Screening Technique Of Pesticide Residues In Tobacco By Gas Chromatography-Quadrupole Time-of-Flight Mass Spectrometry

Due to the abuse of chemical pesticides,the problem of pesticide residues has become an important factor affecting the quality and safety of agricultural products.Tobacco is a special economic crop based on smoking.The problem of pesticide residues seriously affects the safety of tobacco products and becomes an important controlling factor in the global trade.Tobacco samples have complex matrices and many interfering substances.The method is difficult to develop.The traditional detection methods have the problem of complicated procedures,low processing efficiency which result that these methods are difficult to meet the requirements of high-volume and multi-project testing.Therefore,the development of rapid screening and accurate analysis methods for multi-residues of tobacco,as a part of supervision of tobacco safety control,is essential and important.The Cleanert Nano purification column used in this paper is a novel micro solid phase extraction(?-SPE)column that omitted the condition,loading and elution steps and achieves superior purification performance over QuEChERS technology.A rapid screening analysis method for pesticide residues in tobacco was developed which based on GC-QTOF/MS and novel pretreatment method.The main findings were as follows:1.A total of 184 pesticide standards were purchased and standard solutions were prepared.The full-scan mass spectrometry information of each pesticide was collected in TOF scan mode.The accurate mass database of GC-QTOF/MS of 184 pesticides was established using PCDL database software,including information such as name,retention time,and mass spectrum.2.The extraction and purification conditions of the novel SPE method were optimized,including the choice and amount of solvent,the amount of water and purification.The response surface method was used to determine the optimal experimental conditions.The experiment finally selects anhydrous,15 mL of acetonitrile for extraction,and the purification amount is 1 mL for purification.At three concentrations(0.05,0.25,and 0.5 ?g/g),most compounds presented satisfactory recoveries ranging from 62.05%~122.19%,and RSD ranging from 0.03%~14.92%.Compared to traditional method,this method combines good recovery and high efficiency which can applied to rapid and high-throughput detection of 184 pesticide residues in tobacco.3.A screening method for 184 pesticide residues in tobacco was established by gas chromatography-quadrupole time-of-flight mass spectrometry.The screening limits of each pesticide in the method were determined.The average processing time of per sample was 10 min.The screening limit of 71.74% pesticides was less than 0.05 ?g/g,and 92.34% pesticides was less than 0.1 ?g/g.This method achieves rapid,automatic screening of target compounds with low false positives based on high-resolution database,and provides technical support for rapid screening of pesticide residues.