Abstract: In this study, a colorimetric immunochromatography method based on colloidal gold was developed. Under optimal experimental conditions, the standard curve was established. The detection limits of this method for the three organophosphorus pesticides were 0.94, 0.32, 0.03 ng/mL, respectively, and the method was suitable for the preliminary screening of organophosphorus pesticide residues.The recovery of peach samples by standard addition showed that the recoveries rate of fenitrothion were 88%—113%, and the relative standard deviation were less than 10%. The recoveries rate of parathion methyl ranged were 107%—118%, and the relative standard deviation were less than 5%. The recoveries rate of parathion were 106%—113%, and the relative standard deviation were less than 5%.The experimental results showed that the method had high accuracy and reliability, and was not easily affected by the sample matrix, and could accurately detect organophosphorus pesticide residues in peach juice.

Key words: colloidal gold, lateral flow immunochromatography, organophosphorus pesticide