Rapid Untargeted Screening of Pesticide in Fruits and Vegetables by Ultra-performance Liquid Chromatography£­High Resolution Mass Spectrometry

KeyWord:ultra-performance liquid chromatography£­high resolution mass spectrometry £¨UHPLC£­HRMS£©  pesticide residue  untargeted  fruits and vegetables

Abstract:

      Screening of potential risk factors in food is very important for the ensurement of food safety£®Pesticide residue is one of the important factors affecting the quality and safety of agricultural products£¬and the multi-residue detection of pesticides in complex matrices is still a challenging task£®A rapid non-targeted screening strategy for pesticide residues in fruits and vegetables was proposed in this study£¬based on ultra-performance liquid chromatography£­high resolution mass spectrometry£¨UHPLC£­HRMS£©£®Meanwhile£¬an analytical method for pesticide residues in complex substrates was established£¬including rapid sample pretreatment£¬accurate separation by UHPLC and detection by HRMS£®Brief steps for the method construction are described as follows£®Firstly£¬the pre-treatment method including purification agents and extraction solvents were optimized£¬and the acetonitrile containing 1% acetate and dispersive solid phase extraction with 20 mg PSA + 20 mg C18 + 2.5 mg GCB + 150 mg MgSO4 were selected for sample preparation£¬owing to its relatively high recoveries for most of pesticides£®Secondly£¬the instrument conditions were optimized£¬the separation was performed on an Accucore aQ C18 column£¬and the high-throughput qualitative screening and quantitative detection were performed by Full Scan/ dd£­MS2£®More importantly£¬the retention time correction strategy was introduced to calibrate the retention time generated under different LC£­MS conditions£®Finally£¬a high-resolution database containing 651 pesticides was established based on the original commercial database and the actual situation of the limits of different pesticides on agricultural products in various countries£®Under the optimized conditions£¬108 kind of pesticides in fruit and vegetable matrix were analyzed£®Results showed that there were good linear relationships for all the pesticides in the concentration range of 5£­500 ¦Ìg/L£¬with their correlation coefficients£¨r2£© larger than 0.99£®The limits of detection£¨LODs£¬S/N ¡Ý 3£© for all the pesticides were in the range of 0.002£­1.5 ¦Ìg/kg£¬while the limits of quantitation£¨LOQs£© were 5 ¦Ìg/kg£®At three spiked levels of 5£¬25£¬100 ¦Ìg/kg£¬the recoveries for 106 pesticides except cyromazine and chlormequat chloride ranged from 61.2% to 120%£¬with relative standard deviations£¨RSD£© of 0.1%£­9.9%£®The established method was successfully applied to the analysis of fifty£­eight cowpea and twelve citrus samples for pesticides screening£®Results showed that this method was rapid£¬accurate and sensitive£¬and was suitable for the rapid screening and quantitative analysis of unknown pesticide residues in agricultural products.