Capillary gas-chromatography

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. 

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 2.19 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.

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

E. C. Goosens, D. de Jong, G. J. de Jong and U. A. Th Brinkman, Reversed-phase liquid cliromatography coupled on-line with capillary gas chromatography. II. Use of a solvent vapor exit to ina ease introduction volumes and introduction rates into the gas cliromato-graplT, J. Microcolumn Sep 6 207-215 (1994). 

An on-line supercritical fluid chromatography-capillary gas chromatography (SFC-GC) technique has been demonstrated for the direct transfer of SFC fractions from a packed column SFC system to a GC system. This technique has been applied in the analysis of industrial samples such as aviation fuel (24). This type of coupled technique is sometimes more advantageous than the traditional LC-GC coupled technique since SFC is compatible with GC, because most supercritical fluids decompress into gases at GC conditions and are not detected by flame-ionization detection. The use of solvent evaporation techniques are not necessary. SFC, in the same way as LC, can be used to preseparate a sample into classes of compounds where the individual components can then be analyzed and quantified by GC. The supercritical fluid sample effluent is decompressed through a restrictor directly into a capillary GC injection port. In addition, this technique allows selective or multi-step heart-cutting of various sample peaks as they elute from the supercritical fluid... 

Figure 12.20 SFC-GC analysis of a sample of aviation fuel (a) SFC separation into two peaks (b and c) coixesponding GC ttaces of the respective peaks (flame-ionization detection used throughout). Reprinted from Journal of High Resolution Chromatography, 10, J. M. Levy et ah, On-line multidimensional supercritical fluid chromatography/capillary gas chromatography , pp. 337-341, 1987, with permission from Wiley-VCH.

H. J. Goites, B. M. Bell, G. D. Pfeiffer and J. D. Graham, Multidimensional chromatography using on-line coupled microcolumn size exclusion cliromatography-capillary gas chromatography-mass spectrometry for determination of polymer additives , J. Microcolumn Sep. 1 278-288. (1989)... 

J. M. Eevy, J. P. Guzowski and W. E. Huhak, On-line multidimensional superaitical fluid chromatography/capillary gas chromatography. J. High Resolut. Chromatogr. 10 337-341 (1987). 

In general, capillary gas chromatography provides enough resolution for most determinations in environmental analysis. Multidimensional gas chromatography has been applied to environmental analysis mainly to solve separation problems for complex groups of compounds. Important applications of GC-GC can therefore be found in the analysis of organic micropollutants, where compounds such as polychlorinated dibenzodioxins (PCDDs) (10), polychlorinated dibenzofurans (PCDFs) (10) and polychlorinated biphenyls (PCBs) (11-15), on account of their similar properties, present serious separation problems. MDGC has also been used to analyse other pollutants in environmental samples (10, 16, 17). 

E. Podehrad, M. Heil, S. Leih, B. Geier, T. Beck, A. Mosandl, A. C. Sewell and H. Bohles, Analytical approach in diagnosis of inherited metabolic diseases maple syrup urine disease (MSUD)-simultaneous analysis of metabolites in urine by enantioselective multidimensional capillary gas chromatography-mass specti ometiy (enantio-MDGC-MS) , 7. High Resolut. Chromatogr. 20 355-362(1997). 

Jiang GB, Xu FZ, Zhang FJ (1999) Dioctyltin and tributyltin detection at trace levels in water and beverages by capillary gas chromatography with flame photometric detection. Fresenius Journal of Analytical Chemistry, 363(3) 256-260. 

Stan H-J. 1989. Application of capillary gas chromatography with mass selective detection to pesticide residue analysis. J Chromatogr 467 85-98. 

Leung AM, McDonough DM, West CD. 1998. Determination of endosulfans in soil/sediment samples from Point Mugu, Oxnard, CA, using capillary gas chromatography/mass selective detection (CC/MSD). Environmental Monitoring and Assessment 50(l) 85-94. 

Noroozian E, Maris FA, Nielen MWF, et al. 1987. Liquid chromatographic trace enrichment with on-line capillary gas chromatography for the determination of organic pollutants in aqueous samples. Journal of High Resolution Chromatography and Chromatography Communications 10 17-24. 

Because of its high toxicity, there is concern about very low levels of 2,3,7,8-TCDD in biota. This raises analytical problems, and high resolution capillary gas chromatography (GC) is needed to obtain reliable isomer-specific analyses at low concentrations. In the analysis of herring gull eggs collected from the Great Lakes, Hebert et al. (1994)... 

Applications of Glass Capillary Gas Chromatography, edited by Walter G. Jennings... 

Pirini, A. and Conte, L. S. (1992). Capillary gas chromatography determination of free amino acids in honey as a mean of discrimination between different botanical sources. /. Fdigh Res. Chromatogr. 15,165-170. 

W. Herres, "HRGC-FTIR Capillary Gas Chromatography-Fourier Transform Infrared Spectrometry. Theory and Applications", Huethlg, Heidelberg, 1987. 

P. Sandra, (Ed.), "Sample Introduction in Capillary Gas Chromatography", Huethig, Heidelberg, Vol. 1, 1985. 

---