CAPILLARY GAS

Jaeger, H., Capillary Gas Chromatography Mass Spectrometry in Medicine and Pharmacology, Huetig, New York, 1987. 

Many forms of chromatography have been used to separate mixtures of quinoline and isoquinoline homologues. For example, alumina saturated with cobalt chloride, reversed-phase Hquid chromatography, and capillary gas chromatography (gc) with deactivated glass columns have all been employed (38,39). 

More recendy the cis and trans isomers of the mosquito repellent CIC-4, a mixture of citroneUa isomers, have been separated by preparative hplc and bioassayed for effectiveness (23). Chiral-phase capillary gas chromatography and mosquito repellent activity of some oxazoUdine derivatives of (+)-and ( —)-citroneUal have been studied to find stmcture—activity relationships (24). Several 2-aLkyl- -acetyloxahdines have been synthesized and tested against mosquitoes, with further efforts using nmr to determine the rotational isomers of the more active N-acetyl-2,2-dimethyloxazohdine (25). 

Terpene chemists use mainly gas chromatography in dealing with terpene mixtures in research and development as weU as in quahty control. Capillary gas chromatography with stable bonded-phase columns, the primary analytical method, is also being used more frequendy in the 1990s in product quahty control because its greater resolution is helpful in producing consistent products. 

SPME has been utilized for deterrnination of pollutants in aqueous solution by the adsorption of analyte onto stationary-phase coated fused-siUca fibers, followed by thermal desorption in the injection system of a capillary gas chromatograph (34). EuU automation can be achieved using an autosampler. Eiber coated with 7- and 100-p.m film thickness and a nitrogen—phosphoms flame thermionic detector were used to evaluate the adsorption and desorption of four j -triazines. The gc peaks resulting from desorption of fibers were shown to be comparable to those obtained using manual injection. 

Analysis for the butanals is most conveniendy carried out by gas chromatography. Trace quantities of -butyraldehyde (18 ppb) in exhaust gases have been determined employing a combination of capillary gas chromatography with thermionic detection (35). Sinulady, trace amounts of -butyraldehyde in cigarette smoke and coffee aroma have been determined by various capillary gc techniques (36,37). 

Dicyclopentadiene exists ia two stereoisomeric forms, the endo and exo isomers. Commercial DCPD, 3a,4,7,7a-tetrahydro-4,7-methano-lH-iadene, is predominandy the endo isomer (exo endo 6 953 by capillary gas chromatography). The dimer is the form ia which CPD is sold commercially. 

The actual Russian standards allow presentation of hydrocarbon components of UGC as individual compounds only for C -C hydrocai bons. The rest is described as pseudo-compound C,, although its content may reach 60 % m/m. Apparently, the detailed determination of composition of hydrocarbons C, in UGC allows essentially to raise quality of both its processing and its record. The best method for the determination of heavy hydrocai bons is capillary gas chromatography. Typical approach is based on preliminary sepai ation of UGC samples to gaseous and liquid phases. 

There are two main approaches to its solution. Traditional approach is based on preliminary separation of UGC samples to gaseous and liquid phases and their subsequent analyses [1]. This approach is well-developed and it allows obtaining quite precise results being used properly. However, this method is relatively complicated. Multi-stage procedure is a source of potential errors, then, it makes the analyses quite time consuming. More progressive approach is based on the direct analysis of the pressurized UGC samples. In both cases the determination of heavy hydrocarbons (up to C ) is made by capillary gas chromatography. 

P. Sandra (Ed.), Sample Introduction in Capillary Gas Chromatography, Vol 1, Chromatographic Method Series, Huethig, Basel, 1985. 

Together with the techniques described above, other techniques using hot injectors for the transfer of large-volumes in capillary gas chromatography have been developed. Transfer of large-volume solvents in a programmed temperature vaporizing... 

Figure 2.16 Clirotnatograms of a pentane extract of a water sample containing 200 ppb of a naphtha fraction (a) sample extracted by using a continuous flow system, where a pressurized bottle was employed as the sample-delivery system (b) batch-extracted sample. Reprinted from Journal of Chromatography, A 330, J. Roeraade, Automated monitoring of organic Race components in water. I. Continuous flow exti action together with on-line capillary gas cliro-matography , pp. 263 - 274, copyrigth 1985, with permission from Elsevier Science.

Figure 2.19 Schematic representation of an on-line liquid-liquid extraction-GC/AED system. Reprinted from Journal of High Resolution Chromatography, 18, E. C. Goosens et al, Continuous liquid-liquid extraction combined on-line with capillary gas chromatography- atomic emission detection for environmental analysis , pp. 38-44, 1995, with permission from Wiley-VCH.

Figure 2.20 Schematic representation of the set-up used for on-line exti action-GC VI and V2, valves PI and P2, syringe pumps L, sample loop CC flow, countercunent flow CT, cold ti ap. Reprinted from Journal of High Resolution Chromatography, 16, H. G. J. Mol et ai, Use of open-tubular tapping columns for on-line exti action-capillary gas cluomatography of aqueous samples , pp. 413-418, 1993, with permission from Wiley-VCH.

K. Grob, On-Column Injection in Capillary Gas Chromatography, W. Beitsch, W. G. Jennings and P. Sandra (Series Eds), Hiithig, Heidelberg, Gemiany (1991). 

K. Grob and Z. Li, Intr oduction of water and water-containing solvent mixtures in capillary gas clir omatogr aphy. I. Eailure to produce water-wettable precolumns (retention gaps) , J. Chromatogr. 473 381-390 (1998). 

J. Roeraade, Automated monitoring of organic trace components in water. I. Continuous flow extraction together with on-line capillary gas cliromatography , 7. Chromatogr. 330 263-274 (1985). 

H. G. J. Mol, H.-G. Janssen, C. A. Cramers and U. A. Th Brinkman, On-line sample enrichment-capillary gas clir omatography of aqueous samples using geometr ically deformed open-tubular extraction columns , 7. Microcolumn Sep. 7 247-257 (1995). 

R. G. Schafer and J. Holtkemeier, Determination of dimethylnaphthalenes in crtide oils hy means of two-dimensional capillary gas cliromatography . Anal. Chim. Acta 260 107-112(1992). 

S. Blomherg and J. Roeraade, Preparative capillary gas cliromatography. IF Fraction collection on rtaps coated with a very tliick-film of immobilized stationary phase , J. Chromatogr. 394 443-453 (1987). 

J. P. E. M. Rijks and J. A. Rijks, Programmed cold sample intr oduction and multidimensional preparative capillary gas cliromatogr aphy. Part I introduction, design and operation of a new mass flow contr olled multidimensional GC system , J. High Resolut. Chromatogr. 13 261 -266 (1990). 

R. H. M. van Ingen and F. M. Nijssen, Determination of diethylene glycol monoethyl ether in flavors hy two-dimensional capillary gas cliromatography , J. High Resolut. Chromatogr. 12 484-485 (1989). 

R. M. Kinghorti, P. J. Marriott and M. Cumbers, Multidimensional capillary gas chr O-matography of polychlorinated biphenyl marker compounds , 7. High Resolut. Chromatogr. 19 622-626 (1996). 

Figure 11.13 (a-c) Immunoaffinity exti action-SPE-GC-FID ti aces of (a) HPLC-grade water (b) urine (c) urine spiked with /3-19-noitestosti one (0.5 p.g/1) or norethindrone and norgestrel (both 4 p.g/1) (d) SPE-GC-FID ti ace of urine. Reprinted from Analytical Chemistry, 63, A. Faijam et al., Direct inti oduction of large-volume urine samples into an on-line immunoaffinity sample pretreatment-capillary gas cliromatography system, pp. 2481-2487,1991, with permission from the American Chemical Society. 

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