Extraction Efficiency Study—Examination of Three Procedures for Extracting 14C-Labeled and Unlabeled Residues of Organophosphorus Pesticides and Carbaryl from Bean Leaves and Kale
Abstract Two rapid extraction procedures which consist of sample blending with ethyl acetate or acetonitrile and an exhaustive Soxhlet extraction procedure using 10% methanol in chloroform were tested for efficiency of extraction of 14C-labeled residues of carbaryl, malathion, and phosphamidon on laboratory-grown and treated bean plants. The extraction procedures were also tested on field-treated kale containing 7–11 day old residues of azinphosmethyl, parathion, and malathion. The extraction efficiencies of the 3 procedures were in very close agreement for all residues in both studies. More than 90% of the 14C-containing residues were extracted from treated bean leaves. The extraction efficiencies for field-weathered residues on kale were judged to be essentially 100%, since several hours of additional Soxhlet extraction did not remove any more residue.