Detection of 10 kind of pesticides multi-residue in fruits and vegetables by LC-MS/MS

This paper established a multi-residue detection method of amides, neonicotinoids, triazoles, heterocyclic, and other pesticides in fruits and vegetables samples by liquid chromatography -tandem mass spectrometry.Using QuEChERS as sample pretreatment method, then extracted by acetonitrile, cleaned up by graphitized carbon black using dispersed solid phase extraction.After the separation of chromatographic column, the extraction was analyzed under the LC-MS/ MS multiple reaction monitoring mode.Ten kind of pesticides detection is limited between 0.006 ~ 0.133 μg/kg, and the quantitative is limited between 0.018 ~ 0.415 μg/kg.On the three adding levels between 1~10 μg/kg, the average recovery is 76.2 % ~ 96.3 %, RSD is less than 2.4 %.This method can be used in the pesticides multi-residue detection of fruits and vegetables samples.This article selected amides [1-2] , nicotine, carbamate, triazole and methoxyl acrylic ester and other 5 kind of pesticides, boscalid, fluopicolide, flonicamid, desflurane bacteria amide, dinotefuran, epoxiconazole, imidacloprid, thiacloprid, azoxystrobin, isopropyl Granville, and boscalid fungicide belong to amides, mainly applied for controlling gray mold, sclerotinia rot and various other fungi of fruits and vegetables [3-7] .Neonicotinoid pesticides dinotefuran are for aphids, planthoppers and other pests [8-9] .Carbamate pesticides are widely applied in agriculture, forestry, and animal husbandry [12] .Isopropyl Granville are for planthoppers, rice leafhopper, aphids, bugs, etc. [11-12] Azoxystrobin is one strobilurin fungicide first listing, with broad-spectrum, long persistence, and high selection [13-14] .The pesticides are featured about high efficiency and broad spectrum, which has been widely applied in the fruits and vegetables.Studies have shown that these pesticides cause some harm to human health, so our country developed its maximum levels for fruits and vegetables in the standard (MRLs), the imidacloprid is 1 mg/kg, organism bacteria acyl amine is 5 mg/kg, fluorine pyrazole bacterium amine is 0.5 mg/kg, desflurane bacteria amide is 0.9 mg/kg, fluorine organism worm amide is 1 mg/kg, fluorine ring azole to 3 mg/kg, its ester is 5 mg/kg, thiamethoxam moiety to 1 mg/kg, isopropyl is 0.5 mg/kg, cefuroxime worm amine is 0.8 mg/kg [15-16] .Liquid tandem mass spectrometry, featuring of high sensitivity, high accuracy and high selectivity, has been widely used in multi-component analysis and detection of pesticide multi-residues and become an important means of measuring small molecule compounds in complex matrices [20-21] .This article selected apples, grapes, tomatoes, cucumbers, using QuCHERs technology for pretreatment, multiple reaction monitoring mode (MRM) of liquid chromatography-tandem mass spectrometry (LC/MS/MS) for multi-residues detection.By studying test conditions, the linear range, detection limit, and precision of these five classes of 10 kind of pesticides, this article established a multi-residues detection method by liquid chromatography tandem mass spectrometry, to provide faster, more accurate and more practical method for further study.