[Validation of an Analytical Method for Organochlorine Pesticide Residues in Beef Products by GC-MS Using Sampling with Increment Reduction].

We developed a simultaneous determination method for the environmentally persistent organochlorine pesticides aldrin/dieldrin, γ-BHC, DDT, endrin, and heptachlor in beef products. In the method, we adopted incremental reduction for sample collection in order to improve the uniformity of the samples. In incremental reduction, a sample was ground and spread to an even thickness, divided into sections, and collected in an equal amount from each section. After extraction with an acetonitrile/ethanol mixture (1 : 1 v/v), sample clean-up was performed by refrigerated centrifu-gation and solid-phase extraction. This process was easy and did not require gel permeation chromatography. The sample was analyzed by GC-MS. A validation study of the development method showed that the tested pesticides met the target values indicated in the validity evaluation guideline.