Determination of residues of deltamethrin in milk and butter

Abstract
A method is described for the determination of deltamethrin, particularly in milk and dairy products. Residues and fat were co‐extracted with acetone and light petroleum, partitioned with acetonitrile‐methylene chloride and centrifuged (‐ 10 °C). The extract was purified by gel permeation chromatography. A Florisil clean‐up method was tested but did not seem effective enough. Analysis was performed by gas‐liquid chromatography with a 63Ni electron‐capture detector on 3% SE‐30 using a short column (40 cm). Confirmation was effected by gas chromatography‐mass spectrometry with an SE‐30 capillary column (10 m). Recoveries from fortified samples ranged from 72 to 88% for milk spiked with 0.06 ppm and butter spiked with 2 ppm and was 94% for milk spiked with 0.016 ppm of deltamethrin