Abstract:

A new analytical method was developed for the determination of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in wheat samples. The extraction and purification procedures, accelerated solvent extraction (ASE) and gel permeation chromatography (GPC) cleanup  were  respectively presented by optimizing different extraction conditions and the fraction collection time. The detection conditions could be achieved by gas chromatography with electroncapture detection (GC／ECD). The results showed that the method recovery percentages and relative standard deviations (RSD) were 69.8％～87.4％ and 1.48％～11.0％ for PCBs, 70.4％～113.9％ and 3.54％～17.0％ for OCPs. The method detection limits (MDL) ranged in  0.03～0.29μg／kg. This analytical method was applied to exam the wheat samples  collected from Shanghe of Jinan city, Shandong province. The concentrations of these seven kinds of PCBs  ranged in 0～157.9μg／kg, and the concentration of these seven kinds of OCPs 2.38～10.02μg／kg. The method was suitable for batch samples with high accuracy, sensitivity and less pre-treatment time, meanwhile, by which the PCBs and OCPs could  be analyzed simultaneously. Therefore, it is an ideal choice for determining PCBs and OCPs in wheat.

Key words: wheat; organochlorine pesticides; polychlorinated biphenyls; accelerated solvent extraction; gel permeation chromatography