Determination of Polychlorinated Biphenyls in the Presence of Organochlorine Pesticides by Thin-Layer Chromatography

Abstract

A simple, quick, inexpensive and easily reproduced thin-layer chromatographic method for the separation and quantitation of organochlorine pesticides and polychlorinated biphenyls (PCB's) was developed using an aluminum oxide plate, which was developed in a triethylamine: hexane solvent, with steam and U.V. treatment for visualization. The recoveries reported are mostly in the range of 90 to 100%.

Polychlorinated biphenyls (PCB's) were first noted by Reisborough¹ as materials present in wildlife samples that could give rise to interference in analysis of organochlorine pesticides. Of late analysis of PCB's has become as important as analysis of the pesticides. In both groups of materials many individual components exist and separation of the two groups by some method prior to the generally used gas-liquid chromatographic methodology is essential. Early separation methods were based on liquid-solid chromatography on florisil, silicic acid-celite, alumina, silica-gel and charcoal^2,3,4,5,6. Careful activation conditions had to be followed and reports on unsuccessful attempts to duplicate work have appeared.

Thin-layer chromatographic (TLC) methods have been used to separate these two groups of materials. The bulk of the T.L.C. methods however are only semiquantitative or confirmatory. We wish to describe a thin-layer separation technique that we have developed which separates PCB's and the common organochlorine pesticides. Elution of spots and analysis of the eluants by gas liquid chromatography indicated the method is quantitative. Further studies using untrained personnel indicated that the method is easily reproduced.