Investigation of adsorption gas chromatographic determination of polychlorinated biphenyls in oils

Abstract

Polychlorinated biphenyls (PCBs) belong to the group of persistent organic pollutants (POPs). The main sources of PCBs are capacitors and transformers, in which PCBs were used as dielectrics. After the replacement of oils in such equipment, waste oils are formed, in which PCB content must be under control for further use. In addition, due to emergencies edible oils were found to be contaminated with PCBs. The aim of this work is to investigate the employment of multilayer sorption systems based on various sorbents for the development of a method for determination of PCBs in industrial (transformer) and edible (vegetable) oils.

A PCBs mixture consisting of di-, tri-, tetra-, penta-, hexa- and heptachlorobiphenyls prepared from technical mixtures «Trichlorbifenil» and «Sovol» was studied. Multilayer columns with a combination of various sorbents: silica gel, polychrome-1 (polymer based on teflon), polysorb-1 (copolymer of styrene and divinylbenzene), florisil (magnesium silicate), aluminum oxide were used for PCBs extraction. Hexane was the elution solvent. The quantification of recovery rate was carried out using the internal standard method. To obtain more reliable and adequate results, calculations were carried out both for groups of PCB congeners and for the summary of all PCBs. It is shown that use of all multilayer columns with various sorbents allows to achieve 70-90 % recovery rate. The most acceptable is the use of columns with polychrome-1, in this case the recovery rate is the same for all groups of PCB congeners, and a lower consumption of eluent is required. The minimal detectable PCB content in the transformer oil under the conditions of GC-ECD analysis was 0.002%.