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Bhatt SV, Bhatt SV, Fotie J. Pt-catalyzed O-silylation of oximes by tri-substituted organosilanes. Tetrahedron Lett 2019. [DOI: 10.1016/j.tetlet.2019.05.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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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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Couto RAS, Gonçalves LM, Carvalho F, Rodrigues JA, Rodrigues CMP, Quinaz MB. The Analytical Challenge in the Determination of Cathinones, Key-Players in the Worldwide Phenomenon of Novel Psychoactive Substances. Crit Rev Anal Chem 2018; 48:372-390. [DOI: 10.1080/10408347.2018.1439724] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Rosa A. S. Couto
- LAQV/REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Luís Moreira Gonçalves
- LAQV/REQUIMTE, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Porto, Portugal
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo (USP), São Paulo, Brazil
| | - Félix Carvalho
- UCIBIO/REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - José A. Rodrigues
- LAQV/REQUIMTE, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Porto, Portugal
| | - Cecília M. P. Rodrigues
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - M. Beatriz Quinaz
- LAQV/REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
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Frauscher M, Besser C, Allmaier G, Dörr N. Elucidation of oxidation and degradation products of oxygen containing fuel components by combined use of a stable isotopic tracer and mass spectrometry. Anal Chim Acta 2017; 993:47-54. [PMID: 29078954 DOI: 10.1016/j.aca.2017.09.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 08/30/2017] [Accepted: 09/07/2017] [Indexed: 11/30/2022]
Abstract
In order to reveal the degradation products of oxygen-containing fuel components, in particular fatty acid methyl esters, a novel approach was developed to characterize the oxidation behaviour. Combination of artificial alteration under pressurized oxygen atmosphere, a stable isotopic tracer, and gas chromatography electron impact mass spectrometry (GC-EI-MS) was used to obtain detailed information on the formation of oxidation products of (9Z), (12Z)-octadecadienoic acid methyl ester (C18:2 ME). Thereby, biodiesel simulating model compound C18:2 ME was oxidized in a rotating pressurized vessel standardized for lubricant oxidation tests (RPVOT), i.e., artificially altered, under 16O2 as well as 18O2 atmosphere. Identification of the formed degradation products, mainly carboxylic acids of various chain lengths, alcohols, ketones, and esters, was performed by means of GC-EI-MS. Comparison of mass spectra of compounds under both atmospheres revealed not only the degree of oxidation and the origin of oxygen atoms, but also the sites of oxidative attack and bond cleavage. Hence, the developed and outlined strategy based on a gas-phase stable isotopic tracer and mass spectrometry provides insight into the degradation of oxygen-containing fuels and fuel components by means of the accurate differentiation of oxygen origin in a degradation product.
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Affiliation(s)
- Marcella Frauscher
- AC2T Research GmbH, Viktor-Kaplan-Straße 2C, 2700 Wiener Neustadt, Austria; Institute of Chemical Technologies and Analytics, TU Wien (Vienna University of Technology), Getreidemarkt 9/164, Vienna, Austria.
| | - Charlotte Besser
- AC2T Research GmbH, Viktor-Kaplan-Straße 2C, 2700 Wiener Neustadt, Austria.
| | - Günter Allmaier
- Institute of Chemical Technologies and Analytics, TU Wien (Vienna University of Technology), Getreidemarkt 9/164, Vienna, Austria.
| | - Nicole Dörr
- AC2T Research GmbH, Viktor-Kaplan-Straße 2C, 2700 Wiener Neustadt, Austria.
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Atlabachew M, Chandravanshi BS, Redi-Abshiro M. Preparative HPLC for large scale isolation, and salting-out assisted liquid-liquid extraction based method for HPLC-DAD determination of khat (Catha edulis Forsk) alkaloids. Chem Cent J 2017; 11:107. [PMID: 29086876 PMCID: PMC5645267 DOI: 10.1186/s13065-017-0337-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Accepted: 10/12/2017] [Indexed: 12/15/2022] Open
Abstract
Background Khat (Catha edulis Forsk) is an evergreen shrub of the Celastraceae family. It is widely cultivated in Yemen and East Africa, where its fresh leaves are habitually chewed for their momentary pleasures and stimulation as amphetamine-like effects. The main psychostimulant constituents of khat are the phenylpropylamino alkaloids: cathinone, cathine and norephedrine. Results In this study, simple procedures based on preparative HPLC and salting-out assisted liquid–liquid extraction (SALLE) based methods were developed respectively for large scale isolation and the extraction of psychoactive phenylpropylamino alkaloids; cathinone, cathine and norephedrine, from khat (Catha edulis Forsk) chewing leaves, a stimulant and drug of abuse plant. The three khat alkaloids were directly isolated from the crude oxalate salt by preparative HPLC–DAD method with purity > 98%. In addition, a modified (SALLE) method has been developed and evaluated for the extraction efficiency of psychoactive phenylpropylamino alkaloids from khat (Catha edulis Forsk) chewing leaves. An in situ two steps extraction protocol was followed without dispersive SPE clean up. The method involves extraction of the samples with 1% HAc and QuEChERS salt (1.0 g of CH3COONa and 6.0 g of MgSO4) followed by subsequent in situ liquid–liquid partitioning by adding ethyl acetate and NaOH solution. The optimized method allowed recoveries of 80–86% for the three alkaloids from khat sample with relative standard deviation (RSD) values less than 15% and limits of detection (0.85–1.9 μg/mL). Conclusion The method was found to be simple, cost-effective and provides cleaner chromatogram with good selectivity and reproducibility. The SALLE based protocol provided as good results as the conventional extraction method (ultrasonic assisted extraction followed by solid phase extraction, UAE–SPE) and hence the method can be applicable in forensic and biomedical sectors. Electronic supplementary material The online version of this article (doi:10.1186/s13065-017-0337-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Minaleshewa Atlabachew
- Department of Chemistry, Bahir Dar University, P. O. Box 79, Bahir Dar, Ethiopia.,Blue Nile Water Institute, Bahir Dar University, P. O. Box 79, Bahir Dar, Ethiopia
| | | | - Mesfin Redi-Abshiro
- Department of Chemistry, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia
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Fodor B, Molnár-Perl I. The role of derivatization techniques in the analysis of plant cannabinoids by gas chromatography mass spectrometry. Trends Analyt Chem 2017. [DOI: 10.1016/j.trac.2017.07.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Tembrock LR, Broeckling CD, Heuberger AL, Simmons MP, Stermitz FR, Uvarov JM. Employing Two-stage Derivatisation and GC-MS to Assay for Cathine and Related Stimulant Alkaloids across the Celastraceae. PHYTOCHEMICAL ANALYSIS : PCA 2017; 28:257-266. [PMID: 28124803 DOI: 10.1002/pca.2671] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 11/14/2016] [Accepted: 11/27/2016] [Indexed: 06/06/2023]
Abstract
INTRODUCTION Catha edulis (qat, khat, mirra) is a woody plant species that is grown and consumed in East Africa and Yemen for its stimulant alkaloids cathinone, cathine and norephedrine. Two Celastraceae species, in addition to qat, have been noted for their stimulant properties in ethnobotanical literature. Recent phylogenetic reconstructions place four genera in a clade sister to Catha edulis, and these genera are primary candidates to search for cathine and related alkaloids. OBJECTIVE Determine if cathine or related alkaloids are present in species of Celastraceae other than Catha edulis. METHODS Leaf samples from 43 Celastraceae species were extracted in water followed by basification of the aqueous extract and partitioning with methyl-t-butyl ether to provide an alkaloid-enriched fraction. The extract was derivatised in a two-stage process and analysed using GC-MS for the presence of cathine. Related alkaloids and other metabolites in this alkaloid-enriched fraction were tentatively identified. RESULTS Cathinone, cathine and norephedrine were not detected in any of the 43 Celastraceae species assayed other than Catha edulis. However, the phenylalanine- or tyrosine-derived alkaloid phenylethylamine was identified in five species. Nine species were found to be enriched for numerous sterol- and terpene-like compounds. CONCLUSION These results indicate that cathine is unique to Catha edulis, and not the compound responsible for the stimulant properties reported in related Celastraceae species. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
- Luke R Tembrock
- Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Corey D Broeckling
- Proteomics and Metabolomics Facility, Colorado State University, Fort Collins, CO, 80523, USA
| | - Adam L Heuberger
- Department of Horticulture and Landscape Architecture, Colorado State University, Fort Collins, CO, 80523, USA
| | - Mark P Simmons
- Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Frank R Stermitz
- Department of Chemistry, Colorado State University, Fort Collins, CO, 80523, USA
| | - Jessica M Uvarov
- Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA
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Szalay R, Harmat V, Eőri J, Pongor G. Strong influence of intramolecular Si⋯O proximity on reactivity: Systematic molecular structure, solvolysis, and mechanistic study of cyclic N -trimethylsilyl carboxamide derivatives. Tetrahedron Lett 2017. [DOI: 10.1016/j.tetlet.2017.04.057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Molnár B, Fodor B, Csámpai A, Hidvégi E, Molnár-Perl I. Structure-related new approach in the gas chromatography/mass spectrometry analysis of cathinone type synthetic drugs. J Chromatogr A 2016; 1477:70-75. [DOI: 10.1016/j.chroma.2016.11.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 10/21/2016] [Accepted: 11/20/2016] [Indexed: 10/20/2022]
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