Gas chromatographic applications

Nevertheless, a number of gas chromatographic applications exist, epecially those for the determination of crude oil indicators. Such indicators are used as geochemical parameters for the thermal history of the crude as well as to indicate the possible relationship between crudes from different wells. These indicators comprise a number of isomeric aromatic species, such as the individual alkylnaphthalenes (44, 45), the individual Cio-mono-aromatics or the individual C9-mono-aromatics. The ratio between these isomers gives a definite indication of the crude oil. In general, these systems use a Deans switching unit to make a heart-cut, which then is focused, reinjected and separated on a second column with a different polarity. 

Table 1.3. Recoveries and standard deviations for some gas chromatographic applications in inorganic trace analysis...

N2. Natelson, S., and Stellate, R. L., Apparatus for extraction of gases for injection into the gas chromatograph. Application to oxygen and nitrogen in jet fuel and blood. Anal. Chem. 36, 847-851 (1963). 

Mitruka, B.M. (1975) Gas Chromatographic Applications in Microbiology and Medicine, Wiley Biomedical-Health Publication, New York. 

Gras, R., Luong, J., Monagle, M., and Winniford, B., Gas chromatographic applications with the dielectric barrier discharge detector, J. Chromatogr Sci., 44,101-107, 2006. 

Preparative gas chromatography has been reviewed by Verzele (1968) and by Sawyer and Hargrove (1968). Discussions of other topics concerned with gas chromatographic applications have appeared in the volume by the latter authors. 

In Section 6.9.2, alkanes were used as standard compounds, because they are simple hydrophobic compounds that are suitable for, and commonly use in, gas chromatographic applications. However, alkanes are not suitable standards for liquid chromatography because of their very strong hydro-phobicity and poor detectability. Therefore, the feasibility of using allqrl benzene standards was evaluated for the liquid chromatographic analysis of phenolic compounds. 

Silyl derivatives, which are widely used for gas chromatographic applications, are formed by the replacement of active hydrogens atoms from acids, alcohols, thiols, amines, amides, enolizable ketones, and aldehydes with trimethylsilyl groups. A wide variety of reagents are available. These... 

The use of MDGC has also been described in a wide range of enantioselective gas chromatographic applications [103], involving the use of chiral selectors as the stationary phase for the determination of ee and/or ER, as well as for adulteration assessments. 

A New Gas Analysis Apparatus for Biological Samples with a Combination Permeation Tube and Gas Chromatograph Application to Blood... 

Injection into the Gas Chromatograph. Application to Oxygen and Nitrogen in Jet Fuel and Blood Anal. Chem. 35 847-851 (1963) 142nd Natl. Mtg., ACS, Atlantic City, N. J., Program Abstr. p. 53c... 

Column manufacturers rely on the current literatme, results of their own marketing surveys, the number of clicks on their Websites and so forth to keep abreast of the needs of practicing gas chromatographers. The fused silica capillary column has clearly emerged as the column of choice for most gas chromatographic applications. A market research report (3) showed that 100 million were spent on capillary columns worldwide and, at an estimated average cost of 400 for a column, this figure represents about 250,000 columns, just in 1993 alone. The... 

In this chapter gas chromatographic applications to problem samples, routine and nonroutine, encountered in the crime laboratory are discussed. The material is covered in sufficient detail to enable the reader to understand each specific application and to render an appreciation for the type of work in which GC is applied in forensic science. 

Most have to do with the area of drugs of abuse and toxicological analyses, including blood alcohol analysis. There are also some very unique applications in criminalistics, such as analysis of debris from fire scenes for accelerants, explosive analysis, and the examination of trace evidence, such as paints, fibers, and other polymers. Gas chromatographic applications within these specific areas are detailed in the chapter. 

A compilation of gas chromatographic applications of pyrolysis is found in Liebman and Levy [497]. 

Liquid Crystals as Solvents for Spectroscopic, Chemical Reaction, and Gas Chromatographic Applications... 

Liquid crystals have found widespread use as stationary phases in gas chromatographic applications due to the benefits of coupling the usual analytical strengths of gas chromatography with the unique structure and shape selective properties of the liquid crystalline phase. Interaction of solutes with the orientational order provided by the anisotropy of the liquid crystal stationary phase allows for the effective and selective separation of positional and geometric isomers. This remarkable solute structural discrimination is especially important for the separation of isomers that have similar physical properties and thus cannot be conveniently separated on conventional capillary columns that mainly differentiate on the basis of boiling point/molecular weight or polarity differences. The mechanism of separation in liquid crystalline stationary phases is based on specific intermolecular inter-... 

Early studies on the use of liquid crystals as stationary phases focused on packed columns however as with other gas chromatographic applications, the technology has now almost exclusively shifted to capillary columns. Several reviews outlining the fundamentals and applications of liquid crystal stationary phases in both packed and capillary columns are available [444-449]. Stationary phases can be prepared from either monomeric or side-chain polymeric liquid crystals. Particularly relevant to the latter is the increased use of polysiloxane and poly-arylate backbones for the attachment of... 

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