DETERMINATION OF CHLORPYRIFOS IN FRUITS AND VEGETABLES BY ELISA AND CONFIRMATION BY GC-AED

A commercial polyclonal plate ELISA was validated for the analysis of chlorpyrifos in fruits and vegetables. Produce was extracted by high s peed homogenization IO g of a homogeneous subsample in 20 mi of methan ol for 3 min followed by clean-up with C-18 Sep-Paks. All samples and standards were analyzed in 10% final methanol concentration. Reproduci bility studies yielded per cent coefficients of variation (%CVs) from 2.1 to 20. Fruits and vegetables fortified at five different levels de monstrated percent recoveries ranging from 77 to 92 (%CVs of 4.0 to 14 ) for chlorpyrifos. A comparison of the analysis of 35 positive chlorp yrifos samples between ELISA and a gas chromatography-atomic emission detector method indicated good agreement with a correlation coefficien t of 0.967 and a slope of 0.9583.