A multiresidue method for pesticides that enables quantitative, sequential analysis of a large number of vegetable and fruit samples by gas chromatography/mass spectrometry has been developed. First, 89 important target compounds were selected for monitoring, and then the appropriate internal standards for these pesticides, 14 stable isotopically labeled pesticides (surrogates), were used. The sample was extracted with acetonitrile, and the extract was cleaned up by a salting-out step followed by redissolution in ethyl acetate. Coextractives were removed automatically by gel permeation chromatography with a graphitized carbon column, and then by use of a tandem silica-gel/PSA cartridge column. Recoveries of 82 of the 89 pesticides from fortified spinach, tomato, apple, and strawberry were within a range from 70 to 120%, and the relative standard deviation values of 80 of the 89 pesticides were <5%. The method was applied to 188 commercial vegetable and fruit samples to demonstrate its use in routine analysis.

A multiresidue method that enables determination of many pesticides in agricultural products by GC-ECD was studied. First, 63 pesticides were selected as agrochemicals commonly used in crop protection in this country, and/or found in agricultural products over the past 6 years (April 1996ῌMarch 2002) in Aichi Prefecture. A sample was extracted with acetonitrile and the acetonitrile layer was separated by salting-out. The extract was purified on a GPC system with a graphitized carbon columns, and then by a Florisil mini-column fractionation. The test solution was subjected to one-injection, dual-column GC with dual ECD (column: Stx-CLPesticides and Stx-CLPesticides2). The detection limits of the pesticides were in a suitable range (0.0001ῌ0.01 mg/ g) for monitoring pesticide residues in agricultural products. The method was applied to 203 commercial agricultural products to demonstrate its suitability for routine analysis.

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We investigated the determination of spinosyn A and spinosyn D, the active ingredients of spinosad, in animal and fishery products by liquid chromatography with mass spectrometry (LC-MS). The sample was homogenized with 1 mol/L dipotassium hydrogenphosphate aqueous solution and extracted with acetone῍n-hexane under mildly alkaline conditions. After n-hexane῍ acetonitrile partitioning using an EXtrelut ῌ column, the extract was cleaned up on a tandem SAX/PSA mini-column, and examined by means of fragmenter-voltage-switching ESI-SIM mode LC-MS. Mean recoveries (n̮5)