Optimization of Pretreatment Methods for 27 Pesticide Residues in NY/T 761—2008 Standard

Miniaturization, low toxicity, rapidity and low cost are the development trend of sample pretreatment. A new method to detect 27 pesticide residues in fruits and vegetables by the rapid pretreatment of gas chromatography has been developed. The different pretreatment methods of different types of pesticide residues in the standard NY/T 761—2008 were integrated and optimized, and the feasibility of the improved method was carried out. The pesticide residues in samples were extracted with 1% acetic acid-acetonitrile solution. Then, the pesticide residues in the supernatant were cleaned up with graphitized carbon black (GCB) before being subjected to gas chromatographic (GC) analysis. The results showed that good linearity was observed for all 27 analytes with correlation coefficients above 0.999. The limits of detection (LODs) were in the range of 0.000 1~0.006 mg/kg. The recoveries were in the range of 72.1%~111.0% and the relative standard deviations (RSD) were less than 14.5% (n=3). The analysis results of several vegetables confirmed that the pretreatment method can meet the requirements of the multi-pesticide residue analysis and determination, and the average recovery was as high as 98.8%. The optimized pretreatment method not only has high sensitivity, accuracy and convenience, but also greatly reduces the discharge of organic waste liquid and waste gas, improves the detection efficiency and meets environmental friendly requirements, the method meets the requirements of batch sample pretreatment, and provides a more effective guarantee for the quality and safety of agricultural products.