title: Simultaneous determination of 106 pesticides in nuts by LC-MS/MS using freeze-out combined with dispersive solid-phase extraction purification.
abstract: As a result of the low water content and high fat matrices in nuts, it is very difficult to simultaneously determine multi-pesticides in trace levels. Here, a sample pretreatment method was developed in which, microwave-assisted solvent extraction was firstly used to extract pesticides, and then a two-step cleanup method was conducted combining freeze-out with dispersive solid-phase extraction to remove the lipidic matrix. By this way, 106 pesticides were simultaneously determined in the complicated nut sample by using an ultra-high pressure liquid chromatography coupled with a tandem mass spectrometer. Average recoveries were 75.3-119.3% with relative standard deviations < 14% at three concentration levels. The limits of detection and quantification were in the ranges of 0.3-3.0 and 1.0-10.0 μg/kg, respectively. Furthermore, the method was successfully applied to the determination of pesticides in 180 commercial nut samples.
authors.affiliation: Key Laboratory of Oil and Gas Fine Chemicals, Ministry of Education & Xinjiang Uygur Autonomous Region, College of Chemistry and Chemical Engineering Xinjiang University, Urumqi, China.|Technical Center of Xinjiang Entry-Exit Inspection and Quarantine Bureau, Urumqi, China.
authors.forename: Jingjing
authors.identifier: http://orcid.org/0000-0002-6721-2978
authors.initials: J
authors.lastname: Wang
authors.affiliation: Technical Center of Xinjiang Entry-Exit Inspection and Quarantine Bureau, Urumqi, China.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Gong
authors.affiliation: Key Laboratory of Oil and Gas Fine Chemicals, Ministry of Education & Xinjiang Uygur Autonomous Region, College of Chemistry and Chemical Engineering Xinjiang University, Urumqi, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Zhang
authors.affiliation: School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, China.
authors.forename: Shun
authors.initials: S
authors.lastname: Feng
authors.affiliation: Key Laboratory of Oil and Gas Fine Chemicals, Ministry of Education & Xinjiang Uygur Autonomous Region, College of Chemistry and Chemical Engineering Xinjiang University, Urumqi, China.
authors.forename: Jide
authors.initials: J
authors.lastname: Wang
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University, Changsha, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D002853:Chromatography, Liquid; D005506:Food Contamination / Q000032:analysis*; D009754:Nuts / Q000737:chemistry*; D010575:Pesticides / Q000032:analysis*; D052616:Solid Phase Extraction; D053719:Tandem Mass Spectrometry
chemical_list: D010575:Pesticides
keywords: freezing-out cleanup; liquid chromatography-tandem mass spectrometry; microwave-assisted solvent extraction; nuts; pesticide residues