Rj. Bushway et Zh. Fan, DETERMINATION OF CHLORPYRIFOS IN FRUITS AND VEGETABLES BY ELISA AND CONFIRMATION BY GC-AED, FOOD AND AGRICULTURAL IMMUNOLOGY, 10(3), 1998, pp. 215-221
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.