Gas chromatography, in analysis

W. A. Konig, new developments in enantiomer separation by capUlary gas chromatography, in Analysis of Volatiles Methods, Applications, P. Schreier (ed.), Berhn, 1984, pp. 77-91. 

Al-Saigh, Z.Y. and Guillet, J., in " Inverse Gas Chromatography in Analysis of Polymers and Rubbers , Encyclopedia of Analytical Chemistry Instrumentation and Applications, R. Meyers, Editor, Vol. 9, PP. 7159-1192, John Wiley ons Ltd, Chichester, 2000... 

Testfor C through C liydrocarbons in theMtmosphere by Gas Chromatography, ASTM Analysis D2820-72, Vol. 26. 

T. Hyotylainen, T. Andersson and M. E. Riekkola, Eiquid cliromatographic sample cleanup coupled on-line with gas chromatography in the analysis of beta-blockers in human serum and urine , 7. Chromatogr. Sci. 35 280-286 (1997). 

In a series of papers published throughout the 1980s, Colin Poole and his co-workers investigated the solvation properties of a wide range of alkylammonium and, to a lesser extent, phosphonium salts. Parameters such as McReynolds phase constants were calculated by using the ionic liquids as stationary phases for gas chromatography and analysis of the retention of a variety of probe compounds. However, these analyses were found to be unsatisfactory and were abandoned in favour of an analysis that used Abraham s solvation parameter model [5]. 

In contrast to gas chromatography, in which a number of different types of injector are available and the selection of which is often crucial to the success (or otherwise) of the analysis, a single type of injector is used almost exclusively in HPLC. 

Structurally related compounds may cross-react with the antibody, yielding inaccurate results. In screening for the herbicide alachlor in well water by immunoassay, a number of false positives were reported when compared with gas chromatography (GC) analysis. A metabolite of alachlor was found to be present in the samples and it was subsequently determined that the cross-reactivity by this metabolite accounted for the false-positive results. On the other hand, cross-reactivity by certain structural analogs may not be an issue. For example, in an assay for the herbicide atrazine, cross-reactivity by propazine is 196% because of atrazine and propazine field use... 

Gas chromatography in its various forms (GC, HS-GC, HSGC, HTGC, GC-MS, PyGC-MS) is widely used for additive analysis of low- to medium-MW species. As shown in Section 4.1, although some detection methods... 

C30 oil, homopolymer of 1-decene, Ethyl Corp., Inc.) served as the start-up solvent for the experiments. The catalyst (ca. 5-8 g) was added to start-up solvent (ca. 300 g) in the CSTR. The reactor temperature was then raised to 270°C at a rate of l°C/min. The catalyst was activated using CO at a space velocity of 3.0 sl/h/g Fe at 270°C and 175 psig for 24 h. FTS was then started by adding synthesis gas mixture (H2 CO ratio of 0.7) to the reactor at a space velocity of either 3.1 or 5.0 sl/h/g Fe. The conversions of CO and H2 were obtained by gas chromatography (GC) analysis (HP Quad Series Micro-GC equipped with thermal conductivity detectors) of the product gas mixture. The reaction products were collected in three traps maintained at different temperatures—a hot trap (200°C), a warm trap (100°C), and a cold trap (0°C). The products were separated into different fractions (rewax, wax, oil, and aqueous) for quantification by GC analysis. However, the oil and the wax (liquid at room temperature) fractions were mixed prior to GC analysis. 

The detailed composition, referring to classes of compounds, is shown for C6 in Figure 9.3 with and without precolumn hydrogenation. In addition to paraffins, there are olefins—mainly with terminal double bond—and small amounts of alcohols (and aldehydes). The low detection limit of gas chromatography (GC) analysis allows precise determination even of minor compounds and provides exhaustive composition data also for use in kinetic modeling. Because of the short sampling duration of ca. 0.1 s,8 time-resolved selectivity data are obtained. 

All reactions conducted neat in alkene using /-menthyl diazoacetate in the presence of catalyst. bDiastereomer ratio (dr) determined by gas chromatography (GC) analysis. 

In this instrument the sample is first oxidized in a pure oxygen environment. The resulting combustion gases are then controlled to exact conditions of pressure, temperature and volume. Finally the product gases are separated under steady-state conditions and swept by helium or argon into a gas chromatography for analysis of the components. The equipment is supplied with a 60 position autosampler and microprocessor controller... 

In many applications nowadays it is essential to link a mass spectrometer to the gas chromatography in order to achieve positive identification and sensitivity of analysis. Some 12 types of compounds are listed in Table 1.11(a) which are based on the application of this technique, viz. polyaromatic hydrocarbons, polychlorobenphenyls, dioxins, chloro, carbamate and triazine types of herbicides and pesticides, Diazinon, Dicamba, Imidazoline and Cyperquat herbicides and herbicide pesticide mixtures. 

J Gerhardt, K Nokihara, R Yamamoto. Design and applications of a novel amino acid analyzer for D/L and quantitative analysis with gas chromatography, in JA Smith, JE Rivier, eds. Peptides Chemistry and Biology. Proceedings of the 12th American Peptide Symposium, Escom, Leiden, 1992, pp 457-458. 

Within Severn Trent a modified version of this procedure is utilised for the analysis of malodorous emissions. The most significant difference in this approach compared to those already discussed is the use of high resolution gas chromatography in combination with olfactory detection. This method also combines physico-chemical and olfactometric or sensory techniques but in an alternative manner. Utilisation of gas chromatography combined with odour detection is not a new concept and has been employed fairly commonly for the analysis of food aromas, essential oils and other fragrances. The technique is equally applicable to environmental problems and is used frequently in this laboratory for the analysis of atmospheric emissions and taste and odours in water. Three important benefits accrue from this approach in the context of odour emission analysis. 

Huang Z-P, Chen X-H, Wijsbeek J, Franke J-P, de Zeeuw RA. 1996. An enzymic digestion and solid-phase extraction procedure for the screening for acidic, neutral, and basic drugs in liver using gas chromatography for analysis. J Anal Toxicol 20 248. 

Konig WA, Hochmuth DH, Enantioselective gas chromatography in flavor and fragrance analysis Strategies for the identification of known and unknown plant volatiles J Chromatogr Sci. 42 423 39, 2004. 

The submitters found that analysis of the undistilled aldehyde by gas chromatography indicated a purity of 98.6%. The analysis was conducted on a column packed with 16% LS-40 on Chromosorb P/AW at 100°. N.m.r. analysis indicated an isotopic purity of 97.9% (trace of impurity at 9.60 p.p.m. due to CHO, carbon tetrachloride solution, internal tetra-methylsilane as reference). If the crude aldimine is hydrolyzed, the aldehyde is obtained in 96% overall yield however, the purity is only 94% by gas chromatography analysis. The checkers found no detectable impurity by gas chromatography in the distilled aldehyde, and the n.m.r. spectrum indicated very high isotopic purity. 

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