Analysis of Pesticide Residues in Vegetables by Enzyme Inhibition Colorimetric Kit

[Objectives] The paper was to understand the detection effect of commercial enzyme inhibition colorimetric kit. [Methods] Six brands of kits were used to detect pesticide residues in vegetables. The detection results were compared with those of 50 kinds of organophosphorus pesticides and 10 kinds of carbamate pesticides detected by chromatography and mass spectrometry. According to different thresholds, the test results of different kits were evaluated, and the false positive rate, false negative rate and coincidence rate of each kit were obtained. The test results of commercial enzyme inhibition colorimetric kits were compared and analyzed. [Results] The detection effect of kit D was the best among the 6 brands of kits, and the coincidence rate was the highest under the 7 thresholds. There was a certain relationship between the detection effect of commercial enzyme inhibition colorimetric kit and the determination threshold of positive samples. The false positive rate decreased with the increase of determination threshold, and the false negative rate increased with the increase of determination threshold, but the coincidence rate with chromatography and mass spectrometry can not reach 100%. When the threshold was set to 20%, the effect was the best. The coincidence rate of 3 brands of kits with the results of chromatography and mass spectrometry was the highest, and none of the 6 kits involved in the comparison had the lowest coincidence rate under this threshold. [Conclusions] It is suggested to modify the threshold values in national standard and trade standard.