Papers by Author: Ze Min Xu

Abstract: In order to simplify the process of detecting pesticide residues in vegetables, reducing detection time to find a more efficient detection method, ultrahigh pressure processing technique was applied to NIR detection experiments on dimethoate residues in Chinese cabbage, the spectral data was pre-processed and optimized and a spectrum model was established. The results show that: ultrahigh-pressure extraction process did not affect the absorption of near infrared spectroscopy of extraction reagent acetone. A PLS model on near-infrared spectroscopy of samples within the range of 4100-11000cm^-1 was established, obtaining a correlation coefficient R of 87.14%, Rank of 9 and RMSECV of 0.139. Residual concentration of 10^-4-10^-5 has a small relative error, the prediction is better. Further processing and selection of samples will expand the range of predicted concentration.

Abstract: In order to simplify the pretreatment process in detection of pesticide residues in vegetables and improve the extraction recovery, an ultrahigh pressure technique was adopted in pretreatment experiments on organophosphorus pesticide residues in cabbage, and on the basis of single-factor test, orthogonal pre-conditions were optimized. The results showed that: The optimum process conditions for ultrahigh pressure extraction of dimethoate in cabbage at room temperature are: pressure of 400MPa, extraction solvent volume of 60ml, the holding time of 4min, recovery rate up to 91.3%, compared with the conventional homogenization method, extraction efficiency improved significantly.