Gas-liqiid chromatographic determination of pydrin, a synthetic pyrethroid, in cabbage and lettuce

Pydrin, alpha-cyano-3-phenoxybenzyl 2-(4-chlorophenyl)-3-methylbutyrate, a synthetic pyrethroid ester, is extracted from vegetables with acetonitrile, partitioned into petroleum ether before cleanup on a Florisil column, and analyzed by electron capture gas-liquid chromatography. Recoveries of 88-102% at 0.01 ppm, 99-102% at 0.1 ppm, and 98-104% at 1.0 ppm were obtained from fortified cabbage and lettuce samples. The method appears applicable to detection of the residues of Pydrin in the foliage of many types of crops.