title: [Determination of 20 kinds of pesticide residues in soybeans and corn using gas chromatography-negative chemical ionization mass spectrometry coupled with offline disperse solid-phase extraction].
abstract: A method was developed for the determination of 20 kinds of pesticide residues in soybeans and corn with the technique of offline disperse solid-phase extraction and gas chromatography-negative chemical ionization mass spectrometry (GC-NCI/MS). The pesticides interested were extracted twice from the samples with acetonitrile. The combined extract was concentrated to dryness and redissolved in acetonitrile, then cleaned up by dispersive solid-phase extraction with sorbents of N-propyl ethylene diamine (PSA), graphited carbon black, and C18, and determined and confirmed by GC-NCI/MS. The recoveries of all pesticides were in the range of 70%-130% at three spiked levels (5, 10 and 20 microg/kg), and the relative standard deviations were below than 17%. The linearity of the method was good in the concentration range of 20-400 microg/L, and limits of quantification (LOQs) were no more than 2 microg/kg. The method is selective well with no interference and suitable for the confirmatory of pesticide residues in soybeans and corn.
authors.affiliation: Institute of Veterinary Drug, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Chunfeng
authors.initials: C
authors.lastname: Li
authors.forename: Weijian
authors.initials: W
authors.lastname: Shen
authors.forename: Yuan
authors.initials: Y
authors.lastname: Jiang
authors.forename: Chongyu
authors.initials: C
authors.lastname: Shen
authors.forename: Zengyun
authors.initials: Z
authors.lastname: Zhao
authors.forename: Keyao
authors.initials: K
authors.lastname: Yu
authors.forename: Qianwen
authors.initials: Q
authors.lastname: Gui
authors.forename: Ningning
authors.initials: N
authors.lastname: Sun
authors.forename: Zonghui
authors.initials: Z
authors.lastname: Yuan
mesh_terms: D005506:Food Contamination / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D010573:Pesticide Residues / Q000032:analysis*; D052616:Solid Phase Extraction / Q000379:methods*; D013025:Glycine max / Q000737:chemistry*; D003313:Zea mays / Q000737:chemistry*
chemical_list: D010573:Pesticide Residues