Determination of 26 Kinds of Organophosphorus Pesticide Residues in Wheat Germ by Gas Chromatography Method Simultaneously

A gas chromatography method was established to simultaneously detect 26 kinds of organophosphorus pesticide residuesin wheat germ samples, such as dichlorvos, ethoprophos, and cadusafos. By optimizing the pretreating procedures of samples and test conditions of gas chromatography, the target organophosphorus pesticide residues were separated by DB-17 capillary column and temperature programming, and corresponding amounts were detected using flame photometric detector (FPD). The results showed that the concentrations of all organophosphorus pesticide residues were linearly related to their peak areas with correlation coefficients of over 0.999 in the concentration 0.010~1.0 μg/mL, and the minimum quantitative concentrations of all organophosphorus pesticide residues were between 0.005 and 0.010 mg/kg, respectively. The recoveries of spiked samples at 3 levels ranged from 80.61% to 116.19% with relative standard deviations between 0.62%~6.83%. This method had been successfully applied in qualitative screening and quantitative detection of 26 kinds of organophosphorus pesticide residues in wheat germ samples. Alathion, chlorpyrifos-methyl and fenitrothion were detected in actual samples, and the contents of positive organophosphorus pesticides were 0.074±0.005, 0.062±0.004, 0.043±0.002 mg/kg.