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Scholz B, Stiegler V, Eisenreich W, Engel KH. Strategies for UHPLC-MS/MS-Based Analysis of Different Classes of Acyl Chain Oxidation Products Resulting from Thermo-Oxidation of Sitostanyl Oleate. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:12072-12083. [PMID: 31577433 DOI: 10.1021/acs.jafc.9b05197] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Phytostanyl fatty acid esters, which are being added to a variety of foods owing to their cholesterol-lowering properties, are susceptible to thermally induced oxidation reactions. Using sitostanyl oleate as an example, we, in this study, aimed at developing strategies for the detection and the quantitation of acyl chain oxidation products (ACOPs). The elaborated ultra high performance liquid chromatography-mass spectrometry MS/MS-based approach involves (i) derivatizations of hydroxy and oxo groups, (ii) combined use of atmospheric pressure chemical ionization and electrospray ionization as ionization techniques, and (iii) establishment of selective multireaction monitoring transitions. These strategies allow the identification of a broad spectrum of nonpolar short-chain as well as polar short- and long-chain hydroxy, epoxy, and oxo ACOPs. Semiquantitative assessments showed that sitostanyl 9,10-epoxystearate was the predominating ACOP resulting from thermo-oxidation of sitostanyl oleate at 180 °C for 30 min. The elaborated analytical approach paves the way to narrow the existing knowledge gap on the fate of phytostanyl fatty acid esters upon heat treatments.
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Affiliation(s)
- Birgit Scholz
- Lehrstuhl für Allgemeine Lebensmitteltechnologie , Technische Universität München , Maximus-von-Imhof-Forum 2 , D-85354 Freising , Germany
| | - Veronika Stiegler
- Lehrstuhl für Allgemeine Lebensmitteltechnologie , Technische Universität München , Maximus-von-Imhof-Forum 2 , D-85354 Freising , Germany
| | - Wolfgang Eisenreich
- Lehrstuhl für Biochemie , Technische Universität München , Lichtenbergstrasse 4 , D-85748 Garching , Germany
| | - Karl-Heinz Engel
- Lehrstuhl für Allgemeine Lebensmitteltechnologie , Technische Universität München , Maximus-von-Imhof-Forum 2 , D-85354 Freising , Germany
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Alkylsilyl speciation and direct sample preparation of plant cannabinoids prior to their analysis by GC-MS. Anal Chim Acta 2018; 1021:51-59. [PMID: 29681284 DOI: 10.1016/j.aca.2018.03.049] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 03/03/2018] [Accepted: 03/10/2018] [Indexed: 11/20/2022]
Abstract
A literature criticism is given on methods currently using gas chromatography mass spectrometry (GC-MS) to determine plant cannabinoids (p-CBDs). In this study, trialkylsilylation of seven p-CBDs (including their transformation products formed in the drug user's body) was compared applying various alkylsilyl reagents1 and the mass fragmentation properties of the corresponding derivatives were characterized. Derivatization, mass fragmentation and quantitation related model investigations were optimized as a function of the reaction times and conditions. Special emphasis was put (i) on the maximum responses of species, (ii) on the proportions of formed stable products, suitable for selective quantitation of all seven p-CBDs simultaneously. Results, as novel to the field confirmed that HMDS + TFA, for p-CBDs never applied reagent before, serves as their derivatization reagent of choice. These species were characterized by their retention, mass fragmentation and analytical performance characteristics. In model solutions with injected amounts in the range of 20 pg-2000 pg, repeatability (average 4.98% RSD, varying between 2.98 and 6.2% RSD), linearity (R2, 0.9956-0.9995), LOQ (20-80 pg/μL injected species) and recovery (95.2-104%) values were defined. The practical utility of this proposal, along with method development validation, was shown in a particularly unique manner and supported by the novel, extraction free, direct sample preparation working strategy. For this purpose, two Cannabis-type ruderalis (C-trd) plant tissues (C-trd1, C-trd2) were directly derivatized in the presence of the matrix. This process, which approaches green chemistry, performed without the use of organic solvents, was associated with the quantitation of self p-CBD contents of C-trd plant tissues. Applying 0.5-2.0 mg dried tissues, adding standards, the following self p-CBDs contents were confirmed: in C-trd1 6.6 μg/mg CBD, 4.4 μg/mg CBN and 1.3 μg/mg CBC, while in C-trd2 0.46 μg/mg CBD, 0.27 μg/mg CBC and 0.19 μg/mg CBG were found. The latter results were characterized by repeatability (2.52-4.99% RSD), linearity (R2, 0.9640-0.9997) and recovery (87.9-109%) data.
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Nair SG, Patel DP, Gonzalez FJ, Patel BM, Singhal P, Chaudhary DV. Simultaneous determination of etonogestrel and ethinyl estradiol in human plasma by UPLC-MS/MS and its pharmacokinetic study. Biomed Chromatogr 2018; 32:e4165. [PMID: 29228469 DOI: 10.1002/bmc.4165] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 11/24/2017] [Accepted: 11/30/2017] [Indexed: 02/04/2023]
Abstract
A selective, sensitive and rapid ultra-performance liquid chromatography tandem mass spectrometry method was developed and validated for the simultaneous determination of etonogestrel (ENG) and ethinyl estradiol (EE) in human plasma. The analytes and their deuterated internal standards, ENG-d7 and EE-d4, were extracted from plasma samples by solid-phase extraction on HyperSep™ Retain PEP cartridges. The chromatographic analysis was performed on an Acquity UPLC HSS Cyano column, 100 Å (50 × 2.1 mm, 1.8 μm), column using gradient mobile phase, acetonitrile and 2.0 mm ammonium trifluoroacetate at 0-1.7 min (65:35, v/v) and 1.8-2.7 min (95:5, v/v) with 0.250 mL/min flow rate. Analytes and IS protonated precursor → product ion transitions (ENG, m/z 325.2 → 257.2; EE, m/z 530.2 → 171.2; ENG-d7, m/z 332.2 → 263.2; EE-d4, m/z 534.2 → 171.2) were monitored on a Triple Quadrupole Mass spectrometer (TQMS), operating in multiple reaction monitoring and positive ionization mode. The calibration curves were established at 10.00-2500 pg/mL for ENG and 1.500-150.0 pg/mL for EE with a correlation coefficient (r2 ) ≥0.9996 for both. The validated method was successfully applied to support a bioequivalence study of 0.15 mg ENG and EE 0.03 mg tablet formulation, administered in 24 healthy Indian females. Method reliability was assessed by reanalysis of 94 incurred study samples.
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Affiliation(s)
- Sneha G Nair
- Department of Chemistry, School of Sciences, Gujarat University, Ahmedabad, Gujarat, India
| | - Daxesh P Patel
- Department of Chemistry, School of Sciences, Gujarat University, Ahmedabad, Gujarat, India.,Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Frank J Gonzalez
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Bhargav M Patel
- Department of Chemistry, School of Sciences, Gujarat University, Ahmedabad, Gujarat, India
| | - Puran Singhal
- Bioanalytical Department, Alkem Laboratories Ltd, Mumbai, India
| | - Darshan V Chaudhary
- Department of Chemistry, School of Sciences, Gujarat University, Ahmedabad, Gujarat, India.,Department of Chemistry, Government Science College, Idar, Gujarat, India
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Sirén H, El Fellah S. Androgens, oestrogens, and progesterone concentrations in wastewater purification processes measured with capillary electrophoresis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:16765-16785. [PMID: 28567679 DOI: 10.1007/s11356-017-9060-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 04/18/2017] [Indexed: 06/07/2023]
Abstract
A novel analytical-scale concept to improve reliability of detection and analysis of natural and processed wastewater samples from a purification plant was developed. A sequential sample clean-up system of polymer-based octadecyl and silane-based quaternary amine sorbents were used for concentrating human based steroid hormones and their metabolites and detecting them by UV absorption with capillary electrophoresis (CE). The water samples were collected from influent and effluent processes of the water purification plant in Helsinki, Finland.The CE methods were partial-filling micellar electrokinetic chromatography and capillary zone electrophoresis. The analysis times and method concentration levels were optimized with eight steroids at the range of 0.5-10 mg/L. Since in CE the detectable quantities were higher than the existing amounts in the process waters, the real samples needed matrix removal combined with steroid enrichment. After 20,000-fold concentration testosterone-glucoside, androstenedione, progesterone, and estradiol-glucoside could be determined in the process water samples. The amounts of individual steroids in influent and effluent waters were 0-429 and 0-207 ng/L, respectively. Correspondently, their total amounts were 735 and 212 ng/L with excellent in day and inter-day repeatability. The RSD values were less than 1, 9.7, and 19% in repeated analyses, calculated from 60 analyses during 24 h, and from 130 analyses during 15 months, respectively. The steroid removal in purification process was 65% on average. The solid particles separated in three steps during the water clean-up concept contained 9.8-45 ng/g steroids in combined dry precipitates.
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Affiliation(s)
- Heli Sirén
- Department of Chemistry, Laboratory of Analytical Chemistry, University of Helsinki, A.I. Virtasen aukio 1, PO Box 55, FI-00014, Helsinki, Finland.
| | - Samira El Fellah
- Department of Chemistry, Laboratory of Analytical Chemistry, University of Helsinki, A.I. Virtasen aukio 1, PO Box 55, FI-00014, Helsinki, Finland
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Simultaneous determination of anabolic steroids and β-agonists in milk by QuEChERS and ultra high performance liquid chromatography tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2017; 1043:176-186. [DOI: 10.1016/j.jchromb.2016.08.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Revised: 08/05/2016] [Accepted: 08/09/2016] [Indexed: 11/22/2022]
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Analysis of 17-β-estradiol and 17-α-ethinylestradiol in biological and environmental matrices — A review. Microchem J 2016. [DOI: 10.1016/j.microc.2015.12.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Faludi T, Balogh C, Serfőző Z, Molnár-Perl I. Analysis of phenolic compounds in the dissolved and suspended phases of Lake Balaton water by gas chromatography-tandem mass spectrometry. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:11966-11974. [PMID: 26006075 DOI: 10.1007/s11356-015-4734-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 05/14/2015] [Indexed: 06/04/2023]
Abstract
As a novel approach to characterize the phenolic pollutants of Lake Balaton (Central Europe, western Hungary), 26 endocrine disrupting phenols (chlorophenols, nitrophenols, alkylphenols, triclosan, bisphenol-A) were quantified in dissolved and suspended particulate matter (SPM) phases, alike. Sample collection was performed in the western and eastern basins, at 20 sites in April and October 2014. Solid-phase and ultrasound-assisted extractions to withdraw target phenols from dissolved and suspended phases were employed. Compounds were derivatized with hexamethyldisilazane and trifluoroacetic acid for their quantification as trimethylsilyl derivatives by gas chromatography-tandem mass spectrometry. In Lake Balaton's dissolved phase, 2-chlorophenol (103-164 ng/L), 4-chlorophenol (407-888 ng/L), 2,4-dichlorophenol (20.2-72.0 ng/L), 2,4,6-trichlorophenol (10.4-38.1 ng/L), 2-nitrophenol (31.0-66.5 ng/L), 4-nitrophenol (31.5-94.1 ng/L), and bisphenol-A (20.6-112 ng/L), while in its SPM, 4-chlorophenol (<LOQ-1274 μg/kg, dry matter), 4-nitrophenol (423-714 μg/kg), 4-nonylphenol isomers (1500-2910 μg/kg), and bisphenol-A (250-587 μg/kg) were determined. Since phenolics appear partially or exclusively in the SPM, the analysis of both phases proved to be of primary importance. Graphical Abstract ᅟ.
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Affiliation(s)
- T Faludi
- Institute of Chemistry, Department of Analytical Chemistry, L. Eötvös University, 1518, Budapest 112, P.O. Box 32, Hungary
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Toral MI, Nacaratte F, Nova F. Determination of Etonogestrel and Ethinyl Estradiol from an Intrauterine Contraceptive Ring by Extraction and Derivative Spectrophotometry. ANAL LETT 2015. [DOI: 10.1080/00032719.2014.968930] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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9
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Identification, quantification and distribution of substituted phenols in the dissolved and suspended phases of water samples by gas chromatography tandem mass spectrometry: Derivatization, mass fragmentation and acquisition studies. Microchem J 2015. [DOI: 10.1016/j.microc.2014.07.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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10
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Molnár B, Csámpai A, Molnár-Perl I. Hexamethyldisilazane as an Acylation Generator for Perfluorocarboxylic Acids in Quantitative Derivatization of Primary Phenylalkyl Amines Confirmed by GC/MS and Computations. Anal Chem 2014; 87:848-52. [DOI: 10.1021/ac503786j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Borbála Molnár
- Doctoral School
of Pharmaceutical Sciences, Semmelweis University, 1085, Üllői út 26, Budapest, Hungary
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11
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Fetter E, Krauss M, Brion F, Kah O, Scholz S, Brack W. Effect-directed analysis for estrogenic compounds in a fluvial sediment sample using transgenic cyp19a1b-GFP zebrafish embryos. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 154:221-229. [PMID: 24927039 DOI: 10.1016/j.aquatox.2014.05.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Revised: 05/01/2014] [Accepted: 05/08/2014] [Indexed: 06/03/2023]
Abstract
Xenoestrogens may persist in the environment by binding to sediments or suspended particulate matter serving as long-term reservoir and source of exposure, particularly for organisms living in or in contact with sediments. In this study, we present for the first time an effect-directed analysis (EDA) for identifying estrogenic compounds in a sediment sample using embryos of a transgenic reporter fish strain. In the tg(cyp19a1b-GFP) transgenic zebrafish strain, the expression of GFP (green fluorescent protein) in the brain is driven by an oestrogen responsive element in the promoter of the cyp19a1b (aromatase) gene. The selected sediment sample of the Czech river Bilina had already been analysed in a previous EDA using the yeast oestrogen screening assay and had revealed fractions containing estrogenic compounds. When normal phase HPLC (high performance liquid chromatography) fractionation was used for the separation of the sediment sample, the biotest with transgenic fish embryos revealed two estrogenic fractions. Chemical analysis of candidate compounds in these sediment fractions suggested alkylphenols and estrone as candidate compounds responsible for the observed estrogenic effect. Alkylphenol concentrations could partially explain the estrogenicity of the fractions. However, xenoestrogens below the analytical detection limit or non-targeted estrogenic compounds have probably also contributed to the sample's estrogenic potency. The results indicated the suitability of the tg(cyp19a1b-GFP) fish embryo for an integrated chemical-biological analysis of estrogenic effects.
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Affiliation(s)
- Eva Fetter
- Department of Bioanalytical Ecotoxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany.
| | - Martin Krauss
- Department of Effect-Directed Analysis, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - François Brion
- Unité d'écotoxicologie in vitro et in vivo, Direction des Risques Chroniques, Institut National de l'Environnement Industriel et des Risques (INERIS), BP 2, F-60550 Verneuil-en-Halatte, France
| | - Olivier Kah
- Research Institute for Environment, Health and Occupation, INSERM U1085, Biosit, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes cedex, France
| | - Stefan Scholz
- Department of Bioanalytical Ecotoxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Werner Brack
- Department of Effect-Directed Analysis, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany
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12
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Pessoa GP, de Souza NC, Vidal CB, Alves JAC, Firmino PIM, Nascimento RF, dos Santos AB. Occurrence and removal of estrogens in Brazilian wastewater treatment plants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 490:288-295. [PMID: 24858226 DOI: 10.1016/j.scitotenv.2014.05.008] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 05/02/2014] [Accepted: 05/02/2014] [Indexed: 06/03/2023]
Abstract
This paper evaluated the occurrence and removal efficiency of four estrogenic hormones in five biological wastewater treatment plants (WWTPs), located in the State of Ceará, Brazil. The five WWTPs comprised: two systems consisted of one facultative pond followed by two maturation ponds, one facultative pond, one activated sludge (AS) system followed by a chlorination step, and one upflow anaerobic sludge blanket (UASB) reactor followed by a chlorination step. Estrogen occurrence showed a wide variation among the analyzed influent and effluent samples. Estrone (E1) showed the highest occurrence in the influent (76%), whereas both 17β-estradiol (E2) and 17α-ethynylestradiol (EE2) presented a 52% occurrence, and the compound 17β-estradiol 17-acetate (E2-17A), a 32% one. The occurrence in the effluent samples was 48% for E1, 28% for E2, 12% for E2-17A, and 40% for EE2. The highest concentrations of E1 and EE2 hormones in the influent were 3050 and 3180 ng L(-1), respectively, whereas E2 and E2-17A had maximum concentrations of 776 and 2300 ng L(-1), respectively. The lowest efficiencies for the removal of estrogenic hormones were found in WWTP consisted of waste stabilization ponds, ranging from 54 to 79.9%. The high-rate systems (AS and UASB), which have chlorination as post-treatment, presented removal efficiencies of approximately 95%.
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Affiliation(s)
- Germana P Pessoa
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Rua do Contorno, S/N Campus do Pici, Bl. 713, CEP: 60455-900, Fortaleza, CE, Brazil
| | - Neyliane C de Souza
- Department Sanitary and Environmental Engineering, State University of Paraíba, Rua Juvêncio Arruda, S/N, Campus Universitário, Bodocongó, CEP: 58109-790, Campina Grande, PB, Brazil
| | - Carla B Vidal
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Rua do Contorno, S/N Campus do Pici, Bl. 713, CEP: 60455-900, Fortaleza, CE, Brazil
| | - Joana A C Alves
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Rua do Contorno, S/N Campus do Pici, Bl. 713, CEP: 60455-900, Fortaleza, CE, Brazil
| | - Paulo Igor M Firmino
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Rua do Contorno, S/N Campus do Pici, Bl. 713, CEP: 60455-900, Fortaleza, CE, Brazil
| | - Ronaldo F Nascimento
- Department of Analytical Chemistry and Physical Chemistry, Federal University of Ceará, Rua do Contorno, S/N Campus do Pici, Bl. 940, CEP: 60451-970, Fortaleza, CE, Brazil
| | - André B dos Santos
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Rua do Contorno, S/N Campus do Pici, Bl. 713, CEP: 60455-900, Fortaleza, CE, Brazil.
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Zhong Q, Hu Y, Li G. A novel protocol for molecularly imprinted polymer filaments online coupled to GC-MS for the determination of androgenic steroids in urine. J Sep Sci 2013; 36:3903-10. [DOI: 10.1002/jssc.201300874] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 09/21/2013] [Accepted: 10/04/2013] [Indexed: 11/05/2022]
Affiliation(s)
- Qisheng Zhong
- School of Chemistry and Chemical Engineering; Sun Yat-sen University; Guangzhou P. R. China
| | - Yufei Hu
- School of Chemistry and Chemical Engineering; Sun Yat-sen University; Guangzhou P. R. China
| | - Gongke Li
- School of Chemistry and Chemical Engineering; Sun Yat-sen University; Guangzhou P. R. China
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14
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Determination of steroids in the dissolved and in the suspended phases of wastewater and Danube River samples by gas chromatography, tandem mass spectrometry. Talanta 2013; 115:367-73. [DOI: 10.1016/j.talanta.2013.05.029] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 05/13/2013] [Accepted: 05/14/2013] [Indexed: 11/23/2022]
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16
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Caban M, Czerwicka M, Łukaszewicz P, Migowska N, Stepnowski P, Kwiatkowski M, Kumirska J. A new silylation reagent dimethyl(3,3,3-trifluoropropyl)silyldiethylamine for the analysis of estrogenic compounds by gas chromatography–mass spectrometry. J Chromatogr A 2013; 1301:215-24. [DOI: 10.1016/j.chroma.2013.05.073] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 05/29/2013] [Accepted: 05/30/2013] [Indexed: 11/30/2022]
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17
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Faludi T, Andrási N, Vasanits-Zsigrai A, Záray G, Molnár-Perl I. Systematic derivatization, mass fragmentation and acquisition studies in the analysis of chlorophenols, as their silyl derivatives by gas chromatography–mass spectrometry. J Chromatogr A 2013; 1302:133-42. [DOI: 10.1016/j.chroma.2013.06.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 06/04/2013] [Accepted: 06/06/2013] [Indexed: 12/21/2022]
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18
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Characterization of the endogenous enzymatic hydrolyses of Petroselinum crispum glycosides: Determined by chromatography upon their sugar and flavonoid products. J Chromatogr A 2013; 1293:100-6. [DOI: 10.1016/j.chroma.2013.03.037] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Revised: 03/11/2013] [Accepted: 03/12/2013] [Indexed: 02/05/2023]
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19
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Poole CF. Alkylsilyl derivatives for gas chromatography. J Chromatogr A 2013; 1296:2-14. [PMID: 23465130 DOI: 10.1016/j.chroma.2013.01.097] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 01/23/2013] [Accepted: 01/24/2013] [Indexed: 11/19/2022]
Abstract
Alkylsilyl reagents are the most widely used reagents for the derivatization of polar compounds containing labile hydrogen atoms for gas chromatography. In this article the reagents and reaction conditions for the formation of trimethylsilyl, alkyldimethylsilyl (particularly t-butyldimethylsilyl), cyclic siliconides, haloalkyldimethylsilyl, and flophemesyl (pentafluorophenyldimethylsilyl) derivatives for a wide range of functional groups are reviewed. The importance of steric hindrance on reaction rates and completion, choice of reaction conditions, stability of derivatives, and options for selective detection are described.
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Affiliation(s)
- Colin F Poole
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA.
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Laulhé S, Bogdanov B, Johannes LM, Gutierrez O, Harrison JG, Tantillo DJ, Zhang X, Nantz MH. Fragmentation of oxime and silyl oxime ether odd-electron positive ions by the McLafferty rearrangement: new insights on structural factors that promote α,β fragmentation. JOURNAL OF MASS SPECTROMETRY : JMS 2012; 47:676-86. [PMID: 22678949 PMCID: PMC3396437 DOI: 10.1002/jms.2986] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The McLafferty rearrangement is an extensively studied fragmentation reaction for the odd-electron positive ions from a diverse range of functional groups and molecules. Here, we present experimental and theoretical results of 12 model compounds that were synthesized and investigated by GC-TOF MS and density functional theory calculations. These compounds consisted of three main groups: carbonyls, oximes and silyl oxime ethers. In all electron ionization mass spectra, the fragment ions that could be attributed to the occurrence of a McLafferty rearrangement were observed. For t-butyldimethylsilyl oxime ethers with oxygen in a β-position, the McLafferty rearrangement was accompanied by loss of the t-butyl radical. The various mass spectra showed that the McLafferty rearrangement is relatively enhanced compared with other primary fragmentation reactions by the following factors: oxime versus carbonyl, oxygen versus methylene at the β-position and ketone versus aldehyde. Calculations predict that the stepwise mechanism is favored over the concerted mechanism for all but one compound. For carbonyl compounds, C-C bond breaking was the rate-determining step. However, for both the oximes and t-butyldimethylsilyl oxime ethers with oxygen at the β-position, the hydrogen transfer step was rate limiting, whereas with a CH(2) group at the β-position, the C-C bond breaking was again rate determining. n-Propoxy-acetaldehyde, bearing an oxygen atom at the β-position, is the only case that was predicted to proceed through a concerted mechanism. The synthesized oximes exist as both the (E)- and (Z)-isomers, and these were separable by GC. In the mass spectra of the two isomers, fragment ions that were generated by the McLafferty rearrangement were observed. Finally, fragment ions corresponding to the McLafferty reverse charge rearrangement were observed for all compounds at varying relative ion intensities compared with the conventional McLafferty rearrangement.
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Affiliation(s)
- Sébastien Laulhé
- University of Louisville, Department of Chemistry, Louisville, Kentucky 40292, USA
| | - Bogdan Bogdanov
- University of the Pacific, Department of Chemistry, Stockton, California 95211, USA
| | - Leah M. Johannes
- University of Louisville, Department of Chemistry, Louisville, Kentucky 40292, USA
| | - Osvaldo Gutierrez
- University of California, Department of Chemistry, Davis, California 95616, USA
| | - Jason G. Harrison
- University of California, Department of Chemistry, Davis, California 95616, USA
| | - Dean J. Tantillo
- University of California, Department of Chemistry, Davis, California 95616, USA
| | - Xiang Zhang
- University of Louisville, Department of Chemistry, Louisville, Kentucky 40292, USA
| | - Michael H. Nantz
- University of Louisville, Department of Chemistry, Louisville, Kentucky 40292, USA
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Daughton CG. Real-time estimation of small-area populations with human biomarkers in sewage. THE SCIENCE OF THE TOTAL ENVIRONMENT 2012; 414:6-21. [PMID: 22137478 DOI: 10.1016/j.scitotenv.2011.11.015] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 11/03/2011] [Accepted: 11/04/2011] [Indexed: 04/14/2023]
Abstract
A new approach is conceptualized for measuring small-area human populations by using biomarkers in sewage. The basis for the concept (SCIM: Sewage Chemical-Information Mining) is supported by a comprehensive examination and synthesis of data published across several disciplines, including medicine, microbiology, clinical chemistry, and environmental science. Accurate measures of human populations are fundamental to numerous disciplines, including economics, marketing, politics, sociology, public health and safety (e.g., disease management; assessment of natural hazards; disaster prevention and response), quality of life, and the environment. Knowing the size, distribution, and flow of a small-area (local) population facilitates understanding the numerous and complex linkages and interactions between humans and the environment. Examples include material-flow (substance-flow) analysis, determining the magnitude of per capita contribution of pollutant loadings to watersheds, or forecasting future impacts of local populations on the environment or a population's demands on resources. While no definitive approach exists for measuring small-area populations, census-taking is a long-established convention. No approach exists, however, for gauging small-area populations in real-time, as none is able to capture population dynamics, which involve transient changes (e.g., daily influx and efflux) and lasting changes (e.g., births, deaths, change in residence). Accurate measurement of small-area populations in real time has never been possible but is essential for facilitating the design of more sustainable communities. Real-time measurement would provide communities the capability of testing what-if scenarios in design and policy decisions. After evaluation of a range of biomarkers (including the nitrogenous waste product creatinine, which has been long used in clinical chemistry as a parameter to normalize the concentrations of other urinary excretion products to account for urine dilution), the biomarker with the most potential for the SCIM concept for real-time measurement of population was determined to be coprostanol - the major sterol produced by microbial reduction of cholesterol in the colon.
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Affiliation(s)
- Christian G Daughton
- Environmental Sciences Division, National Exposure Research Laboratory, U.S. Environmental Protection Agency, 944 East Harmon Avenue, Las Vegas, NV 89119, USA.
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22
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The role of the acquisition methods in the analysis of natural and synthetic steroids and cholic acids by gas chromatography–mass spectrometry. J Chromatogr A 2011; 1218:8264-72. [DOI: 10.1016/j.chroma.2011.09.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 09/02/2011] [Accepted: 09/05/2011] [Indexed: 11/23/2022]
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