO NPs (0-1000 mg L(-1)); nucleic acid extracts were washed with bathocuproine disulfate; nucleosides were separated on a Luna C18 column coupled via ESI(+) to an AmaZon SL mass spectrometer (Bruker Daltonics). Cytidine, 2´-deoxycytidine, 5-methylcytidine, 5-methyl-2´-deoxycytidine and 5-hydroxymethyl-2´-deoxycytidine were quantified by MRM based on MS(3) ([2M+H](+)/[M+H](+)/[M+H-132](+) or [M+H-116](+)) and MS(2) ([2M+H](+)/[M+H](+) ). Bathocuproine disulfate, added as Cu(I) complexing agent, allowed for elimination of [2M+Cu](+) adducts from the mass spectra. Poorer instrumental detection limits were obtained for MS(3) (20-120 fmol) as compared to MS(2) (9.0-41 fmol); however, two ion transitions helped to eliminate matrix effects in plant extracts. The procedure was tested by analyzing salmon sperm DNA (Sigma) and applied for the evaluation of DNA and RNA methylation in plants; in the absence of NPs, 13.03% and 0.92% methylated cytosines were found in DNA and RNA, respectively; for NPs concentration >50 mg L(-1), DNA hypomethylation was observed with respect to unexposed plants. RNA methylation did not present significant changes upon plant exposure; 5-hydroxymethyl-2´-deoxycytidine was not detected in any sample. The MRM quantification proposed here of cytosine-containing nucleosides using their proton-bound homo

  5. Liquid chromatography electrospray ionization tandem mass spectrometry study of nilutamide and its stress degradation products: in silico toxicity prediction of degradation products.

    Science.gov (United States)

    Ramesh Babu, A; Borkar, Roshan M; Raju, G; Raju, B; Srinivas, R

    2014-06-01

    Nilutamide, a nonsteroidal anti-androgen drug, widely used in the treatment of prostate cancer, was subjected to hydrolytic, photolytic, thermal and oxidative stress conditions as per International Conference on Harmonization guidelines Q1A (R2). Nilutamide showed significant degradation under basic hydrolysis and photolytic stress conditions, while it was stable to neutral, acidic and thermal stress conditions. Five degradation products were formed and the chromatographic separation of nilutamide and its degradation products was achieved on a Waters C18 column (4.6 × 250 mm, 5 µm) using a mobile phase consisting of acetonitrile and 0.1% of formic acid in an isocratic elution method. All these degradation products were characterized by LC/MS/MS in negative ion mode, combined with accurate mass measurements. To assign likely structures for the observed degradation products, the fragmentation patterns of the deprotonated drug and its degradation products were compared. The in silico toxicity of the drug and its degradation products was also assessed using TOPKAT software. The carcinogenicity probability of the degradation products, DP-I-IV, was greater than that of nilutamide. Copyright © 2014 John Wiley & Sons, Ltd.

  6. Rapid screening of low-molecular-weight phenols from persimmon (Diospyros kaki) pulp using liquid chromatography/UV-visible/electrospray mass spectrometry analysis.

    Science.gov (United States)

    Sentandreu, Enrique; Cerdán-Calero, Manuela; Halket, John M; Navarro, José L

    2015-06-01

    Persimmon fruits have been widely used in traditional medicine owing to their phenolic composition. This research aims to perform a rapid, detailed and affordable study of the profile of low-molecular-weight phenols from persimmon pulp. Two different HPLC-DAD/ESI-MS(n) analyses were performed using a routine three-dimensional ion trap mass spectrometer to analyze the ethanolic extract of persimmon pulp: (1) an untargeted data-dependent analysis to identify the majority of small phenols that included full MS and MS(2) scan events; (2) a targeted data-dependent analysis to identify polymerized phenols (dimers and formic acid adducts) through a source-induced dissociation analysis that included full MS and MS(2) scan events. Thirty-two low-molecular-weight phenols were detected, comprising gallic acid and its glycoside and acyl derivatives, glycosides of p-coumaric, vanillic and cinnamic acids and different flavone di-C-hexosides, most of them reported for the first time in persimmon. The use of a straightforward and affordable methodology of analysis led to obtain an up-to-date profiling of low-molecular-weight phenols in persimmon. The results can help future actions aimed to expand the understanding of the phenolic metabolome of persimmon cultivars. © 2014 Society of Chemical Industry.

  7. Analysis of carbohydrates in Lupinus albus stems on imposition of water deficit, using porous graphitic carbon liquid chromatography-electrospray ionization mass spectrometry.

    Science.gov (United States)

    Antonio, Carla; Pinheiro, Carla; Chaves, Maria Manuela; Ricardo, Cândido Pinto; Ortuño, Maria Fernanda; Thomas-Oates, Jane

    2008-04-11

    This work reports the development and application of a negative ion mode online LC-ESI-MS method for studying the effect of water deficit on the carbohydrate content of Lupinus albus stems, using a porous graphitic carbon (PGC) stationary phase and an ion trap mass spectrometer. Using this method, separation and detection of several water soluble carbohydrates, ranging from mono-, di-, and oligosaccharides (raffinose, stachyose, and verbascose) to sugar alcohols was achieved in approximately 10 min. This on-line PGC-LC-ESI-MS method shows good linearity with correlation coefficients R(2)>0.99, selectivity, short analysis time, and limits of detection (LOD) ranging from 0.4 to 9 pmol for sugars and 4-20 pmol for sugar alcohols. This PGC-LC-ESI-MS method is sensitive and allowed us to detect even small alterations in carbohydrate levels in L. albus stems that resulted from a mild/early water deficit (nmol g(-1)DW). This paper describes details of our method and its application to the quantitative analysis of water soluble underivatised carbohydrates extracted from L. albus stem tissues that have been subjected to early and severe water deficit conditions, followed by a rewatering period.

  8. Characterization of Steroidal Saponins from Dioscorea villosa and D. cayenensis Using Ultrahigh Performance Liquid Chromatography/Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry

    Science.gov (United States)

    Avula, Bharathi; Wang, Yan-Hong; Wang, Mei; Ali, Zulfiqar; Smillie, Troy J.; Zweigenbaum, Jerry; Khan, Ikhlas A.

    2017-01-01

    Yam (Dioscorea spp.) is an important edible tuber plant used for medicinal purposes to promote health and longevity in Chinese tradition. Steroidal saponins were reported to be the major physiologically active constituents in yams. In this current work, the structural characteristics of steroidal saponins in methanolic extracts from dried rhizomes of two Dioscorea species (D. villosa L. and D. cayenensis Lam.) and dietary supplements have been identified and analyzed using UHPLC/QTOF-MS in both negative and positive ion modes. The fragmentation patterns of reference standards were determined and the steroidal saponins in the extracts were identified or tentatively characterized from their retention times and mass spectra. The fragments produced by collision-induced dissociation (CID) revealed the characteristic cleavage of glycosidic bonds, and the fragmentation pattern provided structural information about the sugars. Twenty-one saponins, including four tentatively identified compounds, were detected in the crude extracts of two Dioscorea species. These saponins can be used to distinguish D. villosa from D. cayenensis. For example, asperin and gracillin are found only in D. cayenensis, and dioscoreavilloside A and B and parvifloside are only found in D. villosa. This can be used to determine the presence or absence of D. villosa in commercial products, which may help determine the spiking of plant material, and/or prevent the use of potentially mislabeled or misidentified “Dioscorea” material. The analytical method also provided an alternative, fast method for quality control of Dioscorea species in dietary supplements. Principal component analysis showed that Dioscorea species and commercial products were easily distinguished. From this a partial least squares model was constructed to determine what species are in different products. PMID:24510365

  9. Characterization of steroidal saponins from Dioscorea villosa and D. cayenensis using ultrahigh performance liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Avula, Bharathi; Wang, Yan-Hong; Wang, Mei; Ali, Zulfiqar; Smillie, Troy J; Zweigenbaum, Jerry; Khan, Ikhlas A

    2014-03-01

    Yam (Dioscorea spp.) is an important edible tuber plant used for medicinal purposes to promote health and longevity in Chinese tradition. Steroidal saponins were reported to be the major physiologically active constituents in yams. In this current work, the structural characteristics of steroidal saponins in methanolic extracts from dried rhizomes of two Dioscorea species (D. villosa L. and D. cayenensis Lam.) and dietary supplements have been identified and analyzed using UHPLC/QTOF-MS in both negative and positive ion modes. The fragmentation patterns of reference standards were determined and the steroidal saponins in the extracts were identified or tentatively characterized from their retention times and mass spectra. The fragments produced by collision-induced dissociation (CID) revealed the characteristic cleavage of glycosidic bonds, and the fragmentation pattern provided structural information about the sugars. Twenty-one saponins, including four tentatively identified compounds, were detected in the crude extracts of two Dioscorea species. These saponins can be used to distinguish D. villosa from D. cayenensis. For example, asperin and gracillin are found only in D. cayenensis, and dioscoreavilloside A and B and parvifloside are only found in D. villosa. This can be used to determine the presence or absence of D. villosa in commercial products, which may help determine the spiking of plant material, and/or prevent the use of potentially mislabeled or misidentified "Dioscorea" material. The analytical method also provided an alternative, fast method for quality control of Dioscorea species in dietary supplements. Principal component analysis showed that Dioscorea species and commercial products were easily distinguished. From this a partial least squares model was constructed to determine what species are in different products. Georg Thieme Verlag KG Stuttgart · New York.

  10. Analysis of S-adenosylmethionine and related sulfur metabolites in bacterial isolates of Pseudomonas aeruginosa (BAA-47) by liquid chromatography/electrospray ionization coupled to a hybrid linear quadrupole ion trap and Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Cataldi, Tommaso R I; Bianco, Giuliana; Abate, Salvatore; Mattia, Daniela

    2009-11-01

    A comprehensive and highly selective method for detecting in bacterial supernatants a modified sulfur nucleoside, S-adenosyl-L-methionine (SAM), and its metabolites, i.e., S-adenosylhomocysteine (SAH), adenosine (Ado), 5'-deoxy-5'-methylthioadenosine (MTA), adenine (Ade), S-adenosyl-methioninamine (dcSAM), homocysteine (Hcy) and methionine (Met), was developed. The method is based on reversed-phase liquid chromatography with positive electrospray ionization (ESI+) coupled to a hybrid linear quadrupole ion trap (LTQ) and 7-T Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). A gradient elution was employed with a binary solvent of 0.05 M ammonium formate at pH 4 and acetonitrile. The assay involves a simultaneous cleanup of cell-free bacterial broths by solid-phase extraction and trace enrichment of metabolites with a 50-fold concentration factor by using immobilized phenylboronic and anion-exchange cartridges. While the quantitative determination of SAM was performed using stable-isotope-labeled SAM-d3 as an internal standard, in the case of Met and Ade, Met-13C and Ade-15N2 were employed as isotope-labeled internal standards, respectively. This method enabled the identification of SAM and its metabolites in cell-free culture of Pseudomonas aeruginosa grown in Davis minimal broth (formulation without sulphur organic compounds), with routine sub-ppm mass accuracies (-0.27 +/- 0.68 ppm). The resulting contents of S(C)S(S)-SAM, S(S)-dcSAM, MTA, Ado and Met in the free-cell supernatant of P. aeruginosa was 56.4 +/- 2.1 nM, 32.2 +/- 2.2 nM, 0.91 +/- 0.10 nM, 19.6 +/- 1.2 nM and 1.93 +/- 0.02 microM (mean +/- SD, n = 4 extractions), respectively. We report also the baseline separation (Rs > or = 1.5) of both diastereoisomeric forms of SAM (S(C)S(S) and S(C)R(S)) and dcSAM (S(S) and R(S)), which can be very useful to establish the relationship between the biologically active versus the inactive species, S(C)S(S)/S(C)R(S) and S(S)/R(S) of SAM and dc

  11. 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

  12. Frequency dependence of alternating current electrospray ionization mass spectrometry.

    Science.gov (United States)

    Chetwani, Nishant; Cassou, Catherine A; Go, David B; Chang, Hsueh-Chia

    2011-04-15

    The novel effects resulting from the entrainment of low mobility ions during alternating current (ac) electrospray ionization are examined through mass spectrometry and voltage/current measurements. Curious phenomena such as pH modulation at high frequencies (>150 kHz) of an applied ac electric field are revealed and explained using simple mechanistic arguments. Current measurements are utilized to supplement these observations, and a simplified one-dimensional transient diffusion model for charge transport is used to arrive at a scaling law that provides better insight into the ac electrospray ionization process. Moreover, because of the different pathway for ion formation in comparison to direct current (dc) electrospray, ac electrospray (at frequencies >250 kHz) is shown to reduce the effects of ionization suppression in a mixture of two molecules with different surface activities. © 2011 American Chemical Society

  13. Validated method for the simultaneous determination of Delta9-THC and Delta9-THC-COOH in oral fluid, urine and whole blood using solid-phase extraction and liquid chromatography-mass spectrometry with electrospray ionization.

    Science.gov (United States)

    Teixeira, Helena; Verstraete, Alain; Proença, Paula; Corte-Real, Francisco; Monsanto, Paula; Vieira, Duarte Nuno

    2007-08-06

    A fully validated, sensitive and specific method for the extraction and quantification of Delta(9)-tetrahydrocannabinol (THC) and 11-nor-9-carboxy-Delta(9)-THC (THC-COOH) and for the detection of 11-hydroxy-Delta(9)-THC (11-OH THC) in oral fluid, urine and whole blood is presented. Solid-phase extraction and liquid chromatography-mass spectrometry (LC-MS) technique were used, with electrospray ionization. Three ions were monitored for THC and THC-COOH and two for 11-OH THC. The compounds were quantified by selected ion recording of m/z 315.31, 329.18 and 343.16 for THC, 11-OH THC and THC-COOH, respectively, and m/z 318.27 and 346.26 for the deuterated internal standards, THC-d(3) and THC-COOH-d(3), respectively. The method proved to be precise for THC and THC-COOH both in terms of intra-day and inter-day analysis, with intra-day coefficients of variation (CV) less than 6.3, 6.6 and 6.5% for THC in saliva, urine and blood, respectively, and 6.8 and 7.7% for THC-COOH in urine and blood, respectively. Day-to-day CVs were less than 3.5, 4.9 and 11.3% for THC in saliva, urine and blood, respectively, and 6.2 and 6.4% for THC-COOH in urine and blood, respectively. Limits of detection (LOD) were 2 ng/mL for THC in oral fluid and 0.5 ng/mL for THC and THC-COOH and 20 ng/mL for 11-OH THC, in urine and blood. Calibration curves showed a linear relationship for THC and THC-COOH in all samples (r(2)>0.999) within the range investigated. The procedure presented here has high specificity, selectivity and sensitivity. It can be regarded as an alternative method to GC-MS for the confirmation of positive immunoassay test results, and can be used as a suitable analytical tool for the quantification of THC and THC-COOH in oral fluid, urine and/or blood samples.

  14. The influence of salt matrices on the reversed-phase liquid chromatography behavior and electrospray ionization tandem mass spectrometry detection of glyphosate, glufosinate, aminomethylphosphonic acid and 2-aminoethylphosphonic acid in water.

    Science.gov (United States)

    Skeff, Wael; Recknagel, Constantin; Schulz-Bull, Detlef E

    2016-12-02

    The analysis of highly polar and amphoteric compounds in seawater is a continuing challenge in analytical chemistry due to the possible formation of complexes with the metal cations present in salt-based matrices. Here we provide information for the development of analytical methods for glyphosate, glufosinate, AMPA, and 2-AEP in salt water, based on studies of the effects of salt matrices on reversed-phase liquid chromatography-heated electrospray ionization-tandem mass spectrometry (RP-LC-HESI-MS/MS) after derivatization of the target compounds with FMOC-Cl. The results showed that glyphosate was the only analyte with a strong tendency to form glyphosate-metal complexes (GMC), which clearly influenced the analysis. The retention times (RTs) of GMC and free glyphosate differed by approximately 7.00min, reflecting their distinct RP-LC behaviors. Divalent cations, but not monovalent (Na + , K + ) or trivalent (Al 3+ , Fe 3+ ) cations, contributed to this effect and their influence was concentration-dependent. In addition, Cu 2+ , Co 2+ , Zn 2+ , and Mn 2+ prevented glyphosate detection whereas Ca 2+ , Mg 2+ , and Sr 2+ altered the retention time. At certain tested concentrations of Ca 2+ and Sr 2+ glyphosate yielded two peaks, which violated the fundamental rule of LC, that under the same analytical conditions a single substance yields only one LC-peak with a specific RT. Salt-matrix-induced ion suppression was observed for all analytes, especially under high salt concentrations. For glyphosate and AMPA, the use of isotopically labeled internal standards well-corrected the salt-matrix effects, with better results achieved for glufosinate and 2-AEP with the AMPA internal standard than with the glyphosate internal standard. Thus, our study demonstrated that Ca 2+ , Mg 2+ , and Sr 2+ can be used together with FMOC-Cl to form GMC-FMOC which is suitable for RP-LC-HESI-MS/MS analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Increasing Protein Charge State When Using Laser Electrospray Mass Spectrometry

    Science.gov (United States)

    Karki, Santosh; Flanigan, Paul M.; Perez, Johnny J.; Archer, Jieutonne J.; Levis, Robert J.

    2015-05-01

    Femtosecond (fs) laser vaporization is used to transfer cytochrome c, myoglobin, lysozyme, and ubiquitin from the condensed phase into an electrospray (ES) plume consisting of a mixture of a supercharging reagent, m-nitrobenzyl alcohol ( m-NBA), and trifluoroacetic acid (TFA), acetic acid (AA), or formic acid (FA). Interaction of acid-sensitive proteins like cytochrome c and myoglobin with the highly charged ES droplets resulted in a shift to higher charge states in comparison with acid-stable proteins like lysozyme and ubiquitin. Laser electrospray mass spectrometry (LEMS) measurements showed an increase in both the average charge states (Zavg) and the charge state with maximum intensity (Zmode) for acid-sensitive proteins compared with conventional electrospray ionization mass spectrometry (ESI-MS) under equivalent solvent conditions. A marked increase in ion abundance of higher charge states was observed for LEMS in comparison with conventional electrospray for cytochrome c (ranging from 19+ to 21+ versus 13+ to 16+) and myoglobin (ranging from 19+ to 26+ versus 18+ to 21+) using an ES solution containing m-NBA and TFA. LEMS measurements as a function of electrospray flow rate yielded increasing charge states with decreasing flow rates for cytochrome c and myoglobin.

  16. Pre-electrospray ionisation manifold methylation and post-electrospray ionisation manifold cleavage/ion cluster formation observed during electrospray ionisation of chloramphenicol in solutions of methanol and acetonitrile for liquid chromatography-mass spectrometry employing a commercial quadrupole ion trap mass analyser.

    Science.gov (United States)

    Sichilongo, Kwenga F; Famuyiwa, Samson O; Kibechu, Rose

    2011-01-01

    We have observed unusual mass spectra of chloramphenicol (CAP) in solutions of methanol or acetonitrile showing intense ions at m/z 297, m/z 311, m/z 325 and m/z 339. The observed ions were different from those which are traditionally observed in the full scan ESI mass spectra of CAP with ions of m/z 321, m/z 323 and m/z 325. We have evidence to show that this process starts with offline methylation of CAP in solutions of methanol or acetonitrile to give m/z 339. Investigations using nuclear magnetic resonance (NMR) spectroscopy showed that there is a methylene group somewhere within the CAP molecule but not attached to any of the carbon atoms when the CAP is dissolved in methanol or acetonitrile before infusion into the mass spectrometer. The possible locations of attachment were speculated to be the electronegative atoms apart from the chlorine atoms due to valence considerations. The methylene group is attached to the nitrogen atom and forms a bond as observed in the MS/MS spectra of m/z 297, m/z 311, m/z 325 and m/z 339 which give m/z 183 as the base peak in all cases. Further experiments showed that there is cleavage of the methylated CAP molecule followed by cluster ion formation involving addition of methylene groups to the CAP fragment with m/z 183 to produce ions of m/z including m/z 297, m/z 311, m/z 325 and m/z 339. This process occurs in the mass spectrometer in the region housing the tube lens and is triggered when the ions are accelerated through this region by application of a negative tube lens offset voltage. This region affords collision of the charged droplets with a collision gas in this case nitrogen to strip the droplets of their solvent molecules. Experiments to follow the intensities of m/z 183, m/z 311, m/z 321, m/z 323, m/z 325 and m/z 339 as the tube lens offset voltage was varied were done in which the intensities of m/z 311, m/z 325 and m/z 339 were observed to be at their peak when the tube lens offset voltage was set at -40 V. When

  17. Classification of terverticillate Penicillia by electrospray mass spectrometric profiling

    DEFF Research Database (Denmark)

    Smedsgaard, Jørn; Hansen, Michael Edberg; Frisvad, Jens Christian

    2004-01-01

    429 isolates of 58 species belonging to Penicillium subgenus Penicillium are classified from direct infusion electrospray mass spectrometry (diMS) analysis of crude extracts by automated data processing. The study shows that about 70% of the species can be classified correctly into species using...

  18. Plume collimation for laser ablation electrospray ionization mass spectrometry

    Science.gov (United States)

    Vertes, Akos; Stolee, Jessica A.

    2014-09-09

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

  19. Gas chromatography: mass selective detector

    International Nuclear Information System (INIS)

    Lapinskas, R.

    1988-01-01

    The mechanism of mass spectrometry technique directed for detecting molecular structures is described, with some considerations about its operational features. This mass spectrometer is used as a gas chromatography detector. (author)

  20. High-performance liquid chromatography/mass spectrometric identification of dibenzylbutyrolactone-type lignans: insights into electrospray ionization tandem mass spectrometric fragmentation of lign-7-eno-9,9'-lactones and application to the lignans of Linum usitatissimum L. (Common Flax).

    Science.gov (United States)

    Schmidt, Thomas J; Alfermann, A Wilhelm; Fuss, Elisabeth

    2008-11-01

    In continuation of our studies into the mass spectrometric detection of natural lignans and their identification in complex mixtures such as crude plant extracts, the electrospray ionization tandem mass spectrometric (ESI-MS/MS) fragmentation of Delta(7,8)-unsaturated dibenzylbutyrolactone-type lignans (lign-7-eno-9,9'-lactones) was studied in detail. It is demonstrated that the characteristic fragmentation allows unambiguous identification including distinction between constitutional isomers. These lignans containing an alpha,beta-unsaturated lactone structure exist as equilibrium mixtures of E- and Z-isomers indistinguishable by mass spectrometry, but it is shown that chromatographic retention time can be used to distinguish between the isomeric forms. Based on these observations, re-analysis of the dichloromethane extract obtained from flowering aerial parts of Linum usitatissimum L. by high-performance liquid chromatography (HPLC)/ESI-MS/MS led to the identification of eighteen lignans of these types (five lignano- and one lignenolactone previously reported along with five further lignano- as well as seven lignenolactones hitherto unreported for this plant). The simultaneous identification of eighteen different lignans in the complex matrix of a crude plant extract by a single analysis demonstrates the potential of this method, which will certainly lead to new insights into the lignan composition and metabolism of different Linum species and many other plants.

  1. Quantitative Caffeine Analysis Using a Surface Sampling Probe Electrospray Ionization Tandem Mass Spectrometry System

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Michael J [ORNL; Deibel, Michael A. [Earlham College; Tomkins, Bruce A [ORNL; Van Berkel, Gary J [ORNL

    2005-01-01

    Quantitative determination of caffeine on reversed-phase C8 thin-layer chromatography plates using a surface sampling electrospray ionization system with tandem mass spectrometry detection is reported. The thin-layer chromatography/electrospray tandem mass spectrometry method employed a deuterium-labeled caffeine internal standard and selected reaction monitoring detection. Up to nine parallel caffeine bands on a single plate were sampled in a single surface scanning experiment requiring 35 min at a surface scan rate of 44 {mu}m/s. A reversed-phase HPLC/UV caffeine assay was developed in parallel to assess the mass spectrometry method performance. Limits of detection for the HPLC/UV and thin-layer chromatography/electrospray tandem mass spectrometry methods determined from the calibration curve statistics were 0.20 ng injected (0.50 {mu}L) and 1.0 ng spotted on the plate, respectively. Spike recoveries with standards and real samples ranged between 97 and 106% for both methods. The caffeine content of three diet soft drinks (Diet Coke, Diet Cherry Coke, Diet Pepsi) and three diet sport drinks (Diet Turbo Tea, Speed Stack Grape, Speed Stack Fruit Punch) was measured. The HPLC/UV and mass spectrometry determinations were in general agreement, and these values were consistent with the quoted values for two of the three diet colas. In the case of Diet Cherry Coke and the diet sports drinks, the determined caffeine amounts using both methods were consistently higher (by 8% or more) than the literature values.

  2. Ionization of Gas-Phase Polycyclic Aromatic Hydrocarbons in Electrospray Ionization Coupled with Gas Chromatography.

    Science.gov (United States)

    Cha, Eunju; Jeong, Eun Sook; Han, Sang Beom; Cha, Sangwon; Son, Junghyun; Kim, Sunghwan; Oh, Han Bin; Lee, Jaeick

    2018-03-20

    Herein, gas-phase polycyclic aromatic hydrocarbons (PAHs) as nonpolar compounds were ionized to protonated molecular ions [M + H] + without radical cations and simultaneously analyzed using gas chromatography (GC)/electrospray ionization (ESI)-tandem mass spectrometry (MS/MS). The ionization profile, dissociation, and sensitivity were first investigated to understand the significant behavior of gas-phase PAHs under ESI. The formation of protonated molecular ions of PAHs was distinguished according to the analyte phase and ESI spray solvents. The protonated PAHs exhibited characteristic dissociations, such as H-loss, H 2 -loss, and acetylene-loss, via competition of internal energy. In addition, GC/ESI-MS/MS resulted in relatively lower concentration levels (better sensitivity) for the limits-of-detection (LODs) of PAHs than liquid chromatography (LC)/ESI-MS/MS, and it seems to result from the characteristic ionization mechanism of the gas-phase analyte under ESI. Furthermore, the LODs of gas-phase PAHs depended on molecular weight and proton affinity (PA). Consequently, we demonstrated the relationship among the analyte phases, sensitivities, and structural characteristics (molecular weight and PA) under ESI. The gas-phase PAHs provided enhanced protonation efficiency and sensitivity using GC/ESI-MS/MS, as their molecular weight and PA increased. Based on these results, we offered important information regarding the behavior of gas-phase analytes under ESI. Therefore, the present GC/ESI-MS/MS method has potential as an alternative method for simultaneous analysis of PAHs.

  3. Screening therapeutics according to their uptake across the blood-brain barrier: A high throughput method based on immobilized artificial membrane liquid chromatography-diode-array-detection coupled to electrospray-time-of-flight mass spectrometry.

    Science.gov (United States)

    Russo, Giacomo; Grumetto, Lucia; Szucs, Roman; Barbato, Francesco; Lynen, Frederic

    2018-02-07

    The Blood-Brain Barrier (BBB) plays an essential role in protecting the brain tissues against possible injurious substances. In the present work, 79 neutral, basic, acidic and amphoteric structurally unrelated analytes were considered and their chromatographic retention coefficients on immobilized artificial membrane (IAM) stationary phase were determined employing a mass spectrometry (MS) -compatible buffer based on ammonium acetate. Their BBB passage predictive strength was evaluated and the statistical models based on IAM indexes and in silico physico-chemical descriptors showed solid statistics (r 2 (n-1) = 0.78). The predictive strength of the indexes achieved by the MS-compatible method was comparable to that achieved by employing the more "biomimetic" Dulbecco's phosphate buffered saline, even if some differences in the elution order were observed. The method was transferred to the MS, employing a diode-array-detection coupled to an electrospray ionization source and a time-of-flight analyzer. This setup allowed the simultaneous analysis of up to eight analytes, yielding a remarkable acceleration of the analysis time. Copyright © 2018. Published by Elsevier B.V.

  4. Chemical profiling of Qixue Shuangbu Tincture by ultra-performance liquid chromatography with electrospray ionization quadrupole-time-of-flight high-definition mass spectrometry (UPLC-QTOF/MS).

    Science.gov (United States)

    Chen, Lin-Wei; Wang, Qin; Qin, Kun-Ming; Wang, Xiao-Li; Wang, Bin; Chen, Dan-Ni; Cai, Bao-Chang; Cai, Ting

    2016-02-01

    The present study was designed to develop and validate a sensitive and reliable ultra high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) method to separate and identify the chemical constituents of Qixue Shuangbu Tincture (QXSBT), a classic traditional Chinese medicine (TCM) prescription. Under the optimized UPLC and QTOF/MS conditions, 56 components in QXSBT, including chalcones, triterpenoids, protopanaxatriol, flavones and flavanones were identified and tentatively characterized within a running time of 42 min. The components were identified by comparing the retention times, accurate mass, and mass spectrometric fragmentation characteristic ions, and matching empirical molecular formula with that of the published compounds. In conclusion, the established UPLC-QTOF/MS method was reliable for a rapid identification of complicated components in the TCM prescriptions. Copyright © 2016 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Alexandra Christine Helena Frankland Sawaya

    2011-09-01

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

  6. The yeast metabolome addressed by electrospray ionization mass spectrometry: Initiation of a mass spectral library and its applications for metabolic footprinting by direct infusion mass spectrometry

    DEFF Research Database (Denmark)

    Højer-Pedersen, Jesper Juul; Smedsgaard, Jørn; Nielsen, Jens

    2008-01-01

    Mass spectrometry (MS) has been a major driver for metabolomics, and gas chromatography (GC)-MS has been one of the primary techniques used for microbial metabolomics. The use of liquid chromatography (LC)-MS has however been limited, but electrospray ionization (ESI) is very well suited...... into the ionization and fragmentation characteristics of the different metabolites. With this insight, a small study of metabolic footprinting with ESI-MS demonstrated that biological information can be extracted from footprinting spectra. Statistical analysis of the footprinting data revealed discriminating ions...

  7. Metal Cationization Extractive Electrospray Ionization Mass Spectrometry of Compounds Containing Multiple Oxygens

    Science.gov (United States)

    Swanson, Kenneth D.; Spencer, Sandra E.; Glish, Gary L.

    2017-06-01

    Extractive electrospray ionization is an ambient ionization technique that allows real-time sampling of liquid samples, including organic aerosols. Similar to electrospray ionization, the composition of the electrospray solvent used in extractive electrospray ionization can easily be altered to form metal cationized molecules during ionization simply by adding a metal salt to the electrospray solvent. An increase in sensitivity is observed for some molecules that are lithium, sodium, or silver cationized compared with the protonated molecule formed in extractive electrospray ionization with an acid additive. Tandem mass spectrometry of metal cationized molecules can also significantly improve the ability to identify a compound. Tandem mass spectrometry of lithium and silver cationized molecules can result in an increase in the number and uniqueness of dissociation pathways relative to [M + H]+. These results highlight the potential for extractive electrospray ionization with metal cationization in analyzing complex aerosol mixtures. [Figure not available: see fulltext.

  8. Report on three aliphatic dimethylarsinoyl compounds as common minor constituents in marine samples. An investigation using high-performance liquid chromatography inductively coupled plasma mass spectrometry and electrospray ionisation tandem mass spectrometry

    DEFF Research Database (Denmark)

    Sloth, Jens Jørgen; Larsen, Erik Huusfeldt; Julshamn, K.

    2005-01-01

    for the structures of the three compounds. The concentrations of the three arsenicals were determined in 37 marine organisms comprising algae, crustaceans, bivalves, fish and mammals by HPLC/ICPMS. The three arsenicals DMAA, DMAE and DMAP, which occurred at mug kg(-1) concentrations, were detected in 25, 23 and 17...... of the 37 samples analysed, respectively. The limits of detection were 2-3 mug kg(-1) dry mass. The data illustrate that the three compounds are common minor constituents in marine samples. This is the first report on DMAE and DMAP as naturally occurring species in marine samples. The presence of DMAA...

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

    Science.gov (United States)

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

    2009-09-01

    Xiao-xu-ming decoction (XXMD) prescription is a traditional Chinese prescription that has been widely used to treat theoplegia and the sequela of theoplegia. Modern pharmacological research has also indicated that the active fraction from XXMD is able to treat cardiovascular diseases and Alzheimer's disease. In the study reported here, high-performance liquid chromatography coupled with Fourier transform ion cyclotron resonance mass spectrometry (HPLC/FTICR-MS) was developed to identify active compounds and their metabolites after oral administration of active fraction from Xiao-xu-ming decoction to rats, using parent mass list triggered data-dependent multiple-stage mass analysis at a resolving power of 100,000 in the external calibration mode. The mass accuracies obtained for full-scan MS were within 2 ppm in most cases. Fifteen constituents were identified in the active fraction from XXMD and the biological samples of rats. The fragmentation behaviors of these constituents were summarized which would be helpful for structural characterization. The profiles of the constituents in the active fraction and biological samples of rats were obtained which provided us with much information for a better understanding of the chemical basis of the pharmacologic actions of XXMD. Copyright (c) 2009 John Wiley & Sons, Ltd.

  10. Characterization of cationic glycoporphyrins by electrospray tandem mass spectrometry.

    Science.gov (United States)

    Silva, Eduarda M P; Serra, Vanda Vaz; Ribeiro, Anderson O; Tomé, João P C; Domingues, Pedro; Faustino, M Amparo F; Neves, M Graça P M S; Tomé, Augusto C; Cavaleiro, José A S; Ferrer-Correia, António J; Iamamoto, Yassuko; Domingues, M Rosário M

    2006-01-01

    Novel cationic porphyrin derivatives having a galactose or a bis(isopropylidene)galactose unit linked directly to a pyridine or to an aminophenyl group were characterized by electrospray tandem mass spectrometry (ESI-MS/MS). The electrospray mass spectra (ESI-MS) show the M(+) ions, since these porphyrins are already monocharged in solution. The fragmentation of these ions under ESI-MS/MS conditions was studied and it was found that elimination of the sugar residue as a radical (-163 or -243 Da) is a common fragmentation pathway. Loss of the sugar unit as a neutral fragment (-162 or -242 Da) and cross-ring fragmentations typical of glyco-derivatives are also observed for the pyridinium glycoporphyrins, but they are absent in the case of ammonium glycoporphyrins. The cationic beta-pyridiniumvinyl porphyrins show an atypical fragmentation due to the cleavage of the C(5)-C(6) bond of the sugar unit. Overall, the different patterns of fragmentation observed in the ESI-MS/MS spectra of the sugar pyridinium porphyrins and of the sugar ammonium phenyl porphyrins can give important information about the type of spacer between the porphyrin and the sugar unit. Copyright (c) 2006 John Wiley & Sons, Ltd.

  11. Determining aromatic and aliphatic carboxylic acids in biomass-derived oil samples using 2,4-dinitrophenylhydrazine and liquid chromatography-electrospray injection-mass spectrometry/mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Samuel A.; Connatser, Raynella M.; Olarte, Mariefel V.; Keiser, James R.

    2018-01-01

    Converting biomass to a useful fuel commonly incorporates the pyrolysis of the biomass feed stock. The base liquid fraction usually contains high concentrations of ketones, aldehydes and carboxylic acids, of which each can cause detrimental issues related to the storage and upgrading process. Knowing the carbonyl species and the concentration of each will provide value information to the pyrolysis researchers, specifically as that community branches into more targeted end-products such as jet fuel or biogenic-derived oxygenate-containing fuel products. The analysis of aldehydes, ketones and small alkyl carboxylic acids using 2,4-dinitrophenylhydrazine (DNPH) derivation method has been well documented and the method is commonly used the analytical community. By using liquid chromatograph coupled to tandem mass spectrometry, biomass sample analysis can be complete with identification of most carbonyl species. The issue of identifying isobaric ketone and aldehyde compounds can be resolved by utilizing differences in retention time or characteristic fragment ions of ketones and aldehydes. One issue which could not resolved using published methods was identifying aromatic or large non-aromatic carboxylic acids from their corresponding hydroxyl aldehyde or ketone analogs. By modifying the current method for determining carbonyls in biomass samples, carboxylic and hydroxyl-carbonyl can be determined. A careful adjustment of the pH during the extraction procedure and extended heating time of the DNPH solution allowed for the successful derivation of aromatic carboxylic acids. Like other dinitrophenylhydrazones, carboxylic acid derivatives also produce a unique secondary ion pattern, which was useful to distinguish these species from the non-acid analogs.

  12. A comparative study of primary secondary amino (PSA) and multi-walled carbon nanotubes (MWCNTs) as QuEChERS absorbents for the rapid determination of diazepam and its major metabolites in fish samples by high-performance liquid chromatography-electrospray ionisation-tandem mass spectrometry.

    Science.gov (United States)

    Li, Jincheng; Zhang, Jing; Liu, Huan; Wu, Lidong

    2016-01-30

    A simple and fast modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method is presented for the determination of diazepam and its three major metabolites, nordiazepam, temazepam and oxazepam (benzodiazepines) in fish samples by liquid chromatography-electrospray ionisation-tandem mass spectrometry. Muscle tissues were extracted with acetonitrile, and then cleaned with primary secondary amino (PSA) adsorbents. The cleanup effect of PSA was compared with that of multi-walled carbon nanotubes (MWCNTs) in term of extraction efficiency. The better results were obtained when PSA was used. The chromatography separation was achieved within 5.0 min on a C18 column. The limit of detection was 0.5 µg kg(-1) and the limit of quantification was 2.5 µg kg(-1). Average recoveries of diazepam and its main metabolites were in the range of 88.5-110.1%, with a relative standard deviation lower than 10.0%. The proposed method for fish samples gives good recoveries, linearity, precision and accuracy. © 2015 Society of Chemical Industry.

  13. Electrospray ionization mass spectrometric study of thallium complexes with nucleosides.

    Science.gov (United States)

    Frańska, Magdalena

    2017-10-01

    The complexes between Tl + , K + , and nucleosides were studied by using electrospray ionization mass spectrometry. It was found that for complexes of 1:1 stoichiometry, thallium complexes with cytidine were the most abundant and thallium complexes with guanosine were the second most abundant ones. The relative abundances of cytidine-Tl + to cytidine-K + complexes depended on stoichiometry (at higher stoichiometry the potassium complexes were more abundant). In other words, the relative affinity of Tl + and K + to form cytidine complexes depends on the stoichiometry of the formed complexes. Guanosine-Tl + complexes were more abundant than guanosine-K + complexes, irrespective of stoichiometry. Both guanosine tetramer and mixed cytidine/guanosine tetramer were more abundant when they were stabilized by thallium than potassium. Therefore, Tl + may affect the K + stabilization of these tetramers.

  14. Determination of the appetite suppressant P57 in Hoodia gordonii plant extracts and dietary supplements by liquid chromatography/electrospray ionization mass spectrometry (LC-MSD-TOF) and LC-UV methods.

    Science.gov (United States)

    Avula, Bharathi; Wang, Yan-Hong; Pawar, Rahul S; Shukla, Yatin J; Schaneberg, Brian; Khan, Ikhlas A

    2006-01-01

    Hoodia gordonii is traditionally used in South Africa for its appetite suppressant properties. P57AS3 (P57), an oxypregnane steroidal glycoside, is the only reported active constituent from this plant as an appetite suppressant. Effective quality control of these extracts or products requires rapid methods to determine P57 content. New methods of liquid chromatography/mass spectrometry (LC/MS) and LC-UV for analysis of P57 from H. gordonii have been developed. The quantitative determination of P57 was achieved with a Phenomenex Gemini (Torrance, CA) reversed-phase column using gradient mobile phase of water and acetonitrile, both containing 0.1% acetic acid. The method was validated for linearity, repeatability, and limits of detection and quantification. Good results were obtained in terms of repeatability (relative standard deviation <5.0%) and recovery (98.5-103.5%). The developed methods were applied to the determination of P57 for H. gordonii plant samples, one related genus (Opuntia ficus-indica), and dietary supplements that claim to contain H. gordonii.

  15. Development of an ultrahigh-performance liquid chromatography-electrospray ionization-tandem mass spectrometry method for the simultaneous determination of salicylic acid, jasmonic acid, and abscisic acid in rose leaves.

    Science.gov (United States)

    Bosco, Renato; Daeseleire, Els; Van Pamel, Els; Scariot, Valentina; Leus, Leen

    2014-07-09

    This paper describes a method to detect and quantitate the endogenous plant hormones (±)-2-cis-4-trans-abscisic acid, (-)-jasmonic acid, and salicylic acid by means of ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) in hybrid rose leaf matrices. Deuterium-labeled [(2)H6] (+)-2-cis-4-trans-abscisic acid, [(2)H6] (±)-jasmonic acid, and [(2)H4]-salicylic acid were used as internal standards. Rose samples (10 mg) were extracted with methanol/water/acetic acid (10:89:1) and subsequently purified on an Oasis MCX 1 cm(3) Vac SPE cartridge. Performance characteristics were validated according to Commission Decision 2002/657/EC. Recovery, repeatability, and within-laboratory reproducibility were acceptable for all phytohormones tested at three different concentrations. The decision limit and detection capability for (±)-2-cis-4-trans-abscisic acid, (-)-jasmonic acid, and salicylic acid were 0.0075 and 0.015 μg/g, 0.00015 and 0.00030 μg/g, and 0.0089 and 0.018 μg/g, respectively. Matrix effects (signal suppression or enhancement) appeared to be high for all substances considered, implying the need for quantitation based on matrix-matched calibration curves.

  16. A Simple Defined Medium for the Production of True Diketopiperazines in Xylella fastidiosa and Their Identification by Ultra-Fast Liquid Chromatography-Electrospray Ionization Ion Trap Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Michelli Massaroli da Silva

    2017-06-01

    Full Text Available Diketopiperazines can be generated by non-enzymatic cyclization of linear dipeptides at extreme temperature or pH, and the complex medium used to culture bacteria and fungi including phytone peptone and trypticase peptone, can also produce cyclic peptides by heat sterilization. As a result, it is not always clear if many diketopiperazines reported in the literature are artifacts formed by the different complex media used in microorganism growth. An ideal method for analysis of these compounds should identify whether they are either synthesized de novo from the products of primary metabolism and deliver true diketopiperazines. A simple defined medium (X. fastidiosa medium or XFM containing a single carbon source and no preformed amino acids has emerged as a method with a particularly high potential for the grown of X. fastidiosa and to produce genuine natural products. In this work, we identified a range of diketopiperazines from X. fastidiosa 9a5c growth in XFM, using Ultra-Fast Liquid Chromatography coupled with mass spectrometry. Diketopiperazines are reported for the first time from X. fastidiosa, which is responsible for citrus variegated chlorosis. We also report here fatty acids from X. fastidiosa, which were not biologically active as diffusible signals, and the role of diketopiperazines in signal transduction still remains unknown.

  17. A Simple Defined Medium for the Production of True Diketopiperazines in Xylella fastidiosa and Their Identification by Ultra-Fast Liquid Chromatography-Electrospray Ionization Ion Trap Mass Spectrometry.

    Science.gov (United States)

    Silva, Michelli Massaroli da; Andrade, Moacir Dos Santos; Bauermeister, Anelize; Merfa, Marcus Vinícius; Forim, Moacir Rossi; Fernandes, João Batista; Vieira, Paulo Cezar; Silva, Maria Fátima das Graças Fernandes da; Lopes, Norberto Peporine; Machado, Marcos Antônio; Souza, Alessandra Alves de

    2017-06-13

    Diketopiperazines can be generated by non-enzymatic cyclization of linear dipeptides at extreme temperature or pH, and the complex medium used to culture bacteria and fungi including phytone peptone and trypticase peptone, can also produce cyclic peptides by heat sterilization. As a result, it is not always clear if many diketopiperazines reported in the literature are artifacts formed by the different complex media used in microorganism growth. An ideal method for analysis of these compounds should identify whether they are either synthesized de novo from the products of primary metabolism and deliver true diketopiperazines. A simple defined medium ( X. fastidiosa medium or XFM) containing a single carbon source and no preformed amino acids has emerged as a method with a particularly high potential for the grown of X. fastidiosa and to produce genuine natural products. In this work, we identified a range of diketopiperazines from X. fastidiosa 9a5c growth in XFM, using Ultra-Fast Liquid Chromatography coupled with mass spectrometry. Diketopiperazines are reported for the first time from X. fastidiosa , which is responsible for citrus variegated chlorosis. We also report here fatty acids from X. fastidiosa , which were not biologically active as diffusible signals, and the role of diketopiperazines in signal transduction still remains unknown.

  18. Desorption electrospray ionization-mass spectrometry of proteins.

    Science.gov (United States)

    Shin, Yong-Seung; Drolet, Barbara; Mayer, Richard; Dolence, Kurt; Basile, Franco

    2007-05-01

    Desorption electrospray ionization-mass spectrometry (DESI-MS) was evaluated for the detection of proteins ranging in molecular mass from 12 to 66 kDa. Proteins were uniformly deposited on a solid surface without pretreatment and analyzed with a DESI source coupled to a quadrupole ion trap mass spectrometer. DESI-MS parameters optimized for protein detection included solvent flow rate, temperature of heated capillary tube, incident and reflection angle, sheath gas pressure, and ESI voltage. Detection limits were obtained for all protein standards, and they were found to decrease with decreasing protein molecular mass: for cytochrome c (12.3 kDa) and lysozyme (14.3 kDa) a detection limit of 4 ng/mm2 was obtained; for apomyoglobin (16.9 kDa) 20 ng/mm2; for beta-lactoglobulin B (18.2 kDa) 50 ng/mm2; and for chymotrypsinogen A (25.6 kDa) 100 ng/mm2. The DESI-MS analysis of higher molecular mass proteins such as ovalbumin (44.4 kDa) and bovine serum albumin (66.4 kDa) yielded mass spectra of low signal-to-noise ratio, making their detection and molecular weight determination difficult. In this study, DESI-MS proved to be a rapid and robust method for accurate MW determination for proteins up to 17 kDa under ambient conditions. Finally, we demonstrated the DESI-MS detection of the bacteriophage MS2 capsid protein from crude samples with minimal sample preparation.

  19. Simultaneous determination of ten antiepileptic drugs in human plasma by liquid chromatography and tandem mass spectrometry with positive/negative ion-switching electrospray ionization and its application in therapeutic drug monitoring.

    Science.gov (United States)

    Yin, Lei; Wang, Tingting; Shi, Meiyun; Zhang, Ying; Zhao, Xiaojun; Yang, Yan; Gu, Jingkai

    2016-03-01

    A simple, rapid, and high-throughput liquid chromatography with tandem mass spectrometry method for the simultaneous quantitation of ten antiepileptic drugs in human plasma has been developed and validated. The method required only 10 μL of plasma. After simple protein precipitation using acetonitrile, the analytes and internal standard diphenhydramine were separated on a Zorbax SB-C18 column (50 × 4.6 mm, 2.7 μm) using acetonitrile/water as the mobile phase at a flow rate of 0.9 mL/min. The total run time was 6 min for each sample. The validation results of specificity, matrix effects, recovery, linearity, precision, and accuracy were satisfactory. The lower limit of quantification was 0.04 μg/mL for carbamazepine, 0.02 μg/mL for lamotrigine, 0.01 μg/mL for oxcarbazepine, 0.4 μg/mL for 10-hydroxycarbazepine, 0.1 μg/mL for carbamazepine-10,11-epoxide, 0.15 μg/mL for levetiracetam, 0.06 μg/mL for phenytoin, 0.3 μg/mL for valproic acid, 0.03 μg/mL for topiramate, and 0.15 μg/mL for phenobarbital. The intraday precision and interday precision were less than 7.6%, with the accuracy ranging between -8.1 and 7.9%. The method was successfully applied to therapeutic drug monitoring of 1237 patients with epilepsy after administration of standard antiepileptic drugs. The method has been proved to meet the high-throughput requirements in therapeutic drug monitoring. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Desorption electrospray ionization mass spectrometry for trace analysis of agrochemicals in food.

    Science.gov (United States)

    García-Reyes, Juan F; Jackson, Ayanna U; Molina-Díaz, Antonio; Cooks, R Graham

    2009-01-15

    Desorption electrospray ionization (DESI) is applied to the rapid, in situ, direct qualitative and quantitative (ultra)trace analysis of agrochemicals in foodstuffs. To evaluate the potential of DESI mass spectrometry (MS) in toxic residue testing in food, 16 representative multiclass agricultural chemicals (pesticides, insecticides, herbicides, and fungicides) were selected (namely, ametryn, amitraz, azoxystrobin, bitertanol, buprofezin, imazalil, imazalil metabolite, isofenphos-methyl, malathion, nitenpyram, prochloraz, spinosad, terbuthylazine, thiabendazole, and thiacloprid). The DESI-MS experiments were performed using 3 microL of solution spotted onto conventional smooth poly(tetrafluoroethylene) (PTFE) surfaces, with examination by MS and tandem mass spectrometry (MS/MS) using an ion trap mass spectrometer. Optimization of the spray solvent led to the use of acetonitrile/water (80:20) (v/v), with 1% formic acid. Most of the compounds tested showed remarkable sensitivity in the positive ion mode, approaching that attainable with conventional direct infusion electrospray mass spectrometry. To evaluate the potential of the proposed approach in real samples, different experiments were performed including the direct DESI-MS/MS analysis of fruit peels and also of fruit/vegetable extracts. The results proved that DESI allows the detection and confirmation of traces of agrochemicals in actual market-purchased samples. In addition, MS/MS confirmation of selected pesticides in spiked vegetable extracts was obtained at absolute levels as low as 1 pg for ametryn. Quantitation of imazalil residues was also undertaken using an isotopically labeled standard. The data obtained were in agreement with those from the liquid chromatography mass spectrometry (LC-MS) reference method, with relative standard deviation (RSD) values consistently below 15%. The results obtained demonstrate the sensitivity of DESI as they meet the stringent European Union pesticide regulation

  1. Detection and imaging of thermochromic ink compounds in erasable pens using desorption electrospray ionization mass spectrometry.

    Science.gov (United States)

    Khatami, Amin; Prova, Shamina S; Bagga, Aafreen K; Yan Chi Ting, Michelle; Brar, Gurnoor; Ifa, Demian R

    2017-06-30

    Thermochromic ink pens are widely accessible worldwide and have gained popularity among the general public. These pens are very useful to undo mistakes while writing important documents or exams. They are also, however, misused in committing crimes such as counterfeiting checks or wills. Thus, the forensics community is in need of techniques that will allow these forgeries to be detected rapidly, reliably and conveniently. Thermochromic ink compounds were investigated using Desorption Electrospray Ionization (DESI) coupled with an LTQ mass spectrometer and Thin-Layer Chromatography (TLC). Tandem mass spectrometric analysis was conducted using Electrospray Ionization (ESI) coupled with an Orbitrap LTQ mass spectrometer performing Collision-Induced Dissociation (CID) for identification of ink traces. Chemical marker ions characteristic of the state of ink (visible or invisible) were identified and mapped in ink traces by the use of DESI-MS imaging. These ions can be employed by forensic experts as fingerprint markers in forged documents. The marker ions were also characterised by conducting tandem mass spectrometry using paper spray in an Orbitrap LTQ mass spectrometer. Specific chemical components yielding ions of m/z 400, 405, 615 and 786 were distinguished as only being apparent in the invisible and reappeared state of the ink. The absence of these compounds in the original state of the ink enabled their recognition as useful chemical determinants in detecting forgery. DESI-MSI was thus shown to be a very useful, convenient and reliable technique for detecting forgery in paper documents due to its fast and reproducible mode of analysis, with no sample preparation and minimal damage to the document under investigation. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  2. Game-Theory-Based Search Engine to Automate the Mass Assignment in Complex Native Electrospray Mass Spectra

    NARCIS (Netherlands)

    Tseng, Y.H.; Uetrecht, C.; Yang, S.C.; Barendregt, A.; Heck, A.J.R.; Peng, W.P.

    2013-01-01

    Electrospray ionization coupled to native mass spectrometry (MS) has evolved into an important tool in structural biology to decipher the composition of protein complexes. However, the mass analysis of heterogeneous protein assemblies is hampered because of their overlapping charge state

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

    Directory of Open Access Journals (Sweden)

    Yuan-Ming Sun

    2012-05-01

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

  4. Ion-pairing reversed-phased chromatography/mass spectrometry of heparin

    DEFF Research Database (Denmark)

    Henriksen, Jens; Roepstorff, Peter; Ringborg, Lene H.

    2006-01-01

    not well characterised. In order to further characterise such mixtures, two on-line ion-pairing reverse-phased chromatography electrospray ionisation (ESI) mass spectrometry methods have been developed. One of the systems allows the determination of more than 200 components in a medium molecular weight...

  5. High resolution full scan liquid chromatography mass spectrometry comprehensive screening in sports antidoping urine analysis

    NARCIS (Netherlands)

    Abushareeda, Wadha; Vonaparti, Ariadni; Saad, Khadija Al; Almansoori, Moneera; Meloug, Mbarka; Saleh, Amal; Aguilera, Rodrigo; Angelis, Yiannis; Horvatovich, Peter L.; Lommen, Arjen; Alsayrafi, Mohammed; Georgakopoulos, Costas

    2018-01-01

    The aim of this paper is to present the development and validation of a high-resolution full scan (HR-FS) electrospray ionization (ESI) liquid chromatography coupled to quadrupole Orbitrap mass spectrometer (LC/Q/Orbitrap MS) platform for the screening of prohibited substances in human urine

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

    NARCIS (Netherlands)

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

    2007-01-01

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

  7. Determination of hydrolysis products of sulfur mustards by reversed-phase microcolumn liquid chromatography coupled on-line with sulfur flame photometric detection and electrospray ionization mass spectrometry using large-volume injections and peak compression

    NARCIS (Netherlands)

    Hooijschuur, E.W.J.; Kientz, C.E.; Hulst, A.G.; Brinkman, U.A.T.

    2000-01-01

    On-line coupling of reversed-phase microcolumn liquid chromatography (micro-RPLC) and sulfur-selective flame photometric detection (S-FPD) was studied for the selective and direct determination of thiodiglycol, bis(2- hydroxyethylthio)methane, 1,2-bis(2-hydroxyethylthio)ethane, 1,3-bis(2-

  8. Electrospray and MALDI mass spectrometry: fundamentals, instrumentation, practicalities, and biological applications

    National Research Council Canada - National Science Library

    Cole, Richard B

    2010-01-01

    .... Electrochemistry of the Electrospray Ion Source Gary J. Van Berkel and Vilmos Kertesz 75 4. ESI Source Design Andries P. Bruins 123 Part III ES and MALDI Coupling to Mass Spectrometry Instrumentation 9. Coup...

  9. Evaluation of Immobilized Metal-Ion Affinity Chromatography and Electrospray Ionization Tandem Mass Spectrometry for Recovery and Identification of Copper(II)-Binding Ligands in Seawater Using the Model Ligand 8-Hydroxyquinoline

    OpenAIRE

    Nixon, Richard L.; Ross, Andrew R. S.

    2016-01-01

    Complexation by organic ligands dominates the speciation of iron (Fe), copper (Cu), and other bioactive trace metals in seawater, controlling their bioavailability and distribution in the marine environment. Several classes of high-affinity Fe-binding ligands (siderophores) have been identified in seawater but the chemical structures of marine Cu-complexing ligands remain unknown. Immobilized metal-ion affinity chromatography (IMAC) allows Cu ligands to be isolated from bulk dissolved organic...

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

    Science.gov (United States)

    Stock, Naomi L.; March, Raymond E.

    2014-01-01

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

  11. Terverticillate penicillia studied by direct electrospray mass spectrometric profiling of crude extracts II. Database and identification

    DEFF Research Database (Denmark)

    Smedsgaard, Jørn

    1997-01-01

    A mass spectral database was built using standard instrument software from 678 electrospray mass spectra (mass profiles) from crude fungal extracts of terverticillate taxa within the genus Penicillium. The match factors calculated from searching all the mass profiles stored in the database were...

  12. Isotopic variants of light and heavy L-pyroglutamic acid succinimidyl esters as the derivatization reagents for DL-amino acid chiral metabolomics identification by liquid chromatography and electrospray ionization mass spectrometry

    International Nuclear Information System (INIS)

    Mochizuki, Toshiki; Todoroki, Kenichiro; Inoue, Koichi; Min, Jun Zhe; Toyo’oka, Toshimasa

    2014-01-01

    Graphical abstract: -- Highlights: •Isotopic variants of chiral labeling reagents were newly synthesized. •Analysis of DL-amino acids was performed by UPLC–ESI–MS/MS. •Highly efficient enantioseparation and detection of DL-amino acids were performed. •Differential analysis of DL-amino acid was successfully performed in real samples. -- Abstract: L-Pyroglutamic acid succinimidyl ester (L-PGA-OSu) and its isotopic variant (L-PGA[d 5 ]-OSu) were newly synthesized and evaluated as the chiral labeling reagents for the enantioseparation of amino acids, in terms of separation efficiency by reversed-phase chromatography and detection sensitivity by ESI-MS/MS. The enantiomers of amino acids were easily labeled with the reagents at 60 °C within 10 min in an alkaline medium containing triethylamine. Although all the diastereomers derived from 18 proteolytic amino acids could not be satisfactorily separated, the pairs of 9 amino acids were completely separated by reversed-phase chromatography using the small particle (1.7 μm) ODS column (Rs = 1.95–8.05). The characteristic daughter ions, i.e., m/z 84.04 and m/z 89.04, were detected from all the derivatives by the collision induced dissociation of the protonated molecular ions. A highly sensitive detection at a low-fmol level (0.5–3.2 fmol) was also obtained from the selected reaction monitoring (SRM) chromatograms. An isotope labeling strategy using light and heavy L-PGA-OSu for the differential analysis of the DL-amino acids in different sample groups is also presented in this paper. The differential analysis of biological sample (i.e., human serum) and food product (i.e., yogurt) were tried to demonstrate the efficiency of the proposed method. The ratios of the DL-amino acids in human serum samples, spiked with the different concentrations of D-amino acids, were determined by the procedures using L-PGA-OSu and L-PGA[d 5 ]-OSu. The D/L ratios in the two sample groups at different concentrations of amino

  13. Isotopic variants of light and heavy L-pyroglutamic acid succinimidyl esters as the derivatization reagents for DL-amino acid chiral metabolomics identification by liquid chromatography and electrospray ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Mochizuki, Toshiki; Todoroki, Kenichiro; Inoue, Koichi; Min, Jun Zhe; Toyo’oka, Toshimasa, E-mail: toyooka@u-shizuoka-ken.ac.jp

    2014-02-06

    Graphical abstract: -- Highlights: •Isotopic variants of chiral labeling reagents were newly synthesized. •Analysis of DL-amino acids was performed by UPLC–ESI–MS/MS. •Highly efficient enantioseparation and detection of DL-amino acids were performed. •Differential analysis of DL-amino acid was successfully performed in real samples. -- Abstract: L-Pyroglutamic acid succinimidyl ester (L-PGA-OSu) and its isotopic variant (L-PGA[d{sub 5}]-OSu) were newly synthesized and evaluated as the chiral labeling reagents for the enantioseparation of amino acids, in terms of separation efficiency by reversed-phase chromatography and detection sensitivity by ESI-MS/MS. The enantiomers of amino acids were easily labeled with the reagents at 60 °C within 10 min in an alkaline medium containing triethylamine. Although all the diastereomers derived from 18 proteolytic amino acids could not be satisfactorily separated, the pairs of 9 amino acids were completely separated by reversed-phase chromatography using the small particle (1.7 μm) ODS column (Rs = 1.95–8.05). The characteristic daughter ions, i.e., m/z 84.04 and m/z 89.04, were detected from all the derivatives by the collision induced dissociation of the protonated molecular ions. A highly sensitive detection at a low-fmol level (0.5–3.2 fmol) was also obtained from the selected reaction monitoring (SRM) chromatograms. An isotope labeling strategy using light and heavy L-PGA-OSu for the differential analysis of the DL-amino acids in different sample groups is also presented in this paper. The differential analysis of biological sample (i.e., human serum) and food product (i.e., yogurt) were tried to demonstrate the efficiency of the proposed method. The ratios of the DL-amino acids in human serum samples, spiked with the different concentrations of D-amino acids, were determined by the procedures using L-PGA-OSu and L-PGA[d{sub 5}]-OSu. The D/L ratios in the two sample groups at different concentrations of

  14. Improved sensitivity using liquid chromatography mass spectrometry ...

    African Journals Online (AJOL)

    Improved sensitivity using liquid chromatography mass spectrometry (LC-MS) for detection of propyl chloroformate derivatised β-N-methylamino-L-alanine (BMAA) in ... We show a 10-fold increase in sensitivity with the LC-MS method compared to the previously published gas chromatography mass spectrometry (GC-MS) ...

  15. Identification of Bacterial Plant Pathogens Using Multilocus Polymerase Chain Reaction/Electrospray Ionization-Mass Spectrometry

    Science.gov (United States)

    2008-01-01

    1156 PHYTOPATHOLOGY Techniques Identification of Bacterial Plant Pathogens Using Multilocus Polymerase Chain Reaction/Electrospray Ionization... Phytopathology 98:1156-1164. Polymerase chain reaction/electrospray ionization-mass spectrometry (PCR/ESI-MS, previously known as “TIGER”) utilizes PCR with...based assays have been developed for bacterial plant pathogens (6,12,13,16,18, reviewed in 19). PCR-based diagnos- tics can be highly specific and are

  16. Collision-induced dissociation pathways of H1-antihistamines by electrospray ionization quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Do, Jung-Ah; Noh, Eunyoung; Yoon, Soon-Byung; Lee, Ji Hyun; Park, Sung-Kwan; Mandava, Suresh; Baek, Sun Young; Lee, Jongkook

    2017-06-01

    Over the past decades, mass spectrometry technologies have been developed to obtain mass accuracies of one ppm or less. Of the newly developed technologies, quadrupole time-of-flight mass spectrometry (Q-TOF-MS) has emerged as being well suited to routine and high-throughput analyses of pharmaceuticals. Dietary supplements and functional foods have frequently been found to be contaminated with pharmaceuticals. In our continuous efforts to develop methodologies to protect public health against adulterated dietary supplements, we have constructed a mass spectral database for 21 H 1 -antihistamines encountered as adulterants by using liquid chromatography-electrospray ionization (LC-ESI)/Q-TOF-MS, and have proposed their possible collision-induced dissociation pathways. This database will be very useful for the rapid and accurate detection of H 1 -antihistamines (known) and their analogues (unknown) illegally added to dietary supplements as well as in other sample matrices.

  17. Observation of the intermediates of in-source aldolization reaction in electrospray ionization mass spectrometry analysis of heteroaromatic aldehydes.

    Science.gov (United States)

    Jiang, Kezhi; Zhang, Xiaoping; Bai, Xingfeng; Lv, Huiqing; Li, Zuguang; Lee, Maw-Rong

    2015-01-01

    Electrospray ionization mass spectrometry (ESI-MS) analyses of 2-(1,2,4-triazole-1-yl)-6-methyl-3- quinolinecarboxaldehyde were carried out by using an ion trap mass spectrometer in a positive-ion mode. Interestingly, several unusual [M + 15](+), [M + 33](+), and [M + 47](+) ions were observed with a high abundance in the ESI-MS spectrum when methanol was used as the ESI solvent. However, only the protonated molecule was obtained with acetonitrile as the ESI solvent. These unusual ions have been proposed as the intermediates of an aldolization reaction occurring in the ESI source, which have been validated by a tandem mass spectrometry experiment, high-performance liquid chromatography/mass spectrometry analysis, and theoretical calculations. A full understanding of this reaction can contribute to the avoidance of analysis errors in the ESI-MS analysis of unknown heteroaromatic aldehydes.

  18. A comprehensive library-based, automated screening procedure for 46 synthetic cannabinoids in serum employing liquid chromatography-quadrupole ion trap mass spectrometry with high-temperature electrospray ionization.

    Science.gov (United States)

    Huppertz, Laura M; Kneisel, Stefan; Auwärter, Volker; Kempf, Jürgen

    2014-02-01

    Considering the vast variety of synthetic cannabinoids and herbal mixtures - commonly known as 'Spice' or 'K2' - on the market and the resulting increase of severe intoxications related to their consumption, there is a need in clinical and forensic toxicology for comprehensive up-to-date screening methods. The focus of this project aimed at developing and implementing an automated screening procedure for the detection of synthetic cannabinoids in serum using a liquid chromatography-ion trap-MS (LC-MS(n)) system and a spectra library-based approach, currently including 46 synthetic cannabinoids and 8 isotope labelled analogues. In the process of method development, a high-temperature ESI source (IonBooster(TM), Bruker Daltonik) and its effects on the ionization efficiency of the investigated synthetic cannabinoids were evaluated and compared to a conventional ESI source. Despite their structural diversity, all investigated synthetic cannabinoids benefitted from high-temperature ionization by showing remarkably higher MS intensities compared to conventional ESI. The employed search algorithm matches retention time, MS and MS(2)/MS(3) spectra. With the utilization of the ionBooster source, limits for the automated detection comparable to cut-off values of routine MRM methods were achieved for the majority of analytes. Even compounds not identified when using a conventional ESI source were detected using the ionBooster-source. LODs in serum range from 0.1 ng/ml to 0.5 ng/ml. The use of parent compounds as analytical targets offers the possibility of instantly adding new emerging compounds to the library and immediately applying the updated method to serum samples, allowing the rapid adaptation of the screening method to ongoing forensic or clinical requirements. The presented approach can also be applied to other specimens, such as oral fluid or hair, and herbal mixtures and was successfully applied to authentic serum samples. Quantitative MRM results of samples with

  19. Desorption ElectroSpray Ionization - Orbitrap Mass Spectrometry of synthetic polymers and copolymers.

    Science.gov (United States)

    Friia, Manel; Legros, Véronique; Tortajada, Jeanine; Buchmann, William

    2012-08-01

    Desorption ElectroSpray Ionization (DESI) - Orbitrap Mass Spectrometry (MS) was evaluated as a new tool for the characterization of various industrial synthetic polymers (poly(ethylene glycol), poly(propylene glycol), poly(methylmethacrylate), poly(dimethylsiloxane)) and copolymers, with masses ranging from 500 g.mol(-1) up to more than 20 000 g.mol(-1) . Satisfying results in terms of signal stability and sensitivity were obtained from hydrophobic surfaces (HTC Prosolia) with a mixture water/methanol (10/90) as spray solvent in the presence of sodium salt. Taking into account the formation of multiplied charged species by DESI-MS, a strategy based on the use of a deconvolution software followed by the automatic assignment of the ions was described allowing the rapid determination of M(n) , M(w) and PDI values. DESI-Orbitrap MS results were compared to those obtained from matrix-assisted laser desorption/ionization- time-of-flight MS and gel permeation chromatography. An application of DESI-Orbitrap MS for the detection and identification of polymers directly from cosmetics was described. Copyright © 2012 John Wiley & Sons, Ltd.

  20. Desorption electro-spray ionization - orbitrap mass spectrometry of synthetic polymers and copolymers

    International Nuclear Information System (INIS)

    Friia, Manel; Legros, Veronique; Tortajada, Jeanine; Buchmann, William

    2012-01-01

    Desorption Electro-Spray Ionization (DESI) - Orbitrap Mass Spectrometry (MS) was evaluated as a new tool for the characterization of various industrial synthetic polymers (poly(ethylene glycol), poly(propylene glycol), poly(methylmethacrylate), poly(dimethylsiloxane)) and copolymers, with masses ranging from 500 g.mol -1 up to more than 20000 g.mol -1 . Satisfying results in terms of signal stability and sensitivity were obtained from hydrophobic surfaces (HTC Prosolia) with a mixture water/methanol (10/90) as spray solvent in the presence of sodium salt. Taking into account the formation of multiplied charged species by DESI-MS, a strategy based on the use of a deconvolution software followed by the automatic assignment of the ions was described allowing the rapid determination of Mn, Mw and PDI values. DESI-Orbitrap MS results were compared to those obtained from matrix-assisted laser desorption/ionization- time-of-flight MS and gel permeation chromatography. An application of DESI-Orbitrap MS for the detection and identification of polymers directly from cosmetics was described. (authors)

  1. An electrospray ionization-tandem mass spectrometry method for identifying chlorinated drinking water disinfection byproducts.

    Science.gov (United States)

    Zhang, Xiangru; Minear, Roger A; Guo, Yingbo; Hwang, Cordelia J; Barrett, Sylvia E; Ikeda, Kazuhiro; Shimizu, Yoshihisa; Matsui, Saburo

    2004-11-01

    Identification of chlorinated drinking water disinfection byproducts (DBPs) was investigated by using electrospray ionization-mass spectrometry/mass spectrometry (ESI-MS/MS). Chlorine-containing compounds were found to form chloride ion fragments by MS/MS, which can be used as a 'fingerprint' for chlorinated DBPs. Instrumental parameters that affect the formation of chloride ions by ESI-MS/MS were examined, and appropriate conditions for use in finding specific structural information were evaluated. The results show that maximizing the formation of chloride ions by MS/MS required a relatively high collision energy and collision gas pressure; also, limiting the scan range to m/z 30-40 allowed improved sensitivity for detection; but obtaining structural information required the use of lower collision energies. The conditions obtained were demonstrated to be effective in identifying chlorinated DBPs in a standard sample with relatively low concentrations of each component and in a chlorinated humic substance sample. Sample pretreatment techniques including ultrafiltration and size exclusion chromatography appeared to be helpful for identifying highly polar or high molecular weight chlorine-containing DBPs by ESI-MS/MS.

  2. Determination of Sulfonamides in Chicken Muscle by Pulsed Direct Current Electrospray Ionization Tandem Mass Spectrometry.

    Science.gov (United States)

    Fu, Xian; Liang, Hengxing; Xia, Bing; Huang, Chunyan; Ji, Baocheng; Zhou, Yan

    2017-09-20

    A simple and rapid approach for the simultaneous detection of trace amounts of six sulfonamides in chicken muscle was developed using pulsed direct current electrospray ionization tandem mass spectrometry (pulsed-dc ESI-MS/MS). The pretreatment of chicken muscle samples consisted of two steps: acetonitrile extraction and n-hexane delipidation. Sulfonamides do not need to be derivatized or chromatographed prior to pulsed-dc ESI-MS/MS. The factors affecting the performance of pulsed-dc ESI-MS/MS were studied. Under optimum conditions, the quantitative performance of pulsed-dc ESI-MS/MS was validated according to European Union Decision 2002/657/EC, and the sensitivity of pulsed-dc ESI-MS/MS was 3 times higher than that of ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The limits of detection obtained by pulsed-dc ESI-MS/MS were in the range of 0.07-0.11 μg/kg. The proposed method was simple, rapid, and sensitive, and was successfully used for quantitation and rapid screening of sulfonamides in real chicken muscle samples.

  3. Gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) in toxicological analysis. Studies on the detection of clobenzorex and its metabolites within a systematic toxicological analysis procedure by GC-MS and by immunoassay and studies on the detection of alpha- and beta-amanitin in urine by atmospheric pressure ionization electrospray LC-MS.

    Science.gov (United States)

    Maurer, H H; Kraemer, T; Ledvinka, O; Schmitt, C J; Weber, A A

    1997-02-07

    GC-MS is the method of choice for toxicological analysis of toxicants volatile in GC while non-volatile and/or thermally labile toxicants need LC-MS for their determination. Studies are presented on the toxicological detection of the amphetamine-like anorectic clobenzorex in urine by GC-MS after acid hydrolysis, extraction and acetylation and by fluorescence polarization immunoassay (FPIA, TDx (meth)amphetamine II). After ingestion of 60 mg of clobenzorex, the parent compound and/or its metabolites could be detected by GC-MS for up to 84 h or by FPIA for up to 60 h. Since clobenzorex shows no cross-reactivity with the used immunoassay, the N-dealkylated metabolite amphetamine is responsible for the positive TDx results. The intake of clobenzorex instead of amphetamine can be differentiated by GC-MS detection of hydroxyclobenzorex which is detectable for at least as long as amphetamine. In addition, the described GC-MS procedure allows the simultaneous detection of most of the toxicologically relevant drugs. Furthermore, studies are described on the atmospheric pressure ionization electrospray LC-MS detection of alpha- and beta-amanitin, toxic peptides of amanita mushrooms, in urine after solid-phase extraction on RP-18 columns. Using the single ion monitoring mode with the ions m/z 919 and 920 the amanitins could be detected down to 10 ng/ml of urine which allows us to diagnose intoxications with amanita mushrooms.

  4. Electrospray ionization mass spectrometry for the hydrolysis complexes of cisplatin: implications for the hydrolysis process of platinum complexes.

    Science.gov (United States)

    Feifan, Xie; Pieter, Colin; Jan, Van Bocxlaer

    2017-07-01

    Non-enzyme-dependent hydrolysis of the drug cisplatin is important for its mode of action and toxicity. However, up until today, the hydrolysis process of cisplatin is still not completely understood. In the present study, the hydrolysis of cisplatin in an aqueous solution was systematically investigated by using electrospray ionization mass spectrometry coupled to liquid chromatography. A variety of previously unreported hydrolysis complexes corresponding to monomeric, dimeric and trimeric species were detected and identified. The characteristics of the Pt-containing complexes were investigated by using collision-induced dissociation (CID). The hydrolysis complexes demonstrate distinctive and correlative CID characteristics, which provides tools for an informative identification. The most frequently observed dissociation mechanism was sequential loss of NH 3 , H 2 O and HCl. Loss of the Pt atom was observed as the final step during the CID process. The formation mechanisms of the observed complexes were explored and experimentally examined. The strongly bound dimeric species, which existed in solution, are assumed to be formed from the clustering of the parent compound and its monohydrated or dihydrated complexes. The role of the electrospray process in the formation of some of the observed ions was also evaluated, and the electrospray ionization-related cold clusters were identified. The previously reported hydrolysis equilibria were tested and subsequently refined via a hydrolysis study resulting in a renewed mechanistic equilibrium system of cisplatin as proposed from our results. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

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

    Science.gov (United States)

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

    2016-03-25

    Herein, quantitation aspects of a fully automated autosampler/HPLC-MS/MS system applied for unattended droplet-based surface sampling of repaglinide dosed thin tissue sections with subsequent HPLC separation and mass spectrometric analysis of parent drug and various drug metabolites were studied. Major organs (brain, lung, liver, kidney and muscle) from whole-body thin tissue sections and corresponding organ homogenates prepared from repaglinide dosed mice were sampled by surface sampling and by bulk extraction, respectively, and analyzed by HPLC-MS/MS. A semi-quantitative agreement between data obtained by surface sampling and that by employing organ homogenate extraction was observed. Drug concentrations obtained by the two methods followed the same patterns for post-dose time points (0.25, 0.5, 1 and 2 h). Drug amounts determined in the specific tissues was typically higher when analyzing extracts from the organ homogenates. In addition, relative comparison of the levels of individual metabolites between the two analytical methods also revealed good semi-quantitative agreement. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. An electrospray ionization-ion mobility spectrometer as detector for high- performance liquid chromatography.

    Science.gov (United States)

    Zühlke, Martin; Riebe, Daniel; Beitz, Toralf; Löhmannsröben, Hans-Gerd; Zenichowski, Karl; Diener, Marc; Linscheid, Michael W

    2015-01-01

    The application of electrospray ionization (ESI) ion mobility (IM) spectrometry on the detection end of a high-performance liquid chromatograph has been a subject of study for some time. So far, this method has been limited to low flow rates or has required splitting of the liquid flow. This work presents a novel concept of an ESI source facilitating the stable operation of the spectrometer at flow rates between 10 μL mn(-1) and 1500 μL min(-1) without flow splitting, advancing the T-cylinder design developed by Kurnin and co-workers. Flow rates eight times faster than previously reported were achieved because of a more efficient dispersion of the liquid at increased electrospray voltages combined with nebulization by a sheath gas. Imaging revealed the spray operation to be in a rotationally symmetric multijet mode. The novel ESI-IM spectrometer tolerates high water contents (≤90%) and electrolyte concentrations up to 10mM, meeting another condition required of high-performance liquid chromatography (HPLC) detectors. Limits of detection of 50 nM for promazine in the positive mode and 1 μM for 1,3-dinitrobenzene in the negative mode were established. Three mixtures of reduced complexity (five surfactants, four neuroleptics, and two isomers) were separated in the millisecond regime in stand-alone operation of the spectrometer. Separations of two more complex mixtures (five neuroleptics and 13 pesticides) demonstrate the application of the spectrometer as an HPLC detector. The examples illustrate the advantages of the spectrometer over the established diode array detector, in terms of additional IM separation of substances not fully separated in the retention time domain as well as identification of substances based on their characteristic Ims.

  7. Doping control analysis of anabolic steroids in equine urine by gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wong, April S Y; Leung, Gary N W; Leung, David K K; Wan, Terence S M

    2017-09-01

    Anabolic steroids are banned substances in equine sports. Gas chromatography-mass spectrometry (GC-MS) has been the traditional technique for doping control analysis of anabolic steroids in biological samples. Although liquid chromatography-mass spectrometry (LC/MS) has become an important technique in doping control, the detection of saturated hydroxysteroids by LC-MS remains a problem due to their low ionization efficiency under electrospray. The recent development in fast-scanning gas-chromatography-triple-quadrupole mass spectrometry (GC-MS/MS) has provided a better alternative with a significant reduction in chemical noise by means of selective reaction monitoring. Herein, we present a sensitive and selective method for the screening of over 50 anabolic steroids in equine urine using gas chromatography-tandem mass spectrometry (GC-MS/MS). Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

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

    Science.gov (United States)

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

    2014-03-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

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

    African Journals Online (AJOL)

    HP

    Purpose: To determine naproxen levels in human plasma using a new liquid chromatography-Mass spectroscopy/Mass spectroscopy (LC-MS/MS) method that involves a simple and single step extraction procedure using low-cost reagents. Method: A novel liquid chromatography–tandem mass spectrometry method for the ...

  11. Elucidation of urinary metabolites of fluoxymesterone by liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Pozo, Oscar J; Van Thuyne, Wim; Deventer, Koen; Van Eenoo, Peter; Delbeke, Frans T

    2008-03-01

    The suitability of liquid chromatography tandem mass spectrometry (LC-MS/MS) and gas chromatography mass spectrometry (GC-MS) for the elucidation of fluoxymesterone metabolism has been evaluated. Electrospray ionization (ESI) and collision induced dissociation (CID) fragmentation in LC-MS/MS and electron impact spectra (EI) in GC-MS have been studied for fluoxymesterone and two commercially available metabolites. MS(n) experiments and accurate mass measurements performed by an ion-trap analyser and a QTOF instrument respectively have been used for the elucidation of the fragmentation pathway. The neutral loss scan of 20 Da (loss of HF) in LC-MS/MS has been applied for the selective detection of fluoxymesterone metabolites. In a positive fluoxymesterone doping control sample, 9 different analytes have been detected including the parent compound. Seven of these metabolites were also confirmed by GC-MS including 5 previously unreported metabolites. On the basis of the ionization, the CID fragmentation, the accurate mass of the product ions and the EI spectra of these analytes, a tentative elucidation as well as a proposal for the metabolic pathway of fluoxymesterone has been suggested. The presence of these compounds has also been confirmed by the analysis of five other positive fluoxymesterone urine samples. Copyright (c) 2008 John Wiley & Sons, Ltd.

  12. Biases in Ion Transmission Through an Electrospray Ionization-Mass Spectrometry Capillary Inlet

    Energy Technology Data Exchange (ETDEWEB)

    Page, Jason S.; Marginean, Ioan; Baker, Erin Shammel; Kelly, Ryan T.; Tang, Keqi; Smith, Richard D.

    2009-12-01

    The standard heated capillary inlet of an electrospray ionization mass spectrometry (ESI-MS) interface was compared with shorter versions of the inlet to determine the effects on transmission and ionization efficiencies for low-flow electrosprays. The primary finding of the study was a large bias towards higher mobility species in the electrospray current losses to the inside walls of the inlet. The transmission efficiency increased with decreasing capillary length due to reduced losses along the capillary. A decrease in transmission efficiency was also confirmed for electrosprays of higher conductivity solvents. A direct correlation between mass spectrometry sensitivity and the transmitted electrospray current was not observed as some analytes showed little to no increase in sensitivity while others showed as high as a 15 – fold increase. The variation was shown to at least be partially dependent on the analytes’ mobilities. Higher mobility analytes demonstrated a larger increase in sensitivity when shorter inlets were used. The results indicate that considerable biases against higher mobility species can be produced by the use of long capillary inlets in the ESI-MS interface and strategies are provided to minimize the bias against higher mobility species for efficient ion transmission through the heated capillary interface.

  13. Terverticillate Penicillia studied by direct electrospray mass spectrometric profiling of crude extracts: I. Chemosystematics

    DEFF Research Database (Denmark)

    Smedsgaard, Jørn; Frisvad, Jens Christian

    1997-01-01

    A chemosystematic study of 339 isolates from all known terverticillate Penicillium taxa was performed using electrospray mass spectrometric analysis of extractable metabolites. The mass profiles were made by injecting crude plug extracts made from cultures grown on Czapek Yeast Autolysate agar (CYA......) and Yeast Extract Sucrose agar (YES) directly into the electrospray source of the mass spectrometer. A data matrix was made from each substrate by transferring the complete centroid mass spectrum from 200 to 700 amu as 501 variables to individual columns. No attempt was made to identify ions in the mass...... dominated by a single intense ion together, whereas logarithmized data revealed finer detail but with a shorter distance between clusters. The overall results showed that substantial taxonomic information can be extracted from mass profiles even when the identity of ions is unknown. ions corresponding...

  14. Electrospray Ionization with High-Resolution Mass Spectrometry as a Tool for Lignomics: Lignin Mass Spectrum Deconvolution

    Science.gov (United States)

    Andrianova, Anastasia A.; DiProspero, Thomas; Geib, Clayton; Smoliakova, Irina P.; Kozliak, Evguenii I.; Kubátová, Alena

    2018-03-01

    The capability to characterize lignin, lignocellulose, and their degradation products is essential for the development of new renewable feedstocks. Electrospray ionization high-resolution time-of-flight mass spectrometry (ESI-HR TOF-MS) method was developed expanding the lignomics toolkit while targeting the simultaneous detection of low and high molecular weight (MW) lignin species. The effect of a broad range of electrolytes and various ionization conditions on ion formation and ionization effectiveness was studied using a suite of mono-, di-, and triarene lignin model compounds as well as kraft alkali lignin. Contrary to the previous studies, the positive ionization mode was found to be more effective for methoxy-substituted arenes and polyphenols, i.e., species of a broadly varied MW structurally similar to the native lignin. For the first time, we report an effective formation of multiply charged species of lignin with the subsequent mass spectrum deconvolution in the presence of 100 mmol L-1 formic acid in the positive ESI mode. The developed method enabled the detection of lignin species with an MW between 150 and 9000 Da or higher, depending on the mass analyzer. The obtained M n and M w values of 1500 and 2500 Da, respectively, were in good agreement with those determined by gel permeation chromatography. Furthermore, the deconvoluted ESI mass spectrum was similar to that obtained with matrix-assisted laser desorption/ionization (MALDI)-HR TOF-MS, yet featuring a higher signal-to-noise ratio. The formation of multiply charged species was confirmed with ion mobility ESI-HR Q-TOF-MS. [Figure not available: see fulltext.

  15. Comparative urine analysis by liquid chromatography-mass spectrometry and multivariate statistics : Method development, evaluation, and application to proteinuria

    NARCIS (Netherlands)

    Kemperman, Ramses F. J.; Horvatovich, Peter L.; Hoekman, Berend; Reijmers, Theo H.; Muskiet, Frits A. J.; Bischoff, Rainer

    2007-01-01

    We describe a platform for the comparative profiling of urine using reversed-phase liquid chromatography-mass spectrometry (LC-MS) and multivariate statistical data analysis. Urinary compounds were separated by gradient elution and subsequently detected by electrospray Ion-Trap MS. The lower limit

  16. On cluster ions, ion transmission, and linear dynamic range limitations in electrospray (ionspray) mass spectrometry

    NARCIS (Netherlands)

    Zook, D.R; Bruins, A.P.

    The ion transmission in Electrospray (Ionspray) Mass Spectrometry (ESMS) was studied in order to examine the instrumental factors potentially contributing to observed ESMS linear dynamic range (LDR) limitations. A variety of means used for the investigation of ion transmission demonstrated that a

  17. Simultaneous identification of historical pigments Prussian blue and indigo in paintings by electrospray mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Pauk, V.; Havlíček, Vladimír; Papoušková, B.; Sulovský, P.; Lemr, Karel

    2013-01-01

    Roč. 48, č. 8 (2013), s. 927-930 ISSN 1076-5174 R&D Projects: GA ČR(CZ) GAP206/12/1150 Institutional support: RVO:61388971 Keywords : mass spectrometry * electrospray * historical painting Subject RIV: CE - Biochemistry Impact factor: 2.709, year: 2013

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

    NARCIS (Netherlands)

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

    2011-01-01

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

  19. Screening of acetylcholinesterase inhibitors in snake venom by electrospray mass spectrometry

    NARCIS (Netherlands)

    Liesener, A.; Perchuc, Anna-Maria; Schöni, Reto; Schebb, Nils Helge; Wilmer, Marianne; Karst, U.

    2007-01-01

    An electrospray ionization/mass spectrometry (ESI/MS)-based assay for the determination of acetylcholinesterase (AChE)-inhibiting activity in snake venom was developed. It allows the direct monitoring of the natural AChE substrate acetylcholine (AC) and the respective product choline. The assay

  20. Ion clustering in electrospray mass spectrometry of brine and other electrolyte solutions

    Czech Academy of Sciences Publication Activity Database

    Schröder, Detlef

    2012-01-01

    Roč. 14, č. 18 (2012), s. 6382-6390 ISSN 1463-9076 Grant - others:European Research Council(XE) AdG HORIZOMS Institutional research plan: CEZ:AV0Z40550506 Keywords : electrolytes * electrospray ion ization * mass spectrometry * solvation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.829, year: 2012

  1. Complexation between the fungicide tebuconazole and copper(II) probed by electrospray ionization mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Jaklová Dytrtová, Jana; Jakl, M.; Schröder, Detlef; Čadková, E.; Komárek, M.

    2011-01-01

    Roč. 25, č. 8 (2011), s. 1037-1042 ISSN 0951-4198 Institutional research plan: CEZ:AV0Z40550506 Keywords : copper * electrospray ionization * mass spectrometry * tebuconazole * soil solutions Subject RIV: CC - Organic Chemistry Impact factor: 2.790, year: 2011

  2. CAPILLARY ELECTROPHORESIS-ELECTROSPRAY MASS SPECTRA OF THE HERBICIDES PARAQUAT AND DIQUAT

    Science.gov (United States)

    The positive ion electrospray mass spectra of the quaternary ammonium salt herbicides paraquat and diquat are examined by on-line separation with capillary electrophoresis (CE) and by direct infusion of the analytes. The analytes are separated by CE in 7-10 min at pH 3.9 in 50% m...

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

    Science.gov (United States)

    Gross, Deborah S.; Van Ryswyk, Hal

    2014-01-01

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

  4. Feasibility of nonvolatile buffers in capillary electrophoresis-electrospray ionization-mass spectrometry of proteins

    NARCIS (Netherlands)

    Eriksson, Jonas H.C.; Mol, Roelof; Somsen, Govert W.; Hinrichs, Wouter L.J.; Frijlink, Henderik W.; de Jong, Gerhardus J.

    2004-01-01

    The combination of capillary electrophoresis (CE) and electrospray ionization-mass spectrometry (ESI-MS) via a triaxial interface was studied as a potential means for the characterization of intact proteins. To evaluate the possibility to use a nonvolatile electrolyte for CE, the effect of sodium

  5. Complexation of malic acid with cadmium(II) probed by electrospray ionization mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Jaklová Dytrtová, Jana; Jakl, M.; Schröder, Detlef

    2012-01-01

    Roč. 90, 15 Feb (2012), s. 63-68 ISSN 0039-9140 Institutional research plan: CEZ:AV0Z40550506 Keywords : electrospray ionization * hazardous metals * mass spectrometry * root exudates * soil solution Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.498, year: 2012

  6. 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.

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

    Science.gov (United States)

    Rostad, C.E.

    2010-01-01

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

  8. An electrodynamic ion funnel for electrospray ionization source based time-of-flight mass spectrometry

    International Nuclear Information System (INIS)

    Bhushan, K.G.; Rao, K.C.; Sule, U.; Reddy, P.; Rodrigues, S.M.; Gaikwad, D.T.; Mukundhan, R.; Gupta, S.K.

    2016-01-01

    An electrodynamic ion funnel has been developed for improving the sensitivity of electrospray ionization sources widely used in the mass spectrometric study of proteins and other biological macromolecules. The ion funnel consists of 52 electrodes and works under the combined influence of RF and DC voltages in the pressure range of 0.1 to 5 mbar. A novel feature of this ion funnel is the specific shape of the exit electrode that improves transmission of lower mass ions by reducing the depth of effective trapping potentials. In this paper, we report on the optimization of the ion funnel design using ion trajectory simulation software SIMION 8.0 especially in the mass range 500–5000 amu, followed by experimental observations of the ion transmission from the electrospray interface. It is seen that the electrospray-ion funnel combination greatly enhances the transmission when compared with an electrospray-skimmer interface. Ion currents > 1 nA could be obtained at the exit of the ion funnel for dilute Streptomycin Sulphate (∼ 1500 amu) solution with the ion funnel operating in the 500–900 kHz frequency range, amplitude of 70 V p−p , under a DC gradient of about 20 Volts/cm at a background pressure of 0.3 mbar. Details of the construction of the ion funnel along with the experimental results are presented

  9. Electrospray ionization with aluminum foil: A versatile mass spectrometric technique.

    Science.gov (United States)

    Hu, Bin; So, Pui-Kin; Yao, Zhong-Ping

    2014-03-19

    In this study, we developed a novel electrospray ionization (ESI) technique based on household aluminum foil (Al foil) and demonstated the desirable features and applications of this technique. Al foil can be readily cut and folded into desired configuration for effective ionization and for holding sample solution in bulk to allowing acquisition of durable ion signals. The present technique was demonstrated to be applicable in analysis of a wide variety of samples, ranging from pure chemical and biological compounds, e.g., organic compounds and proteins, to complex samples in liquid, semi-solid, and solid states, e.g., beverages, skincare cream, and herbal medicines. The inert, hydrophobic and impermeable surface of Al foil allows convenient and effective on-target extraction of solid samples and on-target sample clean-up, i.e., removal of salts and detergents from proteins and peptides, extending ESI device from usually only for sample loading and ionization to including sample processing. Moreover, Al foil is an excellent heat-conductor and highly heat-tolerant, permitting direct monitoring of thermal reactions, e.g., thermal denaturation of proteins. Overall, the present study showed that Al-foil ESI could be an economical and versatile method that allows a wide range of applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Rapid differentiation of refined fuels using negative electrospray ionization/mass spectrometry

    Science.gov (United States)

    Rostad, C.E.; Hostettler, F.D.

    2005-01-01

    Negative electrospray ionization/MS enabled rapid, specific, and selective screening for unique polar components at parts per million concentrations in commercial hydrocarbon products without extensive sample preparation, separation, chromatography, or quantitation. Commercial fuel types were analyzed with this method, including kerosene, jet fuel, white gas, charcoal lighter fluid, on-road and off-road diesel fuels, and various grades and brands of gasolines. The different types of fuels produced unique and relatively simple spectra. These analyses were then applied to hydrocarbon samples from a large, long-term fuel spill. Although the alkane, isoprenoid, and alkylcyclohexane portions began to biodegrade or weather, the polar components in these samples remained relatively unchanged. The type of fuel involved was readily identified by negative electrospray ionization/MS. This is an abstract of a paper presented at the 230th ACS National Meeting (Washington, DC 8/28/2005-9/1/2005).

  11. Analysis of triacetone triperoxide complexes with alkali metal ions by electrospray and extractive electrospray ionisation combined with ion mobility spectrometry and mass spectrometry.

    Science.gov (United States)

    Hill, Alex R; Edgar, Mark; Chatzigeorgiou, Maria; Reynolds, James C; Kelly, Paul F; Creaser, Colin S

    2015-01-01

    The complexation of triacetone triperoxide (TATP) with a range of alkali metals has been studied by electrospray ionisation-mass spectrometry yield [M+Cat](+) ions for all of the alkali metals. The formation of [2TATP+Li+LiX](+) (X = Br, Cl) sandwich complexes was also observed. Collision cross- sections for the lithium-containing complexes of TATP were measured by travelling wave ion mobility spectrometry mass spectrometry, and compared well with computationally determined structures. Extractive electrospray ionisation (EESI) using a lithium doped electrospray is demonstrated for the detection of TATP vapours desorbed from a metal surface. The limit of detection for EESI was shown to be 20 ng using the [TATP+Li](+) ion.

  12. Electrospray ionizer for mass spectrometry of aerosol particles

    Science.gov (United States)

    He, Siqin; Hogan, Chris; Li, Lin; Liu, Benjamin Y. H.; Naqwi, Amir; Romay, Francisco

    2017-09-19

    A device and method are disclosed to apply ESI-based mass spectroscopy to submicrometer and nanometer scale aerosol particles. Unipolar ionization is utilized to charge the particles in order to collect them electrostatically on the tip of a tungsten rod. Subsequently, the species composing the collected particles are dissolved by making a liquid flow over the tungsten rod. This liquid with dissolved aerosol contents is formed into highly charged droplets, which release unfragmented ions for mass spectroscopy, such as time-of-flight mass spectroscopy. The device is configured to operate in a switching mode, wherein aerosol deposition occurs while solvent delivery is turned off and vice versa.

  13. Development of a multiplexed interface for capillary electrophoresis-electrospray ion trap mass spectrometry.

    Science.gov (United States)

    Li, Fu-An; Wu, Ming-Chi; Her, Guor-Rong

    2006-08-01

    A four-channel multiplexed electrospray capillary electrophoresis interface has been developed. This new interface permits up to four capillary electrophoresis columns to be sampled sequentially by means of a stepper motor and a notched rotating plate assembly, which at any instant occludes all but a single sprayer. In this design, four sheath liquid electrospray probes are oriented in a circular array situated 90 degrees relative to one another. The rotating metal disk, which contains a one-quarter notch, is mounted to the stepper motor assembly and is located between the sprayers and the entrance aperture of an ion trap mass spectrometer. By using the data acquisition signal from the ion trap mass spectrometer, the scan event is synchronized with the rotation of the metal disk. With this device, four discrete sample streams can be simultaneously analyzed, resulting in a 4-fold increase in analytical throughput.

  14. High-frequency AC electrospray ionization source for mass spectrometry of biomolecules.

    Science.gov (United States)

    Chetwani, Nishant; Cassou, Catherine A; Go, David B; Chang, Hsueh-Chia

    2010-11-01

    A novel high-frequency alternating current (AC) electrospray ionization (ESI) source has been developed for applications in mass spectrometry. The AC ESI source operates in a conical meniscus mode, analogous to the cone-jet mode of direct current (DC) electrosprays but with significant physical and mechanistic differences. In this stable conical-meniscus mode at frequencies greater than 50 kHz, the low mobility ions, which can either be cations or anions, are entrained within the liquid cone and ejected as droplets that eventually form molecular ions, thus making AC ESI a viable tool for both negative and positive mode mass spectrometry. The performance of the AC ESI source is qualitatively shown to be frequency-dependent and, for larger bio-molecules, the AC ESI source produced an ion signal intensity that is an order of magnitude higher than its DC counterpart. Copyright © 2010. Published by Elsevier Inc.

  15. Matrix-assisted laser desorption and electrospray ionization mass spectrometry of carminic acid isolated from cochineal

    Science.gov (United States)

    Maier, Marta S.; Parera, Sara D.; Seldes, Alicia M.

    2004-04-01

    Carminic acid, isolated from cochineal, was analyzed by matrix-assisted laser desorption/ionization (MALDI) and electrospray mass spectrometry (ESI-MS). Application of both techniques to the analysis of carminic acid suspended in linseed oil and applied to a piece of canvas, demonstrated the ability of MALDI and ESI-MS to identify this organic dye in a mixture as those used in easel painting.

  16. Aerodynamic mass spectrometry interfacing of microdevices without electrospray tips

    Czech Academy of Sciences Publication Activity Database

    Grym, Jakub; Otevřel, Marek; Foret, František

    2006-01-01

    Roč. 6, č. 10 (2006), s. 1306-1314 E-ISSN 1473-0189 R&D Projects: GA ČR GA203/06/1685; GA AV ČR IAA400310506; GA MŠk LC06023; GA AV ČR KJB400310510 Institutional research plan: CEZ:AV0Z40310501 Keywords : mass spectrometry * microfluidic device Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 5.265, year: 2005

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

    DEFF Research Database (Denmark)

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

    1996-01-01

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

  18. A comparison of flavonoid glycosides by electrospray tandem mass spectrometry

    Science.gov (United States)

    March, Raymond E.; Lewars, Errol G.; Stadey, Christopher J.; Miao, Xiu-Sheng; Zhao, Xiaoming; Metcalfe, Chris D.

    2006-01-01

    A comparison is presented of product ion mass spectra of protonated and deprotonated molecules of kaempferol-3-O-glucoside, quercitin-3-O-glucoside (isoquercitrin), quercitin-3-O-galactoside (hyperoin), apigenin-7-O-glucoside, luteolin-7-O-glucoside, genistein-7-O-glucoside, naringenin-7-O-glucoside (prunin), luteolin-4'-O-glucoside, luteolin-6-C-glucoside (homoorientin, known also as isoorientin), apigenin-8-C-glucoside (vitexin), and luteolin-8-C-glucoside (orientin) together with the product ion mass spectrum of deprotonated kaempferol-7-O-glucoside. All isomeric ions were distinguishable on the basis of their product ion mass spectra. For protonated 3-O-, 7-O-, and 4'-O-glycosides at a collision energy of 46-47 eV, homolytic cleavage of the O-glycosidic bond yielded aglycon Y+ ions, whereas in deprotonated 3-O-, 7-O-, and 4'-O-glycosides, heterolytic and homolytic cleavage of the O-glycosidic bond yielded radical aglycon (Y-H)- and aglycon (Y-) ions. In each case, fragmentation of either the glycan or the aglycon or both was observed. For 6-C- and 8-C-glycosides at a collision energy of 46-47 eV, fragmentation was restricted almost exclusively to the glycan. For luteolin-6-C-glucoside, the integrity of the aglycon structure is preserved at the expense of the glycan for which some 30 fragmentations were observed. Breakdown curves were determined as a function of collision energy for protonated and deprotonated luteolin-6-C-glucoside. An attempt has been made to rationalize the product ion mass spectra derived from C-O- and C-C-luteolin glucosides in terms of computed structures that indicate significant intramolecular hydrogen bonding and rotation of the B-ring to form a coplanar luteolin structure. It is proposed that protonated and deprotonated luteolin-6-C-glucoside may afford examples of cooperative interactive bonding that plays a major role in directing fragmentation.

  19. Dual reductive/oxidative electrochemistry/liquid chromatography/mass spectrometry: Towards peptide and protein modification, separation and identification.

    Science.gov (United States)

    Büter, Lars; Frensemeier, Lisa M; Vogel, Martin; Karst, Uwe

    2017-01-06

    A new hyphenated technique based on on-line dual (oxidative and reductive) electrochemistry coupled to liquid chromatography and high resolution electrospray mass spectrometry is presented. Two liquid streams are combined, with one containing a disulfide, which is reduced to the respective thiol in an electrochemical cell based on a titanium working electrode. The other stream contains phenol, which is electrochemically activated to benzoquinone on a boron-doped diamond working electrode. Upon combination of the two streams, a Michael addition takes places, leading to the covalent coupling of thiol to quinone. In continuous flow, the reaction mixture is transferred into an injection valve and the products are separated by reversed phase liquid chromatography and detected by electrospray-high resolution mass spectrometry. Proof of concept is demonstrated for low molecular mass disulfides and peptides, but further optimization will be required in future work to achieve efficient protein labelling. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. A qualitative study of amlodipine and its related compounds by electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Gibbons, John; Pugh, Jonathan; Dimopoulos-Italiano, Gina; Pike, Richard

    2006-01-01

    A comprehensive structural analysis of amlodipine and certain related compounds was performed by electrospray ionization tandem mass spectrometry. Triple quadrupole and quadrupole time-of-flight instruments were used to provide collision-induced dissociation and accurate mass measurement for selected product and second-generation product ions. A unique ion rearrangement was observed, which was found to be characteristic of certain dihydropyridines. This study provides a fundamental understanding of the fragmentation of these compounds. The structural elucidation of an unknown impurity is presented as an example. Copyright (c) 2006 John Wiley & Sons, Ltd.

  1. Interrogating the Venom of the Viperid Snake Sistrurus catenatus edwardsii by a Combined Approach of Electrospray and MALDI Mass Spectrometry.

    Directory of Open Access Journals (Sweden)

    Alex Chapeaurouge

    Full Text Available The complete sequence characterization of snake venom proteins by mass spectrometry is rather challenging due to the presence of multiple isoforms from different protein families. In the present study, we investigated the tryptic digest of the venom of the viperid snake Sistrurus catenatus edwardsii by a combined approach of liquid chromatography coupled to either electrospray (online or MALDI (offline mass spectrometry. These different ionization techniques proved to be complementary allowing the identification a great variety of isoforms of diverse snake venom protein families, as evidenced by the detection of the corresponding unique peptides. For example, ten out of eleven predicted isoforms of serine proteinases of the venom of S. c. edwardsii were distinguished using this approach. Moreover, snake venom protein families not encountered in a previous transcriptome study of the venom gland of this snake were identified. In essence, our results support the notion that complementary ionization techniques of mass spectrometry allow for the detection of even subtle sequence differences of snake venom proteins, which is fundamental for future structure-function relationship and possible drug design studies.

  2. Characterisation of fulvic acids by electrospray with quadrupole / time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Plancque, G. [Commissariat a l' Energie Atomique, Centre de Saclay, Direction de l' Energie Nucleaire / DPC / SECR / Lab. de Speciation des Radionucleides et des Molecules, Gif-sur-Yvette (France)

    2004-07-01

    Characterisation of fulvic and humic acids (FA and HA) - synthetic model substances M1 and M42 from FZR, FA and HA Gohy 573 from the Gorleben groundwaters from FZK and purified Aldrich HA from CTU - has been performed using a quadrupole time-of-flight (QTOF) mass spectrometer equipped with an electrospray ionisation interface. The same conclusions as for Mol fulvic acids, previously studied in the laboratory, can be drawn: molecular masses centred around 350 Da, sinusoidal spectral distributions, even and odd integral masses distributions and presence of dimmers (and possible trimmers) in negative-mode experiments have been observed for all humic substances. Tandem mass spectrometry (MS/MS) has also been used and experiments showed losses of 18 Da (H{sub 2}O), 28 Da (CO) and 44 Da (CO{sub 2}) as for Mol FA. No obvious differences, in terms of molecular structure, are observed compared to Mol FA. (orig.)

  3. Distribution of terfenadine and its metabolites in locusts studied by desorption electrospray ionization mass spectrometry imaging

    DEFF Research Database (Denmark)

    Olsen, Line Rørbæk; Hansen, Steen Honoré; Janfelt, Christian

    2015-01-01

    Desorption electrospray ionization (DESI) mass spectrometry (MS) imaging was used to image locusts dosed with the antihistamine drug terfenadine. The study was conducted in order to elucidate a relatively high elimination rate of terfenadine from the locust hemolymph. In this one of the few MS....... With use of DESI-MS imaging, no colocalization of the drug and the metabolites was observed, suggesting a very rapid excretion of metabolites into the feces. Additional liquid chromatography–MS investigations were performed on hemolymph and feces and showed some abundance of terfenadine and the three...

  4. The fragmentation mechanism of five-membered lactones by electrospray ionisation tandem mass spectrometry

    Science.gov (United States)

    Crotti, Antônio E. M.; Fonseca, Tatiana; Hong, Hui; Staunton, James; Galembeck, Sérgio E.; Lopes, Norberto P.; Gates, Paul J.

    2004-04-01

    A series of five-membered lactones (both saturated and unsaturated) and a lactam were analysed by electrospray ionisation tandem (ESI-MS/MS) and sequential mass spectrometry (ESI-MSn). It was observed that the main fragment ions were derived from neutral losses of CO and/or H2O (NH3 for the lactam). The fragmentation pathways followed are rationalised in terms of the resulting carbocation stability and the energy of the possible fragment ions, calculated by the CBS-Q composite method.

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

    DEFF Research Database (Denmark)

    Janfelt, Christian

    2015-01-01

    of cuticular wax present in leaves and petals. The cuticle protects the plant from drying out, but also makes it difficult for the DESI sprayer to reach the analytes of interest inside the plant material. A solution to this problem is to imprint the plant material onto a surface, thus releasing the analytes......Indirect desorption electrospray ionization mass spectrometry (DESI-MS) imaging is a method for imaging distributions of metabolites in plant materials, in particular leaves and petals. The challenge in direct imaging of such plant materials with DESI-MS is particularly the protective layer...

  6. Determination of Aspartame and Caffeine in Carbonated Beverages Utilizing Electrospray Ionization-Mass Spectrometry

    Science.gov (United States)

    Bergen, H. Robert, III; Benson, Linda M.; Naylor, Stephen

    2000-10-01

    Mass spectrometry has undergone considerable changes in the past decade. The advent of "soft ionization" techniques such as electrospray ionization (ESI) affords the direct analysis of very polar molecules without need for the complex inefficient derivatization procedures often required in GC-MS. These ionization techniques make possible the direct mass spectral analysis of polar nonvolatile molecules such as DNA and proteins, which previously were difficult or impossible to analyze by MS. Compounds that readily take on a charge (acids and bases) lend themselves to ESI-MS analysis, whereas compounds that do not readily accept a charge (e.g. sugars) are often not seen or are seen only as inefficient adducts (e.g., M+Na+). To gain exposure to this state-of-the-art analytical procedure, high school students utilize ESI-MS in an analysis of aspartame and caffeine. They dilute a beverage sample and inject the diluted sample into the ESI-MS. The lab is procedurally simple and the results clearly demonstrate the potential and limitations of ESI-coupled mass spectrometry. Depending upon the instructional goals, the outlined procedures can be used to quantify the content of caffeine and aspartame in beverages or to understand the capabilities of electrospray ionization.

  7. Rapid analysis of raw solution samples by C18 pipette-tip electrospray ionization mass spectrometry.

    Science.gov (United States)

    Wang, Haixing; So, Pui-Kin; Ng, Tsz-Tsun; Yao, Zhong-Ping

    2014-09-24

    A C18 pipette-tip electrospray ionization mass spectrometry technique was developed for rapid analysis of raw solution samples. In this technique, a C18 pipette tip was employed for rapid purification and enrichment of analytes in raw sample solutions. The adsorbed analytes were eluted by solvents supplied by a syringe and a syringe pump, and a high voltage was applied onto the syringe needle to induce electrospray ionization at the pipette tip end for mass spectrometric analysis. This technique is simple, easy to assemble, enables generation of stable and reproducible signals, and can be conveniently used for qualitative and quantitative analysis of raw solution samples. Analysis by the technique only involved simple sample preparation procedures followed by direct mass spectrometric detection, all of which could be completed within minutes, while the analytical performances of the technique, including the limit of detection, limit of quantitation, liner range, accuracy and precision, were comparable to those by conventional methods. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. A Comparison of Tissue Spray and Lipid Extract Direct Injection Electrospray Ionization Mass Spectrometry for the Differentiation of Eutopic and Ectopic Endometrial Tissues

    Science.gov (United States)

    Chagovets, Vitaliy; Wang, Zhihao; Kononikhin, Alexey; Starodubtseva, Natalia; Borisova, Anna; Salimova, Dinara; Popov, Igor; Kozachenko, Andrey; Chingin, Konstantin; Chen, Huanwen; Frankevich, Vladimir; Adamyan, Leila; Sukhikh, Gennady

    2018-02-01

    Recent research revealed that tissue spray mass spectrometry enables rapid molecular profiling of biological tissues, which is of great importance for the search of disease biomarkers as well as for online surgery control. However, the payback for the high speed of analysis in tissue spray analysis is the generally lower chemical sensitivity compared with the traditional approach based on the offline chemical extraction and electrospray ionization mass spectrometry detection. In this study, high resolution mass spectrometry analysis of endometrium tissues of different localizations obtained using direct tissue spray mass spectrometry in positive ion mode is compared with the results of electrospray ionization analysis of lipid extracts. Identified features in both cases belong to three lipid classes: phosphatidylcholines, phosphoethanolamines, and sphingomyelins. Lipids coverage is validated by hydrophilic interaction liquid chromatography with mass spectrometry of lipid extracts. Multivariate analysis of data from both methods reveals satisfactory differentiation of eutopic and ectopic endometrium tissues. Overall, our results indicate that the chemical information provided by tissue spray ionization is sufficient to allow differentiation of endometrial tissues by localization with similar reliability but higher speed than in the traditional approach relying on offline extraction.

  9. A Comparison of Tissue Spray and Lipid Extract Direct Injection Electrospray Ionization Mass Spectrometry for the Differentiation of Eutopic and Ectopic Endometrial Tissues

    Science.gov (United States)

    Chagovets, Vitaliy; Wang, Zhihao; Kononikhin, Alexey; Starodubtseva, Natalia; Borisova, Anna; Salimova, Dinara; Popov, Igor; Kozachenko, Andrey; Chingin, Konstantin; Chen, Huanwen; Frankevich, Vladimir; Adamyan, Leila; Sukhikh, Gennady

    2017-09-01

    Recent research revealed that tissue spray mass spectrometry enables rapid molecular profiling of biological tissues, which is of great importance for the search of disease biomarkers as well as for online surgery control. However, the payback for the high speed of analysis in tissue spray analysis is the generally lower chemical sensitivity compared with the traditional approach based on the offline chemical extraction and electrospray ionization mass spectrometry detection. In this study, high resolution mass spectrometry analysis of endometrium tissues of different localizations obtained using direct tissue spray mass spectrometry in positive ion mode is compared with the results of electrospray ionization analysis of lipid extracts. Identified features in both cases belong to three lipid classes: phosphatidylcholines, phosphoethanolamines, and sphingomyelins. Lipids coverage is validated by hydrophilic interaction liquid chromatography with mass spectrometry of lipid extracts. Multivariate analysis of data from both methods reveals satisfactory differentiation of eutopic and ectopic endometrium tissues. Overall, our results indicate that the chemical information provided by tissue spray ionization is sufficient to allow differentiation of endometrial tissues by localization with similar reliability but higher speed than in the traditional approach relying on offline extraction. [Figure not available: see fulltext.

  10. Detection of trace ink compounds in erased handwritings using electrospray-assisted laser desorption ionization mass spectrometry.

    Science.gov (United States)

    Kao, Yi-Ying; Cheng, Sy-Chyi; Cheng, Chu-Nian; Shiea, Jentaie; Ho, Hsiu-O

    2014-06-01

    Writings made with erasable pens on paper surfaces can either be rubbed off with an eraser or rendered invisible by changing the temperature of the ink. However, trace ink compounds still remain in the paper fibers even after rubbing or rendering. The detection of these ink compounds from erased handwritings will be helpful in knowing the written history of the paper. In this study, electrospray-assisted laser desorption ionization/mass spectrometry was used to characterize trace ink compounds remaining in visible and invisible ink lines. The ink compounds were desorbed from the paper surface by irradiating the handwritings with a pulsed laser beam; the desorbed analytes were subsequently ionized in an electrospray plume and detected by a quadrupole time-of-flight mass spectrometry mass analyzer. Because of the high spatial resolution of the laser beam, electrospray-assisted laser desorption ionization/mass spectrometry analysis resulted in minimal damage to the sample documents. Copyright © 2014 John Wiley & Sons, Ltd.

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  12. Optimization of solid phase extraction clean up and validation of quantitative determination of corticosteroids in urine by liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Andersen, Jens Hinge; Hansen, Lene Gram; Pedersen, Mikael

    2008-01-01

    A solid phase extraction (SPE) method for extraction and clean up of 9 synthetic corticosteroids was optimized for quantification by reversed-phase high-performance liquid chromatography/negative electrospray ionisation mass spectrometry. Clean up was accomplished using a mixed mode polymeric...

  13. Direct Analysis of Proteins from Solutions with High Salt Concentration Using Laser Electrospray Mass Spectrometry

    Science.gov (United States)

    Karki, Santosh; Shi, Fengjian; Archer, Jieutonne J.; Sistani, Habiballah; Levis, Robert J.

    2018-03-01

    The detection of lysozyme, or a mixture of lysozyme, cytochrome c, and myoglobin, from solutions with varying salt concentrations (0.1 to 250 mM NaCl) is compared using laser electrospray mass spectrometry (LEMS) and electrospray ionization-mass spectrometry (ESI-MS). Protonated protein peaks were observed up to a concentration of 250 mM NaCl in the case of LEMS. In the case of ESI-MS, a protein solution with salt concentration > 0.5 mM resulted in predominantly salt-adducted features, with suppression of the protonated protein ions. The constituents in the mixture of proteins were assignable up to 250 mM NaCl for LEMS and were not assignable above a NaCl concentration of 0.5 mM for ESI. The average sodium adducts () bound to the 7+ charge state of lysozyme for LEMS measurements from salt concentrations of 2.5, 25, 50, and 100 mM NaCl are 1.71, 5.23, 5.26, and 5.11, respectively. The conventional electrospray measurements for lysozyme solution containing salt concentrations of 0.1, 1, 2, and 5 mM NaCl resulted in of 2.65, 6.44, 7.57, and 8.48, respectively. LEMS displays an approximately two orders of magnitude higher salt tolerance in comparison with conventional ESI-MS. The non-equilibrium partitioning of proteins on the surface of the charged droplets is proposed as the mechanism for the high salt tolerance phenomena observed in the LEMS measurements. [Figure not available: see fulltext.

  14. Ion fragmentation in an electrospray ionization mass spectrometer interface with different gases.

    Science.gov (United States)

    Schneider, B B; Douglas, D J; Chen, D D

    2001-01-01

    Nitrogen, argon, and krypton are used as curtain gases in an electrospray ionization mass spectrometer in an attempt to study the effect of these gases on the extent of ion fragmentation between the orifice and the skimmer of the interface region. A previously published collision model predicts that the degree of ion fragmentation increases with increasing mass of the curtain gas. However, the fragmentation yields are found to be the opposite to that expected. It is believed that the reversed trend with argon and krypton is caused by condensation of the gases within the free jet expansion between the orifice and the skimmer. A condensation parameter can be used to predict the degree of clustering of gases within a free jet expansion. When the condensation parameter is minimized, the predicted trend of fragmentation with mass is observed. Copyright 2001 John Wiley & Sons, Ltd.

  15. Analysis of monomeric and oligomeric organophosphorus flame retardants in fish muscle tissues using liquid chromatography–electrospray ionization tandem mass spectrometry: Application to Nile tilapia (Oreochromis niloticus) from an e-waste processing area in northern Vietnam

    OpenAIRE

    Matsukami, Hidenori; Suzuki, Go; Tue, Nguyen Minh; Tuyen, Le Huu; Viet, Pham Hung; Takahashi, Shin; Tanabe, Shinsuke; Takigami, Hidetaka

    2016-01-01

    Using electrospray ionization tandem mass spectrometry combined with liquid chromatography (LC), a novel analytical method was developed to quantify eight monomeric organophosphorus flame retardants (m-PFRs) and three oligomeric organophosphorus flame retardants (o-PFRs) in fish muscle samples. The optimization and validation experiments indicate that the developed method can determine accurately the concentrations of analytes in fish muscle samples. The recoveries of analytes in fish muscle ...

  16. Imaging the Unimaginable: Desorption Electrospray Ionization - Imaging Mass Spectrometry (DESI-IMS) in Natural Product Research.

    Science.gov (United States)

    Parrot, Delphine; Papazian, Stefano; Foil, Daniel; Tasdemir, Deniz

    2018-01-31

    Imaging mass spectrometry (IMS) has recently established itself in the field of "spatial metabolomics." Merging the sensitivity and fast screening of high-throughput mass spectrometry with spatial and temporal chemical information, IMS visualizes the production, location, and distribution of metabolites in intact biological models. Since metabolite profiling and morphological features are combined in single images, IMS offers an unmatched chemical detail on complex biological and microbiological systems. Thus, IMS-type "spatial metabolomics" emerges as a powerful and complementary approach to genomics, transcriptomics, and classical metabolomics studies. In this review, we summarize the current state-of-the-art IMS methods with a strong focus on desorption electrospray ionization (DESI)-IMS. DESI-IMS utilizes the original principle of electrospray ionization, but in this case solvent droplets are rastered and desorbed directly on the sample surface. The rapid and minimally destructive DESI-IMS chemical screening is achieved at ambient conditions and enables the accurate view of molecules in tissues at the µm-scale resolution. DESI-IMS analysis does not require complex sample preparation and allows repeated measurements on samples from different biological sources, including microorganisms, plants, and animals. Thanks to its easy workflow and versatility, DESI-IMS has successfully been applied to many different research fields, such as clinical analysis, cancer research, environmental sciences, microbiology, chemical ecology, and drug discovery. Herein we discuss the present applications of DESI-IMS in natural product research. Georg Thieme Verlag KG Stuttgart · New York.

  17. In situ analysis of soybeans and nuts by probe electrospray ionization mass spectrometry.

    Science.gov (United States)

    Petroselli, Gabriela; Mandal, Mridul K; Chen, Lee C; Hiraoka, Kenzo; Nonami, Hiroshi; Erra-Balsells, Rosa

    2015-04-01

    The probe electrospray ionization (PESI) is an ESI-based ionization technique that generates electrospray from the tip of a solid metal needle. In the present work, we describe the PESI mass spectra obtained by in situ measurement of soybeans and several nuts (peanuts, walnuts, cashew nuts, macadamia nuts and almonds) using different solid needles as sampling probes. It was found that PESI-MS is a valuable approach for in situ lipid analysis of these seeds. The phospholipid and triacylglycerol PESI spectra of different nuts and soybean were compared by principal component analysis (PCA). PCA shows significant differences among the data of each family of seeds. Methanolic extracts of nuts and soybean were exposed to air and sunlight for several days. PESI mass spectra were recorded before and after the treatment. Along the aging of the oil (rancidification), the formation of oxidated species with variable number of hydroperoxide groups could be observed in the PESI spectra. The relative intensity of oxidated triacylglycerols signals increased with days of exposition. Monitoring sensitivity of PESI-MS was high. This method provides a fast, simple and sensitive technique for the analysis (detection and characterization) of lipids in seed tissue and degree of oxidation of the oil samples. Copyright © 2015 John Wiley & Sons, Ltd.

  18. Electrolytic electrospray ionization mass spectrometry of quaterthiophene-bridged bisporphyrins: beyond the identification tool.

    Science.gov (United States)

    Rondeau, David; Rogalewicz, Françoise; Ohanessian, Gilles; Levillain, Eric; Odobel, Fabrice; Richomme, Pascal

    2005-05-01

    Several quaterthiophene-bridged bisporphyrins were analyzed by electrospray ionization mass spectrometry (ESI-MS). The active centers of these molecular assemblies are two porphyrins moieties complexed (Z) or not (H) with a metal ion, typically Zn(2+), and the spacer is a quaterthiophene. The two end-groups were chemically linked to the quaterthiophene spacers by (i) a C--C single bond, (ii) a trans double bond or (iii) a triple bond. The formation of charged species either by protonation ([M + H](+) and [M + 2H](2+)) or electron(s) loss (M(+) and M(2+)), account for the occurrence of electrochemical processes in the basic operation of an electrospray source acting in a non-aqueous solvent. The nature of the observed charged species is correlated with the electro-oxidation properties and proton production by electro-oxidation of residual water. The occurence of these electrochemical reaction is proposed when the electroactivity of the electrosprayed substrates is not sufficient to support the current demand of the ESI source. In this way, the results obtained from the analysed series suggest the occurrence of such a process when the interfacial potential of the metal capillary reaches a value of 0.75 V vs Ag/AgCl. The results of theoretical calculations confirm the importance of the ionization energy with regard to the protonation energy in the course of the ionization reaction. The structural differences at the porphyrin-linker junctions lead to significantly smaller ionization energy in the case of the trans double bond. The MS observation of discharged dimers from molecular assemblies, including two complexed porphyrins ZZ or two free bases HH as end-group and a triple bond as the quaterthiophene-bisporphyrin junction, indicates together with molecular modelling (carried out at the semi-empirical PM3 level), that the planar and symmetric structures favour stacking. Copyright 2005 John Wiley & Sons, Ltd.

  19. eCRAM computer algorithm for implementation of the charge ratio analysis method to deconvolute electrospray ionization mass spectra

    Science.gov (United States)

    Maleknia, Simin D.; Green, David C.

    2010-02-01

    A computer program (eCRAM) has been developed for automated processing of electrospray mass spectra based on the charge ratio analysis method. The eCRAM algorithm deconvolutes electrospray mass spectra solely from the ratio of mass-to-charge (m/z) values of multiply charged ions. The program first determines the ion charge by correlating the ratio of m/z values for any two (i.e., consecutive or non-consecutive) multiply charged ions to the unique ratios of two integers. The mass, and subsequently the identity of the charge carrying species, is further determined from m/z values and charge states of any two ions. For the interpretation of high-resolution electrospray mass spectra, eCRAM correlates isotopic peaks that share the same isotopic compositions. This process is also performed through charge ratio analysis after correcting the multiply charged ions to their lowest common ion charge. The application of eCRAM algorithm has been demonstrated with theoretical mass-to-charge ratios for proteins lysozyme and carbonic anhydrase, as well as experimental data for both low and high-resolution FT-ICR electrospray mass spectra of a range of proteins (ubiquitin, cytochrome c, transthyretin, lysozyme and calmodulin). This also included the simulated data for mixtures by combining experimental data for ubiquitin, cytochrome c and transthyretin.

  20. UV Lamp as a Facile Ozone Source for Structural Analysis of Unsaturated Lipids Via Electrospray Ionization-Mass Spectrometry

    Science.gov (United States)

    Stinson, Craig A.; Zhang, Wenpeng; Xia, Yu

    2017-12-01

    Ozonolysis of alkene functional groups is a type of highly specific and effective chemical reaction, which has found increasing applications in structural analysis of unsaturated lipids via coupling with mass spectrometry (MS). In this work, we utilized a low-pressure mercury lamp (6 W) to initiate ozonolysis inside electrospray ionization (ESI) sources. By placing the lamp near a nanoESI emitter that partially transmits 185 nm ultraviolet (UV) emission from the lamp, dissolved dioxygen in the spray solution was converted into ozone, which subsequently cleaved the double bonds within fatty acyls of lipids. Solvent conditions, such as presence of water and acid solution pH, were found to be critical in optimizing ozonolysis yields. Fast (on seconds time scale) and efficient (50%-100% yield) ozonolysis was achieved for model unsaturated phospholipids and fatty acids with UV lamp-induced ozonolysis incorporated on a static and an infusion nanoESI source. The method was able to differentiate double bond location isomers and identify the geometry of the double bond based on yield. The analytical utility of UV lamp-induced ozonolysis was further demonstrated by implementation on a liquid chromatography (LC)-MS platform. Ozonolysis was effected in a flow microreactor that was made from ozone permeable tubing, so that ambient ozone produced by the lamp irradiation could diffuse into the reactor and induce online ozonolysis post-LC separation and before ESI-MS.

  1. UV Lamp as a Facile Ozone Source for Structural Analysis of Unsaturated Lipids Via Electrospray Ionization-Mass Spectrometry

    Science.gov (United States)

    Stinson, Craig A.; Zhang, Wenpeng; Xia, Yu

    2018-03-01

    Ozonolysis of alkene functional groups is a type of highly specific and effective chemical reaction, which has found increasing applications in structural analysis of unsaturated lipids via coupling with mass spectrometry (MS). In this work, we utilized a low-pressure mercury lamp (6 W) to initiate ozonolysis inside electrospray ionization (ESI) sources. By placing the lamp near a nanoESI emitter that partially transmits 185 nm ultraviolet (UV) emission from the lamp, dissolved dioxygen in the spray solution was converted into ozone, which subsequently cleaved the double bonds within fatty acyls of lipids. Solvent conditions, such as presence of water and acid solution pH, were found to be critical in optimizing ozonolysis yields. Fast (on seconds time scale) and efficient (50%-100% yield) ozonolysis was achieved for model unsaturated phospholipids and fatty acids with UV lamp-induced ozonolysis incorporated on a static and an infusion nanoESI source. The method was able to differentiate double bond location isomers and identify the geometry of the double bond based on yield. The analytical utility of UV lamp-induced ozonolysis was further demonstrated by implementation on a liquid chromatography (LC)-MS platform. Ozonolysis was effected in a flow microreactor that was made from ozone permeable tubing, so that ambient ozone produced by the lamp irradiation could diffuse into the reactor and induce online ozonolysis post-LC separation and before ESI-MS.

  2. Liquid chromatography-mass spectrometry for metabolic footprinting of co-cultures of lactic and propionic acid bacteria

    DEFF Research Database (Denmark)

    Honore, Anders H.; Thorsen, Michael; Skov, Thomas

    2013-01-01

    (UPLC) coupled to high-resolution mass spectrometry (MS) via electrospray ionisation (ESI) operated in both positive and negative modes is regarded as the optimum instrumental technique. The applicability of a range of liquid chromatographic techniques ranging from ion-pair (IPC) and hydrophilic...... could be a potent approach to elucidation of the mechanism. The purpose of this review is to discuss the two pre-requisites for such a study-the compound classes expected in the co-cultures, and on the basis of these, the most suitable analytical technique(s). Ultrahigh-performance liquid chromatography...... interaction (HILIC) to reversed-phase chromatography (RPC) is discussed in terms of the expected metabolome. Use of both HILIC and RPC is suggested, on account of the complementarity of these modes. The most promising strategy uses a combination of the two electrospray polarities and two modes of LC...

  3. Microfluidic platform for liquid chromatography-tandem mass spectrometry analyses of complex peptide mixtures.

    Science.gov (United States)

    Xie, Jun; Miao, Yunan; Shih, Jason; Tai, Yu-Chong; Lee, Terry D

    2005-11-01

    A microfluidic chip that integrates all the fluidic components of a gradient liquid chromatography (LC) system is described. These chips were batch-fabricated on a silicon wafer using photolithographic processes and with Parylene as the main structural material. The fabricated chip includes three electrolysis-based electrochemical pumps, one for loading the sample and the other two for delivering the solvent gradient; platinum electrodes for delivering current to the pumps and establishing the electrospray potential; a low-volume static mixer; a column packed with silica-based reversed-phase support; integrated frits for bead capture; and an electrospray nozzle. The fabricated structures were able to withstand pressures in excess of 250 psi. The device was used to perform a liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of a mixture of peptides from the trypsin digestion of bovine serum albumen (BSA). Gradient elution through the 1.2-cm column was performed at a flow rate of 80 nL/min. Compared to the analysis of the same sample using a commercial nanoflow LC system, the chromatographic resolution was nearly as good, and the total cycle time was significantly reduced because of the minimal volume between the pumps and the column. Results demonstrate the potential of mass-produced, low-cost microfluidic systems capable of performing LC separations for proteomics applications.

  4. A Comparison of Alternating Current and Direct Current Electrospray Ionization for Mass Spectrometry

    Science.gov (United States)

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

    2014-04-01

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

  5. Probing uranyl(VI) speciation in the presence of amidoxime ligands using electrospray ionization mass spectrometry.

    Science.gov (United States)

    Mustapha, Adetayo M; Pasilis, Sofie P

    2013-10-15

    Extraction processes using poly(acrylamidoxime) resins are being developed to extract uranium from seawater. The main complexing agents in these resins are thought to be 2,6-dihydroxyiminopiperidine (DHIP) and N(1),N(5)-dihydroxypentanediimidamide (DHPD), which form strong complexes with uranyl(VI) at the pH of seawater. It is important to understand uranyl(VI) speciation in the presence of these and similar amidoxime ligands to understand factors affecting uranyl(VI) adsorption to the poly(acrylamidoxime) resins. Experiments were carried out in positive ion mode on a quadrupole ion trap mass spectrometer equipped with an electrospray ionization source. The ligands investigated were DHIP, DHPD, and N(1),N(2)-dihydroxyethanediimidamide (DHED). DHED and DHPD differ only in the number of carbons separating the oxime groups. The effects on the mass spectra of changes in uranyl(VI):ligand ratio, pH, and ligand type were examined. DHIP binds uranyl(VI) more effectively than DHPD or DHED in the pH range investigated, forming ions derived from solution-phase species with uranyl(VI):DHIP stoichiometries of 1:1, 1:2, and 2:3. The 2:3 uranyl(VI):DHIP complex appears to be a previously undescribed solution species. Ions related to uranyl(VI):DHPD complexes were detected in very low abundance. DHED is a more effective complexing agent for uranyl(VI) than DHPD, forming ions having uranyl(VI):DHED stoichiometries of 1:1, 1:2, 1:3, and 2:3. This study presents a first look at the solution chemistry of uranyl(VI)-amidoxime complexes using electrospray ionization mass spectrometry. The appearance of previously undescribed solution species suggests that the uranyl-amidoxime system is a rich and relatively complex one, requiring a more in-depth investigation. Copyright © 2013 John Wiley & Sons, Ltd.

  6. Analysis of small carbohydrates in several bioactive botanicals by gas chromatography with mass spectrometry and liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Moldoveanu, Serban; Scott, Wayne; Zhu, Jeff

    2015-11-01

    Bioactive botanicals contain natural compounds with specific biological activity, such as antibacterial, antioxidant, immune stimulating, and taste improving. A full characterization of the chemical composition of these botanicals is frequently necessary. A study of small carbohydrates from the plant materials of 18 bioactive botanicals is further described. The study presents the identification of the carbohydrate using a gas chromatographic-mass spectrometric analysis that allows detection of molecules as large as maltotetraose, after changing them into trimethylsilyl derivatives. A number of carbohydrates in the plant (fructose, glucose, mannose, sucrose, maltose, xylose, sorbitol, and myo-, chiro-, and scyllo-inositols) were quantitated using a novel liquid chromatography with tandem mass spectrometric technique. Both techniques involved new method developments. The gas chromatography with mass spectrometric analysis involved derivatization and separation on a Rxi(®)-5Sil MS column with H2 as a carrier gas. The liquid chromatographic separation was obtained using a hydrophilic interaction type column, YMC-PAC Polyamine II. The tandem mass spectrometer used an electrospray ionization source in multiple reaction monitoring positive ion mode with the detection of the adducts of the carbohydrates with Cs(+) ions. The validated quantitative procedure showed excellent precision and accuracy allowing the analysis in a wide range of concentrations of the analytes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Game-theory-based search engine to automate the mass assignment in complex native electrospray mass spectra.

    Science.gov (United States)

    Tseng, Yao-Hsin; Uetrecht, Charlotte; Yang, Shih-Chieh; Barendregt, Arjan; Heck, Albert J R; Peng, Wen-Ping

    2013-12-03

    Electrospray ionization coupled to native mass spectrometry (MS) has evolved into an important tool in structural biology to decipher the composition of protein complexes. However, the mass analysis of heterogeneous protein assemblies is hampered because of their overlapping charge state distributions, fine structure, and peak broadening. To facilitate the mass analysis, it is of importance to automate preprocessing raw mass spectra, assigning ion series to peaks and deciphering the subunit compositions. So far, the automation of preprocessing raw mass spectra has not been accomplished; Massign was introduced to simplify data analysis and decipher the subunit compositions. In this study, we develop a search engine, AutoMass, to automatically assign ion series to peaks without any additional user input, for example, limited ranges of charge states or ion mass. AutoMass includes an ion intensity-dependent method to check for Gaussian distributions of ion series and an ion intensity-independent method to address highly overlapping and non-Gaussian distributions. The minimax theorem from game theory is adopted to define the boundaries. With AutoMass, the boundaries of ion series in the well-resolved tandem mass spectra of the hepatitis B virus (HBV) capsids and those of the mass spectrum from CRISPR-related cascade protein complex are accurately assigned. Theoretical and experimental HBV ion masses are shown in agreement up to ~0.03%. The analysis is finished within a minute on a regular workstation. Moreover, less well-resolved mass spectra, for example, complicated multimer mass spectra and norovirus capsid mass spectra at different levels of desolvation, are analyzed. In sum, this first-ever fully automatic program reveals the boundaries of overlapping ion peak series and can further aid developing high-throughput native MS and top-down proteomics.

  8. A fragmentation study of kaempferol using electrospray quadrupole time-of-flight mass spectrometry at high mass resolution

    Science.gov (United States)

    March, Raymond E.; Miao, Xiu-Sheng

    2004-02-01

    A mass spectrometric method based on the combined use of electrospray ionization, collision-induced dissociation and tandem mass spectrometry at high mass resolution has been applied to an investigation of the structural characterization of protonated and deprotonated kaempferol (3,5,7,4'-tetrahydroxyflavone). Low-energy product ion mass spectra of [M+H]+ ions showed simple fragmentations of the C ring that permitted characterization of the substituents in the A and B rings. In addition, four rearrangement reactions accompanied by losses of C2H2O, CHO[radical sign], CO, and H2O were observed. Low-energy product ion mass spectra of [M-H]- ions showed only four rearrangement reactions accompanied by losses of OH[radical sign], CO, CH2O, and C2H2O. The use of elevated cone voltages permitted observation of product ion mass spectra of selected primary and secondary fragment ions so that each fragment ion reported was observed as a direct product of its immediate precursor ion. Product ion mass spectra examined at high mass resolution allowed unambiguous determination of the elemental composition of fragment ions and resolution of two pairs of isobars. Fragmentation mechanisms and ion structures have been proposed.

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

    Science.gov (United States)

    Flanigan, Paul; Levis, Robert

    2014-06-01

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

  10. 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

  11. Chemical profile of mango (Mangifera indica L.) using electrospray ionisation mass spectrometry (ESI-MS).

    Science.gov (United States)

    Oliveira, Bruno G; Costa, Helber B; Ventura, José A; Kondratyuk, Tamara P; Barroso, Maria E S; Correia, Radigya M; Pimentel, Elisângela F; Pinto, Fernanda E; Endringer, Denise C; Romão, Wanderson

    2016-08-01

    Mangifera indica L., mango fruit, is consumed as a dietary supplement with purported health benefits; it is widely used in the food industry. Herein, the chemical profile of the Ubá mango at four distinct maturation stages was evaluated during the process of growth and maturity using negative-ion mode electrospray ionisation Fourier transform ion cyclotron resonance mass spectrometry (ESI(-)FT-ICR MS) and physicochemical characterisation analysis (total titratable acidity (TA), total soluble solids (TSS), TSS/TA ratio, and total polyphenolic content). Primary (organic acids and sugars) and secondary metabolites (polyphenolic compounds) were mostly identified in the third maturation stage, thus indicating the best stage for harvesting and consuming the fruit. In addition, the potential cancer chemoprevention of the secondary metabolites (phenolic extracts obtained from mango samples) was evaluated using the induction of quinone reductase activity, concluding that fruit polyphenols have the potential for cancer chemoprevention. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Electrospray ionization ion-trap multiple-stage mass spectrometry of Quillaja saponins.

    Science.gov (United States)

    Bankefors, Johan; Broberg, Susanna; Nord, Lars I; Kenne, Lennart

    2011-07-01

    Fifteen identified C-18 fatty acyl-containing saponin structures from Quillaja saponaria Molina have been investigated by electrospray ionization ion-trap multiple-stage mass spectrometry (ESI-IT-MS(n)) in positive ion mode. Their MS(1)-MS(3) spectra were analyzed and ions corresponding to useful fragments, important for the structural identification of Quillaja saponins, were recognized. A few key fragments could describe the structural variations in the C-3 and the C-28 oligosaccharides of the Quillaja saponins. A flowchart involving a stepwise procedure based on key fragments from the MS(1)-MS(3) spectra of these saponins, together with key fragments from these saponins and 13 previously investigated saponins, was constructed for the identification of structural elements in Quillaja saponins. Peak intensity ratios in MS(3) spectra were found to be correlated to structural features of the investigated saponins and is therefore of value for the identification of regioisomers. Copyright © 2011 John Wiley & Sons, Ltd.

  13. Complexation between the fungicide tebuconazole and copper(II) probed by electrospray ionization mass spectrometry.

    Science.gov (United States)

    Dytrtová, Jana Jaklová; Jakl, Michal; Schröder, Detlef; Čadková, Eva; Komárek, Michael

    2011-04-30

    Electrospray ionization mass spectrometry (ESI-MS) is used to probe the complex formation between tebuconazole (1) and copper(II) salts, which both are commonly used fungicides in agriculture. Experiments with model solutions containing 1 and CuCl(2) reveal the initial formation of the copper(II) species [(1)CuCl](+) and [(1)(2)CuCl](+) which undergo reduction to the corresponding copper(I) ions [(1)Cu](+) and [(1)(2)Cu](+) under more drastic ionization conditions in the ESI source. In additional experiments, copper/tebuconazole complexes were also detected in samples made from soil solutions of various origin and different amount of mineralization. The direct sampling of such solutions via ESI-MS is thus potentially useful for understanding of the interactions between copper(II) salts and tebuconazole in environmental samples. Copyright © 2011 John Wiley & Sons, Ltd.

  14. Simultaneous identification of historical pigments Prussian blue and indigo in paintings by electrospray mass spectrometry.

    Science.gov (United States)

    Pauk, Volodymyr; Havlíček, Vladimír; Papoušková, Barbora; Sulovský, Petr; Lemr, Karel

    2013-08-01

    A new analytical protocol for identification of Prussian blue (PB) and indigo was proposed. Pigments useful for dating of artworks were detected by flow injection analysis/electrospray ionization mass spectrometry after alkalization of their suspensions in water, decomposition of PB to iron (III) hydroxide and hexacyanoferrate (II) and reduction of indigo to soluble leucoindigo using sodium dithionite. Limits of detection (PB 47 pg, indigo 59 pg) complied with requirements for analysis of microsamples of historical paintings. Potential of the developed method was proven in analysis of blue samples of two oil paintings from the 20(th) century. Further, PB was confirmed in a microsample from a painting of 'Crucifixion', St. Sebestian church on St. Hill in Mikulov, Czech Republic. Copyright © 2013 John Wiley & Sons, Ltd.

  15. Feasibility of desorption atmospheric pressure photoionization and desorption electrospray ionization mass spectrometry to monitor urinary steroid metabolites during pregnancy

    Czech Academy of Sciences Publication Activity Database

    Vaikkinen, A.; Rejšek, Jan; Vrkoslav, Vladimír; Kauppila, T. J.; Cvačka, Josef; Kostiainen, R.

    2015-01-01

    Roč. 880, Jun 23 (2015), s. 84-92 ISSN 0003-2670 Grant - others:GA AV ČR(CZ) M200551204 Institutional support: RVO:61388963 Keywords : desorption electrospray ionization * desorption atmospheric pressure * photoionization * mass spectrometry * pregnancy Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.712, year: 2015

  16. Electrospray mass spectrometry characterization of post-translational modifications of barley alpha-amylase 1 produced in yeast

    DEFF Research Database (Denmark)

    Søgaard, M; Andersen, Jens S.; Roepstorff, P

    1993-01-01

    We have used electrospray mass spectrometry (ESMS) in combination with protein chemistry and genetics to delineate post-translational modifications in yeast of barley alpha-amylase 1 (AMY1), a 45 kD enzyme crucial for production of malt, an important starting material in the manufacture of beer...

  17. Negative electrospray, ion trap multistage mass spectrometry of synthetic fragments of the O-PS of Vibrio cholerae O : 1

    Czech Academy of Sciences Publication Activity Database

    Bekešová, S.; Kováčik, V.; Chmelík, Josef; Kováč, P.

    2006-01-01

    Roč. 12, č. 1 (2006), s. 43-49 ISSN 1469-0667 Institutional research plan: CEZ:AV0Z40310501 Keywords : electrospray ionization * negative multistage ion trap mass spectra * synthetic fragments of the lipopolysaccharide of Vibrio cholerae Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.438, year: 2006

  18. Desorption electrospray ionisation mass spectrometry: A rapid screening tool for veterinary drug preparations and forensic samples from hormone crime investigations

    NARCIS (Netherlands)

    Nielen, M.W.F.; Hooijerink, H.; Claassen, F.C.; Engelen, M.C.; Beek, van T.A.

    2009-01-01

    Hormone and veterinary drug screening and forensics can benefit from the recent developments in desorption electrospray ionisation (DESI) mass spectrometry (MS). In this work the feasibility of DESI application has been studied. Using a linear ion trap or quadrupole time-of-flight (TOF) MS

  19. Liquid Chromatography-Mass Spectrometry Interface for Detection of Extraterrestrial Organics

    Science.gov (United States)

    Southard, Adrian E.; Getty, Stephanie A.; Balvin, Manuel; Cook, Jamie E.; Espiritu, Ana Mellina; Kotecki, Carl; Towner, Deborah W.; Dworkin, J. P.; Glavin, Daniel P.; Mahaffy, Paul R.; hide

    2014-01-01

    The OASIS (Organics Analyzer for Sampling Icy surfaces) microchip enables electrospray or thermospray of analyte for subsequent analysis by the OASIS time-of-flight mass spectrometer. Electrospray of buffer solution containing the nucleobase adenine was performed using the microchip and detected by a commercial time-of-flight mass spectrometer. Future testing of thermospray and electrospray capability will be performed using a test fixture and vacuum chamber developed especially for optimization of ion spray at atmosphere and in low pressure environments.

  20. Electrospray tandem mass spectrometry of a novel series of amphipathic functionalized ether-linked di- and trisaccharides and cyclic oligosaccharides.

    Science.gov (United States)

    Banoub, J; Thibault, P; Gouéth, P Y; Ronco, G; Villa, P

    1997-01-01

    Electrospray mass spectrometry (ESMS) has aided the structural characterization of a novel series of amphipathic functionalized ether-linked di- and trisaccharides, composed of units of alkyl derivatives of glucofuranose and either units of glucofuranose or diacetylgalactose. The structural elucidation of a novel eight-membered macrocyclic ether-linked disaccharide and an 11-membered macrocyclic ether-linked trisaccharide was also effected using ESMS. Low-energy collision-induced dissociation MS/MS analysis of the [M + H]+ precursor ions confirmed the characteristic fingerprint patterns obtained in the conventional electrospray spectra and proved to be a specific and very sensitive method for the detection and characterization of these novel amphipathic molecules.

  1. Power of Ultra Performance Liquid Chromatography/Electrospray Ionization-MS Reconstructed Ion Chromatograms in the Characterization of Small Differences in Polymer Microstructure.

    Science.gov (United States)

    Epping, Ruben; Panne, Ulrich; Falkenhagen, Jana

    2018-03-06

    From simple homopolymers to functionalized, 3-dimensional structured copolymers, the complexity of polymeric materials has become more and more sophisticated. With new applications, for instance, in the semiconductor or pharmaceutical industry, the requirements for the characterization have risen with the complexity of the used polymers. For each additional distribution, an additional dimension in analysis is needed. Small, often isomeric heterogeneities in topology or microstructure can usually not be simply separated chromatographically or distinguished by any common detector but affect the properties of materials significantly. For a drug delivery system, for example, the degree of branching and branching distribution is crucial for the formation of micelles. Instead of a complicated, time-consuming, and/or expensive 2D-chromatography or ion mobility spectrometry (IMS) method, that also has its limitations, in this work, a simple approach using size exclusion chromatography (SEC) coupled with electrospray ionization (ESI) mass spectrometry is proposed. The online coupling allows the analysis of reconstructed ion chromatograms (RICs) of each degree of polymerization. While a complete separation often cannot be achieved, the derived retention times and peak widths lead to information on the existence and dispersity of heterogeneities. Although some microstructural heterogeneities like short chain branching can for large polymers be characterized with methods such as light scattering, for oligomers where the heterogeneities just start to form and their influence is at the maximum, they are inaccessible with these methods. It is also shown that with a proper calibration even quantitative information can be obtained. This method is suitable to detect small differences in, e.g., branching, 3D-structure, monomer sequence, or tacticity and could potentially be used in routine analysis to quickly determine deviations.

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

    Science.gov (United States)

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

    2010-01-01

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

  3. Detection of diethyl phthalate in perfumes by extractive electrospray ionization mass spectrometry.

    Science.gov (United States)

    Chingin, Konstantin; Chen, Huanwen; Gamez, Gerardo; Zhu, Liang; Zenobi, Renato

    2009-01-01

    Recent findings suggest that long-term exposure to diethyl phthalate (DEP), one of the widely used phthalate esters, can lead to serious health problems. Most perfumes contain non-negligible amounts of DEP. Rapid and sensitive detection of DEP in perfumes is thus of increasing importance. A novel procedure based on extractive electrospray ionization mass spectrometry (EESI-MS) has been developed for fast detection and identification of DEP in perfumes without the need for any sample pretreatment. The limit of determination for DEP in perfume was less than 100 ppb using tandem mass spectrometry on a commercial quadrupole time-of-flight mass spectrometer. The dynamic range of this method was about 4 orders of magnitude. A single sample analysis was completed within a few seconds, providing a rapid way to obtain semiquantitative information on the DEP content in perfumes. This study shows that both volatile and nonvolatile analytes (e.g., amino acids) in liquids can be directly sampled by neutral desorption, providing a convenient way for high-throughput screening of target compounds using EESI-MS.

  4. Electrospray mass spectrometry for characterization of lipid A from Enterobacter agglomerans.

    Science.gov (United States)

    Harrata, A K; Domelsmith, L N; Cole, R B

    1993-01-01

    Negative ion and positive ion electrospray mass spectrometry have been employed to characterize the lipid A mixture produced by hydrolysis of lipopolysaccharides from Enterobacter agglomerans, a Gram-negative bacterium commonly found in field cotton. Neutral monophosphoryl lipid A molecules form stable anions via deprotonation, but adduct formation via cation attachment occurs in low yield. Dephosphorylated lipid A molecules, on the other hand, readily form adducts with Na+, whereas deprotonation occurs in low yield. The mass spectra of lipid A produced by E. agglomerans reveal the presence of lipid A ions which differ in the nature of attached fatty acid side chains. At least two heptaacyl forms of lipid A are present, one of which has a structure which appears to be the same as the structure of heptaacyl lipid A produced by Salmonella minnesota. The second structure differs only by the nature of the side chain at position 3' of the disaccharide backbone where a hydroxymyristoyloxymyristoyl group replaces the myristoyloxymyristoyl substituent. Collisionally activated dissociations prior to mass analysis enable the identification of fragment ions which can be distinguished from at least eight intact deprotonated molecules present in crude lipid A.

  5. Characterization of N,N-dimethyl amino acids by electrospray ionization-tandem mass spectrometry.

    Science.gov (United States)

    Naresh Chary, V; Sudarshana Reddy, B; Kumar, Ch Dinesh; Srinivas, R; Prabhakar, S

    2015-05-01

    Methylation is an essential metabolic process for a number of critical reactions in the body. Methyl groups are involved in the healthy function of the body life processes, by conducting methylation process involving specific enzymes. In these processes, various amino acids are methylated, and the occurrence of methylated amino acids in nature is diverse. Nowadays, mass-spectrometric-based identification of small molecules as biomarkers for diseases is a growing research. Although all dimethyl amino acids are metabolically important molecules, mass spectral data are available only for a few of them in the literature. In this study, we report synthesis and characterization of all dimethyl amino acids, by electrospray ionization-tandem mass spectrometry (MS/MS) experiments on protonated molecules. The MS/MS spectra of all the studied dimethyl amino acids showed preliminary loss of H2O + CO to form corresponding immonium ions. The other product ions in the spectra are highly characteristic of the methyl groups on the nitrogen and side chain of the amino acids. The amino acids, which are isomeric and isobaric with the studied dimethyl amino acids, gave distinctive MS/MS spectra. The study also included MS/MS analysis of immonium ions of dimethyl amino acids that provide information on side chain structure, and it is further tested to determine the N-terminal amino acid of the peptides. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Automated mass correction and data interpretation for protein open-access liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Wagner, Craig D; Hall, John T; White, Wendy L; Miller, Luke A D; Williams, Jon D

    2007-02-01

    Characterization of recombinant protein purification fractions and final products by liquid chromatography-mass spectrometry (LC/MS) are requested more frequently each year. A protein open-access (OA) LC/MS system was developed in our laboratory to meet this demand. This paper compares the system that we originally implemented in our facilities in 2003 to the one now in use, and discusses, in more detail, recent enhancements that have improved its robustness, reliability, and data reporting capabilities. The system utilizes instruments equipped with reversed-phase chromatography and an orthogonal accelerated time-of-flight mass spectrometer fitted with an electrospray source. Sample analysis requests are accomplished using a simple form on a web-enabled laboratory information management system (LIMS). This distributed form is accessible from any intranet-connected company desktop computer. Automated data acquisition and processing are performed using a combination of in-house (OA-Self Service, OA-Monitor, and OA-Analysis Engine) and vendor-supplied programs (AutoLynx, and OpenLynx) located on acquisition computers and off-line processing workstations. Analysis results are then reported via the same web-based LIMS. Also presented are solutions to problems not addressed on commercially available, small-molecule OA-LC/MS systems. These include automated transforming of mass-to-charge (m/z) spectra to mass spectra and automated data interpretation that considers minor variants to the protein sequence-such as common post-translational modifications (PTMs). Currently, our protein OA-LC/MS platform runs on five LC/MS instruments located in three separate GlaxoSmithKline R&D sites in the US and UK. To date, more than 8000 protein OA-LC/MS samples have been analyzed. With these user friendly and highly automated OA systems in place, mass spectrometry plays a key role in assessing the quality of recombinant proteins, either produced at our facilities or bought from external

  7. A sensitive estimation of residual ethylene glycol in ethylene oxide sterilized medical devices by HPLC with electrospray ionization mass spectrometric detection.

    Science.gov (United States)

    Hari, P R; Naseerali, C P; Sreenivasan, K

    2009-01-15

    A novel analytical methodology for the estimation of residual ethylene glycol (EG) in ethylene oxide sterilized polymer is reported. The method involves the monitoring of ammonium adduct of EG ions in the presence of 10 mM ammonium acetate buffer and methanol using electrospray ionization liquid chromatography and mass spectrometry (LC-ESI-MS). The method enables the detection and quantification of EG without prior derivatization up to a level of 0.06 microg/ml. The potentiality of the method is demonstrated by estimating EG in ethylene oxide (EtO) sterilized polyethylene terephthalate fabric used in heart valve sewing ring. The method is simple, rapid and can routinely be used for the quantification of residual EG in EtO sterilized medical devices.

  8. Quantitative detection of nitric oxide in exhaled human breath by extractive electrospray ionization mass spectrometry

    Science.gov (United States)

    Pan, Susu; Tian, Yong; Li, Ming; Zhao, Jiuyan; Zhu, Lanlan; Zhang, Wei; Gu, Haiwei; Wang, Haidong; Shi, Jianbo; Fang, Xiang; Li, Penghui; Chen, Huanwen

    2015-03-01

    Exhaled nitric oxide (eNO) is a useful biomarker of various physiological conditions, including asthma and other pulmonary diseases. Herein a fast and sensitive analytical method has been developed for the quantitative detection of eNO based on extractive electrospray ionization mass spectrometry (EESI-MS). Exhaled NO molecules selectively reacted with 2-phenyl-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) reagent, and eNO concentration was derived based on the EESI-MS response of 1-oxyl-2-phenyl-4, 4, 5, 5-tetramethylimidazoline (PTI) product. The method allowed quantification of eNO below ppb level (~0.02 ppbv) with a relative standard deviation (RSD) of 11.6%. In addition, eNO levels of 20 volunteers were monitored by EESI-MS over the time period of 10 hrs. Long-term eNO response to smoking a cigarette was recorded, and the observed time-dependent profile was discussed. This work extends the application of EESI-MS to small molecules (mass spectrometers. Long-term quantitative profiling of eNO by EESI-MS opens new possibilities for the research of human metabolism and clinical diagnosis.

  9. Flame Atmospheric Pressure Chemical Ionization Coupled with Negative Electrospray Ionization Mass Spectrometry for Ion Molecule Reactions

    Science.gov (United States)

    Cheng, Sy-Chyi; Bhat, Suhail Muzaffar; Shiea, Jentaie

    2017-07-01

    Flame atmospheric pressure chemical ionization (FAPCI) combined with negative electrospray ionization (ESI) mass spectrometry was developed to detect the ion/molecule reactions (IMRs) products between nitric acid (HNO3) and negatively charged amino acid, angiotensin I (AI) and angiotensin II (AII), and insulin ions. Nitrate and HNO3-nitrate ions were detected in the oxyacetylene flame, suggesting that a large quantity of nitric acid (HNO3) was produced in the flame. The HNO3 and negatively charged analyte ions produced by a negative ESI source were delivered into each arm of a Y-shaped stainless steel tube where they merged and reacted. The products were subsequently characterized with an ion trap mass analyzer attached to the exit of the Y-tube. HNO3 showed the strongest affinity to histidine and formed (Mhistidine-H+HNO3)- complex ions, whereas some amino acids did not react with HNO3 at all. Reactions between HNO3 and histidine residues in AI and AII resulted in the formation of dominant [MAI-H+(HNO3)]- and [MAII-H+(HNO3)]- ions. Results from analyses of AAs and insulin indicated that HNO3 could not only react with basic amino acid residues, but also with disulfide bonds to form [M-3H+(HNO3)n]3- complex ions. This approach is useful for obtaining information about the number of basic amino acid residues and disulfide bonds in peptides and proteins.

  10. An Automated Platform for High-Resolution Tissue Imaging Using Nanospray Desorption Electrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lanekoff, Ingela T.; Heath, Brandi S.; Liyu, Andrey V.; Thomas, Mathew; Carson, James P.; Laskin, Julia

    2012-10-02

    An automated platform has been developed for acquisition and visualization of mass spectrometry imaging (MSI) data using nanospray desorption electrospray ionization (nano-DESI). The new system enables robust operation of the nano-DESI imaging source over many hours. This is achieved by controlling the distance between the sample and the probe by mounting the sample holder onto an automated XYZ stage and defining the tilt of the sample plane. This approach is useful for imaging of relatively flat samples such as thin tissue sections. Custom software called MSI QuickView was developed for visualization of large data sets generated in imaging experiments. MSI QuickView enables fast visualization of the imaging data during data acquisition and detailed processing after the entire image is acquired. The performance of the system is demonstrated by imaging rat brain tissue sections. High resolution mass analysis combined with MS/MS experiments enabled identification of lipids and metabolites in the tissue section. In addition, high dynamic range and sensitivity of the technique allowed us to generate ion images of low-abundance isobaric lipids. High-spatial resolution image acquired over a small region of the tissue section revealed the spatial distribution of an abundant brain metabolite, creatine, in the white and gray matter that is consistent with the literature data obtained using magnetic resonance spectroscopy.

  11. Confirmation of the structure of lipid A from Enterobacter agglomerans by electrospray ionization tandem mass spectrometry

    Science.gov (United States)

    Boue; Cole

    2000-03-01

    Electrospray ionization (ESI) combined with tandem mass spectrometry (MS/MS) was utilized for the structural confirmation of lipid A derived from Enterobacter agglomerans, a Gram-negative bacterium commonly found in field cotton. Previous ESI-MS studies conducted in our laboratory found that similarities exist between the fatty acid side-chains in the lipid A of E. agglomerans and that of Salmonella minnesota. It was noted that heterogeneity at the fatty acyl chain at position 3' of the diglucosamine backbone of E. agglomerans can take the form of either a myristyloxymyristyl group or, less commonly, a hydroxymyristyloxymyristyl moiety. In this work, tandem mass spectra obtained from heptaacyl and hexaacyl lipid A precursors derived from E. agglomerans and a known standard S. minnesota were compared to assist in structural elucidation. These ESI-MS/MS experiments confirmed the previously reported structure for lipid A derived from E. agglomerans. Moreover, MS/MS data indicated that the additional hydroxyl group of the 3'-position hydroxymyristyloxymyristyl moiety is present as the alpha-isomer.

  12. Ammonium Bicarbonate Addition Improves the Detection of Proteins by Desorption Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Honarvar, Elahe; Venter, Andre R.

    2017-06-01

    The analysis of protein by desorption electrospray ionization mass spectrometry (DESI-MS) is considered impractical due to a mass-dependent loss in sensitivity with increase in protein molecular weights. With the addition of ammonium bicarbonate to the DESI-MS analysis the sensitivity towards proteins by DESI was improved. The signal to noise ratio (S/N) improvement for a variety of proteins increased between 2- to 3-fold relative to solvent systems containing formic acid and more than seven times relative to aqueous methanol spray solvents. Three methods for ammonium bicarbonate addition during DESI-MS were investigated. The additive delivered improvements in S/N whether it was mixed with the analyte prior to sample deposition, applied over pre-prepared samples, or simply added to the desorption spray solvent. The improvement correlated well with protein pI but not with protein size. Other ammonium or bicarbonate salts did not produce similar improvements in S/N, nor was this improvement in S/N observed for ESI of the same samples. As was previously described for ESI, DESI also caused extensive protein unfolding upon the addition of ammonium bicarbonate. [Figure not available: see fulltext.

  13. Flame Atmospheric Pressure Chemical Ionization Coupled with Negative Electrospray Ionization Mass Spectrometry for Ion Molecule Reactions.

    Science.gov (United States)

    Cheng, Sy-Chyi; Bhat, Suhail Muzaffar; Shiea, Jentaie

    2017-07-01

    Flame atmospheric pressure chemical ionization (FAPCI) combined with negative electrospray ionization (ESI) mass spectrometry was developed to detect the ion/molecule reactions (IMRs) products between nitric acid (HNO 3 ) and negatively charged amino acid, angiotensin I (AI) and angiotensin II (AII), and insulin ions. Nitrate and HNO 3 -nitrate ions were detected in the oxyacetylene flame, suggesting that a large quantity of nitric acid (HNO 3 ) was produced in the flame. The HNO 3 and negatively charged analyte ions produced by a negative ESI source were delivered into each arm of a Y-shaped stainless steel tube where they merged and reacted. The products were subsequently characterized with an ion trap mass analyzer attached to the exit of the Y-tube. HNO 3 showed the strongest affinity to histidine and formed (M histidine -H+HNO 3 ) - complex ions, whereas some amino acids did not react with HNO 3 at all. Reactions between HNO 3 and histidine residues in AI and AII resulted in the formation of dominant [M AI -H+(HNO 3 )] - and [M AII -H+(HNO 3 )] - ions. Results from analyses of AAs and insulin indicated that HNO 3 could not only react with basic amino acid residues, but also with disulfide bonds to form [M-3H+(HNO 3 ) n ] 3- complex ions. This approach is useful for obtaining information about the number of basic amino acid residues and disulfide bonds in peptides and proteins. Graphical Abstract ᅟ.

  14. Effect of Nanoemitters on Suppressing the Formation of Metal Adduct Ions in Electrospray Ionization Mass Spectrometry.

    Science.gov (United States)

    Hu, Jun; Guan, Qi-Yuan; Wang, Jiang; Jiang, Xiao-Xiao; Wu, Zeng-Qiang; Xia, Xing-Hua; Xu, Jing-Juan; Chen, Hong-Yuan

    2017-02-07

    In the work, we showed that the use of nanoemitters (tip dimension metal adduction to peptide or protein ions as well as improve the matrix tolerance of electrospray ionization mass spectrometry (ESI-MS). The proton-enriched smaller initial droplets are supposed to have played a significant role in suppressing the formation of metal adduct ions in nanoemitters. The proton-enrichment effect in the nanoemitters is related to both the exclusion-enrichment effect (EEE) and the ion concentration polarization effect (ICP effect), which permit the molecular ions to be regulated to protonated ones. Smaller initial charged droplets generated from nanoemitters need less fission steps to release the gas-phase ions; thus, the enrichment effect of salt was not as significant as that of microemitters (tip dimension >1 μm), resulting in the disappearing of salt cluster peaks in high mass-to-charge (m/z) region. The use of nanoemitters demonstrates a novel method for tuning the distribution of the metal-adducted ions to be in a controlled manner. This method is also characterized by ease of use and high efficiency in eliminating the formation of adduct ions, and no pretreatment such as desalting is needed even in the presence of salt at millimole concentration.

  15. Electrospray ionization FT-ICR mass spectrometry of ARN naphthenic acids in crudes : preconcentration and quantification

    Energy Technology Data Exchange (ETDEWEB)

    Mapolelo, M.M.; Rodgers, R.P.; Marshall, A.G. [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry and Biochemistry; Florida State Univ., Tallahassee, FL (United States). Cyclotron Resonance Program, National High Magnetic Field Laboratory

    2008-07-01

    The deposition of naphthenate solids and formation of sodium soaps in oil production equipment are known to create flow assurance problems for oilfield operators. Calcium naphthenate formation depends largely on tetraprotic naphthenic acids known as ARN acids in crude oil, whereas sodium naphthenates originate from less substituted lower molecular weight naphthenic acids. This study attempted to preconcentrate and quantify ARN-type acids in whole crude oils. Fourier transform ion cyclotron resonance (FT-ICR) mass spectroscopy (MS) provided detailed acidic speciation for all crudes and deposits analyzed. The preconcentration step involved bubbling ammonia into toluene-diluted crudes known to have ARN-type acids. ARN acids from the crystals increased from undetectable in the parent crude, to the most abundant acid species in the extract mass spectrum. A pure ARN acid standard was prepared for quantitation from successive cleaning and acid digestion of a naphthenate deposit. Analysis of the standard by negative-ion electrospray ionization (ESI) FT-ICR MS showed only ARN acid species. The paper described how API gravity, solvent systems and the paraffinic versus aromatic composition in the crude oil can influence crystal formation. Correlation of FT-ICR MS data of the respective crudes known to contain ARN acids naturally and crudes spiked with ARN acid standard were discussed and the significance of the preconcentration step was highlighted as a method to enhance the detection of ARN acids in crudes.

  16. Surfactant effects on protein structure examined by electrospray ionization mass spectrometry.

    Science.gov (United States)

    Loo, R. R.; Dales, N.; Andrews, P. C.

    1994-01-01

    Electrospray ionization mass spectrometry (ESI-MS) has proven to be a useful tool for examining noncovalent complexes between proteins and a variety of ligands. It has also been used to distinguish between denatured and refolded forms of proteins. Surfactants are frequently employed to enhance solubilization or to modify the tertiary or quaternary structure of proteins, but are usually considered incompatible with mass spectrometry. A broad range of ionic, nonionic, and zwitterionic surfactants was examined to characterize their effects on ESI-MS and on protein structure under ESI-MS conditions. Solution conditions studied include 4% acetic acid/50% acetonitrile/46% H2O and 100% aqueous. Of the surfactants examined, the nonionic saccharides, such as n-dodecyl-beta-D-glucopyranoside, at 0.1% to 0.01% (w/v) concentrations, performed best, with limited interference from chemical background and adduct formation. Under the experimental conditions used, ESI-MS performance in the presence of surfactants was found to be unrelated to critical micelle concentration. It is demonstrated that surfactants can affect both the tertiary and quaternary structures of proteins under conditions used for ESI-MS. However, several of the surfactants caused significant shifts in the charge-state distributions, which appeared to be independent of conformational effects. These observations suggest that surfactants, used in conjunction with ESI-MS, can be useful for protein structure studies, if care is used in the interpretation of the results. PMID:7703844

  17. Online molecular characterisation of organic aerosols in an atmospheric chamber using extractive electrospray ionisation mass spectrometry

    Science.gov (United States)

    Gallimore, Peter J.; Giorio, Chiara; Mahon, Brendan M.; Kalberer, Markus

    2017-12-01

    The oxidation of biogenic volatile organic compounds (VOCs) represents a substantial source of secondary organic aerosol (SOA) in the atmosphere. In this study, we present online measurements of the molecular constituents formed in the gas and aerosol phases during α-pinene oxidation in the Cambridge Atmospheric Simulation Chamber (CASC). We focus on characterising the performance of extractive electrospray ionisation (EESI) mass spectrometry (MS) for particle analysis. A number of new aspects of EESI-MS performance are considered here. We show that relative quantification of organic analytes can be achieved in mixed organic-inorganic particles. A comprehensive assignment of mass spectra for α-pinene derived SOA in both positive and negative ion modes is obtained using an ultra-high-resolution mass spectrometer. We compare these online spectra to conventional offline ESI-MS spectra and find good agreement in terms of the compounds identified, without the need for complex sample work-up procedures. Under our experimental conditions, EESI-MS signals arise only from particle-phase analytes. High-time-resolution (7 min) EESI-MS spectra are compared with simulations from the near-explicit Master Chemical Mechanism (MCM) for a range of reaction conditions. We show that MS peak abundances scale with modelled concentrations for condensable products (pinonic acid, pinic acid, OH-pinonic acid). Relative quantification is achieved throughout SOA formation as the composition, size and mass (5-2400 µg m-3) of particles is evolving. This work provides a robust demonstration of the advantages of EESI-MS for chamber studies over offline ESI-MS (time resolution, relative quantification) and over hard online techniques (molecular information).

  18. Quantifying Protein-Carbohydrate Interactions Using Liquid Sample Desorption Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Yao, Yuyu; Shams-Ud-Doha, Km; Daneshfar, Rambod; Kitova, Elena N.; Klassen, John S.

    2015-01-01

    The application of liquid sample desorption electrospray ionization mass spectrometry (liquid sample DESI-MS) for quantifying protein-carbohydrate interactions in vitro is described. Association constants for the interactions between lysozyme and β-D-GlcNAc-(1 → 4)-β-D-GlcNAc-(1 → 4)-D-GlcNAc and β-D-GlcNAc-(1 → 4)-β-D-GlcNAc-(1 → 4)-β-D-GlcNAc-(1 → 4)-D-GlcNAc, and between a single chain antibody and α-D-Galp-(1 → 2)-[α-D-Abep-(1 → 3)]-α-D-Manp-OCH3 and β-D-Glcp-(1 → 2)-[α-D-Abep-(1 → 3)]-α-D-Manp-OCH3 measured using liquid sample DESI-MS were found to be in good agreement with values measured by isothermal titration calorimetry and the direct ESI-MS assay. The reference protein method, which was originally developed to correct ESI mass spectra for the occurrence of nonspecific ligand-protein binding, was shown to reliably correct liquid sample DESI mass spectra for nonspecific binding. The suitability of liquid sample DESI-MS for quantitative binding measurements carried out using solutions containing high concentrations of the nonvolatile biological buffer phosphate buffered saline (PBS) was also explored. Binding of lysozyme to β-D-GlcNAc-(1 → 4)-β-D-GlcNAc-(1 → 4)-D-GlcNAc in aqueous solutions containing up to 1× PBS was successfully monitored using liquid sample DESI-MS; with ESI-MS the binding measurements were limited to concentrations less than 0.02 X PBS.

  19. Characterization of the Cathode Electrolyte Interface in Lithium Ion Batteries by Desorption Electrospray Ionization Mass Spectrometry.

    Science.gov (United States)

    Liu, Yao-Min; G Nicolau, Bruno; Esbenshade, Jennifer L; Gewirth, Andrew A

    2016-07-19

    The solid electrolyte interface (SEI) formed via electrolyte decomposition on the anode of lithium ion batteries is largely responsible for the stable cycling of conventional lithium ion batteries. Similarly, there is a lesser-known analogous layer on the cathode side of a lithium ion battery, termed the cathode electrolyte interface (CEI), whose composition and role are debated. To confirm the existence and composition of the CEI, desorption electrospray ionization mass spectrometry (DESI-MS) is applied to study common lithium ion battery cathodes. We observe CEI formation on the LiMn2O4 cathode material after cycling between 3.5 and 4.5 V vs Li/Li(+) in electrolyte solution containing 1 M LiPF6 or LiClO4 in 1:1 (v/v) ethylene carbonate (EC) and dimethyl carbonate (DMC). Intact poly(ethylene glycol) dimethyl ether is identified as the electrolyte degradation product on the cathode surface by the high mass-resolution Orbitrap mass spectrometer. When EC is paired with ethyl methyl carbonate (EMC), poly(ethylene glycol) dimethyl ether, poly(ethylene glycol) ethyl methyl ether, and poly(ethylene glycol) are found on the surface simultaneously. The presence of ethoxy and methoxy end groups indicates both methoxide and ethoxide are produced and involved in the process of oligomerization. Au surfaces cycled under different electrochemical windows as model systems for Li-ion battery anodes are also examined. Interestingly, the identical oligomeric species to those found in the CEI are found on Au surfaces after running five cycles between 2.0 and 0.1 V vs Li/Li(+) in half-cells. These results show that DESI-MS provides intact molecular information on battery electrodes, enabling deeper understanding of the SEI or CEI composition.

  20. Microbial metabolomics with gas chromatography/mass spectrometry

    NARCIS (Netherlands)

    Koek, M.M.; Muilwijk, B.; Werf, M.J. van der; Hankemeier, T.

    2006-01-01

    An analytical method was set up suitable for the analysis of microbial metabolomes, consisting of an oximation and silylation derivatization reaction and subsequent analysis by gas chromatography coupled to mass spectrometry. Microbial matrixes contain many compounds that potentially interfere with

  1. Imprint Desorption Electrospray Ionization Mass Spectrometry Imaging for Monitoring Secondary Metabolites Production during Antagonistic Interaction of Fungi.

    Science.gov (United States)

    Tata, Alessandra; Perez, Consuelo; Campos, Michel L; Bayfield, Mark A; Eberlin, Marcos N; Ifa, Demian R

    2015-12-15

    Direct analysis of microbial cocultures grown on agar media by desorption electrospray ionization mass spectrometry (DESI-MS) is quite challenging. Due to the high gas pressure upon impact with the surface, the desorption mechanism does not allow direct imaging of soft or irregular surfaces. The divots in the agar, created by the high-pressure gas and spray, dramatically change the geometry of the system decreasing the intensity of the signal. In order to overcome this limitation, an imprinting step, in which the chemicals are initially transferred to flat hard surfaces, was coupled to DESI-MS and applied for the first time to fungal cocultures. Note that fungal cocultures are often disadvantageous in direct imaging mass spectrometry. Agar plates of fungi present a complex topography due to the simultaneous presence of dynamic mycelia and spores. One of the most devastating diseases of cocoa trees is caused by fungal phytopathogen Moniliophthora roreri. Strategies for pest management include the application of endophytic fungi, such as Trichoderma harzianum, that act as biocontrol agents by antagonizing M. roreri. However, the complex chemical communication underlying the basis for this phytopathogen-dependent biocontrol is still unknown. In this study, we investigated the metabolic exchange that takes place during the antagonistic interaction between M. roreri and T. harzianum. Using imprint-DESI-MS imaging we annotated the secondary metabolites released when T. harzianum and M. roreri were cultured in isolation and compared these to those produced after 3 weeks of coculture. We identified and localized four phytopathogen-dependent secondary metabolites, including T39 butenolide, harzianolide, and sorbicillinol. In order to verify the reliability of the imprint-DESI-MS imaging data and evaluate the capability of tape imprints to extract fungal metabolites while maintaining their localization, six representative plugs along the entire M. roreri/T. harzianum

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

    Science.gov (United States)

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

    2016-03-01

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

  3. Rapid determination of bacterial aminoglycoside resistance in environmental samples using membrane electrospray ionization mass spectrometry.

    Science.gov (United States)

    Fan, Liusheng; Ke, Ming; Yuan, Min; Pu, Ji; Li, Juan; Lu, Jinxing; Xu, Jianguo; Zhang, Mei; Xu, Wei

    2016-08-01

    Antibiotic resistance in pathogenic bacteria is becoming a global public health problem, such as aminoglycoside resistance encoded by the armA gene. Although many methods have been reported, rapid analysis of environmental samples is still challenging. A rapid analytical method was developed in this study to determine bacterial aminoglycoside resistance using membrane electrospray ionization mass spectrometry (MESI-MS). Precursor/product-ion pairs of ArmA unique peptides were detected with minimal sample preparation. Standard peptides were synthesized and used for developing and validating the methodology, and then the method was verified by both ArmA positive and ArmA negative simulated environmental samples. A rapid method for determination of bacterial aminoglycoside resistance was developed using MESI-MS/MS. The bacterial cultural time was optimized to 2 hours, and the precision, accuracy and recovery of this method were investigated. The peptide IHSSTNER (IR-8) unique to ArmA in simulated environmental samples can be successfully identified within 3 hours. The novel assay offered a rapid method to determine bacterial aminoglycoside resistance with high sensitivity, accuracy and precision in simulated environmental samples. This method could also be applied to identify other drug-resistance proteins in clinical/environmental samples. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  4. Imaging Nicotine in Rat Brain Tissue by Use of Nanospray Desorption Electrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lanekoff, Ingela T.; Thomas, Mathew; Carson, James P.; Smith, Jordan N.; Timchalk, Charles; Laskin, Julia

    2013-01-15

    Imaging mass spectrometry offers simultaneous detection of drugs, drug metabolites and endogenous substances in a single experiment. This is important when evaluating effects of a drug on a complex organ system such as the brain, where there is a need to understand how regional drug distribution impacts function. Nicotine is an addictive drug and its action in the brain is of high interest. Here we use nanospray desorption electrospray ionization, nano-DESI, imaging to discover the localization of nicotine in rat brain tissue after in vivo administration of nicotine. Nano-DESI is a new ambient technique that enables spatially-resolved analysis of tissue samples without special sample pretreatment. We demonstrate high sensitivity of nano-DESI imaging that enables detection of only 0.7 fmole nicotine per pixel in the complex brain matrix. Furthermore, by adding deuterated nicotine to the solvent, we examined how matrix effects, ion suppression, and normalization affect the observed nicotine distribution. Finally, we provide preliminary results suggesting that nicotine localizes to the hippocampal substructure called dentate gyrus.

  5. Time-resolved method to distinguish protein/peptide oxidation during electrospray ionization mass spectrometry.

    Science.gov (United States)

    Pei, Jiying; Hsu, Cheng-Chih; Yu, Kefu; Wang, Yinghui; Huang, Guangming

    2018-06-29

    Electrospray ionization mass spectrometry (ESI-MS) is one of the most prevalent techniques used to monitor protein/peptide oxidation induced by reactive oxygen species (ROSs). However, both corona discharge (CD) and electrochemistry (EC) can also lead to protein/peptide oxidation during ESI. Because the two types of oxidation occur almost simultaneously, determining the extent to which the two pathways contribute to protein/peptide oxidation is difficult. Herein, a time-resolved method was introduced to identify and differentiate CD- and EC-induced oxidation. Using this approach, we separated the instantaneous CD-induced oxidation from the hysteretic EC-induced oxidation, and the effects of the spray voltage and flow rate of the ESI source on both oxidation types were investigated with a homemade ESI source. For angiotensin II analogue (b-DRVYVHPF-y), the dehydrogenation and oxygenation species were the detected EC-induced oxidation products, while the oxygenation species were the major CD-induced oxidation products. This time-resolved approach was also applicable to a commercial HESI source, in which both CD and EC were responsible for hemoglobin and cytochrome c oxidation with upstream grounding while CD dominated the oxidation without upstream grounding. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Metabolic Profiling Directly from the Petri Dish Using Nanospray Desorption Electrospray Ionization Imaging Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Watrous, Jeramie D.; Roach, Patrick J.; Heath, Brandi S.; Alexandrov, Theodore; Laskin, Julia; Dorrestein, Pieter C.

    2013-11-05

    Understanding molecular interaction pathways in complex biological systems constitutes a treasure trove of knowledge that might facilitate the specific, chemical manipulation of the countless microbiological systems that occur throughout our world. However, there is a lack of methodologies that allow the direct investigation of chemical gradients and interactions in living biological systems, in real time. Here, we report the use of nanospray desorption electrospray ionization (nanoDESI) imaging mass spectrometry for in vivo metabolic profiling of living bacterial colonies directly from the Petri dish with absolutely no sample preparation needed. Using this technique, we investigated single colonies of Shewanella oneidensis MR-1, Bacillus subtilis 3610, and Streptomyces coelicolor A3(2) as well as a mixed biofilm of S. oneidensis MR-1 and B. subtilis 3610. Data from B. subtilis 3610 and S. coelicolor A3(2) provided a means of validation for the method while data from S. oneidensis MR-1 and the mixed biofilm showed a wide range of compounds that this bacterium uses for the dissimilatory reduction of extracellular metal oxides, including riboflavin, iron-bound heme and heme biosynthetic intermediates, and the siderophore putrebactin.

  7. Direct analysis of ethylenediaminetetraacetic acid (EDTA) on concrete by reactive-desorption electrospray ionization mass spectrometry.

    Science.gov (United States)

    Lebeau, D; Reiller, P E; Lamouroux, C

    2015-01-01

    Analysis of organic ligands such as ethylenediaminetetraacetic acid (EDTA) is today an important challenge due to their ability to increase the mobility of radionuclides and metals. Reactive desorption electrospray ionization mass spectrometry (reactive-DESI-MS) was used for direct analysis of EDTA on concrete samples. EDTA forms complexes and those with Fe(III) ions are among the most thermodynamically favored. This complexing capacity was used to improve the specific detection of EDTA directly on a concrete matrix by doping the solvent spray of DESI with a solution of FeCl3 to selectively create the complex between EDTA and Fe(III). Thus, EDTA sensitivity was largely improved by two orders of magnitude with reactive-DESI-MS experiments thanks to the specific detection of EDTA as a [EDTA-4H+Fe(III)](-) complex. The proof of principle that reactive DESI can be applied to concrete samples to detect EDTA has been demonstrated. Its capacity for semi-quantitative determination and localization of EDTA under ambient conditions and with very little sample preparation, minimizing sample manipulations and solvent volumes, two important conditions for the development of new methodologies in the field of analytical chemistry, has been shown. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Fragmentation studies and electrospray ionization mass spectrometry of lapachol: protonated, deprotonated and cationized species.

    Science.gov (United States)

    Vessecchi, Ricardo; Emery, Flavio S; Galembeck, Sérgio E; Lopes, Norberto P

    2010-07-30

    Electrospray ionization mass spectrometric analysis of lapachol (2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphthoquinone) was accomplished in order to elucidate the gas-phase dissociation reactions of this important biologically active natural product. The occurrence of protonated and cationized species in the positive mode and of deprotonated species in the negative mode was explored by means of collision-induced dissociation (CID) experiments. For the protonated molecule, the H(2)O and C(4)H(8) losses occur by two competitive channels. For the deprotonated molecule, the even-electron rule is not conserved, and the radicalar species are eliminated by formation of distonic anions. The fragmentation mechanism for each ion was suggested on the basis of computational thermochemistry. Atomic charges, relative energies, and frontier orbitals were employed aiming at a better understanding of the gas-phase reactivity of lapachol. Potential energy surfaces for fragmentation reactions were obtained by the B3LYP/6-31+G(d,p) model. Copyright 2010 John Wiley & Sons, Ltd.

  9. Study of the non-covalent interactions of ginsenosides and lysozyme using electrospray ionization mass spectrometry.

    Science.gov (United States)

    Tang, Jun; Fu, Qiang; Cui, Meng; Xing, Junpeng; Liu, Zhiqiang; Liu, Shuying

    2015-11-15

    Ginsenosides are an important class of natural products extracted from ginseng that possess various important biological activities. Studies of interactions of ginsenosides with proteins are essential for comprehensive understanding of the biological activities of ginsenosides. In this study, the interactions of ginsenosides with lysozyme were investigated by electrospray ionization mass spectrometry (ESI-MS). Both protopanaxadiol-type and protopanaxatriol-type ginsenosides were chosen to explore the interactions of ginsenosides towards lysozyme near the physiological conditions by direct ESI-MS, respectively. Comparative experiments were conducted to confirm the interactions were specific. In addition, the dissociation constants of ginsenoside-lysozyme complexes were determined by a ESI-MS titration strategy. The results showed ginsenosides bound to lysozyme at the stoichiometries of 1:1 and 2:1. The association constants of ginsenosides to lysozyme were in the order of Re>Rd>Rf>Rg2 >Rg3 . According to their structures, the binding affinities associated with the type of aglycone and the type and the number of sugar moieties linked on the aglycone. It has been demonstrated that ESI-MS is a powerful tool to probe the non-covalent interactions between lysozyme and ginsenosides. These results provide insights into the interaction of ginsenosides with lysozyme at the molecular level. The developed strategy could be applied to determine the interactions of proteins with other natural products. Copyright © 2015 John Wiley & Sons, Ltd.

  10. Oligosaccharide sequences in Quillaja saponins by electrospray ionization ion trap multiple-stage mass spectrometry.

    Science.gov (United States)

    Broberg, Susanna; Nord, Lars I; Kenne, Lennart

    2004-06-01

    Ten different samples with 13 previously identified saponin structures from Quillaja saponaria Molina were investigated by electrospray ionization ion trap multiple-stage mass spectrometry (ESI-ITMS(n)) in positive and negative ion modes. Both positive and negative ion mode MS(1)-MS(4) spectra were analyzed, showing that structural information on the two oligosaccharide parts in the saponin can be obtained from positive ion mode spectra whereas negative ion mode spectra mainly gave information on one of the oligosaccharide parts. Analysis of MS(1)-MS(4) spectra identified useful key fragment ions important for the structural elucidation of Quillaja saponins. A flowchart involving a stepwise procedure based on key fragments from MS(1)-MS(3) spectra was constructed for the identification of structural elements in the saponin. Peak intensity ratios in MS(3) spectra were found to be correlated with structural features of the investigated saponins and are therefore of value for the identification of terminal monosaccharide residues. Copyright 2004 John Wiley & Sons, Ltd.

  11. Real-time hydrogen/deuterium exchange kinetics via supercharged electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Sterling, Harry J; Williams, Evan R

    2010-11-01

    Amide hydrogen/deuterium exchange (HDX) rate constants of bovine ubiquitin in an ammonium acetate solution containing 1% of the electrospray ionization (ESI) "supercharging" reagent m-nitrobenzyl alcohol (m-NBA) were obtained using top-down, electron transfer dissociation (ETD) tandem mass spectrometry (MS). The supercharging reagent replaces the acid and temperature "quench" step in the conventional MS approach to HDX experiments by causing rapid protein denaturation to occur in the ESI droplet. The higher charge state ions that are produced with m-NBA are more unfolded, as measured by ion mobility, and result in higher fragmentation efficiency and higher sequence coverage with ETD. Single amino acid resolution was obtained for 44 of 72 exchangeable amide sites, and summed kinetic data were obtained for regions of the protein where adjacent fragment ions were not observed, resulting in an overall spatial resolution of 1.3 residues. Comparison of these results with previous values from NMR indicates that the supercharging reagent does not cause significant structural changes to the protein in the initial ESI solution and that scrambling or back-exchange is minimal. This new method for top-down HDX-MS enables real-time kinetic data measurements under physiological conditions, similar to those obtained using NMR, with comparable spatial resolution and significantly better sensitivity.

  12. Interactions of nucleobases with alkali earth metal cations--electrospray ionization mass spectrometric study.

    Science.gov (United States)

    Frańska, Magdalena

    2007-01-01

    Interactions of nucleobases with alkali earth metal cations have been studied by electrospray ionization mass spectrometry (ESI-MS). Nucleobases containing at least one oxygen atom form stable complexes with alkali earth metal cations. This phenomenon can be explained on the grounds of the well known theory of hard and soft acids and bases. Uracil and thymine make complexes only when in their deprotonoted forms. The cations of great radii (Sr(2+), Ba(2+)) are more prone to form complexes of stoichiometry 1:1 with uracil and thymine than the cations of small radii (Mg(2+), Ca(2+)). On the other hand, Mg(2+) forms complexes of stoichiometry 2:1 and 3:2 with uracil and thymine. Gas-phase stabilities of the 1:1 complexes are higher for the cations of small radii, in contrast to the solution stabilities. For cytosine and 9- methylhypoxantine the 1:1 complexes of their deprotonated forms are observed at higher cone voltage as a result of HCl molecule loss from the complexes containing the counter ion (Cl(-)). In solution, more stable complexes are formed with metal cations of low radii. Gas-phase stability of the complexes formed by deprotonated 9- methyl-hypoxantine increases with increasing metal cation radius.

  13. Simple atmospheric hydrogen/deuterium exchange method for enumeration of labile hydrogens by electrospray ionization mass spectrometry.

    Science.gov (United States)

    Kostyukevich, Yury; Kononikhin, Alexey; Popov, Igor; Nikolaev, Eugene

    2013-06-04

    A simple method for hydrogen/deuterium exchange in a standard electrospray (ESI) ionization source is presented. In this method, a D₂O droplet is placed between the ESI needle and the entrance of the mass spectrometer and thus saturation of the atmosphere with deuterated vapor in the ESI region is achieved. It was shown that full exchange of up to 23 labile acidic hydrogens with a minimal back exchange with the surrounding atmospheric water can be performed by this method.

  14. Internal energy effects on the solvation and reactivity of multiply charged biomolecules for electrospray ionization mass spectroscopy. [Bovine ubiquitin

    Energy Technology Data Exchange (ETDEWEB)

    Light-Wahl, K.J.; Winger, B.E.; Rockwood, A.L.; Smith, R.D.

    1992-06-01

    Mild (capillary) interface conditions which do not completely desolvate the ions of proteins in electrospray ionization mass spectrometry (ESI-MS) may be required to probe the higher order structures and weak associations. For the small protein bovine ubiquitin, two ion distributions (unsolvated ions and unresolved solvated ions) were observed. The resolvable solvation for leucine-enkephalin with methanol and water shows that the use of countercurrent N{sub 2} flow at the capillary affects the solvation observed. 2 figs. (DLC)

  15. Identification of Guest-Host Inclusion Complexes in the Gas Phase by Electrospray Ionization-Mass Spectrometry

    Science.gov (United States)

    Mendes, De´bora C.; Ramamurthy, Vaidhyanathan; Da Silva, Jose´ P.

    2015-01-01

    In this laboratory experiment, students follow a step-by-step procedure to prepare and study guest-host complexes in the gas phase using electrospray ionization-mass spectrometry (ESI-MS). Model systems are the complexes of hosts cucurbit[7]uril (CB7) and cucurbit[8]uril (CB8) with the guest 4-styrylpyridine (SP). Aqueous solutions of CB7 or CB8…

  16. Determination of dapsone in meat and milk by liquid chromatography tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Hadjigeorgiou, M. [State General Laboratory of Cyprus, Veterinary Drug Residues Lab, Kimonos 44, 1451 Nicosia (Cyprus)], E-mail: mhadjigeorgiou@sgl.moh.gov.cy; Papachrysostomou, Ch.; Theodorou, Z.; Kanari, P.; Constantinou, S. [State General Laboratory of Cyprus, Veterinary Drug Residues Lab, Kimonos 44, 1451 Nicosia (Cyprus)

    2009-04-01

    Within the EU the use of dapsone (4,4-diaminodiphenylsulfone) is prohibited in food-producing animals and consequently it's included in the Annex IV of the Directive 90/2377/EC. A quantitative confirmatory method has been developed and validated according to the criteria defined in the Commission Decision 2002/657/EC, for the determination of dapsone in meat and milk. Samples, after homogenization in alkaline conditions and organic solvent extraction, were purified on silica gel solid phase extraction cartridges. The eluate was evaporated and redissolved in mobile phase and was analysed by liquid chromatography tandem mass spectrometry (LC-MS/MS) in positive electrospray ionisation (ESI) using deuterium labelled Sulphadimidine-d7 as internal standard. The calculated value for, decision limit, CC{alpha} is 0.12 {mu}g kg{sup -1}, and the detection capability; CC{beta} value is 0.16 {mu}g kg{sup -1}.

  17. Determination of dapsone in meat and milk by liquid chromatography tandem mass spectrometry

    International Nuclear Information System (INIS)

    Hadjigeorgiou, M.; Papachrysostomou, Ch.; Theodorou, Z.; Kanari, P.; Constantinou, S.

    2009-01-01

    Within the EU the use of dapsone (4,4-diaminodiphenylsulfone) is prohibited in food-producing animals and consequently it's included in the Annex IV of the Directive 90/2377/EC. A quantitative confirmatory method has been developed and validated according to the criteria defined in the Commission Decision 2002/657/EC, for the determination of dapsone in meat and milk. Samples, after homogenization in alkaline conditions and organic solvent extraction, were purified on silica gel solid phase extraction cartridges. The eluate was evaporated and redissolved in mobile phase and was analysed by liquid chromatography tandem mass spectrometry (LC-MS/MS) in positive electrospray ionisation (ESI) using deuterium labelled Sulphadimidine-d7 as internal standard. The calculated value for, decision limit, CCα is 0.12 μg kg -1 , and the detection capability; CCβ value is 0.16 μg kg -1

  18. Pressurized liquid extraction followed by liquid chromatography with tandem mass spectrometry to determine pharmaceuticals in mussels.

    Science.gov (United States)

    Núñez, Mireia; Borrull, Francesc; Pocurull, Eva; Fontanals, Núria

    2016-02-01

    An analytical method based on pressurized liquid extraction and solid-phase extraction with a mixed-mode Oasis(®) MAX sorbent as cleanup, followed by liquid chromatography with electrospray ionization and tandem mass spectrometry was developed and validated for the determination of seven widely used pharmaceuticals in mussel species. The optimization of the pressurized liquid extraction and the solid-phase extraction parameters is described. The method provided extraction recoveries ranging from 61 to 90%, and limits of detection ranging from 2 to 50 ng/g (dry weight). The repeatability and reproducibility of the method, expressed as relative standard deviation, were lower than 15 and 19%, respectively. The method was successfully applied to the analysis of mussel samples from different locations. The analyses showed that salicylic acid was present in mussels at concentrations up to 177 ng/g (dry weight). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Simultaneous determination of plasma total homocysteine and methionine by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Jiang, Yi; Mistretta, Brandon; Elsea, Sarah; Sun, Qin

    2017-01-01

    The sulfur-containing amino acid homocysteine is a cardiac risk factor and a biomarker for several inborn errors of metabolism in methionine synthesis. A simple LC-MS/MS method was developed and validated for determination of homocysteine and methionine in human plasma. Rapid separation was achieved using a reverse phase liquid chromatography. Mass spectrometry identification was performed in positive electrospray ionization mode for homocysteine and methionine. Accuracy, precision, linearity, recovery and sample stability were evaluated in the method validation. The test is applied in diagnosis of homocystinuria and monitoring total homocysteine levels. Moreover, simultaneous measurement of methionine helps in the differentiation of homocystinuria and some cobalamin disorders (such as cblC and cblD defects) without additional amino acid testing. Lastly, this assay is sensitive to detect reduced total homocysteine levels that are possibly seen in sulfocysteinuria and molybdenum cofactor deficiencies. Copyright © 2016. Published by Elsevier B.V.

  20. On-line coupling of a microelectrode array equipped poly(dimethylsiloxane) microchip with an integrated graphite electrospray emitter for electrospray ionisation mass spectrometry.

    Science.gov (United States)

    Liljegren, Gustav; Dahlin, Andreas; Zettersten, Camilla; Bergquist, Jonas; Nyholm, Leif

    2005-10-01

    A novel method for the manufacturing of microchips for on-chip combinations of electrochemistry (EC) and sheathless electrospray ionisation mass spectrometry (ESI-MS) is described. The technique, which does not require access to clean-room facilities, is based on the incorporation of an array of gold microcoil electrodes into a poly(dimethylsiloxane)(PDMS) microflow channel equipped with an integrated graphite based sheathless ESI emitter. Electrochemical measurements, which were employed to determine the electroactive area of the electrodes and to test the microchips, show that the manufacturing process was reproducible and that the important interelectrode distance in the electrochemical cell could to be adequately controlled. The EC-ESI-MS device was evaluated based on the ESI-MS detection of the oxidation products of dopamine. The results demonstrate that the present on-chip approach enables full potentiostatic control of the electrochemical cell and the attainment of very short transfer times between the electrochemical cell and the electrospray emitter. The transfer times were 0.6 and 1.2 s for flow rates of 1.0 and 0.5 microL min(-1), respectively, while the electrochemical conversion efficiency of the electrochemical cell was found to be 30% at a flow rate of 0.5 microL min(-1). To decouple the electrochemical cell from the ESI-MS high voltage and to increase the user-friendliness, the on-line electrochemistry-ESI-MS experiments were performed using a wireless Bluetooth battery-powered instrument with the chip floating at the potential induced by the ESI high voltage. The described on-chip EC-ESI-MS device can be used for fundamental electrochemical investigations as well as for applications based on the use of electrochemically controlled sample pretreatment, preconcentration and ionisation steps prior to ESI-MS.

  1. Analysis of triazines and associated metabolites with electrospray ionization field-asymmetric ion mobility spectrometry/mass spectrometry

    DEFF Research Database (Denmark)

    Mie, Axel; Sandulescu, Madaline; Mathiasson, Lennart

    2008-01-01

    Triazines comprise an important pollutant class owing to continued use in certain countries, and owing to strong environmental persistence that leads to problems even in countries like Sweden where the use of triazines has been prohibited for some years. We investigated mass-selective detection...... for analysis of triazines. More specifically, we studied the background reduction and sensitivity enhancement that result from the use of a new interface technique, field-asymmetric ion mobility spectrometry (FAIMS), in conjunction with electrospray ionization ion-trap mass spectrometry. This technique allows...... analysis with mass-selective detection coupled to membrane-based sample cleanup and enrichment for additional enhancement in sensitivity....

  2. New Mechanism of Extractive Electrospray Ionization Mass Spectrometry for Heterogeneous Solid Particles.

    Science.gov (United States)

    Kumbhani, S; Longin, T; Wingen, L M; Kidd, C; Perraud, V; Finlayson-Pitts, B J

    2018-02-06

    Real-time in situ mass spectrometry analysis of airborne particles is important in several applications, including exposure studies in ambient air, industrial settings, and assessing impacts on visibility and climate. However, obtaining molecular and 3D structural information is more challenging, especially for heterogeneous solid or semisolid particles. We report a study of extractive electrospray ionization mass spectrometry (EESI-MS) for the analysis of solid particles with an organic coating. The goal is to elucidate how much of the overall particle content is sampled, and determine the sensitivity of this technique to the surface layers. It is shown that, for NaNO 3 particles coated with glutaric acid (GA), very little of the solid NaNO 3 core is sampled compared to the GA coating, whereas for GA particles coated with malonic acid (MA), significant signals from both the MA coating and the GA core are observed. However, conventional ESI-MS of the same samples collected on a Teflon filter (and then extracted) detects much more core material compared to EESI-MS in both cases. These results show that, for the experimental conditions used here, EESI-MS does not sample the entire particle but, instead, is more sensitive to surface layers. Separate experiments on single-component particles of NaNO 3 , GA, or citric acid show that there must be a kinetics limitation to dissolution that is important in determining EESI-MS sensitivity. We propose a new mechanism of EESI solvent droplet interaction with solid particles that is consistent with the experimental observations. In conjunction with previous EESI-MS studies of organic particles, these results suggest that EESI does not necessarily sample the entire particle when solid, and that not only solubility but also surface energies and the kinetics of dissolution play an important role.

  3. Observing the real time formation of phosphine-ligated gold clusters by electrospray ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ligare, Marshall R.; Johnson, Grant E.; Laskin, Julia

    2017-01-01

    Early stages of the reduction and nucleation of solution-phase gold clusters are largely unknown. This is due, in part, to the high reaction rates and the complexity of the cluster synthesis process. Through the addition of a diphosphine ligand, 1-4,Bis(diphenylphosphino)butane (L4) to the gold precursor, chloro(triphenylphosphine) gold(I) (Au(PPh3)Cl), in methanol organometallic complexes of the type, [Au(L4)x(L4O)y(PPh3)z]+, are formed. These complexes lower the rate of reduction so that the reaction can be directly monitored from 1 min to over an hour using on-line electrospray ionization mass spectrometry (ESI-MS). Our results indicate that the formation of Au8(L4)42+, Au9(L4)4H2+ and Au10(L4)52+ cationic clusters occurs through different reaction pathways that may be kinetically controlled either through the reducing agent concentration or the extent of oxidation of L4. Through comparison of selected ion chronograms our results indicate that Au2(L4)2H+ may be an intermediate in the formation of Au8(L4)42+and Au10(L4)52+ while a variety of chlorinated clusters are involved in the formation of Au9(L4)4H2+. Additionally, high-resolution mass spectrometry was employed to identify 53 gold containing species produced under highly oxidative conditions. New intermediate species are identified which help understand how different gold cluster nuclearities can be stabilized during the growth process.

  4. Electrospray ionization mass spectrometry monitoring of indigo carmine degradation by advanced oxidative processes.

    Science.gov (United States)

    Dalmázio, Ilza; de Urzedo, Ana P F M; Alves, Tania M A; Catharino, Rodrigo R; Eberlin, Marcos N; Nascentes, Clésia C; Augusti, Rodinei

    2007-10-01

    The degradation of the dye indigo carmine in aqueous solution induced by two oxidative processes (H(2)O(2)/iodide and O(3)) was investigated. The reactions were monitored by electrospray ionization mass spectrometry in the negative ion mode, ESI(-)-MS, and the intermediates and oxidation products characterized by ESI(-)-MS/MS. Both oxidative systems showed to be highly efficient in removing the color of the dye aqueous solutions. In the ESI(-)-MS of the indigo carmine solution treated with H(2)O(2) and H(2)O(2)/iodide, the presence of the ions of m/z 210 (indigo carmine in its anionic form, 1), 216, 226, 235, and 244 was noticeable. The anion of m/z 235 was proposed to be the unprecedented hydroperoxide intermediate 2 formed in solution via an electrophilic attack by hydroxyl and hydroperoxyl radicals of the exocyclic C=C bond of 1. This intermediate was suggested to be rapidly converted into the anionic forms of 2,3-dioxo-1H-indole-5-sulfonic acid (3, m/z 226), 2-amino-alpha-oxo-5-sulfo-benzeneacetic acid (4, m/z 244), and 2-amino-5-sulfo-benzoic acid (5, m/z 216). In the ESI(-)-MS of the indigo carmine solution treated with O(3), two main anions were detected: m/z 216 (5) and 244 (4). Both products were proposed to be produced via an unstable ozonide intermediate. Other anions in this ESI(-) mass spectrum were attributed to be [4 - H + Na](-) of m/z 266, [4 - H](2-) of m/z 121.5, and [5 - H](2-) of m/z 107.5. ESI-MS/MS data were consistent with the proposed structures for the anionic products 2-5.

  5. Electrochemical oxidation and protein adduct formation of aniline: a liquid chromatography/mass spectrometry study.

    Science.gov (United States)

    Melles, Daniel; Vielhaber, Torsten; Baumann, Anne; Zazzeroni, Raniero; Karst, Uwe

    2012-04-01

    Historically, skin sensitization tests are typically based on in vivo animal tests. However, for substances used in cosmetic products, these tests have to be replaced according to the European Commission regulation no. 1223/2009. Modification of skin proteins by electrophilic chemicals is a key process associated with the induction of skin sensitization. The present study investigates the capabilities of a purely instrumental setup to determine the potential of commonly used non-electrophilic chemicals to cause skin sensitization by the generation of electrophilic species from the parent compound. In this work, the electrophiles were generated by the electrochemical oxidation of aniline, a basic industrial chemical which may also be released from azo dyes in cosmetics. The compound is a known sensitizer and was oxidized in an electrochemical thin-layer cell which was coupled online to electrospray ionization-mass spectrometry. The electrochemical oxidation was performed on a boron-doped diamond working electrode, which is able to generate hydroxyl radicals in aqueous solutions at high potentials. Without any pretreatment, the oxidation products were identified by electrospray ionization/time-of-flight mass spectrometry (ESI-ToF-MS) using their exact masses. A mass voltammogram was generated by plotting the obtained mass spectra against the applied potential. Oligomerization states with up to six monomeric units in different redox states of aniline were observed using this setup. This approach was extended to generate adducts between the oxidation products of aniline and the tripeptide glutathione. Two adducts were identified with this trapping experiment. Protein modification was carried out subsequently: Aniline was oxidized at a constant potential and was allowed to react with β-lactoglobulin A (β-LGA) or human serum albumin (HSA), respectively. The generated adducts were analyzed by liquid chromatography coupled to ESI-ToF-MS. For both β-LGA and HSA, aniline

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

    Science.gov (United States)

    Owis, Asmaa Ibrahim; El-Naggar, El-Motaz Bellah

    2016-01-01

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

  7. Evaluation of IMAC and Electrospray Ionization Mass Spectrometry for Recovery and Analysis of Copper-Binding Ligands in Seawater

    Science.gov (United States)

    Nixon, R. L.; Ross, A.

    2016-02-01

    Complexation by organic ligands dominates the speciation of iron, copper, and other bioactive trace metals in seawater, controlling their bioavailability and distribution in the marine environment. Several classes of high-affinity Fe-binding ligands (siderophores) have been identified in seawater and such compounds are known to mediate iron uptake by marine bacteria, thereby influencing biological productivity in the ocean. However, little is known about the origin, structure, or ecological role of marine Cu-binding ligands (chalcophores). Immobilized metal-ion affinity chromatography (IMAC) allows selective recovery of such compounds from seawater, while electrospray ionization mass spectrometry (ESI-MS) has been used to identify marine siderophores and to characterise Cu ligands in coastal waters. Here, we use model compounds to evaluate a Cu(II)-IMAC/ESI-MS workflow for recovery and analysis of Cu-binding ligands in seawater. One-litre samples of artificial and natural filtered seawater were spiked with model Cu(II) ligands at realistic concentrations and fractionated by IMAC. Retained compounds were eluted by acidification and detected by UV absorption. Linear plots of concentration versus UV chromatographic peak area were obtained for model synthetic and natural organic ligands at concentrations ranging from 5 to 500 nM (r2=0.9988) and 50 and 750 nM (r2=0.9899), respectively, in artificial seawater. Variable though similar results were obtained for oceanic seawater spiked with 5 nM to 1 µM of ligand (r2=0.9893). Chromatographic peak data suggests that natural UV-absorbing Cu ligands are more concentrated in nearshore than in oceanic surface waters, and that these ligands are susceptible to photolysis by artificial sunlight. Eluted IMAC fractions corresponding to UV absorbance peaks were collected and different techniques evaluated for concentration and desalting of the recovered ligands prior to analysis by ESI-MS and tandem mass spectrometry (MS/MS). MS data

  8. High-expression EGFR/cell membrane chromatography-online-high-performance liquid chromatography/mass spectrometry: rapid screening of EGFR antagonists from Semen Strychni.

    Science.gov (United States)

    Sun, Meng; Guo, Ying; Dai, Bingling; Wang, Chen; He, Langchong

    2012-09-15

    Traditional methods for screening active compounds from complex system such as traditional Chinese medicines are relatively cumbersome and time-consuming. In order to improve this situation, we established an online analytical method for screening, separation and identification EGFR antagonists from traditional Chinese medicines, which is described in this study. Cells with high EGFR expression levels were used to prepare the cell membrane stationary phase for the EGFR cell membrane chromatography model with the purpose of screening active compounds. Separation of the retention fractions was achieved by the high-performance liquid chromatography, and identification was conducted via electrospray ionization quadrupole mass spectrometry. The inhibitory effects of active compounds on EGFR cell growth were also demonstrated in vitro. The screening results showed that vauquline and strychnine from Semen Strychni could be active components acting on EGFR similarly to gefitinib as a control drug. Results from biological trials showed that vauquline and strychnine inhibited cell proliferation of HEK293/EGFR cells, and inhibited Erk phosphorylation, and can effectively reduce expression of downstream signaling molecules. This EGFR cell membrane chromatography-online-high-performance liquid chromatography/tandem mass spectrometry method can be applied for rapid screening, separation and identification of EGFR antagonists from traditional Chinese medicines and should be useful for drug discovery with natural medicinal herbs. Copyright © 2012 John Wiley & Sons, Ltd.

  9. Characterisation of chemically-modified proteins by electrospray ionisation mass spectrometry

    International Nuclear Information System (INIS)

    Bennett, K.L.

    1996-09-01

    Electrospray mass spectrometry (ESI-MS) has been used to examine a range of intact monoclonal antibodies (MAbs), antibody fragments such as F(ab') 2 , F ab and F c , chemically-modified fragments and a range of other chemically-modified peptides and proteins as part of a broader study aimed at establishing ESI-MS as a method for the characterisation of radioimmunoconjugates (radiolabelled monoclonal antibodies). For example, the addition of up to 10 biotin molecules to the 'papain-sensitive' 50 kDa F ab fragment can be easily detected in ESI mass spectra. For intact MAbs, however, it is only possible to detect average shifts in the mass of intact antibodies following modification. Successful ESI-MS analysis of complexes formed between chelators and other small molecules conjugated to synthetic peptides, hen egg-white Iysozyme (HEL) (M r 14 306) and horse heart myoglobin (M r 16 951) has been demonstrated. ESI-MS offers considerable advantages compared with existing methods for the characterisation of chemically-conjugated proteins including speed and sensitivity of analysis and the capability for obtaining specific structural information. The conditions for ESI-MS of intact MAbs and MAb fragments have been examined in detail and it was found that 150 kDa MAbs generally required lower sample concentration and higher skimmer potentials compared with the 50 kDa F ab fragment and other lower molecular weight proteins. In addition, the m/z range over which ions from MAbs were observed was higher (m/z ∼2000-4500) than for smaller proteins. ESI-MS was also found to be useful for probing the action of the protease papain, that is used to generate MAb fragments (F(ab) '2, F ab and F c ). Further, different sensitivities to papain for different MAb preparations was demonstrated. Finally, the tandem mass spectra of a range of peptides modified by iodine and biotin were examined. In the case of biotinylated peptides, a characteristic fragment ion was identified that could

  10. Quantitative Detection of Trace Malachite Green in Aquiculture Water Samples by Extractive Electrospray Ionization Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Xiaowei Fang

    2016-08-01

    Full Text Available Exposure to malachite green (MG may pose great health risks to humans; thus, it is of prime importance to develop fast and robust methods to quantitatively screen the presence of malachite green in water. Herein the application of extractive electrospray ionization mass spectrometry (EESI-MS has been extended to the trace detection of MG within lake water and aquiculture water, due to the intensive use of MG as a biocide in fisheries. This method has the advantage of obviating offline liquid-liquid extraction or tedious matrix separation prior to the measurement of malachite green in native aqueous medium. The experimental results indicate that the extrapolated detection limit for MG was ~3.8 μg·L−1 (S/N = 3 in lake water samples and ~0.5 μg·L−1 in ultrapure water under optimized experimental conditions. The signal intensity of MG showed good linearity over the concentration range of 10–1000 μg·L−1. Measurement of practical water samples fortified with MG at 0.01, 0.1 and 1.0 mg·L−1 gave a good validation of the established calibration curve. The average recoveries and relative standard deviation (RSD of malachite green in lake water and Carassius carassius fish farm effluent water were 115% (6.64% RSD, 85.4% (9.17% RSD and 96.0% (7.44% RSD, respectively. Overall, the established EESI-MS/MS method has been demonstrated suitable for sensitive and rapid (<2 min per sample quantitative detection of malachite green in various aqueous media, indicating its potential for online real-time monitoring of real life samples.

  11. Chemical Analysis of Complex Organic Mixtures Using Reactive Nanospray Desorption Electrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Laskin, Julia; Eckert, Peter A.; Roach, Patrick J.; Heath, Brandi S.; Nizkorodov, Sergey A.; Laskin, Alexander

    2012-08-21

    Reactive nanospray desorption electrospray ionization (nano-DESI) combined with high-resolution mass spectrometry was utilized for the analysis of secondary organic aerosol produced through ozonolysis of limonene (LSOA). Previous studies showed that LSOA constituents are multifunctional compounds containing aldehyde and ketone groups. In this study, we used the selectivity of the Girard T (GT) reagent towards carbonyl compounds to examine the utility of reactive nano-DESI for the analysis of complex organic mixtures. In these experiments, 1-100 {micro}M GT solution was used as a working solvent for reactive nano-DESI analysis. Abundant products of a single addition of GT to LSOA constituents were observed at GT concentrations in excess of 10 {micro}M. We found that LSOA compounds with 18-20 carbon atoms (dimers) and 27-30 carbon atoms (trimers) react with GT through a simple addition reaction resulting in formation of the carbinolamine derivative. In contrast, reactions of GT with monomeric species result in formation of both the carbinolamine and the hydrazone derivatives. In addition, several monomers did not react with GT on the timescale of our experiment. These molecules were characterized by relatively high values of the double bond equivalent (DBE) and low oxygen content. Furthermore, because addition of a charged GT tag to a neutral molecule eliminates the discrimination against the low proton affinity compounds in the ionization process, reactive nano-DESI analysis enables quantification of individual compounds in the complex mixture. For example, we were able to estimate for the first time the amounts of dimers and trimers in the LSOA mixture. Specifically, we found that the most abundant LSOA dimer was detected at ca. 0.5 pg level and the total amount of dimers and trimers in the analyzed sample was just around 11 pg. Our results indicate that reactive nano-DESI is a valuable approach for examining the presence of specific functional groups and

  12. Vapor Pressure of Hexamethylene Triperoxide Diamine (HMTD) Estimated Using Secondary Electrospray Ionization Mass Spectrometry.

    Science.gov (United States)

    Aernecke, Matthew J; Mendum, Ted; Geurtsen, Geoff; Ostrinskaya, Alla; Kunz, Roderick R

    2015-11-25

    A rapid method for vapor pressure measurement was developed and used to derive the vapor pressure curve of the thermally labile peroxide-based explosive hexamethylene triperoxide diamine (HMTD) over the temperature range from 28 to 80 °C. This method uses a controlled flow of vapor from a solid-phase HMTD source that is presented to an ambient-pressure-ionization mass spectrometer equipped with a secondary-electrospray-ionization (SESI) source. The subpart-per-trillion sensitivity of this system enables direct detection of HMTD vapor through an intact [M + H](+) ion in real time at temperatures near 20 °C. By calibrating this method using vapor sources of cocaine and heroin, which have known pressure-temperature (P-T) curves, the temperature dependence of HMTD vapor was determined, and a Clausius-Clapeyron plot of ln[P (Pa)] vs 1/[T (K)] yielded a straight line with the expression ln[P (Pa)] = {(-11091 ± 356) × 1/[T (K)]} + 25 ± 1 (error limits are the standard error of the regression analysis). From this equation, the sublimation enthalpy of HMTD was estimated to be 92 ± 3 kJ/mol, which compares well with the theoretical estimate of 95 kJ/mol, and the vapor pressure at 20 °C was estimated to be ∼60 parts per trillion by volume, which is within a factor of 2 of previous theoretical estimates. Thus, this method provides not only the first direct experimental determination of HMTD vapor pressure but also a rapid, near-real-time capability to quantitatively measure low-vapor-pressure compounds, which will be useful for aiding in the development of training aids for bomb-sniffing canines.

  13. Analysis of triacetone triperoxide (TATP) and TATP synthetic intermediates by electrospray ionization mass spectrometry.

    Science.gov (United States)

    Sigman, Michael E; Clark, C Douglas; Caiano, Tara; Mullen, Rebecca

    2008-01-01

    The explosive triacetone triperoxide (TATP) has been analyzed by electrospray ionization mass spectrometry (ESI-MS) on a linear quadrupole instrument, giving a 62.5 ng limit of detection in full scan positive ion mode. In the ESI interface with no applied fragmentor voltage the m/z 245 [TATP + Na](+) ion was observed along with m/z 215 [TATP + Na - C(2)H(6)](+) and 81 [(CH(3))(2)CO + Na](+). When TATP was ionized by ESI with an applied fragmentor voltage of 75 V, ions at m/z 141 [C(4)H(6)O(4) + Na](+) and 172 [C(5)H(9)O(5) + Na](+) were also observed. When the precipitates formed in the synthesis of TATP were analyzed before the reaction was complete, a new series of ions was observed in which the ions were separated by 74 m/z units, with ions occurring at m/z 205, 279, 353, 427, 501, 575, 649 and 723. The series of evenly spaced ions is accounted for as oligomeric acetone carbonyl oxides terminated as hydroperoxides, [HOOC(CH(3))(2){OOC(CH(3))(2)}(n)OOH + Na](+) (n = 1, 2 ... 8). The ESI-MS spectra for this homologous series of oligoperoxides have previously been observed from the ozonolysis of tetramethylethylene at low temperatures. Precipitates from the incomplete reaction mixture, under an applied fragmentor voltage of 100 V in ESI, produced an additional ion observed at m/z 99 [C(2)H(4)O(3) + Na](+), and a set of ions separated by 74 m/z units occurring at m/z 173, 247, 321, 395, 469 and 543, proposed to correspond to [CH(3)CO{OOC(CH(3))(2)}(n)OOH + Na](+) (n = 1,2 ... 5). Support for the assigned structures was obtained through the analysis of both protiated and perdeuterated TATP samples. Copyright (c) 2007 John Wiley & Sons, Ltd.

  14. Probing Conformational Changes of Ubiquitin by Host-Guest Chemistry Using Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Lee, Jong Wha; Heo, Sung Woo; Lee, Shin Jung C.; Ko, Jae Yoon; Kim, Hyungjun; Kim, Hugh I.

    2013-01-01

    We report mechanistic studies of structural changes of ubiquitin (Ub) by host-guest chemistry with cucurbit[6]uril (CB[6]) using electrospray ionization mass spectrometry (ESI-MS) combined with circular dichroism spectroscopy and molecular dynamics (MD) simulation. CB[6] binds selectively to lysine (Lys) residues of proteins. Low energy collision-induced dissociation (CID) of the protein-CB[6] complex reveals CB[6] binding sites. We previously reported ( Anal. Chem. 2011, 83, 7916-7923) shifts in major charge states along with Ub-CB[6] complexes in the ESI-MS spectrum with addition of CB[6] to Ub from water. We also reported that CB[6] is present only at Lys6 or Lys11 in high charge state (+13) complex. In this study, we provide additional information to explain unique conformational change mechanisms of Ub by host-guest chemistry with CB[6] compared with solvent-driven conformational change of Ub. Additional CID study reveals that CB[6] is bound only to Lys48 and Lys63 in low charge state (+7) complex. MD simulation studies reveal that the high charge state complexes are attributed to the CB[6] bound to Lys11. The complexation prohibits salt bridge formation between Lys11 and Glu34 and induces conformational change of Ub. This results in formation of high charge state complexes in the gas phase. Then, by utilizing stronger host-guest chemistry of CB[6] with pentamethylenediamine, refolding of Ub via detaching CB[6] from the protein is performed. Overall, this study gives an insight into the mechanism of denatured Ub ion formation via host-guest interactions with CB[6]. Furthermore, this provides a direction for designing function-controllable supramolecular system comprising proteins and synthetic host molecules.

  15. Subzero temperature chromatography for reduced back-exchange and improved dynamic range in amide hydrogen/deuterium exchange mass spectrometry.

    Science.gov (United States)

    Venable, John D; Okach, Linda; Agarwalla, Sanjay; Brock, Ansgar

    2012-11-06

    Amide hydrogen/deuterium exchange is a commonly used technique for studying the dynamics of proteins and their interactions with other proteins or ligands. When coupled with liquid chromatography and mass spectrometry, hydrogen/deuterium exchange provides several unique advantages over other structural characterization techniques including very high sensitivity, the ability to analyze proteins in complex environments, and a large mass range. A fundamental limitation of the technique arises from the loss of the deuterium label (back-exchange) during the course of the analysis. A method to limit loss of the label during the separation stage of the analysis using subzero temperature reversed-phase chromatography is presented. The approach is facilitated by the use of buffer modifiers that prevent freezing. We evaluated ethylene glycol, dimethyl formamide, formamide, and methanol for their freezing point suppression capabilities, effects on peptide retention, and their compatibilities with electrospray ionization. Ethylene glycol was used extensively because of its good electrospray ionization compatibility; however, formamide has potential to be a superior modifier if detrimental effects on ionization can be overcome. It is demonstrated using suitable buffer modifiers that separations can be performed at temperatures as low as -30 °C with negligible loss of the deuterium label, even during long chromatographic separations. The reduction in back-exchange is shown to increase the dynamic range of hydrogen/deuterium exchange mass spectrometry in terms of mixture complexity and the magnitude with which changes in deuteration level can be quantified.

  16. Aging effects on macadamia nut oil studied by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Proschogo, Nicholas W; Albertson, Peter L; Bursle, Johanna; McConchie, Cameron A; Turner, Athol G; Willett, Gary D

    2012-02-29

    High-resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry is successfully used in the detailed molecular analysis of aged macadamia nut oils. The results are consistent with peroxide values, the current industry measure for rancidity, and provide detailed molecular information on the oxidative and hydrolytic degeneration of such oils. Mass analysis of macadamia oil samples stored for extended periods at 6 °C revealed that oils obtained by the cold press method are more susceptible to aging than those obtained using modified Soxhlet or accelerated solvent extraction methods.

  17. Chemotaxonomic markers of organic, natural, and genetically modified soybeans detected by direct infusion electrospray ionization mass spectrometry

    International Nuclear Information System (INIS)

    Santos, L.S.; Catharino, R.R.; Eberlin, M.N.; Tsai, S.M.

    2006-01-01

    The crude methanolic extracts of a single bean from samples of organic, natural or genetically modified (GM) soybeans [Glycine max. (Merrill) L.] were analyzed by direct infusion electrospray ionization mass spectrometry (ESI-MS). These extracts, containing the most polar natural products of soybeans (free aglycones, monoglucosides, diglucosides and esters including isoflavones and flavones) provide characteristic fingerprinting mass spectra owing to different proportions or sets of components. Spectra distinctiveness is confirmed by chemometric multivariate analysis of the ESIMS data, which place the three-types of beans into well-defined groups. When ESI-MS is applied, these polar components constitute therefore unique chemotaxonomic markers able to provide fast soybean typification. (author)

  18. Approaches towards the automated interpretation and prediction of electrospray tandem mass spectra of non-peptidic combinatorial compounds.

    Science.gov (United States)

    Klagkou, Katerina; Pullen, Frank; Harrison, Mark; Organ, Andy; Firth, Alistair; Langley, G John

    2003-01-01

    Combinatorial chemistry is widely used within the pharmaceutical industry as a means of rapid identification of potential drugs. With the growth of combinatorial libraries, mass spectrometry (MS) became the key analytical technique because of its speed of analysis, sensitivity, accuracy and ability to be coupled with other analytical techniques. In the majority of cases, electrospray mass spectrometry (ES-MS) has become the default ionisation technique. However, due to the absence of fragment ions in the resulting spectra, tandem mass spectrometry (MS/MS) is required to provide structural information for the identification of an unknown analyte. This work discusses the first steps of an investigation into the fragmentation pathways taking place in electrospray tandem mass spectrometry. The ultimate goal for this project is to set general fragmentation rules for non-peptidic, pharmaceutical, combinatorial compounds. As an aid, an artificial intelligence (AI) software package is used to facilitate interpretation of the spectra. This initial study has focused on determining the fragmentation rules for some classes of compound types that fit the remit as outlined above. Based on studies carried out on several combinatorial libraries of these compounds, it was established that different classes of drug molecules follow unique fragmentation pathways. In addition to these general observations, the specific ionisation processes and the fragmentation pathways involved in the electrospray mass spectra of these systems were explored. The ultimate goal will be to incorporate our findings into the computer program and allow identification of an unknown, non-peptidic compound following insertion of its ES-MS/MS spectrum into the AI package. The work herein demonstrates the potential benefit of such an approach in addressing the issue of high-throughput, automated MS/MS data interpretation. Copyright 2003 John Wiley & Sons, Ltd.

  19. Visualisation of abscisic acid and 12-oxo-phytodienoic acid in immature Phaseolus vulgaris L. seeds using desorption electrospray ionisation-imaging mass spectrometry

    Science.gov (United States)

    Enomoto, Hirofumi; Sensu, Takuya; Sato, Kei; Sato, Futoshi; Paxton, Thanai; Yumoto, Emi; Miyamoto, Koji; Asahina, Masashi; Yokota, Takao; Yamane, Hisakazu

    2017-02-01

    The plant hormone abscisic acid (ABA) and the jasmonic acid related-compound 12-oxo-phytodienoic acid (OPDA) play crucial roles in seed development, dormancy, and germination. However, a lack of suitable techniques for visualising plant hormones has restricted the investigation of their biological mechanisms. In the present study, desorption electrospray ionisation-imaging mass spectrometry (DESI-IMS), a powerful tool for visualising metabolites in biological tissues, was used to visualise ABA and OPDA in immature Phaseolus vulgaris L. seed sections. The mass spectra, peak values and chemical formulae obtained from the analysis of seed sections were consistent with those determined for ABA and OPDA standards, as were the precursor and major fragment ions observed in tandem mass spectrometry (MS/MS) imaging. Furthermore, the precursor and fragment ion images showed similar distribution patterns. In addition, the localisation of ABA and OPDA using DESI-IMS was confirmed using liquid chromatography-MS/MS (LC-MS/MS). The results indicated that ABA was mainly distributed in the radical and cotyledon of the embryo, whereas OPDA was distributed exclusively in external structures, such as the hilum and seed coat. The present study is the first to report the visualisation of plant hormones using IMS, and demonstrates that DESI-IMS is a promising technique for future plant hormone research.

  20. Visualisation of abscisic acid and 12-oxo-phytodienoic acid in immature Phaseolus vulgaris L. seeds using desorption electrospray ionisation-imaging mass spectrometry.

    Science.gov (United States)

    Enomoto, Hirofumi; Sensu, Takuya; Sato, Kei; Sato, Futoshi; Paxton, Thanai; Yumoto, Emi; Miyamoto, Koji; Asahina, Masashi; Yokota, Takao; Yamane, Hisakazu

    2017-02-17

    The plant hormone abscisic acid (ABA) and the jasmonic acid related-compound 12-oxo-phytodienoic acid (OPDA) play crucial roles in seed development, dormancy, and germination. However, a lack of suitable techniques for visualising plant hormones has restricted the investigation of their biological mechanisms. In the present study, desorption electrospray ionisation-imaging mass spectrometry (DESI-IMS), a powerful tool for visualising metabolites in biological tissues, was used to visualise ABA and OPDA in immature Phaseolus vulgaris L. seed sections. The mass spectra, peak values and chemical formulae obtained from the analysis of seed sections were consistent with those determined for ABA and OPDA standards, as were the precursor and major fragment ions observed in tandem mass spectrometry (MS/MS) imaging. Furthermore, the precursor and fragment ion images showed similar distribution patterns. In addition, the localisation of ABA and OPDA using DESI-IMS was confirmed using liquid chromatography-MS/MS (LC-MS/MS). The results indicated that ABA was mainly distributed in the radical and cotyledon of the embryo, whereas OPDA was distributed exclusively in external structures, such as the hilum and seed coat. The present study is the first to report the visualisation of plant hormones using IMS, and demonstrates that DESI-IMS is a promising technique for future plant hormone research.

  1. Electrospray Ionization Mass Spectrometry: From Cluster Ions to Toxic metal Ions in Biology

    Energy Technology Data Exchange (ETDEWEB)

    Lentz, Nicholas B. [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    This dissertation focused on using electrospray ionization mass spectrometry to study cluster ions and toxic metal ions in biology. In Chapter 2, it was shown that primary, secondary and quarternary amines exhibit different clustering characteristics under identical instrument conditions. Carbon chain length also played a role in cluster ion formation. In Chapters 3 and 4, the effects of solvent types/ratios and various instrumental parameters on cluster ion formation were examined. It was found that instrument interface design also plays a critical role in the cluster ion distribution seen in the mass spectrum. In Chapter 5, ESI-MS was used to investigate toxic metal binding to the [Gln11]-amyloid β-protein fragment (1-16). Pb and Cd bound stronger than Zn, even in the presence of excess Zn. Hg bound weaker than Zn. There are endless options for future work on cluster ions. Any molecule that is poorly ionized in positive ion mode can potentially show an increase in ionization efficiency if an appropriate anion is used to produce a net negative charge. It is possible that drug protein or drug/DNA complexes can also be stabilized by adding counter-ions. This would preserve the solution characteristics of the complex in the gas phase. Once in the gas phase, CID could determine the drug binding location on the biomolecule. There are many research projects regarding toxic metals in biology that have yet to be investigated or even discovered. This is an area of research with an almost endless future because of the changing dynamics of biological systems. What is deemed safe today may show toxic effects in the future. Evolutionary changes in protein structures may render them more susceptible to toxic metal binding. As the understanding of toxicity evolves, so does the demand for new toxic metal research. New instrumentation designs and software make it possible to perform research that could not be done in the past. What was undetectable yesterday will

  2. Pyrolysis - gas chromatography - mass spectrometry of lignins

    Energy Technology Data Exchange (ETDEWEB)

    Martin, F.; Saiz-Jimenez, C.; Gonzalez-Vila, F.J.

    1979-01-01

    Milled wood lignins from spruce, beech and bamboo were pyrolysed. The high-boiling products of pyrolysis were studied by GLC and mass spectrometry. The forty-three products identified provide information on the structural units of lignin.

  3. Radiogas chromatography mass spectrometry in the selected ion monitoring mode

    International Nuclear Information System (INIS)

    Doerfler, D.L.; Rosenblum, E.R.; Malloy, J.M.; Naworal, J.D.; McManus, I.R.; Campbell, I.M.

    1980-01-01

    The value of selected ion monitoring in analyzing biological radio isotope incorporation experiments by radiogas chromatography mass spectrometry is illustrated with reference to the biosynthesis of the mycotoxin mycophenolic acid in Penicillium brevicompactum and the mode of action of the anticholesterolemic drug 20,25-diazacholesterol. Both examples used 1-[ 14 C]acetate precursors. It is shown that the increased sensitivity and specificity of the selected ion monitoring mode detector permits straightforward detection and identification of the relatively small cellular pools associated with metabolic intermediates. The computer program RADSIM is described. Problems that still exist in using radiogas gas chromatography mass spectrometry technology to analyse isotope incorporation experiments are discussed. (author)

  4. Therapeutic drug monitoring of immunosuppressant drugs by high-performance liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Taylor, Paul J

    2004-04-01

    The currently expanding range of immunosuppressant agents has placed new challenges on therapeutic drug-monitoring (TDM) services. Many of these drugs require the measurement of concentrations with subsequent dosage adjustment to maximize efficacy while minimizing toxicity. HPLC-mass spectrometry (HPLC-MS) is a relatively new technique for drug quantification and thus TDM of immunosuppressant drugs. Although mass spectrometry relies on producing, differentiating, and detecting ions in the gas phase, the development of the atmospheric pressure ionization interface (electrospray and chemical ionization) has enabled the direct coupling of solution introduction of compounds, via HPLC, to the mass analyzer. The impetus for using HPLC-MS for immunosuppressant measurement has come from the highly potent low-dose immunosuppressant drugs tacrolimus and sirolimus, which have low nanogram per milliliter circulating concentrations. A number of strategies have been reported for sample preparation and ways to automate these processes with solid-phase extraction and 2-dimensional chromatography. The disadvantages of HPLC-MS are initial cost of equipment and availability of suitably skilled scientific staff. The advantages of HPLC-mass spectrometry are high sensitivity, specificity, small sample requirements, minimal sample preparation, rapid throughput, and simultaneous measurement. Further, scientists have the ability to develop methods to measure new immunosuppressant drugs by HPLC-MS before commercial assays become available. With potential applications increasing in immunosuppressive drug monitoring, it can be envisaged that HPLC-MS may become standard equipment in TDM laboratories of the future.

  5. Applicability of generic assays based on liquid chromatography–electrospray mass spectrometry to study in vitro metabolism of 55 structurally diverse compounds

    Directory of Open Access Journals (Sweden)

    Timo Rousu

    2010-08-01

    Full Text Available Liquid chromatography-mass spectrometry (LC/MS with generic gradient elution for a large number of chemically different compounds is a common approach in drug development, used to acquire a large amount of data in a short time frame for drug candidates. The analysis with non-optimised parameters however may lead to a poor method performance for many compounds, and contains a risk of losing important information. Here, generic electrospray-time-of-flight (ESI-TOF MS methods in various pH conditions were tested for 55 chemically diverse compounds (10 acids, 25 bases, 17 neutrals and 3 amphoterics, aiming to find best analytical conditions for each compound, for studies of in vitro metabolic properties in liver preparations. The effect of eluent pH and elution gradient strength on chromatographic performance and electrospray MS ionisation efficiency were examined for each compound. The data are evaluated how well the best generic approach could cover the analysis of test compounds and how many compounds would still need completely different analytical conditions after that. Aqueous mobile phase consisting of 0.05% acetic acid and 5 mM ammonium acetate (pH 4.4 showed the best general suitability for the analyses, showing adequate performance for metabolite profiling for 41 out of 55 compounds either in positive or negative ion mode. In positive ion mode, the main limitation of performance in various pH conditions was generally not the lack of ionisation, but rather the poor chromatographic performance (inadequate retention or poor peak shape, suggesting that more emphasis should be put in finding conditions providing best chromatographic performance, rather than highest ionisation properties. However, a single generic approach for a large number of different compounds is not likely to produce good results for all compounds. Preferably, at least two or three different conditions are needed for the coverage of a larger number of structurally diverse

  6. Turnover rates in microorganisms by laser ablation electrospray ionization mass spectrometry and pulse-chase analysis

    Energy Technology Data Exchange (ETDEWEB)

    Stopka, Sylwia A.; Mansour, Tarek R.; Shrestha, Bindesh [Department of Chemistry, W.M. Keck Institute for Proteomics Technology and Applications, The George Washington University, Washington, DC 20052 (United States); Maréchal, Éric; Falconet, Denis [Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, CEA-CNRS-INRA-Univ. Grenoble Alpes, Grenoble (France); Vertes, Akos, E-mail: vertes@gwu.edu [Department of Chemistry, W.M. Keck Institute for Proteomics Technology and Applications, The George Washington University, Washington, DC 20052 (United States)

    2016-01-01

    Biochemical processes rely on elaborate networks containing thousands of compounds participating in thousands of reaction. Rapid turnover of diverse metabolites and lipids in an organism is an essential part of homeostasis. It affects energy production and storage, two important processes utilized in bioengineering. Conventional approaches to simultaneously quantify a large number of turnover rates in biological systems are currently not feasible. Here we show that pulse-chase analysis followed by laser ablation electrospray ionization mass spectrometry (LAESI-MS) enable the simultaneous and rapid determination of metabolic turnover rates. The incorporation of ion mobility separation (IMS) allowed an additional dimension of analysis, i.e., the detection and identification of isotopologs based on their collision cross sections. We demonstrated these capabilities by determining metabolite, lipid, and peptide turnover in the photosynthetic green algae, Chlamydomonas reinhardtii, in the presence of {sup 15}N-labeled ammonium chloride as the main nitrogen source. Following the reversal of isotope patterns in the chase phase by LAESI-IMS-MS revealed the turnover rates and half-lives for biochemical species with a wide range of natural concentrations, e.g., chlorophyll metabolites, lipids, and peptides. For example, the half-lives of lyso-DGTS(16:0) and DGTS(18:3/16:0), t{sub 1/2} = 43.6 ± 4.5 h and 47.6 ± 2.2 h, respectively, provided insight into lipid synthesis and degradation in this organism. Within the same experiment, half-lives for chlorophyll a, t{sub 1/2} = 24.1 ± 2.2 h, and a 2.8 kDa peptide, t{sub 1/2} = 10.4 ± 3.6 h, were also determined. - Highlights: • High-throughput pulse-chase analysis using direct sampling of biological cells. • Ion mobility separation for the elucidation of isotopologs. • Identification of isotopologs in difference heat plots of DT vs. m/z. • Simultaneous determination of turnover rates for lipids and

  7. Toward unraveling grape tannin composition: application of online hydrophilic interaction chromatography × reversed-phase liquid chromatography-time-of-flight mass spectrometry for grape seed analysis.

    Science.gov (United States)

    Kalili, Kathithileni M; Vestner, Jochen; Stander, Maria A; de Villiers, André

    2013-10-01

    Despite the significant importance of tannins in viticulture and enology, relatively little is known about the detailed chemical composition of these molecules. This is due to challenges associated with the accurate analytical determination of the highly structurally diverse proanthocyanidins which comprise tannins. In this contribution, we address this limitation by demonstrating how online comprehensive two-dimensional liquid chromatography (LC × LC) coupled to high resolution mass spectrometry (HR-MS) can be exploited as a powerful analytical approach for the detailed characterization of grape seed tannins. Hydrophilic interaction chromatography (HILIC) and reversed-phase liquid chromatography (RP-LC) were employed in the two dimensions to provide complementary information in terms of separation according to hydrophilicity and hydrophobicity, respectively. Online coupling of HILIC × RP-LC with fluorescence detection and electrospray ionization MS delivered high resolution analysis in a practical analysis time, while allowing selective detection and facilitating compound identification. Time-of-flight (TOF) MS provided high acquisition rates and sensitivity coupled to accurate mass information, which allowed detection of procyanidins up to a degree of polymerization (DP) of 16 and a degree of galloylation up to 8 in a red grape seed extract. This analytical methodology promises to shed new light on these important grape constituents and potentially on their evolution during wine production.

  8. Gas-phase copper and silver complexes with phosphorothioate and phosphorodithioate pesticides investigated using electrospray ionization mass spectrometry.

    Science.gov (United States)

    Mustapha, Adetayo M; Pasilis, Sofie P

    2015-01-01

    Efforts to improve agricultural productivity have led to a growing dependency on organophosphorus pesticides. Phosphorothioate and phosphorodithioate pesticides are organophosphorus pesticide subclasses with widespread application for the control of insects feeding on vegetables and fruits. However, even low doses of these pesticides can cause neurological problems in humans; thus, their determination and monitoring in agricultural foodstuffs is important for human health. Phosphorothioate and phosphorodithioate pesticides may be poorly ionized during electrospray, adversely affecting limits of detection. These pesticides can form complexes with Cu(2+) and Ag(+) , however, potentially improving ionization. In the present work, we used electrospray ionization/mass spectrometry (ESI/MS) to study fenitrothion, parathion, diazinon, and malathion coordination complexes with silver and copper ions. Stable 1 : 1 and 1 : 2 metal/pesticide complexes were detected. Mass spectra acquired from pesticide solutions containing Ag(+) or Cu(2+) showed a significant increase in signal-to-background ratio over those acquired from solutions containing only the pesticides, with Ag(+) improving detection more effectively than Cu(2+). Addition of Ag(+) to a pesticide solution improved the limit of detection by ten times. The relative affinity of each pesticide for Ag(+) was related to complex stability, following the order diazinon > malathion > fenitrothion > parathion. The formation of Ag(+)-pesticide complexes can significantly improve the detection of phosphorothioate and phosphorodithioate pesticides using ESI/MS. The technique could potentially be used in reactive desorption electrospray ionization/mass spectrometry to detect phosphorothioate and phosphorodithioate pesticides on fruit and vegetable skins. Copyright © 2015 John Wiley & Sons, Ltd.

  9. Subtle differences in molecular recognition between modified glycopeptide antibiotics and bacterial receptor peptides identified by electrospray ionization mass spectrometry

    DEFF Research Database (Denmark)

    Jørgensen, Thomas J. D.; Staroske, T; Roepstorff, P

    1999-01-01

    showing that electrospray ionization mass spectrometry (ESI-MS) can be used in the rapid quantitative analysis of mixtures of vancomycin-group antibiotics and their bacterial cell-wall receptors allowing the identification of even subtle differences in binding constants. Differences in affinities...... are quantified for a mixture of vancomycin antibiotics (vancomycin, dechlorovancomycin and N-demethylvancomycin) and for a mixture of ristocetin A and its pseudoaglycone. Binding constants determined by ESI-MS were found to be in close agreement with those determined by more direct methods in aqueous solution....

  10. Novel product ions of 2-aminoanilide and benzimidazole Ag(I) complexes using electrospray ionization with multi-stage tandem mass spectrometry.

    Science.gov (United States)

    Johnson, Byron S; Burinsky, David J; Burova, Svetlana A; Davis, Roman; Fitzgerald, Russ N; Matsuoka, Richard T

    2012-05-15

    The 2-aminoaniline scaffold is of significant value to the pharmaceutical industry and is embedded in a number of pharmacophores including 2-aminoanilides and benzimidazoles. A novel application of coordination ion spray mass spectrometry (CIS-MS) for interrogating the silver ion (Ag(+)) complexes of a homologous series of these compounds using multi-stage tandem mass spectrometry is described. Unlike the ubiquitous alkali metal ion complexes, Ag(+) complexes of 2-aminoanilides and benzimidazoles were found to yield [M - H](+) ions in significant abundance via gas-phase elimination of the metal hydride (AgH) resulting in unique product ion cascades. Sample introduction was by liquid chromatography with mass spectrometry analysis performed on a hybrid linear ion trap/orbitrap instrument capable of high-resolution measurements. Rigorous structural characterization by multi-stage tandem mass spectrometry using [M +  H](+), [M - H](-) and [M - H](+) precursor ions derived from ESI and CIS experiments was performed for the homologous series of 2-aminoanilide and benzimidazole compounds. A full tabular comparison of structural information resulting from these product ion cascades was produced. Multi-stage tandem mass spectrometry of [M - H](+) ions resulting from Ag(+) complexes of 2-aminoanilides and benzimidazoles in CIS-MS experiments produced unique product ion cascades that exhibited complementary structural information to that obtained from tandem mass spectrometry of [M  +  H](+) and [M - H](-) ions by electrospray ionization (ESI). These observations may be broadly applicable to other compounds that are observed to form Ag(+) complexes and eliminate AgH. Copyright © 2012 John Wiley & Sons, Ltd.

  11. Liquid Microjunction Surface Sampling Probe Electrospray Mass Spectrometry for Detection of Drugs and Metabolites in Thin Tissue Sections

    Energy Technology Data Exchange (ETDEWEB)

    Van Berkel, Gary J [ORNL; Kertesz, Vilmos [ORNL; Koeplinger, Kenneth A. [Merck Research Laboratories; Vavek, Marissa [Merck Research Laboratories; Kong, Ah-Ng Tony [Rutgers University

    2008-01-01

    A self-aspirating, liquid micro-junction surface sampling probe/electrospray emitter mass spectrometry system was demonstrated for use in the direct analysis of spotted and dosed drugs and their metabolites in thin tissue sections. Proof-of-principle sampling and analysis directly from tissue without the need for sample preparation was demonstrated first by raster scanning a region on a section of rat liver onto which reserpine was spotted. The mass spectral signal from selected reaction monitoring was used to develop a chemical image of the spotted drug on the tissue. The probe was also used to selectively spot sample areas of sagittal whole mouse body tissue sections that had been dosed orally (90 mg/kg) with R,S-sulforaphane 3 hrs prior to sacrifice. Sulforaphane and its glutathione and N-acetyl cysteine conjugates were monitored with selected reaction monitoring and detected in the stomach and various other tissues from the dosed mouse. No signal for these species was observed in the tissue from a control mouse. The same dosed tissue section was used to illustrate the possibility of obtaining a line scan across the whole body section. In total these results illustrate the potential for rapid screening of the distribution of drugs and metabolites in tissue sections with the micro-liquid junction surface sampling probe/electrospray mass spectrometry approach.

  12. Matrix effect on the determination of synthetic corticosteroids and diuretics by liquid chromatography-tandem mass spectrometry

    Science.gov (United States)

    Dikunets, M. A.; Appolonova, S. A.; Rodchenkov, G. M.

    2009-04-01

    This work presents a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) procedure for selective and reliable screening of corticosteroids and diuretics in human urine. Sample preparation included the extraction, evaporation of the organic extract under nitrogen, and solution of the dry residue. The extract was analyzed by HPLC combined with tandem mass spectrometry using electro-spraying ionization at atmospheric pressure with negative ion recording. The mass spectra of all compounds were recorded, and the characteristic ions, retention times, and detection limits were determined. The procedure was validated by evaluating the degree of the matrix suppression of ionization, extraction of analytes from human biological liquid, and the selectivity and specificity of determination.

  13. Liquid ChromatographyMass Spectrometry Method for the ...

    African Journals Online (AJOL)

    Purpose: To develop and validate a simple and selective high performance liquid chromatography photo diode array mass spectrometry (HPLC-PDA-MS/MS) method for simultaneous determination and confirmation of seven major active alkaloids (6-Hydroxy-ß-Carboline-1-carboxylic acid, ß-Carboline-1- carboxylic acid, ...

  14. Analysis of essential oils by gas chromatography and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Masada, Y.

    1976-01-01

    The book is in two parts: first part Essential Oil includes compositae; labiatae; verbenaceae; oleaceae; umbelliferae; myrtaceae; euphorbiaceae; rutaceae; geraniaceae; rosaceae; lauraceae; myristicaceae; anonaceae; santalaceae; moraceae; piperaceae; zingiberaceae; araceae; gramineae; and cupressaceae written in English and Japanese. Part two includes essential oil; gas chromatography, and mass spectrometry written in Japanese. (DP)

  15. Gas chromatography mass spectrometry : key technology in metabolomics

    NARCIS (Netherlands)

    Koek, Maud Marijtje

    2009-01-01

    Metabolomics involves the unbiased quantitative and qualitative analysis of the complete set of metabolites present in cells, body fluids and tissues. Gas chromatography coupled to mass spectrometry (GC-MS) is very suitable for metabolomics analysis, as it combines high separation power with

  16. Gas Chromatography Mass Spectrometry of Quassia undulata Seed ...

    African Journals Online (AJOL)

    Prof. Ogunji

    Key words: Quassia undulata, GC MS, Biodiesel, Gbur, seed oil, Gas Chromatography, Mass. Spectrometry. Correspondence: waneniko@yahoo.co.uk ... these triglycerides and their applications depend on the fatty acid constituents .... injector temperature of 250°C and ion source temperature of 200°C and a split ratio of ...

  17. Gas Chromatography-Mass Spectrometric Analysis of Nematicidal ...

    African Journals Online (AJOL)

    chromatography (GC) and gas chromaotography-mass spectrometry (GC-MS). The nematicidal activity of the essential oil and its major constituents was determined against second stage juveniles of H. avenae. Results: A total of 33 components of the essential oil were identified. The major constituents were bornyl acetate ...

  18. Specialized Gas Chromatography--Mass Spectrometry Systems for Clinical Chemistry.

    Science.gov (United States)

    Gochman, Nathan; And Others

    1979-01-01

    A discussion of the basic design and characteristics of gas chromatography-mass spectrometry systems used in clinical chemistry. A comparison of three specific systems: the Vitek Olfax IIA, Hewlett-Packard HP5992, and Du Pont DP-102 are included. (BB)

  19. Coordination chemistry of nickel(II) nitrate with superbasic guanidines studied by electrospray mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Glasovac, Z.; Štrukil, V.; Eckert-Maksič, M.; Schröder, Detlef; Schlangen, M.; Schwarz, H.

    2010-01-01

    Roč. 290, č. 1 (2010), s. 22-31 ISSN 1387-3806 R&D Projects: GA ČR GA203/08/1487 Grant - others: ERC (XE) HORIZOMS AdG226373 Institutional research plan: CEZ:AV0Z40550506 Keywords : electrospray ionization * guanidine * ion association * nickel(II) nitrate * solvation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.009, year: 2010

  20. Clinical applications of gas chromatography and gas chromatography-mass spectrometry of steroids

    NARCIS (Netherlands)

    Wolthers, BG; Kraan, GPB

    1999-01-01

    This review article underlines the importance of gas chromatography-mass spectrometry (GC-MS) for determination of steroids in man. The use of steroids labelled with stable isotopes as internal standard and subsequent analysis by GC-MS yields up to now the only reliable measurement of steroids in

  1. Determination of quaternary ammonium biocides by liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Núñez, Oscar; Moyano, Encarnación; Galceran, Maria Teresa

    2004-11-26

    In this study we have developed a method for the direct determination of benzalkonium chloride (BAC) homologues and didecyldimethylammonium chloride (DDMAC), generally used as biocides. The chromatographic separation was performed using a Luna C18 column and gradient elution. A 50 mM formic acid-ammonium formate buffer at pH 3.5 was used as aqueous phase to allow ion-pair formation with the quaternary ammonium biocides. The detection was carried out using an ion trap mass analyser and electrospray ionisation (ESI) source. Parameters such as the magnitude and duration of the resonant excitation voltage and the magnitude of the trapping RF voltage for full scan tandem mass spectrometry (MS-MS) experiments were studied to establish the optimal experimental conditions. Instrumental quality parameters of both liquid chromatography coupled to mass spectrometry (LC-MS) and LC-MS-MS methods were studied and good run-to-run and day-to-day precision values (relative standard deviations, RSDs lower than 11%) and LODs down to 0.1 microg L(-1) (LC-MS-MS) were obtained. Finally, the applicability of the LC-MS-MS method was demonstrated by analysis of a spiked water sample and some commercial products containing BAC.

  2. Rapid characterization of trace aflatoxin B1 in groundnuts, wheat and maize by dispersive liquid-liquid microextraction followed by direct electrospray probe tandem mass spectrometry.

    Science.gov (United States)

    Satarpai, Thiphol; Siripinyanond, Atitaya; Su, Hung; Shiea, Jentaie

    2017-04-30

    Aflatoxins are poisonous and cancer-related chemical compounds commonly found in crops and plants. Aflatoxin B 1 is the most toxic compound among aflatoxins and has been classified as group 1 carcinogenic to humans, especially in liver cancer. Herein, an ambient mass spectrometric method was developed for rapid characterization of trace aflatoxin B 1 in peanuts. Direct electrospray probe tandem mass spectrometry (DEP-MS/MS) was used to detect aflatoxin B 1 in peanuts. To avoid the matrix effect, the aflatoxin B 1 in the samples was extracted and concentrated by dispersive liquid-liquid microextraction. The mass spectrometer was operated in the positive ion mode to monitor the intact molecular ion (m/z 313, MH + ) and product ion (m/z 241) of aflatoxin B 1 using multiple reaction monitoring. Since no clean-up procedure of the sample was required, the sampling step and the subsequent mass spectrometric detection of the aflatoxin B 1 was completed in less than 5 min. The limit of detection of aflatoxin B 1 is at the sub-ppb level. The results obtained by DEP-MS/MS were also validated by liquid chromatography/tandem mass spectrometry (LC/MS/MS). Recovery of aflatoxin B 1 in the sample was evaluated by analyzing spiked aflatoxin B 1 with LC/MS/MS to be 85% and DEP-MS/MS to be 84%. DEP-MS/MS combined with a simple dispersive liquid-liquid microextraction procedure was successfully used for the quantitative analysis of AFB 1 in nut samples. Due to its high efficiency, it is promising in providing important toxicological information for food safety in the real world. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  3. Golf ball-assisted electrospray ionization of mass spectrometry for the determination of trace amino acids in complex samples.

    Science.gov (United States)

    Li, Yen-Hsien; Chen, Chung-Yu; Kuo, Cheng-Hsiung; Lee, Maw-Rong

    2016-09-28

    During the electrospray ionization (ESI) process, ions move through a heated capillary aperture to be detected on arrival at a mass analyzer. However, the ESI process creates an ion plume, which expands into an ion cloud with an area larger than that of the heated capillary aperture, significantly contributing to an ion loss of 50% due to coulombic repulsion. The use of DC and RF fields to focus ions from the ion source into the vacuum chamber has been proposed in the literature, but the improvement of ion transmission efficiency is limited. To improve ion transmission, in this study we propose a novel method using a home-made golf ball positioned between the ion source and the inlet of the mass analyzer to hydrodynamically focus the ions passing through the golf ball. The ion plume produced by the ESI process passes through the golf ball will reduce the size of the ion cloud then be focused and most of them flowed into the mass analyzer. Therefore, the sensitivity will be improved, the aim of this investigation is to study the enhancing of the signal using golf ball-assisted electrospray ionization liquid chromatography tandem mass spectrometry (LC-MS/MS) to determine 20 trace amino acids in complex samples, including tea, urine and serum. The results showed that the analytical performance of the determination of the 20 amino acids in tea, urine and serum samples using the home-made golf ball-assisted ESI source is better than that of a commercial ESI source. The signal intensities of the 20 amino acids were enhanced by factors of 2-2700, 11-2525, and 31-342680 in oolong tea, urine and serum analyses, respectively. The precision of the proposed method ranged from 1-9%, 0.4-9% and 0.4-8% at low, medium and high concentration levels of amino acids, respectively. The home-made golf ball-assisted ESI source effectively increased the signal intensity and enhanced the ion transmission efficiency and is also an easy, convenient and economical device. This technique can

  4. The detection of iron protoporphyrin (heme b) in phytoplankton and marine particulate material by electrospray ionisation mass spectrometry – comparison with diode array detection

    Energy Technology Data Exchange (ETDEWEB)

    Gledhill, Martha, E-mail: m.gledhill@geomar.de

    2014-09-02

    Highlights: • Mass spectrometry was applied to the analysis of heme b in biological material. • Optimal conditions involved selective reactant monitoring of the heme b product ion. • The isotopic signature for this iron tetrapyrrole further improved selectivity. • Mass spectrometry and spectrophotometry were compared for heme b analysis. • Combining techniques made a powerful tool for analysis of heme in marine microbes. - Abstract: A mass spectrometric (MS) method for the identification of iron protoporphyrin (IX) (FePTP, heme b) in marine particulate material and phytoplankton is described. Electrospray ionisation of FePTP produced the molecular Fe(III)PTP{sup +} ion (m/z = 616) or the pseudomolecular [Fe(II)PTP + H]{sup +} ion (m/z = 617), depending on the oxidation state of the central iron ion. Collision induced dissociation (CID) in the ion trap mass spectrometer resulted in a single detected product ion (m/z = 557) indicative of loss of ethanoic acid from a carboxylic acid side chain. Widening the isolation width to 616 ± 3 resulted in production of a mass spectrum demonstrating the distinctive isotopic ratio of the iron containing fragment, further increasing the specificity of the analysis. Selective reactant monitoring (SRM) of the fragment ion (m/z = 557) was applied to the detection of FePTP after chromatography of ammoniacal OGP extracts of marine samples. The detection limit for FePTP analysed by SRM after chromatography was 1.2 ± 0.5 fmol. For phytoplankton samples, reasonably good agreement was achieved between results obtained with SRM and those obtained by monitoring absorbance at λ = 400 nm using a diode array detector (DAD). Use of SRM for analysis of particulate material obtained from the high latitude North Atlantic allowed for the analysis of FePTP in the presence of a co-eluting compound that interfered with detection by DAD. Simultaneous collection of mass spectra from m/z = 300 to 1500 resulted in identification of the

  5. Stabilization of gas-phase uranyl complexes enables rapid speciation using electrospray ionization and ion mobility-mass spectrometry.

    Science.gov (United States)

    Davis, Austen L; Clowers, Brian H

    2018-01-01

    Significant challenges exist when characterizing f-element complexes in solution using traditional approaches such as electrochemical and spectroscopic techniques as they do not always capture information for lower abundance species. However, provided a metal-complex with sufficient stability, soft ionization techniques such as electrospray offer a means to quantify and probe the characteristics of such systems using mass spectrometry. Unfortunately, the gas-phase species observed in ESI-MS systems do not always reflect the solution phase distributions due to the inherent electrochemical mechanism of the electrospray process, ion transfer from ambient to low pressures conditions, and other factors that are related to droplet evaporation. Even for simple systems (e.g. hydrated cations), it is not always clear whether the distribution observed reflects the solution phase populations or whether it is simply a result of the ionization process. This complexity is further compounded in mixed solvent systems and when multiply charged species are present. Despite these challenges, the benefits of mass spectrometry with respect to speed, sensitivity, and the ability to resolve isotopes continue to drive efforts to develop techniques for the speciation of metal complexes. Using an electrospray ionization atmospheric pressure ion mobility mass spectrometer (ESI-apIMS-MS), we demonstrate an approach to stabilize simple uranyl complexes during the ionization process and mobility separation to aid speciation and isotope profile analysis. Specifically, we outline and demonstrate the capacity of ESI-apIMS-MS methods to measure mobilities of different uranyl species, in simple mixtures, by promoting stable gas phase conformations with the addition of sulfoxides (i.e. dimethyl sulfoxide (DMSO), dibutyl sulfoxide (DBSO), and methyl phenyl sulfoxide (MPSO)). Addition of these sulfoxides, as observed in the mass spectrum and mobility domain, produce stable gas-phase conformations that

  6. Profiling an electrospray plume by laser-induced fluorescence and Fraunhofer diffraction combined to mass spectrometry: influence of size and composition of droplets on charge-state distributions of electrosprayed proteins.

    Science.gov (United States)

    Girod, Marion; Dagany, Xavier; Boutou, Véronique; Broyer, Michel; Antoine, Rodolphe; Dugourd, Philippe; Mordehai, Alex; Love, Craig; Werlich, Mark; Fjeldsted, John; Stafford, George

    2012-07-14

    We investigated how physico-chemical properties of charged droplets are affected by the electrospray process, using simultaneous in situ measurements by laser-induced fluorescence (LIF), Fraunhofer diffraction and mass spectrometry. For this purpose, we implemented a laser-induced-fluorescence profiling setup in conjunction with a fast, high-resolution particle sizing scheme on a modified Agilent Jet Stream electrospray source coupled to a single quadrupole mass analyser. The optical setup permits us to profile the solvent fractionation and the size of the droplets as they evaporate in an electrospray plume by measuring both the angular scattering pattern and emission spectra of a solvatochromic fluorescent dye. Mass spectra are recorded simultaneously. These mass spectrometry and optical spectroscopy investigations allow us to study the relation between the observed charge-state distributions of protein anions and physico-chemical properties of evaporating droplets in the spray plume. By mixing water with methanol, a refolding of cytochrome C is observed as the water percentage increases in the plume due to the preponderant evaporation of volatile methanol.

  7. Chemical fingerprint analysis of phenolics of Albizia chinensis based on ultra-performance LC-electrospray ionization-quadrupole time-of-flight mass spectrometry and antioxidant activity.

    Science.gov (United States)

    Chaudhary, Abha; Kaur, Pushpinder; Kumar, Neeraj; Singh, Bikram; Awasthi, Shiv; Lal, Brij

    2011-11-01

    Albizia species have been shown to have anti-inflammatory and anti-allergic properties. However, efficient analytical methods for identification of their active constituents are still lacking. Ultra-performance liquid chromatography coupled with electrospray ionization-quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOF-MS) was used to study the phenolic composition of the ethanolic extracts of different parts (flowers, leaves, pods and bark) of A. chinensis. In addition, the antioxidant activity of the ethanolic extracts was evaluated by the 1,1-diphenyl-2-picryl hydrazyl (DPPH) free-radical and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical cation scavenging methods. Four compounds were isolated from the ethanolic extract of the flowers and characterized by 1H and 13C NMR spectroscopy as quercetin-3-O-rhamnoside, quercetin, quercetin-3-O-arabinofuranoside, and myricetin-3-O-rhamnoside. Separation and quantification of the phenolics was accomplished using a reversed-phase BEH C18 column with the mobile phase of methanol-water (0.05% formic acid), and detection wavelengths of 360 and 254 nm.

  8. Structural classification of acyl-substituted Quillaja saponins by electrospray ionisation ion trap multiple-stage mass spectrometry in combination with multivariate analysis.

    Science.gov (United States)

    Bankefors, Johan; Nord, Lars I; Kenne, Lennart

    2008-12-01

    Thirty-eight saponins in two chromatographic fractions (QH-B and QH-C) from Quillaja saponaria Molina have been separated by a two-step high-performance liquid chromatography (HPLC) procedure and investigated by electrospray ionisation ion trap multiple-stage mass spectrometry (ESI-ITMS(n)) in positive ion mode. MS(2) and MS(3) spectra of the compounds were investigated by principal component analysis (PCA) and could be classified by partial least squares - discriminant analysis (PLS-DA) according to the structures of the oligosaccharides at C-3 and C-28 of the saponins. Four minor components with novel structures were found in a previously non-investigated fraction of QH-C. The structures of two of these components, J1 and J1a, were predicted by PLS-DA whereas the structures of the two others, J2 and J3, were only partly predicted. The structures of J1 and J1a were composed of structural elements found in the 34 known saponins whereas a new acyl substituent, not included in the training set used for calibration of the PLS-DA models, was found in J2 and J3, making these two components outliers. The complete structures of the four components were confirmed by monosaccharide analysis, MS(n) data and (1)H NMR spectroscopy.

  9. Determination of olanzapine in whole blood using simple protein precipitation and liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Nielsen, Marie Katrine Klose; Johansen, Sys Stybe

    2009-01-01

    A simple, sensitive, and reproducible liquid chromatography-tandem mass spectrometry method has been developed and validated for the quantification of the antipsychotic drug olanzapine in whole blood using dibenzepine as internal standard (IS). After acidic methanol-induced protein precipitation...... of the whole blood samples, olanzapine and IS were chromatographed on a reversed-phase Zorbax Extend-C(18)-column at pH 9.0. Quantification was performed on a triple-quadrupole mass spectrometer employing electrospray ionization technique operating in multiple reaction monitoring and positive ion mode. Total...... chromatographic run time was 15 min, and calibration curve was linear over the concentration range of 0.005 to 0.50 mg/kg olanzapine in whole blood. The method was validated for selectivity, matrix interference, recovery, linearity, limit of detection, limit of quantitation (LOQ), accuracy, precision...

  10. Characterization of bis-carboxyethyl germanium sesquioxide and its complexes with amino acids using electrospray QqTOF mass spectrometry

    Science.gov (United States)

    Jirásko, R.; Holcapek, M.; Rosenberg, E.

    2009-02-01

    This work deals with the application of electrospray ionization mass spectrometry (ESI-MS) with QqTOF analyzer for the characterization of Ge-132 complexes with different amino acids in aqueous solution with the emphasis on the determination of elemental composition. ESI mass spectra provide complementary structural information in both polarity modes. Some reaction products were suggested based on the interpretation of high resolution mass spectra. Moreover, the experimental isotopic distributions of ions were compared with theoretical calculated isotopic clusters. The superposition of many ion overlays was observed due to the wide isotopic distributions of studied polyisotopic complexes. The high resolution QqTOF analyzer enabled the discrimination of these ion signals differing at least by 0.12 mass units. The occurrence of overlaid signals from ions with smaller mass difference was successfully recognized based on the shift of isotopic distribution, and their elemental composition was verified using mass accuracies of non-overlaid isotopes at the borders of the isotopic cluster. Mass spectra obtained with ion trap and single quadrupole analyzers support QqTOF data.

  11. Absolute quantification of norovirus capsid protein in food, water, and soil using synthetic peptides with electrospray and MALDI mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, Erica M. [Center for Environmental Security and Security Defense Systems Initiative, The Biodesign Institute, Arizona State University, 781 E. Terrace Mall, Tempe, AZ 85287-5904 (United States); Colquhoun, David R.; Schwab, Kellogg J. [Department of Environmental Health Sciences, The Johns Hopkins University, Bloomberg School of Public Health, 615 N. Wolfe St., Baltimore, MD 21205 (United States); Halden, Rolf U., E-mail: halden@asu.edu [Center for Environmental Security and Security Defense Systems Initiative, The Biodesign Institute, Arizona State University, 781 E. Terrace Mall, Tempe, AZ 85287-5904 (United States); Department of Environmental Health Sciences, The Johns Hopkins University, Bloomberg School of Public Health, 615 N. Wolfe St., Baltimore, MD 21205 (United States)

    2015-04-09

    Highlights: • Mass spectrometry-based methods for norovirus quantification are developed. • Absolute quantification is achieved using internal heavy isotope-labeled standards. • A single labeled peptide serves in two distinct detection strategies. • These methods are validated for food, water, and soil analysis. • MS-based detection limits are lowered by two orders of magnitude. - Abstract: Norovirus infections are one of the most prominent public health problems of microbial origin in the U.S. and other industrialized countries. Surveillance is necessary to prevent secondary infection, confirm successful cleanup after outbreaks, and track the causative agent. Quantitative mass spectrometry, based on absolute quantitation with stable-isotope labeled peptides, is a promising tool for norovirus monitoring because of its speed, sensitivity, and robustness in the face of environmental inhibitors. In the current study, we present two new methods for the detection of the norovirus genogroup I capsid protein using electrospray and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The peptide TLDPIEVPLEDVR was used to quantify norovirus-like particles down to 500 attomoles with electrospray and 100 attomoles with MALDI. With MALDI, we also demonstrate a detection limit of 1 femtomole and a quantitative dynamic range of 5 orders of magnitude in the presence of an environmental matrix effect. Due to the rapid processing time and applicability to a wide range of environmental sample types (bacterial lysate, produce, milk, soil, and groundwater), mass spectrometry-based absolute quantitation has a strong potential for use in public health and environmental sciences.

  12. Absolute quantification of norovirus capsid protein in food, water, and soil using synthetic peptides with electrospray and MALDI mass spectrometry

    International Nuclear Information System (INIS)

    Hartmann, Erica M.; Colquhoun, David R.; Schwab, Kellogg J.; Halden, Rolf U.

    2015-01-01

    Highlights: • Mass spectrometry-based methods for norovirus quantification are developed. • Absolute quantification is achieved using internal heavy isotope-labeled standards. • A single labeled peptide serves in two distinct detection strategies. • These methods are validated for food, water, and soil analysis. • MS-based detection limits are lowered by two orders of magnitude. - Abstract: Norovirus infections are one of the most prominent public health problems of microbial origin in the U.S. and other industrialized countries. Surveillance is necessary to prevent secondary infection, confirm successful cleanup after outbreaks, and track the causative agent. Quantitative mass spectrometry, based on absolute quantitation with stable-isotope labeled peptides, is a promising tool for norovirus monitoring because of its speed, sensitivity, and robustness in the face of environmental inhibitors. In the current study, we present two new methods for the detection of the norovirus genogroup I capsid protein using electrospray and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The peptide TLDPIEVPLEDVR was used to quantify norovirus-like particles down to 500 attomoles with electrospray and 100 attomoles with MALDI. With MALDI, we also demonstrate a detection limit of 1 femtomole and a quantitative dynamic range of 5 orders of magnitude in the presence of an environmental matrix effect. Due to the rapid processing time and applicability to a wide range of environmental sample types (bacterial lysate, produce, milk, soil, and groundwater), mass spectrometry-based absolute quantitation has a strong potential for use in public health and environmental sciences

  13. Characterization of the limonene oxidation products with liquid chromatography coupled to the tandem mass spectrometry

    Science.gov (United States)

    Witkowski, Bartłomiej; Gierczak, Tomasz

    2017-04-01

    Composition of the secondary organic aerosol (SOA) generated during ozonolysis of limonene was investigated with liquid chromatography coupled to the negative electrospray ionization (ESI), quadrupole tandem mass spectrometry (MS/MS) as well as high resolution Time-of-Flight mass spectrometry. Aerosol was generated in the flow-tube reactor. HR-MS/MS analysis allowed for proposing structures for the several up-to-date unknown limonene oxidation products. In addition to the low MW limonene oxidation products, significant quantities of oligomers characterized by elemental compositions: C19H30O5, C18H28O6, C19H28O7, C19H30O7 and C20H34O9 were detected in the SOA samples. It was concluded that these compounds are most likely esters, aldol reaction products and/or hemiacetals. In addition to detailed study of the limonene oxidation products, the reaction time as well as initial ozone concentration impact on the limonene SOA composition was investigated. The relative intensities of the two esters of the limonic acid and 7-hydroxy limononic acid increased as a result of lowering the initial ozone concentration and shortening the reaction time, indicating that esterification may be an important oligomerization pathway during limonene SOA formation.

  14. Quantitative analysis of mitragynine in human urine by high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Lu, Shijun; Tran, Buu N; Nelsen, Jamie L; Aldous, Kenneth M

    2009-08-15

    Mitragynine is the primary active alkaloid extracted from the leaves of Mitragyna speciosa Korth, a plant that originates in South-East Asia and is commonly known as kratom in Thailand. Kratom has been used for many centuries for their medicinal and psychoactive qualities, which are comparable to that of opiate-based drugs. Kratom abuse can lead to a detectable content of mitragynine residue in urine. Ultra trace amount of mitragynine in human urine was determined by a high performance liquid chromatography coupled to an electrospray tandem mass spectrometry (HPLC-ESI/MS/MS). Mitragynine was extracted by methyl t-butyl ether (MTBE) and separated on a HILIC column. The ESI/MS/MS was accomplished using a triple quadrupole mass spectrometer in positive ion detection and multiple reactions monitoring (MRM) mode. Ajmalicine, a mitragynine's structure analog was selected as internal standard (IS) for method development. Quality control (QC) performed at three levels 0.1, 1 and 5 ng/ml of mitragynine in urine gave mean recoveries of 90, 109, and 98% with average relative standard deviation of 22, 12 and 16%, respectively. The regression linearity of mitragynine calibration ranged from 0.01 to 5.0 ng/ml was achieved with correlation coefficient greater than 0.995. A detection limit of 0.02 ng/ml and high precision data within-day and between days analysis were obtained.

  15. Urinary screening for methylphenidate (Ritalin) abuse: a comparison of liquid chromatography-tandem mass spectrometry, gas chromatography-mass spectrometry, and immunoassay methods.

    Science.gov (United States)

    Eichhorst, J; Etter, M; Lepage, J; Lehotay, D C

    2004-03-01

    To develop a routine method for detecting methylphenidate (Ritalin) use among drug abusers using liquid chromatography-tandem mass spectrometry (LC/MS/MS). The new methodology was designed to replace less reliable and/or more expensive and time-consuming techniques (GC/MS and ELISA) currently employed in our laboratory, and to provide a combined one-step screening and confirmation LC/MS/MS method. Because methylphenidate abuse is very prevalent in Saskatchewan, there is a demand to provide high volume urine screening both to detect abuse, and to monitor compliance. Random urine samples sent for drugs of abuse testing, standards, and controls were diluted 1:100 in methanol. Diluted specimens were injected directly into an Agilent 1100 liquid chromatograph coupled to a Sciex API 2000 mass spectrometer. The method utilized selected reaction monitoring (SRM) as well as an electrospray ionization source (EIS) to detect both urinary methylphenidate and the more prevalent metabolite, ritalinic acid (RA). There appeared to be little or no sacrifice in sensitivity because the higher dilutions exhibited much less matrix effect. Limit of quantitation (LOQ) for methylphenidate was 100 nM and 500 nM for RA. Linear calibration curves from 100 to 1000 nM for Ritalin and 500 to 5000 nM for RA were acquired. Imprecision of spiked and true specimens did not exceed 10% and at the LOQ, it was less than 20%. A rapid, sensitive, reliable, and highly specific method by LC/MS/MS for detecting methylphenidate and its metabolite, RA, were developed. Both the cost and performance of the LC/MS/MS method were superior to GC/MS or ELISA, and it allows use of a single rapid procedure for both screening and confirmation.

  16. FRAGMENTATION STUDIES OF D6,7-ANHIDROERITROMISIN-A BY LIQUID CHROMATOGRAPHY-MASS SPECTROSCOPY (LC-MS

    Directory of Open Access Journals (Sweden)

    Khairan Khairan

    2010-06-01

    Full Text Available Semisynthesis of D6,7-Anhydroerythromycin-A was done by biomodification technique by addition of 0.2% INH into a culture fermentation of Saccharopolyspora erythraea ATCC 11635 in medium Hutchinson. The aim of this research is to studies of fragmentation pattern from new matabolite of D6,7-Anhydroerythromycin-A by Liquid Chromatography-Mass Spectroscopy (LC-MS and the ionization of mass spectroscopy is use by ESI (Electrospray Ionization pattern. The FT-IR spectrometric analyzes showed a stretching vibration of C=C conjugated group at wave number 1602.7 cm-1. This C=C conjugated vibration indicated the existence of double bond between C6 and C7 (D6,7, this confirmed that isolate contained D6,7-Anhydroerythromycin-A (the possibility of D6,7 was positive. For complementation, a LC-MS (Liquid Chromatography-Mass Spectroscopy analyzes using ESI-MS (Electrospray Ionization-Mass Spectroscopy ionization pattern was conducted to the isolate which resulted Quassimolecular ions [M+H]+ of D7,8- and D6,7-Anhydroerythromycin-A. LC-MS spectrogram of the isolate, which gave two peaks of m/z 732.2460 and m/z 716.2522, confirmed that the m/z 732.2460 possibly was D7,8-Anhydroerythromycin-A, while the m/z 716.2502 and m/z 715.2522 possibly were D6,7-Anhydroerythromycin-A.   Keywords: isoniazid, enoyl reduction, D6,7-Anhidroeritromisin-A, fragmentation, LC-MS.

  17. Comprehensive speciation of low-molecular weight selenium metabolites in mustard seeds using HPLC-electrospray linear trap/Orbitrap tandem mass spectrometry.

    Science.gov (United States)

    Ouerdane, Laurent; Aureli, Federica; Flis, Paulina; Bierla, Katarzyna; Preud'homme, Hugues; Cubadda, Francesco; Szpunar, Joanna

    2013-09-01

    An analytical methodology based on high-resolution high mass accuracy electrospray ionization (ESI) tandem MS assisted by Se-specific detection using inductively coupled plasma mass spectrometry (ICP MS) was developed for speciation of selenium (Se) in seeds of black mustard (Brassica nigra) grown on Se-rich soil. Size-exclusion LC-ICP MS allowed the determination of the Se distribution according to the molecular mass and the control of the species stability during extraction. The optimization of hydrophilic interaction of LC and cation-exchange HPLC resulted in analytical conditions making it possible to detect and characterize over 30 Se species using ESI MS, including a number of minor (<0.5%) metabolites. Selenoglucosinolates were found to be the most important class of species accounting for at least 15% of the total Se present and over 50% of all the metabolites. They were found particularly unstable during aqueous extraction leading to the loss of Se by volatilization as methylselenonitriles and methylselenoisothiocyanates identified using gas chromatography (GC) with the parallel ICP MS and atmospheric pressure chemical ionization (APCI) MS/MS detection. However, selenoglucosinolates could be efficiently recovered by extraction with 70% methanol. Other classes of identified species included selenoamino acids, selenosugars, selenosinapine and selenourea derivatives. The three types of reactions leading to the formation of selenometabolites were: the Se-S substitution in the metabolic pathway, oxidative reactions of -SeH groups with endogenous biomolecules, and chemical reactions, e.g., esterification, of Se-containing molecules and other biomolecules through functional groups not involving Se.

  18. Gas-phase complexes formed between amidoxime ligands and vanadium or iron investigated using electrospray ionization mass spectrometry.

    Science.gov (United States)

    Mustapha, Adetayo M; Pasilis, Sofie P

    2016-08-15

    Amidoxime-functionalized sorbents can be used to extract uranium from seawater. Iron(III) and vanadium(V) may compete with uranium for adsorption sites. We use 2,6-dihydroxyiminopiperidine (DHIP) and N(1) ,N(5) -dihydroxypentanediimidamide (DHPD) to model amidoxime functional groups and characterize the vanadium(V) and iron(III) complexes with these ligands. We also examine the effect of iron(III) and vanadium(V) on uranyl(VI) complexation by DHIP and DHPD. The experiments were carried out in positive ion mode using a quadrupole ion trap mass spectrometer equipped with an electrospray ionization source. The effect on the mass spectra of changes in ligand, metal:ligand mole ratio, and pH was examined. Iron(III) formed a 1:2 metal:ligand complex with DHIP at all metal:ligand mole ratios and pH values investigated; it formed both 1:2 and 1:3 metal:ligand complexes with DHPD. Vanadium(V) formed 1:1 and 1:2 metal:ligand complexes with DHIP. A 1:2 metal:ligand complex was formed with DHPD at all vanadium(V):DHPD mole ratios investigated. Changes in solution pH did not affect the ions observed. The relative binding affinities of the metal ions towards DHIP followed the order iron(III) > vanadium(V) > uranyl(VI). This study presents a first look at the gas-phase vanadium(V)- and iron(III)-DHIP and -DHPD complexes using electrospray ionization mass spectrometry. These metals form stronger complexes with amidoxime ligands than uranyl(VI), and will affect uranyl(VI) adsorption to amidoxime-based sorbents. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  19. [Determination of congo red in beef by high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry].

    Science.gov (United States)

    Lin, Hui; Xu, Chunxiang; Yan, Chunrong; Zhang, Zheng; Wang, Suilou

    2013-09-01

    A method was developed for the determination of congo red in beef. The analyte was identified by high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry (LC-QTOF MS) and quantitatively determined by ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry. After purified by liquid-liquid extraction, the congo red in the beef sample was separated on an Agilent ZORBAX Eclipse Plus C18 Rapid Resolution HD UPLC column (50 mm x 2.1 mm, 1.8 microm) HPLC , using 95% (volume percentage) methanol as the mobile phase at 0.2 mL/min. The detection was performed on an AB 4000 + triple quadrupole mass spectrometer utilizing electrospray ionization (ESI) interface operated in negative ion mode and multiple-reaction monitoring (MRM) mode. The results showed that the linear range of congo red mass concentration was 0.03 - 1 mg/L with the correlation coefficient of 0.999 8. The method had a good precision with the RSDs lower than 5% and the recoveries ranging from 88% to 91%. The limit of detection (LOD) of congo red was 0.01 mg/L. With good reproducibility, the method is simple, fast and effective for the determination of the illegally added congo red in beef and other meat products.

  20. Tandem mass spectrometry of doubly charged poly(ethylene oxide) oligomers produced by electrospray ionization

    Science.gov (United States)

    Girod, Marion; Carissan, Yannick; Humbel, Stéphane; Charles, Laurence

    2008-04-01

    Electrospray ionization combined with collision-induced dissociation has been applied to characterize fragmentation pathways of doubly charged poly(ethylene oxide) polymers. MS/MS spectra of doubly lithiated precursors were shown to provide the most informative data for this polymer structural analysis. Most fragment ions could be accounted for by applying the mechanisms proposed in the literature for singly charged oligomers. Although MS/MS experiments were conducted in a low collision energy regime, radical cationic fragments were also detected and were shown to further dissociate. This consecutive dissociation was explored performing hydrogen/deuterium exchange experiments and ab initio studies. Two different mechanisms had to be envisaged depending on the size of the fragmenting radical cationic species.

  1. Mass spectrometric studies on selective androgen receptor modulators (SARMs) using electron ionization and electrospray ionization/collision-induced dissociation.

    Science.gov (United States)

    Thevis, Mario; Volmer, Dietrich A

    2018-02-01

    Selective androgen receptor modulators (SARMs) have been identified as a promising class of drug candidates potentially applicable to diverse pathological conditions commonly associated with significantly reduced muscle mass. Due to a suspected and meanwhile repeatedly proven misuse of SARMs in elite and amateur sport, sustaining constantly updated doping control analytical methods is critical for sports drug testing laboratories. These test methods predominantly utilize mass spectrometry-based instrumentations and, consequently, studies on the mass spectrometric behavior of new compounds and, where available, their metabolic products are vital for comprehensive doping controls. In this communication, the dissociation patterns of three new SARM drug candidates referred to as GSK2881078, PF-06260414, and TFM-4 AS-1 as observed under electron ionization as well as electrospray ionization/collision-induced dissociation are discussed. By means of high resolution/high accuracy tandem mass spectrometry employing quadrupole-orbitrap mass analyzers, information on precursor-product ion relationships and elemental compositions was obtained and subsequently utilized to suggest dissociation routes of the target compounds. This information can contribute to future studies concerning structure assignments of metabolites and accelerate the identification of related substances if distributed and/or illicitly used in the world of sport.

  2. 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

  3. The detection of piroxicam, tenoxicam and their metabolites in equine urine by electrospray ionisation ion trap mass spectrometry.

    Science.gov (United States)

    McKinney, Andrew R; Suann, Craig J; Stenhouse, Allen M

    2004-01-01

    An investigation has been conducted into the metabolism and urinary excretion of orally administered piroxicam and tenoxicam in the horse. The major component detected in urine after the administration of piroxicam was 5'-hydroxypiroxicam, which was detectable up to 24 h post-administration. Unchanged piroxicam was present only as a minor component. In contrast, unchanged tenoxicam was the major component observed after the administration of tenoxicam, being detectable for 72 h post-administration, while 5'-hydroxytenoxicam was a minor component. Phase II beta-glucuronide conjugation in each case was found to be negligible. The ion trap mass spectral characteristics of piroxicam, tenoxicam, 5'-hydroxypiroxicam and 5'-hydroxytenoxicam under electrospray ionisation conditions were examined in some detail. Copyright 2004 John Wiley & Sons, Ltd.

  4. Interaction Between Cytochrome c and the Hapten 2,4-Dinitro-fluorobenzene by Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Wu, Bo; Chu, Yan-qiu; Dai, Zhao-yun; Ding, Chuan-fan

    2008-06-01

    Allergic contact dermatitis is a delayed hypersensitivity reaction, which results from skin exposure to low molecular weight chemicals such as haptens. To clarify the pathogenic mechanism, electrospray ionization mass spectrometry (ESI-MS) and hydrogen/deuterium (H/D) exchange, as well as UV spectroscopy, were applied to determine the interaction between the model protein cytochrome c (cyt c) and the hapten 2,4-dinitro-fluorobenzene (DNFB). The ESI-MS results demonstrate that the conformation of cyt c can change from native folded state into partially unfolded state with the increase of DNFB. The equilibrium state H/D exchange followed by ESI-MS further confirms the above results. UV spectroscopy indicates that the strong-field coordination between iron of heme (prosthetic group) and His18 or Met80 of cyt c is not obviously affected by the hapten.

  5. The Morita-Baylis-Hillman Reaction: Insights into Asymmetry and Reaction Mechanisms by Electrospray Ionization Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Verónica Carrasco-Sanchez

    2009-10-01

    Full Text Available This short review presents new insights on the mechanism and online monitoring using electrospray ionization tandem mass spectrometry (ESI–MS/MS of Morita–Baylis–Hillman (MBH reactions. MBH reactions are versatile carbon-carbon organocatalyzed bond forming reactions, making them environmentally friendly due to general organocatalysts employed. The organocatalyst behavior, which controls the transition state and thus the enantioselectivities in the obtained products, is very important in the performance of asymmetric MBH transformations. Some recent techniques and advances in asymmetric transformations are reviwed, as well as online reaction monitoring and analysis of the reaction intermediates. The mechanism accepted nowadays is also review through the insights gained from the use of ESI–MS/MS techniques.

  6. The Use of Gas Chromatography and Mass Spectrometry to Introduce General Chemistry Students to Percent Mass and Atomic Mass Calculations

    Science.gov (United States)

    Pfennig, Brian W.; Schaefer, Amy K.

    2011-01-01

    A general chemistry laboratory experiment is described that introduces students to instrumental analysis using gas chromatography-mass spectrometry (GC-MS), while simultaneously reinforcing the concepts of mass percent and the calculation of atomic mass. Working in small groups, students use the GC to separate and quantify the percent composition…

  7. Spatially resolved chemical analysis of cicada wings using laser-ablation electrospray ionization (LAESI) imaging mass spectrometry (IMS).

    Science.gov (United States)

    Román, Jessica K; Walsh, Callee M; Oh, Junho; Dana, Catherine E; Hong, Sungmin; Jo, Kyoo D; Alleyne, Marianne; Miljkovic, Nenad; Cropek, Donald M

    2018-03-01

    Laser-ablation electrospray ionization (LAESI) imaging mass spectrometry (IMS) is an emerging bioanalytical tool for direct imaging and analysis of biological tissues. Performing ionization in an ambient environment, this technique requires little sample preparation and no additional matrix, and can be performed on natural, uneven surfaces. When combined with optical microscopy, the investigation of biological samples by LAESI allows for spatially resolved compositional analysis. We demonstrate here the applicability of LAESI-IMS for the chemical analysis of thin, desiccated biological samples, specifically Neotibicen pruinosus cicada wings. Positive-ion LAESI-IMS accurate ion-map data was acquired from several wing cells and superimposed onto optical images allowing for compositional comparisons across areas of the wing. Various putative chemical identifications were made indicating the presence of hydrocarbons, lipids/esters, amines/amides, and sulfonated/phosphorylated compounds. With the spatial resolution capability, surprising chemical distribution patterns were observed across the cicada wing, which may assist in correlating trends in surface properties with chemical distribution. Observed ions were either (1) equally dispersed across the wing, (2) more concentrated closer to the body of the insect (proximal end), or (3) more concentrated toward the tip of the wing (distal end). These findings demonstrate LAESI-IMS as a tool for the acquisition of spatially resolved chemical information from fragile, dried insect wings. This LAESI-IMS technique has important implications for the study of functional biomaterials, where understanding the correlation between chemical composition, physical structure, and biological function is critical. Graphical abstract Positive-ion laser-ablation electrospray ionization mass spectrometry coupled with optical imaging provides a powerful tool for the spatially resolved chemical analysis of cicada wings.

  8. The Spatial Distribution of Alkaloids in Psychotria prunifolia (Kunth) Steyerm and Palicourea coriacea (Cham.) K. Schum Leaves Analysed by Desorption Electrospray Ionisation Mass Spectrometry Imaging

    DEFF Research Database (Denmark)

    Kato, Lucilia; Moraes, Aline Pereira; de Oliveira, Cecília Maria Alves

    2018-01-01

    INTRODUCTION: Species of the genera Psychotria and Palicourea are sources of indole alkaloids, however, the distribution of alkaloids within the plants is not known. Analysing the spatial distribution using desorption electrospray ionisation mass spectrometry imaging (DESI-MSI) has become attract...

  9. Structural analysis and differentiation of reducing and nonreducing neutral model starch oligosaccharides by negative-ion electrospray ionization ion-trap mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Čmelík, Richard; Chmelík, Josef

    2010-01-01

    Roč. 291, 1-2 (2010), s. 33-40 ISSN 1387-3806 R&D Projects: GA MŠk 2B06037 Institutional research plan: CEZ:AV0Z40310501 Keywords : structural analysis * oligosaccharides * electrospray mass spectrometry Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.009, year: 2010

  10. Macroscopic and microscopic spatially-resolved analysis of food contaminants and constituents using laser-ablation electrospray ionization mass spectrometry imaging

    NARCIS (Netherlands)

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

    2014-01-01

    Laser-ablation electrospray ionization (LAESI) mass spectrometry imaging (MSI) does not require very flat surfaces, high-precision sample preparation, or the addition of matrix. Because of these features, LAESI-MSI may be the method of choice for spatially-resolved food analysis. In this work, LAESI

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

    Science.gov (United States)

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

    2016-07-02

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

  12. Quantitative Profiling Method for Oxylipin Metabolome by Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometry

    OpenAIRE

    Yang, Jun; Schmelzer, Kara; Georgi, Katrin; Hammock, Bruce D

    2009-01-01

    Cyclooxygenase, lipoxygenase and epoxygenase derived oxylipins, especially eicosanoids play important roles in many physiological processes. Assessment of oxidized fatty acid levels is important for understanding their homeostatic and pathophysiological roles. Most reported methods examine these pathways in isolation. The work described here employed a SPE-LC-ESI MS/MS method to monitor these metabolites. In 21 minutes, 39 oxylipins were quantified along with eight corresponding internal stan...

  13. Characterization of impurities in tylosin using dual liquid chromatography combined with ion trap mass spectrometry.

    Science.gov (United States)

    Chopra, Shruti; Van Schepdael, Ann; Hoogmartens, Jos; Adams, Erwin

    2013-03-15

    Investigation of unknown impurities in a tylosin sample was performed using liquid chromatography coupled to mass spectrometry (LC/MS). Separation was performed according to the recently described LC-UV method of Ashenafi et al. (2011) [14]. This method was reported to have a good selectivity as it was able to separate the four main components of tylosin from the already known and 23 unknown impurities. However, as this method uses a mobile phase with non-volatile constituents, direct characterization of these impurities using LC/MS was not possible. The impurity fractions were therefore first collected and then desalted before sending them to the MS. Identification of the impurities in the tylosin sample was performed with a quadruple ion trap (IT) MS, with an electrospray ionization (ESI) source in the positive ion mode. The structure of the impurities was deduced by comparing their fragmentation pattern with those of the main components of tylosin. As several peaks in the LC-UV method contained multiple compounds, using this method in total 41 new impurities were (partly) characterized. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Rapid characterization of biotherapeutic proteins by size-exclusion chromatography coupled to native mass spectrometry.

    Science.gov (United States)

    Haberger, Markus; Leiss, Michael; Heidenreich, Anna-Katharina; Pester, Oxana; Hafenmair, Georg; Hook, Michaela; Bonnington, Lea; Wegele, Harald; Haindl, Markus; Reusch, Dietmar; Bulau, Patrick

    2016-01-01

    High-molecular weight aggregates such as antibody dimers and other side products derived from incorrect light or heavy chain association typically represent critical product-related impurities for bispecific antibody formats. In this study, an approach employing ultra-pressure liquid chromatography size-exclusion separation combined with native electrospray ionization mass spectrometry for the simultaneous formation, identification and quantification of size variants in recombinant antibodies was developed. Samples exposed to storage and elevated temperature(s) enabled the identification of various bispecific antibody size variants. This test system hence allowed us to study the variants formed during formulation and bio-process development, and can thus be transferred to quality control units for routine in-process control and release analytics. In addition, native SEC-UV/MS not only facilitates the detailed analysis of low-abundant and non-covalent size variants during process characterization/validation studies, but is also essential for the SEC-UV method validation prior to admission to the market.

  15. Comparison of derivatization/ionization techniques for liquid chromatography tandem mass spectrometry analysis of oxylipins.

    Science.gov (United States)

    Meckelmann, Sven W; Hellhake, Stefan; Steuck, Maryvonne; Krohn, Michael; Schebb, Nils Helge

    2017-05-01

    The performance of two derivatization and ionization techniques for the quantitative reversed phase liquid chromatography (LC)- mass spectrometry (MS) analysis of hydroxy fatty acids (OH-PUFA) in plasma was evaluated: One used AMPP (N-(4-aminomethylphenyl)pyridinium chloride) leading to a positive charged amid-derivate which can be detected by electrospray ionization (ESI)-MS. Second yielded penta fluorobenzyl bromide (PFB) ester derivates allowing detection in electron capture atmospheric pressure chemical ionization (ecAPCI)-MS. The sensitivity of detection of a comprehensive set of hydroxy fatty acids of n6- and n3- poly unsaturated fatty acids was investigated. On the SCIEX3200 MS the applied PFB derivatization led to poor limits of detection (LOD) of 10-100nM (0.1-1pmol/0.03-0.3ng on column). By contrast, AMPP derivatization led to a similar sensitivity compared to the standard ESI(-) of non derivatized analytes (LOD about 1nM (10fmol/3pg on column)). For several analytes, including 9-HETE, 11-HETE and 17-HDHA the AMPP derivatization improved sensitivity enabling their detection in human plasma. However, precision was reduced by AMPP derivatization and variation in IS recovery indicated a strong matrix influence on the MS-signal. In sum, with the instrumentation used, neither of these derivatization methods improves in our hands the LC-MS based quantification of oxylipins. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. [Determination of 25 quinolones in cosmetics by liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Lin, Li; Zhang, Yi; Tu, Xiaoke; Xie, Liqi; Yue, Zhenfeng; Kang, Haining; Wu, Weidong; Luo, Yao

    2015-03-01

    An analytical method was developed for the simultaneous determination of 25 quinolones, including danofloxacin mesylate, enrofloxacin, flumequine, oxloinic acid, ciprofloxacin, sarafloxacin, nalidixic acid, norfloxacin, and ofloxacin etc in cosmetics using direct extraction and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Cosmetic sample was extracted by acidified acetonitrile, defatted by n-hexane and separated on Poroshell EC-C18 column with gradient elution program using acetonitrile and water (both containing 0. 1% formic acid) as the mobile phases and analyzed by LC-ESI-MS/MS under the positive mode using multiple reaction monitoring (MRM). The interference of matrix was reduced by the matrix-matched calibration standard curve. The method showed good linearities over the range of 1-200 mg/kg for the 25 quinolones with good linear correlation coefficients (r ≥ 0.999). The method detection limit of the 25 quinolones was 1.0 mg/kg, and the recoveries of all analytes in lotion, milky and cream cosmetics matrices ranged from 87.4% to 105% at the spiked levels of 1, 5 and 10 mg/kg with the relative standard deviations (RSD) of 4.54%-19.7% (n = 6). The results indicated that this method is simple, fast and credible, and suitable for the simultaneous determination of the quinolones in the above three types of cosmetics.

  17. Detection of Metastatic Breast and Thyroid Cancer in Lymph Nodes by Desorption Electrospray Ionization Mass Spectrometry Imaging

    Science.gov (United States)

    Zhang, Jialing; Feider, Clara L.; Nagi, Chandandeep; Yu, Wendong; Carter, Stacey A.; Suliburk, James; Cao, Hop S. Tran; Eberlin, Livia S.

    2017-06-01

    Ambient ionization mass spectrometry has been widely applied to image lipids and metabolites in primary cancer tissues with the purpose of detecting and understanding metabolic changes associated with cancer development and progression. Here, we report the use of desorption electrospray ionization mass spectrometry (DESI-MS) to image metastatic breast and thyroid cancer in human lymph node tissues. Our results show clear alterations in lipid and metabolite distributions detected in the mass spectra profiles from 42 samples of metastatic thyroid tumors, metastatic breast tumors, and normal lymph node tissues. 2D DESI-MS ion images of selected molecular species allowed discrimination and visualization of specific histologic features within tissue sections, including regions of metastatic cancer, adjacent normal lymph node, and fibrosis or adipose tissues, which strongly correlated with pathologic findings. In thyroid cancer metastasis, increased relative abundances of ceramides and glycerophosphoinisitols were observed. In breast cancer metastasis, increased relative abundances of various fatty acids and specific glycerophospholipids were seen. Trends in the alterations in fatty acyl chain composition of lipid species were also observed through detailed mass spectra evaluation and chemical identification of molecular species. The results obtained demonstrate DESI-MSI as a potential clinical tool for the detection of breast and thyroid cancer metastasis in lymph nodes, although further validation is needed. [Figure not available: see fulltext.

  18. An approach to on-line electrospray mass spectrometric detection of polypeptide antibiotics of enramycin for high-speed counter-current chromatographic separation.

    Science.gov (United States)

    Inoue, Koichi; Hattori, Yasuko; Hino, Tomoaki; Oka, Hisao

    2010-04-06

    In the field of pharmaceutical and biomedical analysis of peptides, a rapid on-line detection and identification for a methodology have been required for the discovery of new biological active products. In this study, a high-speed counter-current chromatography with electrospray mass spectrometry (HSCCC/ESI-MS) was developed for the on-line detection and purification of polypeptide antibiotics of enramycin-A and -B. The analytes were purified on HSCCC model CCC-1000 (multi-layer coil planet centrifuge) with a volatile solvent of two-phase system composed of n-butanol/hexane/0.05% aqueous trifluoroacetic acid solution (43/7/50, V/V/V), and detected on an LCMS-2010EV quadrupole mass spectrometer fitted with an ESI source system in positive ionization following scan mode (m/z 100-2000). The HSCCC/ESI-MS peaks indicated that enramycin-A (major m/z 786 [M+3H](3+) and minor m/z 1179 [M+2H](2+)) and enramycin-B (major m/z 791 [M+3H](3+) and minor m/z 1185 [M+2H](2+)) have the peak resolution value of 2.9 from 15mg of loaded enramycin powder. The HSCCC collected amounts of the peak fractions were additionally 4.3mg (enramycin-A), and 5.9mg (enramycin-B), respectively. These purified substances were analyzed by LC/ESI-MS with scan positive mode. Based on the LC/ESI-MS chromatograms and spectra of the fractions, enramycin-A and -B were estimated to be over 95% purity. The overall results indicate that this approach of HSCCC/ESI-MS is a powerful technique for the purification and identification of bioactive peptides. Copyright 2009 Elsevier B.V. All rights reserved.

  19. Solvent-assisted electrospray ionization for direct analysis of various compounds (complex) from low/nonpolar solvents and eluents.

    Science.gov (United States)

    Zhang, Jun-Ting; Wang, Hao-Yang; Zhu, Wei; Cai, Ting-Ting; Guo, Yin-Long

    2014-09-16

    Electrospray ionization (ESI) is a powerful ionization technique with a wide range of applications. However, the analytes in low/nonpolar solvents cannot be analyzed directly in electrospray ionization-mass spectrometry (ESI-MS), because low/nonpolar solvents are incompatible with ESI, because of their low conductivity. To circumvent this problem, we introduce an electrospray-based ionization method termed solvent-assisted electrospray ionization (SAESI). With the help of electrospray solvents at the tip of the spray needle, compounds in "non-electrospray ionization-friendly" solvents can be ionized directly using solvent-assisted electrospray ionization-mass spectrometry (SAESI-MS). The key features that the assistant solvent can be chosen flexibly and makes little interference to samples lead to better ionization performance in detection of organic reaction intermediates and real-time analysis of polymers and chiral drugs separated by gel permeation chromatography (GPC) and normal phase liquid chromatography (NPLC). Furthermore, it can achieve online hydrogen/deuterium (H/D) exchange reaction and even mitigate the signal suppression caused by strong acid modifiers in liquid chromatography. In addition, all parts of this device are commercially available and it only requires two parameters to be optimized, which makes SAESI easy to handle.

  20. Untargeted screening of sulfonamides and their metabolites in salmon using liquid chromatography coupled to quadrupole Orbitrap mass spectrometry.

    Science.gov (United States)

    Jia, Wei; Shi, Lin; Chu, Xiaogang

    2018-01-15

    An analytical method for the non-target screening of sulfonamides and metabolites in salmon was developed, using automated on-line extraction procedure followed by ultra-high performance liquid chromatography coupled to electrospray ionization quadrupole Orbitrap high-resolution mass spectrometry (UHPLC Q-Orbitrap), including three systematic workflows (i) fully non-targeted data acquisition with fragmentation, (ii) suspect library spectra searching followed by characteristic structural fragments filtering and (iii) confirmation of non-target analytes and structural characterization of unknown analytes based on the availability of reference standards. The estimated performance characteristics were satisfactory complying with the requirements of the guidelines specified in European Commission Decision 2002/657/EC. Four untargeted compounds were identified and confirmed from salmon samples of different origin taken from monitoring control program. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. High-throughput determination of cortisol, cortisone, and melatonin in oral fluid by on-line turbulent flow liquid chromatography interfaced with liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Fustinoni, Silvia; Polledri, Elisa; Mercadante, Rosa

    2013-07-15

    Cortisol, cortisone, and melatonin (CORTol, CORTone, and MELA, respectively) are hormones related to stress and sleep disorders. Their detection is relevant to epidemiological studies aimed at investigating the effects of circadian cycle disruption. The aim of this study was to develop and evaluate a high-throughput assay for the detection of CORTol, CORTone, and MELA concentrations in non-invasively collected oral fluid samples. A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method to measure levels of CORTol, CORTone, and MELA in oral fluid samples in the presence of deuterated analogs was optimized and validated. A 50 μL aliquot of oral fluid sample, obtained by centrifugation of a chewed swab, was purified using on-line turbulent flow liquid chromatography. Analytes were then separated using C18 reversed-phase chromatography, subjected to positive ionization using an electrospray source, then quantitated using a triple quadrupole mass detector in the selected reaction monitoring mode. Limits of quantification and linear dynamic ranges were found to be 0.55 nmol/L, 5.5 nmol/L, and 0.004 nmol/L, and up to 28 nmol/L, 277 nmol/L, and 0.43 nmol/L for CORTol, CORTone, and MELA, respectively. Inter- and intra-run precisions as relative standard deviation values were <5%, and accuracies were within 95-106% of theoretical concentrations. An evaluation of matrix effects showed that the use of deuterated analogs controlled sources of bias. Furthermore, the total analysis time per sample was 13 min, resulting in a throughput of approximately 100 samples/day. To our knowledge, this is the first automated, high-throughput assay for the simultaneous quantification of CORTol, CORTone, and MELA in oral fluid specimens. Copyright © 2013 John Wiley & Sons, Ltd.

  2. High-performance liquid chromatography on-line coupled to high-field NMR and mass spectrometry for structure elucidation of constituents of Hypericum perforatum L

    DEFF Research Database (Denmark)

    Hansen, S. H.; Jensen, A. G.; Cornett, Claus

    1999-01-01

    (MS) is described. A conventional reversed-phase HPLC system using ammonium acetate as the buffer substance in the eluent tvas used, and proton NMR spectra were obtained on a 500 MHz NMR instrument. The MS and MS/MS analyses were performed using negative electrospray ionization, In the present study......The on-line separation and structure elucidation of naphthodianthrones, flavonoids, and other constituents of an extract from Hypericum perforatum L, using high performance liquid chromatography (HPLC) coupled on-line with ultraviolet-visible, nuclear magnetic resonance (NMR), and mass spectrometry...

  3. Characterisation of proanthocyanidin aglycones and glycosides from rose hips by high-performance liquid chromatography-mass spectrometry, and their rapid quantification together with vitamin C.

    Science.gov (United States)

    Salminen, Juha-Pekka; Karonen, Maarit; Lempa, Kyösti; Liimatainen, Jaana; Sinkkonen, Jari; Lukkarinen, Marjo; Pihlaja, Kalevi

    2005-06-10

    Fifteen individual proanthocyanidin aglycones and 19 glycosides, together with a complex mixture of chromatographically non-separated tetra- to octameric proanthocyanidin glycosides were detected--the non-separated glycosides being novel natural products--and characterised from dog rose hips using high-performance liquid chromatography-electrospray ionisation mass spectrometry (HPLC-ESI-MS). Along with these phenolics, a 50% aqueous ethanol extract of rose hips was found to contain high levels of Vitamin C. A simple and rapid HPLC method assisted by diode array detection for the estimation of the total concentration of proanthocyanidin aglycones and glycosides, as well as Vitamin C, in rose hip extracts was developed.

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

    DEFF Research Database (Denmark)

    Hørning, Ole B; Kjeldsen, Frank; Theodorsen, Søren

    2008-01-01

    Reversed-phase liquid chromatography interfaced to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) allows analysis of very complex peptide mixtures at great sensitivity, but it can be very time-consuming, typically using 60 min, or more, per sample analysis. We recently introduced...... was demonstrated by the analysis of SDS-PAGE and SPE-LC-MS/MS. A total of 88 unique gene products spanning 3 orders of magnitude in serum protein concentration were identified using stringent database search criteria....

  5. Dispersive solid phase extraction combined with ion-pair ultra high-performance liquid chromatography tandem mass spectrometry for quantification of nucleotides in Lactococcus lactis

    DEFF Research Database (Denmark)

    Magdenoska, Olivera; Martinussen, Jan; Thykær, Jette

    2013-01-01

    solid phase extraction with charcoal and subsequent analysis with ion-pair liquid chromatography coupled with electrospray ionization tandem mass spectrometry was established for quantification of intracellular pools of the 28 most important nucleotides. The method can handle extracts where cells leak...... was validated by determination of the recovery, matrix effects, accuracy, linearity, and limit of detection based on spiking of medium blank as well as standard addition to quenched Lactococcus lactis samples. For standard addition experiments, the isotope-labeled standards needed to be added in similar...

  6. Detection of base pair mismatches in duplex DNA and RNA oligonucleotides using electrospray mass spectrometry

    Science.gov (United States)

    Griffey, Richard H.; Greig, Michael J.

    1997-05-01

    The identify and location of base pair mismatches in non- covalent DNA:RNA duplexes are established using MS and MS-MS on a quadruple ion trap with electrospray ionization (ESI). MS-MS experiments on a 14mer duplex (D) with a single C:A base pair mismatch using lower activation energy results in selective cleavage of the mismatched A nucleobase, even in the presence of the wild-type duplex. The location of the mismatch base pair can be discerned via presence of the wild-type duplex. The location of the mismatch base pair can be discerned via selection of the (D-5H)5- ion and fragmentation of the backbone at that location in a n additional MS-MS experiment. Selective fragmentation is observed for C in a C-C mismatched base pair, which is very difficult to detect using chemical cleavage or E. coli mismatch binding protein. In an RNA:DNA duplex with a single base pair mismatch, the DNA base is removed without fragmentation of the RNA strand, greatly simplifying the interpretation of the resulting MS spectrum. A method is presented for detecting two DNA strands, for example a point mutation which generates an oncogenic phenotype, and the wild-type message. The results suggest that ESI-MS-MS may provide a rapid and selective method to identify and locate genetic mutations without the need for chemical degradation or protein binding followed by gel electrophoresis.

  7. Determination of triacylglycerol regioisomers using electrospray ionization-quadrupole ion trap mass spectrometry with a kinetic method.

    Science.gov (United States)

    Leveque, Nathalie L; Acheampong, Akwasi; Heron, Sylvie; Tchapla, Alain

    2012-04-13

    The kinetic method was applied to differentiate and quantify mixtures of regioisomeric triacylglycerols (TAGs) by generating and mass selecting alkali ion bound metal dimeric clusters with a TAG chosen as reference (ref) and examining their competitive dissociations in a quadrupole ion trap mass spectrometer. This methodology readily distinguished pairs of regioisomers (AAB/ABA) such as LLO/LOL, OOP/OPO and SSP/SPS and consequently distinguished sn-1/sn-3, sn-2 substituents on the glycerol backbone. The dimeric complex ions [ref, Li, TAG((AAB and/or ABA))](+) generated by electrospray ionization mass spectrometry were subjected to collision induced dissociation causing competitive loss of either the neutral TAG reference (ref) leading to [Li(AAB and/or ABA)](+) or the neutral TAG molecule (TAG((AAB and/or ABA))) leading to [ref, Li](+). The ratio of the two competitive dissociation rates, defined by the product ion branching ratio (R(iso)), was related via the kinetic method to the regioisomeric composition of the investigated TAG mixture. In this work, a linear correlation was established between composition of the mixture of each TAG regioisomer and the logarithm of the branching ratio for competitive fragmentation. Depending on the availability of at least one TAG regioisomer as standard, the kinetic method and the standard additions method led to the quantitative analysis of natural TAG mixtures. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Direct Visualization of Neurotransmitters in Rat Brain Slices by Desorption Electrospray Ionization Mass Spectrometry Imaging (DESI - MS)

    Science.gov (United States)

    Fernandes, Anna Maria A. P.; Vendramini, Pedro H.; Galaverna, Renan; Schwab, Nicolas V.; Alberici, Luciane C.; Augusti, Rodinei; Castilho, Roger F.; Eberlin, Marcos N.

    2016-12-01

    Mass spectrometry imaging (MSI) of neurotransmitters has so far been mainly performed by matrix-assisted laser desorption/ionization (MALDI) where derivatization reagents, deuterated matrix and/or high resolution, or tandem MS have been applied to circumvent problems with interfering ion peaks from matrix and from isobaric species. We herein describe the application of desorption electrospray ionization mass spectrometry imaging (DESI)-MSI in rat brain coronal and sagittal slices for direct spatial monitoring of neurotransmitters and choline with no need of derivatization reagents and/or deuterated materials. The amino acids γ-aminobutyric (GABA), glutamate, aspartate, serine, as well as acetylcholine, dopamine, and choline were successfully imaged using a commercial DESI source coupled to a hybrid quadrupole-Orbitrap mass spectrometer. The spatial distribution of the analyzed compounds in different brain regions was determined. We conclude that the ambient matrix-free DESI-MSI is suitable for neurotransmitter imaging and could be applied in studies that involve evaluation of imbalances in neurotransmitters levels.

  9. Diesel characterization by high-resolution mass spectrometry - gas chromatography

    International Nuclear Information System (INIS)

    Baldrich, C.A

    1998-01-01

    High-resolution mass spectrometry-gas chromatography is combined with the HC22 method in order to obtain detailed information about the chemical composition of diesel and the distribution of different compound types in terms of its final boiling temperature from a single analysis. The total time elapsed from sample injection and signal processing to obtain final results is 90 minutes. This fact makes this methodology a new and very important tool for the decision making process concerning the most suitable final boiling temperature and the type of treatment of the product in order to obtain diesel that fulfills the international standards. The consistency and repeatability of the experimental results are demonstrated

  10. 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,

  11. 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

  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. The weight of flash chromatography: A tool to predict its mass intensity from thin-layer chromatography

    Directory of Open Access Journals (Sweden)

    Freddy Pessel

    2016-11-01

    Full Text Available Purification by flash chromatography strongly impacts the greenness of a process. Unfortunately, due to the lack of the relevant literature data, very often this impact cannot be assessed thus preventing the comparison of the environmental factors affecting the syntheses. We developed a simple mathematical approach to evaluate the minimum mass intensity of flash chromatography from the retention factor values determined by thin-layer chromatography.

  14. Analysis by high-performance liquid chromatography diode array detection mass spectrometry of phenolic compounds in fruit of Eucalyptus globulus cultivated in Algeria.

    Science.gov (United States)

    Boulekbache-Makhlouf, Lila; Meudec, Emmanuelle; Chibane, Mohamed; Mazauric, Jean-Paul; Slimani, Sakina; Henry, Max; Cheynier, Veronique; Madani, Khodir

    2010-12-22

    A method based on high-performance liquid chromatography coupled with diode array detection and electrospray ionization mass spectrometry (HPLC-DAD-ESI-MS) following fractionation by chromatography on a Sephadex LH-20 column has been developed to determine the phenolic composition of fruit of Eucalyptus globulus growing in Algeria. The presence of 18 gallotannins, 26 ellagitannins, and 2 flavonols was established. Tentative identification is provided for these compounds on the basis of UV-visible spectra and mass spectrometry data. Most compounds described in this study have not previously detected in fruit of E. globulus. Moreover, this is the first report of methyl digalloyl diglucose, 3,3'-O-dimethylellagic acid 4-O-β-glucopyranoside, ellagic acid hexose, methyl ellagic acid pentose, methyltetragalloylglucose, and valoneic acid isomers (sanguisorbic, flavogallic acid dilactone) in the genus Eucalyptus. Quantitatively, ellagic acid and its derivatives, including ellagitannins, are largely predominant.

  15. Determination of three natural pesticides in processed fruit and vegetables using high-performance liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Sannino, Anna

    2007-01-01

    This paper describes a method for the sensitive and selective determination of two macrocyclic lactones (abamectin and spinosad) and azadirachtin in apple purée, concentrated lemon juice, tomato purée and canned peas. The general sample extraction-partitioning method for our gas chromatography and liquid chromatography multiresidue methods has been used. The analytical procedure involves an extraction with acetone and liquid-liquid partitioning with ethyl acetate/cyclohexane combined in one step. The extracts are analyzed by liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) without any further clean-up step. The pesticides are separated on a reversed-phase C12 column using a gradient elution. Thirteen simultaneous MS/MS transitions of precursor ions were monitored. Studies at fortification levels of 2.5-10 microg/kg and 25-100 microg/kg gave mean recoveries ranging from 70-100% for all compounds with satisfactory precision (relative standard deviation (RSD) from 3-20%). The excellent selectivity and sensitivity allows quantification and identification of low levels of pesticides in canned peas, tomato and apple purées (limits of quantitation (LOQs) 1-5 microg/kg) and in concentrated lemon juice (LOQs 2-10 microg/kg). The quantification of analytes was carried out using the most sensitive transition for every compound and by 'matrix-matched' standards calibration. Copyright (c) 2007 John Wiley & Sons, Ltd.

  16. ESIprot: a universal tool for charge state determination and molecular weight calculation of proteins from electrospray ionization mass spectrometry data.

    Science.gov (United States)

    Winkler, Robert

    2010-02-01

    Electrospray ionization (ESI) ion trap mass spectrometers with relatively low resolution are frequently used for the analysis of natural products and peptides. Although ESI spectra of multiply charged protein molecules also can be measured on this type of devices, only average spectra are produced for the majority of naturally occurring proteins. Evaluating such ESI protein spectra would provide valuable information about the native state of investigated proteins. However, no suitable and freely available software could be found which allows the charge state determination and molecular weight calculation of single proteins from average ESI-MS data. Therefore, an algorithm based on standard deviation optimization (scatter minimization) was implemented for the analysis of protein ESI-MS data. The resulting software ESIprot was tested with ESI-MS data of six intact reference proteins between 12.4 and 66.7 kDa. In all cases, the correct charge states could be determined. The obtained absolute mass errors were in a range between -0.2 and 1.2 Da, the relative errors below 30 ppm. The possible mass accuracy allows for valid conclusions about the actual condition of proteins. Moreover, the ESIprot algorithm demonstrates an extraordinary robustness and allows spectral interpretation from as little as two peaks, given sufficient quality of the provided m/z data, without the necessity for peak intensity data. ESIprot is independent from the raw data format and the computer platform, making it a versatile tool for mass spectrometrists. The program code was released under the open-source GPLv3 license to support future developments of mass spectrometry software. Copyright 2010 John Wiley & Sons, Ltd.

  17. A High Voltage Power Supply That Mitigates Current Reversals in Capillary Zone Electrophoresis-Electrospray Mass Spectrometry.

    Science.gov (United States)

    Flaherty, Ryan J; Sarver, Scott A; Sun, Liangliang; Brownell, Greg A; Go, David B; Dovichi, Norman J

    2017-02-01

    Capillary electrophoresis coupled with electrospray ionization typically employs two power supplies, one at each end of the capillary. One power supply is located at the proximal (injection) end of the capillary. The power supply located at the distal (detector) end of the capillary drives the electrospray. Electrophoresis is driven by the difference in potential between these power supplies. Separations that employ large capillary inner diameter, high conductivity background electrolyte, and high separation potentials generate higher current than that produced by the electrospray. Excess current flows through the electrospray power supply. Most power supplies are not designed to sink current, and the excess current will cause the electrospray voltage to deviate from its set point. We report a simple circuit to handle this excess current, allowing separations under a wide range of electrophoretic conditions. Graphical Abstract ᅟ.

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

    Science.gov (United States)

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

    2012-07-03

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