| Based on the organophosphorus pesticides have a strong catalytic function on oxidization of hydrogen peroxide and benzidine, one study investigating of dichlorvos was perforemed. With the Triton X-114 as extractant, the characteristics of the cloud point extraction system in dichlorvos determination was studied. In pH 8.5 ammonia buffer solution, a stable yellow complex was formed in the reaction of catalytic of dichlorvos on hydrogen peroxide and benzidine. This complex was determined by cloud point extraction. The maximum absorption wave length is 425 nm. In the range of 0 μg ～ 250 μg, the linear relationship of the absorbance values is good. The relation coefficient is 0.999 8. The molar absorbance coefficient is 5.3×104 L·mol-1·cm-1. The method detection limit of 22.2 μg/L was measured. On determination for dichlorvos in five kinds of vegetables, the average spiked recoveries were 82.3% ～ 102%, RSD ≤ 8.9%. |
