title: Determination of 17 pyrethroid residues in troublesome matrices by gas chromatography/mass spectrometry with negative chemical ionization.
abstract: An analytical method with the technique of QuEChERS (quick, easy, cheap, effective, rugged and safe) and gas chromatography (GC)/mass spectrometry (MS) in negative chemical ionization (NCI) has been developed for the determination of 17 pyrethroid pesticide residues in troublesome matrices, including garlic, onion, spring onion and chili. Pyrethroid residues were extracted with acidified acetonitrile saturated by hexane. After a modified QuEChERS clean-up step, the extract was analyzed by GC-NCI/MS in selected ion monitoring (SIM) mode. An isotope internal standard of trans-cypermethrin-D(6) was employed for quantitation. Chromatograms of pyrethroids obtained in all these matrices were relatively clean and without obvious interference. The limits of detection (LODs) ranged from 0.02 to 6 μg kg(-1) and recovery yields were from 54.0% to 129.8% at three spiked levels (20, 40 and 60 μg kg(-1) for chili, and 10, 20 and 30 μg kg(-1) for others) in four different matrices depending on the compounds determined. The relative standard deviations (RSDs) were all below 14%. Isomerization enhancement of pyrethroids in chili extract was observed and preliminarily explained, especially for acrinathrin and deltamethrin.
authors.affiliation: Jiangsu Entry-Exit Inspection and Quarantine Bureau of PRC, 99 Zhonghua Road, Nanjing 210001, China. shchy@jsciq.gov.cn
authors.forename: Chong-yu
authors.initials: CY
authors.lastname: Shen
authors.forename: Xiao-wen
authors.initials: XW
authors.lastname: Cao
authors.forename: Wei-jian
authors.initials: WJ
authors.lastname: Shen
authors.forename: Yuan
authors.initials: Y
authors.lastname: Jiang
authors.forename: Zeng-yun
authors.initials: ZY
authors.lastname: Zhao
authors.forename: Bin
authors.initials: B
authors.lastname: Wu
authors.forename: Ke-yao
authors.initials: KY
authors.lastname: Yu
authors.forename: Han
authors.initials: H
authors.lastname: Liu
authors.forename: Hong-zhen
authors.initials: HZ
authors.lastname: Lian
mesh_terms: D005504:Food Analysis / Q000191:economics / Q000379:methods*; D005506:Food Contamination / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000191:economics / Q000379:methods*; D057230:Limit of Detection; D016014:Linear Models; D010573:Pesticide Residues / Q000032:analysis* / Q000737:chemistry; D011722:Pyrethrins / Q000032:analysis* / Q000737:chemistry; D015203:Reproducibility of Results; D013997:Time Factors; D014675:Vegetables / Q000737:chemistry*
chemical_list: D010573:Pesticide Residues; D011722:Pyrethrins