Li Chunfeng, Shen Weijian, Jiang Yuan, Shen Chongyu, Zhao Zengyun, Yu Keyao, Gui Qianwen, Sun Ningning, Yuan Zonghui
Institute of Veterinary Drug, Huazhong Agricultural University, Wuhan 430070, China.
Se Pu. 2009 Mar;27(2):176-80.
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.
建立了一种采用离线分散固相萃取和气相色谱-负化学电离质谱法（GC-NCI/MS）测定大豆和玉米中20种农药残留量的方法。用乙腈从样品中萃取两次目标农药。合并萃取液浓缩至干，再用乙腈重新溶解，然后用N-丙基乙二胺（PSA）、石墨化炭黑和C18吸附剂进行分散固相萃取净化，并用GC-NCI/MS进行测定和确证。在三个加标水平（5、10和20μg/kg）下，所有农药的回收率在70%-130%之间，相对标准偏差低于17%。该方法在20-400μg/L浓度范围内线性良好，定量限不超过2μg/kg。该方法选择性好，无干扰，适用于大豆和玉米中农药残留的确证。
