分散固相萃取-气相色谱-质谱联用法检测葱、韭菜和姜中多种农药残留

Determination of Pestiside Multi-Residues in Onion, Leek and Ginger by Dispersive Solid-Phase Extraction and GC/MS

建立了葱、韭菜和姜中28种农药多残留的气相色谱-质谱分析方法。在搅碎样品之前,采用500W微波加热处理样品90s,使酶钝化从而消除其基质干扰。经乙腈提取后,样品净化同时使用乙二胺-N-丙基硅烷(PSA)和C18的混合吸附剂,使净化更充分,达到快速、简单、有效、可靠和安全的目的,并采用三苯基磷酸酯(TPP)作为内标物克服GC/MS基质效应和准确定量。28种化合物的相关系数均高于0.995,检出限为0.1～20.8μg/kg。在空白基质中进行0.05、0.1mg/kg两个水平的加标回收实验,除姜中的甲拌磷、氧乐果和氟氯氰菊酯受到干扰不能很好定量,甲胺磷、乙酰甲胺磷和百菌清的回收率低于70%外,其他农药的平均回收率为70%～130%,相对标准偏差为0.5%～20%。

A multi-residue analytical method was developed for the determination of 28 pesti- cide residues in onion, leek and ginger using gas chromatography-mass spectrometry （GC/MS）. The samples were treated with microwave （500 W,90 s） before being crushed to make the allinase inactive and to eliminate the matrix effect. The pesticide residues were extracted from samples by acetonitrile, primary secondary amine （PSA） and C18 mixed adsorbents, which were used for purification at the same time to achieve quick, easy, cheap, effective, rugged and safe analysis. Internal standard substance-triphenyl phosphate （TPP） was used to overcome matrix effect and achieve quantitatively determination. The correlation coefficients are geater than 0. 995, and the limits of the detection are in the range of 0.1--20.8μg/kg. The method is validated at two fortification levels of 0.05 mg/kg and 0.1 mg/kg in blank samples, phorate, omethoate and cyfluthrin cannot be quantitatively determined in ginger due to interference. The averge recoveries are in lhe range of 70o/oo excepted for methmidopos, aeephate and chtorothalonil that below 70%. The standard deviations（RSl）s） are in the range of 0.5%- 20%.