The Study Of Pesticides Multi-residue System In Tobacco By Liquid Chromatography-Tandem Mass Spectrum Analysis Method

Tobacco is a kind of very important cash crops in our country, and the tobacco industry is also important source of national and local fiscal revenue. However, pollution of pesticides residue in tobacco is a serious threat to the health of human, especially of smokers. Tobacco consumers and the tobacco industry pay close attention to security issues of smoking. Therefore, control of maximum pesticides residues in tobacco is an important means of ensuring the safety of tobacco smoking. With the continuous development of analytical techniques, more and more pesticides residues in tobacco can be detected, and the LOD is continually reduced, too. In this paper, the multi-pesticide residues system of organophosphorus, heterocyclic and amides pesticides in tobacco is analyzed.This dissertation includes four parts:In chapter one, the analysis method and research status of multi-pesticide residues in tobacco were summarized.In chapter two, a rapid determination method based on high performance liquid chromatography-mass spectrum had been developed for determination of fifteen pesticides residues in tobacco. This new method was easy, rapid, economical and less solvent consumption. The recoveries of fifteen pesticides ranged from 70% to 118% at the spiking levels of 0.10,0.25 and 0.50 mg/kg with the obtained RSD in the range of 1.2% to 14%. The LOD is from 0.004 to 0.030 mg/kg. The LOD, recovery and RSD of this method could meet present demands on multi-residue determination in tobacco well.In chapter three, A rapid method for the analysis of 38 organophosphorus, heterocyclic and amides pesticides residues in tobacco by means of QuEChERS method and LC-MS/MS is presented. Samples were extracted by acetonitrile, cleaned up with PSA. This pretreatment of the method was easy, rapid, cheap and environmental. The recoveries of thirty-eight pesticides ranged from 60% to 116% at the spiking levels of 0.25,0.50 and 1.0 mg/kg, with relative standard deviation from 0.57% to 19%. This method could be a reference for advanced study of pesticides multi-residue in tobacco.In chapter four, a fast and easy analytical method of multi-pesticide residues in tobacco using LC-MS/MS was introduced, in which all 73 pesticides were extracted at the same time. When the analysis method was established, the influence of analytical conditions in detection process and matrix effects on the analysis results were studied from multiple aspects, and the best analytical conditions were selected.