Chemical ionization Gas chromatography-mass

The urine samples were analyzed using a modified version of a published method.8 The method involved fortification of the urine samples with an internal standard 3,4,5-trichloro-2-pyridinyl, which is a structural isomer of the 3,5,6-TCP metabolite of chlorpyrifos hydrolysis of labile acid conjugates to 3,5,6-TCP solvent extraction derivitization to the f-butyl-dimethylsilyl ester of 3,5,6-TCP and subsequent negative-ion chemical ionization gas chromatography/mass spectrometry (GC/MS) analysis. Creatinine was determined in urine using a modification of a method of Fabiny and Erting-shausen.9... 

Bartels, M.J. and Kastl, P.E., Analysis of 3,5,6-trichlopyridinol in human urine using negative-ion chemical ionization gas chromatography-mass spectrometry, Journal of Chromatography, 575, 69-74, 1992. 

Vallee M, Rivera JD, Koob GF, Purdy RH, Fitzgerald RL. 2000. Quantification of neurosteroids in rat plasma and brain following swim stress and aUopregnanolone administration using negative chemical ionization gas chromatography/ mass spectrometry. Anal Biochem 287 153. 

Fitzgerald RL, Herold DA. 1996. Serum total testosterone immunoassay compared with negative chemical ionization gas chromatography—mass spectrometry. Clin Chem 42 749-755. 

Fischer, J. and J. Michael (1995). Thermospray ionization liquid chromatography-mass spectrometry and chemical ionization gas chromatography-mass spectrometry of hexazione metabolites in soil and vegetation extracts. J. Chromatogr. A, 704(1) 131-139. 

P.A. D Agostino and L.R. Provost, Detection of sarin and soman in a complex airborne matrix by capillary column ammonia chemical ionization gas chromatography-mass spectrometry and gas... 

G.S. Baird, R.L. Fitzgerald, S.K. Aggarwal and D.A. Herold, Determination of blood lead by electron-capture negative chemical ionization gas chromatography-mass spectrometry. Clin. Chem. 42, 286-291 (1996). 

Cheng, D., Lidgard, R.O., Duffield, P.H., Duffield, A.M. and Brophy, J.J. (1988) Identification by methane chemical ionization gas chromatography/mass spectrometry of the products obtained by steam distillation and aqueous acid extraction of commercial Piper methysticum. Biomedical Environmental Mass Spectrometry, 17, 371—376. 

Trichothecene mycotoxins are secondary metabolites of various fungal species. Structures of some trichothecene mycotoxins of interest to the US ARMY are given in Figure 1. Several methods have been reported for the analysis of these toxins (1-11, 15). Of these, mass spectrometry techniques are both sensitive and definitive when applied to toxicologic and environmental samples. With current technology, the most sensitive and qualitatively definitive analytical technique for the determination of these toxins is derivatization with an electron deficient moiety followed by analysis with negative ion chemical ionization gas chromatography-mass spectrometry (NICI-GC/HS). 

Melchert, H.-U. Pabel, E (2004). Reliable identification and quantification of trichothecenes and other mycotoxins by electron impact and chemical ionization-gas chromatography-mass spectrometry, using an ion-trap system in the multiple mass spectrometry mode. Candidate reference method for complex matrices. Journal of Chromatography A, Vol. 1056, No. 1-2, (November 2004), 195-199, ISSN 0021-9673. 

Dzidic, L, Petersen, H. A., Wadsworth, P. A., and Hart, H. V., Townsend Discharge Nitric Oxide Chemical Ionization Gas Chromatography/Mass Spectrometry for Hydrocarbon Analysis of the Middle Distillates, Analytical Chemistry, Vol. 64, 1992, pp. 2227-2232. 

Bartels, M.J. Quantitation of the Tetra-chloroethylene Metabolite A-Acetyl-5-(trichlorovinyl)cysteine in Rat Urine Via Negative Ion Chemical Ionization Gas Chromatography/Tandem Mass Spectrometry. Biol. Mass Spectrom. 1994, 23, 689-694. 

Analytical pyrolysis is defined as the characterization of a material or a chemical process by the instrumental analysis of its pyrolysis products (Ericsson and Lattimer, 1989). The most important analytical pyrolysis methods widely applied to environmental samples are Curie-point (flash) pyrolysis combined with electron impact (El) ionization gas chromatography/mass spectrometry (Cp Py-GC/MS) and pyrolysis-field ionization mass spectrometry (Py-FIMS). In contrast to the fragmenting El ionization, soft ionization methods, such as field ionization (FI) and field desorption (FD) each in combination with MS, result in the formation of molecule ions either without, or with only very low, fragmentation (Lehmann and Schulten, 1976 Schulten, 1987 Schulten and Leinweber, 1996 Schulten et al., 1998). The molecule ions are potentially similar to the original sample, which makes these methods particularly suitable to the investigation of complex environmental samples of unknown composition. 

One of the reasons for lack offlterature was probably because environmental analysis depends heavily on gas chromatography/mass spectrometry, which is not suitable for most dyes because of their lack of volatility (254). However, significant progress is being made in analyzing nonvolatile dyes by newer mass spectral methods such as fast atom bombardment (EAB), desorption chemical ionization, thermospray ionization, etc. 

Wester PG, J de Boer, UAT Brinkman (1996) Determination of polychlorinated terphenyls in aquatic biota and sediment with gas chromatography/mass spectrometry using negative chemical ionization. Environ Sci Technol 30 473-480. 

The lncos-50 is a relatively low-cost benchtop instrument as opposed to the research grade instruments discussed earlier. The gas chromatography-mass spectrometer transfer lines allow it to be used with either the Hewlett Packard 5890 or the Varian 3400 gas chromatographs. The Incos 50 provides data system control of the gas chromatography and accessories such as autosampler or liquid sample concentration. It can be used with capillary, wide-bore or packed columns. It performs electron ionization or chemical ionization with positive or negative detection. It also accepts desorption or other solids controls. 

Thomas etal. [72] used pyrolysis gas chromatography-mass spectrometry as a fast economic screening technique for polyaromatic hydrocarbons. Thomas used reverse-phase liquid chromatography with atmospheric pressure chemical ionization mass spectrometry/mass spectrometry for the determination of polycyclic aromatic sulphur heterocycles in sediments. 

Maurer HH. 2002. Role of gas chromatography-mass spectrometry with negative ion chemical ionization in clinical and forensic toxicology, doping control, and biomonitoring. Ther Drug Monit 24 247. 

Stan H-J, Kellner G. 1989. Confirmation of organophosphorus pesticide residues in food applying gas chromatography/mass spectrometry with chemical ionization and pulsed positive negative detection. Biomed and Environ Mass Spectrom 18(9) 645-651. 

Goto J, Watanabe K, Miura H, Nambara T, Iida T (1987) Trace analysis of bile acids by gas chromatography-mass spectrometry with negative ion chemical ionization detection. J Chro-matogr 388 379-387... 

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