Screening of food samples for carbamate and organophosphate pesticides using an electrochemical bioassay

In this work we report the application of an electrochemical enzyme inhibition assay, based on screen printed electrodes, for the determination of carbaryl, and parathion methyl in complex food matrices. The calibration curves for carbaryl and parathion methyl showed a comparable working range, respectively 2-90 and 1-100 ng/ml with a I-50% at 35 ng/ml, and a coefficient of variation (CV) less than or equal to 10%. The method was applied to food samples showing negligible matrix effect (+ 1% to -5%). Samples were tested after spiking of two concentration levels: 10 and 30 ng/g of the investigated pesticides. The assay allowed to detect the tested pesticides at 10 ng/ml level in non-purified solvent extract of different complex matrices with an overall assay time of 15 min. (C) 2003 Elsevier Ltd. All rights reserved.