Mass spectroscopy gas chromatography and

One determines the overall reaction by using some of the many tools of chemical analysis. Coulometeiy, gas chromatography, mass spectroscopy, and, in complex cases, computerized pattern-recognition programs applied to GC-MS data (see Section 7.5.19) are the typical tools used in determining the overall reaction. The current efficiency for the reaction concerned is important here and may vaty with potential. 

With today s advanced analytical procedures, it is possible to describe the composition of these fuels in considerable detail. By combining several sequenced liquid chromatographic separations with gas chromatography-mass spectroscopy and by using specific gas chromatographic detectors for sulfur compounds, it has been possible to identify the majority of individual sulfur species in some fuels (12-19). A typical separation scheme is shown... 

BHT levels found in mammary tissue and mammary lipid are shown in Table V. A high concentration of BHT was found in mammary tissue, along with several suspected metabolite peaks. The BHT peak was collected, analyzed by gas chromatography/mass spectroscopy and confirmed by comparison with an authentic sample. 

V. Pacakova and P. A. Leclercq, Gas chromatography-mass spectroscopy and high performance liquid chromatographic analyses of thermal degradation products of common plastics.. Journal of Chromatography, 555, 229-237, (1991). 

Research on co-operation in insect societies mainly involves the study of this elaborate pheromonal communication system. Such studies generally involve three steps (1) identification of a putative pheromone secreting gland (morphological research), (2) study of the chemical composition of the secreted pheromones (gas chromatography-mass spectroscopy and NMR techniques) and (3) performing bio-assays with glandular extracts or artificially synthesised pheromones to establish their function. 

ESR, by itself, is considered a very specific, yet semiquan-tifiable, technique for the measurement of free radicals. It can be used in conjunction with other analytical techniques, such as gas chromatography, mass spectroscopy, and high performance liquid chromatography (HPLC) for the study of free radicals [Cranton and Frackelton (27A20)]. ESR used in conjunction with other analytical techniques is an emerging field. 

Formula and data, see morphinan alkaloids. M. is the most important morphine (opium) alkaloid. M. is poorly soluble in boiling water and chloroform, soluble in alcohol, aqueous calcium and magnesium hydroxides and phenol. M. is obtained by extraction from the poppy Papaver somniferum. M. can be detected by sever color reactions (e. g. violet color with Fe in alkaline solution), particularly sensitive procedures are gas chromatography, mass spectroscopy, and radio-immuno assays. 

Gas Chromatography, Mass Spectroscopy, and Combined Gas Chromatography-Mass Spectroscopy 221... 

CoupiGd Pyrolysis Techniques. Perhaps the most powerful techniques currently available are those in which the polymer is pyrolyzed for a short time in a pyrolysis system directly coupled to a modem analytical instmment capable of analysis of the volatile products. Although direct pyrolysis coupled with ftir is available, the most common techniques have been gas chromatography, mass spectroscopy, and combinations of the two. In contrast to tga, these techniques provide no real information on the onset temperature of degradation or on the number of distinct stages, but they can give very detailed information about the products of reaction. 

Complementary Thermogravimetry, Gas chromatography-Mass Spectroscopy and Fourier-Transform-Infrared Spectroscopy... 

Acrylonitrile in both biological and environmental samples is most commonly determined by gas chromatography with a nitrogen-phosphorus detector (GC/NPD) (Page 1985), gas chromatography/flame ionization detection (GC/FID) (EPA 1982a), or gas chromatography/mass spectroscopy (GC/MS) (Anderson and Harland 1980). Infrared spectroscopy (Jacobs and Syrjala... 

Gas chromatography-mass spectroscopy is used to obtain extensive compositional information on rubbers. It can identify minor components of the sample such as the breakdown products of the cure system and the antidegradants. 

Although the metabolism of several phthalate esters has been studied in vitro, essentially all of the in vivo studies have involved DEHP. A summary of these experiments which involved exposure offish to aqueous - C-DEHP is presented in Table IV (11,12). Tissue C was isolated and separated into parent and the various metabolites by preparative thin layer chromatography on silica gel. Metabolites were hydrolyzed where appropriate and identified by gas chromatography-mass spectroscopy. In whole catfish, whole fathead minnow and trout muscle, the major metabolite was the monoester while in trout bile the major metabolite was the monoester glucuronide. The fact that in all cases the major metabolite was monoester or monoester glucuronide despite the differences in species, exposure level and duration, etc. represented by these data, suggests that hydrolysis of DEHP to monoester is important in the biotransformation of DEHP by fish. 

Lamey SC, Hesbach PA, White KD. 1991. Liquid fuel analyses using high-performanee liquid chromatography and gas chromatography-mass spectroscopy. Energy and Fuels 5 222-226. 

Isolation and identification of pyrazine alkaloids (Table III) have been achieved in most cases by a combination of gas chromatography and mass spectrometry (35,36,38,69,97,142). Methyl-, 2,3,6-trimethyl-, and tetramethylpyrazines (23a, 21a, and 22a) from the melon fly are identified by utilizing a solid sampling technique in conjunction with gas chromatography-mass spectroscopy (147). Methylpyrazines show the molecule ion as a base peak. Fragmentation proceeds mainly by the loss of HCN or CH3CN from the molecular ion (141). Eth-... 

Nishimura, O. Identification of the characteristic odorants in fresh rhizomes of ginger (Zingiber officinale Roscoe) using aroma extract dilution analysis and modified multidimensional gas chromatography-mass spectroscopy. J Agr Food Chem 1995 43(11) 2941-2945. 

Munson, J. W., and Abdine, H., "Determination of N-Nitroso-nornicotine in Tobacco by Gas Chromatography/Mass Spectroscopy", Analytical Letters, 1977, 10f 777-786. 

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