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GC-MS Method (gc-m + method)
Selected AbstractsDiscrimination and identification of the six aromatic positional isomers of trimethoxyamphetamine (TMA) by gas chromatography-mass spectrometry (GC-MS)JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 4 2008Kei Zaitsu Abstract A reliable and accurate GC-MS method was developed that allows both mass spectrometric and chromatographic discrimination of the six aromatic positional isomers of trimethoxyamphetamine (TMA). Regardless of the trifluoroacetyl (TFA) derivatization, chromatographic separation of all the investigated isomers was achieved by using DB-5ms capillary columns (30 m × 0.32 mm i.d.), with run times less than 15 min. However, the mass spectra of the nonderivatized TMAs, except 2,4,6-trimethoxyamphetmine (TMA-6), showed insufficient difference for unambiguous discrimination. On the other hand, the mass spectra of the TFA derivatives of the six isomers exhibited fragments with significant intensity differences, which allowed the unequivocal identification of all the aromatic positional isomers investigated in the present study. This GC-MS technique in combination with TFA derivatization, therefore, is a powerful method to discriminate these isomers, especially useful to distinguish the currently controlled 3,4,5-trimethoxyamphetmine (TMA-1) and 2,4,5-trimethoxyamphetmine (TMA-2) from other uncontrolled TMAs. Copyright © 2007 John Wiley & Sons, Ltd. [source] Analysis of urinary biomarkers for exposure to alkyl benzenes by isotope dilution gas chromatography-mass spectrometryJOURNAL OF SEPARATION SCIENCE, JSS, Issue 18 2005Adriaan A. S. Marais Abstract A validated GC-MS method for the analysis of urinary metabolites of alkyl benzenes is reported. Metabolites for exposure to toluene, xylene and ethylbenzene were analyzed simultaneously using stable isotope substituted internal standards. The method entailed acidic deconjugation of urine samples followed by extractive alkylation with pentafluorobenzyl bromide as alkylating agent. The resulting pentafluorobenzyl derivatives of ortho -, meta -, para -cresol, mandelic acid (MA), hippuric acid (HA) and ortho -, meta -, para -methylhippuric acid (MHA) were then quantified by SIM. Optimized reaction conditions for the extractive alkylation step are reported. The derivatives were found to be sufficiently stable for overnight batch analysis. The LODs were below 0.1 ,mol/L for the cresols and below 1 ,mol/L for MA and the HAs. Within-batch precision for o -MHA was 7%, for m -MHA 5%, for p -MHA 5.2% and below 5% for the rest of the analytes. [source] Rapid and sensitive determination of morphine in street opium samples by thermal desorption gas chromatography using a microfurnace pyrolyzerJOURNAL OF SEPARATION SCIENCE, JSS, Issue 12 2004Minemasa Hida Abstract Thermal desorption of the alkaloids in opium samples at 300°C using a vertical microfurnace pyrolyzer was followed by their on-line gas chromatographic (GC) analysis on a large-bore glass capillary column. This method permitted rapid and sensitive determination of the content of the main alkaloid, morphine, in the small (ca. 100 ,g) opium samples with a relative standard deviation within 4% for 5 runs. The observed morphine contents of about 12 to 15 w/w% in the given opium samples were in fairly good agreement with those estimated by a conventional GC-MS method. [source] Determination of tribromophenol and pentachlorophenol and its metabolite pentachloroanisole in Asparagus officinalis by gas chromatography/mass spectrometryJOURNAL OF SEPARATION SCIENCE, JSS, Issue 9-10 2003Claudia Mardones Abstract A GC-MS method was developed and optimized for simultaneous determination of pentachlorophenol (PCP), 2,4,6-tribromophenol (TBP), and pentachloroanisole (PCA) residues in the edible part of Asparagus officinalis. For this purpose, two procedures were evaluated: the direct separation of PCP, TBP, and PCA and the separation of acetyl-PCP, acetyl-TBP, and non-acetylated PCA. Better sensitivity and quantitative results, especially for PCP, were obtained after acetylation. The residues of PCP and TBP were extracted as phenolates and acetylated in a carbonate solution. Acetylated compounds were extracted by liquid-liquid extraction with hexane, while PCA was directly leached with this solvent. The proposed method allows the rapid quantification of traces of PCP, TBP, and PCA in a concentration ranging between 1.0 and 8.0 ng mL,1 in solution (corresponding to 0.3 and 8.0 ,g kg,1 in asparagus). In this concentration range, typical recoveries for PCA, TBP, and PCP from asparagus samples were 59%, 86%, and 97% respectively (RSDs 3,7%). [source] Identification of the alkaloids of Galipea officinalis by gas chromatography,mass spectrometryPHYTOCHEMICAL ANALYSIS, Issue 5 2001Ingrid Jacquemond-Collet Abstract Galipea officinalis Hancock, a Venezuelan shrubby tree which is acclaimed in folk medicine for its many healing properties, is the only species of the genus to contain tetrahydroquinoline alkaloids. A GC-MS method has been developed in order to analyse the essential oil, hexane and chloroform extracts of the trunk bark of this plant, without prior derivatisation of the alkaloidal components. A study of the MS fragmentation patterns of the components permitted the identification of five new minor quinoline alkaloids together with the known alkaloids. In addition, the method could also be used for the characterisation of alkaloids within the genus Galipea. Copyright © 2001 John Wiley & Sons, Ltd. [source] | ||||||||||