Multiresidue Analysis Of Thirteen Pesticides In Panax Notoginseng And Residue Transfer During Processing

Panax Notoginseng is a kind of distinctive Chinese medicine and its problems of using pesticides and residues have aroused general concern.In this thesis,a multi-residue analytical method of 13 pesticides in Panax Notoginseng was established,and the behavior of pesticide residue during processing was also studied.The results of the study could help us better evaluate the dietary intake risk assessment and give forward a guidance of pesticides application on Panax Notoginseng.The paper includes there chapters and the first part is to establish a method using QuEChERS cleanup followed by LC-MS/MS for determination of 13 pesticides multiresidues in dried flower bud and root of Panax Notoginseng.The pesticide residues were soaked with 5mL water,cleaned up with 5mg MWCNTs and 50mg PSA for flower bud and 5mg MWCNTs and 25mg PSA for root,respectively.The recoveries of these 13 pesticides in the range of 80%-120%,the RSD%lower than 18%and the LOQs within 2?g/kg-10?g/kg.In the second chapter of this thesis,the method can be successfully applied to detect 20 dried flower buds and 20 roots of Panax Notoginseng.All of samples were detected pesticide residues,with the highest(90%)detection rates of Pyrimethanil and Dimethomorph in two kinds of samples.Besides,the residue values of triazole fungicide were relatively high,and the residue values of each detected pesticide in flower bud were higher than in root of Panax Notoginseng.Finally,drying and cooking for root of Panax Notoginseng procedures were conducted in this study to evaluate the processing factors(Pfs),while conducting the factorial experiment in flower bud and root with two factors,immersion time and temperatue.Pfs of 13 pesticides in drying procedure ranged from 2.44-3.26.The reductions of Pyrimethamine,Triazolone and Pyraclostrobin in cooking procedure respectively were 46%,36%and 76%,whereas the others were little changed.During the immersion with different time and temperature,brew factors of 13 pesticides in the flower bud and root respectively were 3%-87%and 4%-36%.And there was a inverse correlation between the brew factor and logP,meaning the higher the logP,the lower the brew factor.