STUDIES ON THE REMOVAL OF LIPIDS IN THE A NALYSIS OF PYRETHROID PESTICIDE-RESIDUES IN SALAD OIL, BROWN RICE AND SOYBEAN

Three methods for the removal of lipids, i.e., the GPC method with a m ixture of ethyl acetate-cyclohexane (1 : 1, v/v), the n-hexane/acetoni trile partition method, and the Extrelut-3/Sep-pak (R) C-18 method, we re compared in the analysis of pyrethroid pesticide residues in crops. Efficiencies of the removal of lipids in salad oil, brown rice and so ybean were 51.0 similar to 77.4% by GPC, 61.6 similar to 96.4% by n-he xane/acetonitrile partition and 73.8 similar to 98.4% by the Extrelut- 3/Sep-pak (R) C-18 method. Recoveries of 10 pyrethroid pesticides from brown rice (fortified at 0.2 similar to 0.4 ppm) were 72.2 similar to 130% by GPC, 62.5 similar to 100% by n-hexane/acetonitrile partition, and 61.5 similar to 96.3% by the Extrelut-3/Sep-pak (R) C-18 method, respectively. Therefore, the Extrelut-3/Sep-pak (R) C-18 method seems to be the most suitable for the removal of lipids in the analysis of p yrethroid pesticide residues in crops because of its efficiency and si mplicity.