STUDY ON THE DETECTION OF FOOD PESTICIDE RESIDUES BASED ONLIQUID CHROMATOGRAP

摘要

The improvement of food pesticide residue detection methods is critical to improve the quality of food.By taking apple as a case, this study carried out the detection experiments of the pesticide residues by using the liquid chromatography method. In order to obtain the fastest detection environment, we optimized the parameters including the concentration of hydrochloric acid, the amount of sodium nitrite, and the extraction reagents in the process. The recovery rate, intra-day precision and inter-day precision of morpholine-spiked samples of apples were determined, to compare the liquid chromatography method with the traditional detection method. In addition, the derivatization principle and properties of morpholine were also analyzed. The experimental results indicated that Under acidic conditions, N-nitrosomorpholine produced by the reaction of morpholine and sodium nitrite has both stable and volatile properties and can be detected by liquid chromatography. The derivatization efficiency of morpholine molecules is optimal when the derivatization temperature is 40°C. the HCl concentration is 0.05mol/L,and sodium nitrite are 200μL，and the derivative is extracted with 0.5mL dichloromethane after standing for 10min. The recovery rate and precision was measured in five groups of apple samples, it indicated that the liquid chromatography is 65 times more sensitive than traditional methods, and verified the reliability and convenience of liquid chromatography in the detection of morpholine pesticides.