Biological packed column

Although the majority of chiral CEC—MS applications still involve packed columns, few reports on chiral OT-CEC-MS are found in recent literature. The feasibility of coupling OT-CEC (using a short Chirasil-Dex-coated capillary column) to MS and MS/MS for trace analysis of hexobarbital enantiomers in biological fluids was reported by Schurig and Mayer. More recently, Kamande et al. investigated polyelectrolyte multilayer (PEM) coating as a new medium for the separation of chiral analytes, and PEM-coated capillaries were successfully coupled to ESI/MS for the stereoselective analysis of five /1-blockers. 

C. In "Chromatography of Synthetic and Biological Polymers Column Packings, GPC, GF, and Gradient Elution", Epton, R., Ed., Ellis Horwood Ltd. England, Volume I, Chapter 24, p. 

Packed columns. Packed columns were introduced by Martin in 1952 [33]. Since then, they have been developed for application to compounds derived from biological sources [34,35] and are now the most widely used columns for gas phase chromatography in this field. 

While it is clearly apparent that packed columns are mainly used for the various compendial tests, the use of capillary columns for the determination of therapeutic agents in biological fluids has become increasingly popular. The high resolution capability of capillary columns often overcomes the problems of interference from the biological sample matrix and, coupled with specificity and increased sensitivity has made possible the quantitative analysis of many, formerly undeterminable drugs in biological fluids. In particular. 

Packed column separation and analysis is certainly valuable for many routine tests and even very useful and necessary at times. However, it cannot meet the analytical requirements of many of today s investigations. For example, if the sample size is a limiting and critical factor, as in blood testing or other biological samples, or if complex mixtures are of interest, the packed column will in most cases fail to generate satisfactory results. 

The opium alkaloids have engaged the interest of scientists since the isolation of morphine by Sertlirner in 1806. The Isolation, characterization and quantification of these alkaloids have been a continuing challenge. Gas chromatography of opium alkaloids has been performed i.a. for the analysis of the alkaloids present in the crude drug itself, especially for the quantitative determination of morphine, as well as for the analysis of opium alkaloids, mainly morphine - and heroin - in biological materials. Most studies have so far been carried out with packed columns, only a limited number with capillary columns. 

Merriman et al. improved the method of Grab and Reinstein. They developed a gas chroma tographic-mass spectrometric micromethod. As little as 20 ng of caffeine can be measured, and, therefore accurate estimates of caffeine concentrations in 100 pi or less of biological samples can be made. The method is rapid, specific and sensitive. A packed column of 3 % Dexsil 300 on Chromosorb Q was used at 210°C, and glutethimide was used as an internal standard. 

Zuidema et al.6 used Propyl-8 ( = dimethylformamide-dipropylacetal) for propylation of theophylline. Fluoranthene was used as an internal standard for the determination of theophylline in biological fluids. Extraction was obtained with chloroform-isopropanol (95 5) after acidifying the sample (1 ml) with hydrochloric acid. After evaporation of the solvent the residue was dissolved in 0.5 ml of a methanolic solution of the internal standard. The methanol was evaporated and the residue dissolved in 30 ul Propyl-8 and gas chromatographed on a packed column of 3 % OV-17 on Gas Chrom Q at a column temperature of 220°C... 

Recently, supercritical fluid extraction (SFE) has been utilized for extraction and cleanup of biological samples. The procedure is quick and avoids the use of flammable or toxic organic solvents (Anitescu and Tavlarides 1998 Djordjevic et al. 1994). Packed-column GC techniques are still widely used however, HRGC has made it possible to achieve better separation of PCB congeners for quantitation (Ballschmiter and Zell 1980 Mullin et al. 1984). 

Cobalt ultra-trace On-line preconcentration and determination using a PTFE turnings packed column and electrothermal atomic absorption spectrometry. Applications in natural waters and biological samples. J Anal Atom Spectrom 17 1330-1334. 

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