Evaluation of inexpensive thin-layer chromatographic procedures for the estimation of some organophosphorus and carbamate insecticide residues in fruit and vegetables

Modified versions of previously published procedures for the extraction and clean-up of some organophosphorus insecticide residues in fruits and vegetables are described, and their usefulness in combination with selected thin-layer chromatographic procedures is experimentally assessed for several pesticides in apples, oranges, tomatoes, carrots and peas. A simple extraction procedure for insecticidal carbamates is similarly evaluated for carbaryl and propoxur residues in apples, carrots and peas. Semi-quantitative estimation, by visual comparison with standards, is shown to be possible in many cases at residue levels as low as 0.4 mg kg^?1, and the combined procedures should be useful in the screening of fruits or vegetables for compliance with maximum residue limits.