QuEChERS-气相色谱(FPD)法测定甜玉米中21种农药残留量

Determinatian of 21 pesticide residues in sweet corn by QuEChERS-gas chromatography

优选QuEChERS方法中甜玉米21种有机磷农药残留净化剂的最佳组合。采用正交试验法,以农药加标回收率(气相色谱法)为指标,考察提取液V(甲苯)∶V(乙腈)、净化剂PSA(N-丙基乙二胺)、C_(18)(十八烷基键合硅胶)、GCB(石墨化碳黑)四个因素的影响。结果表明甜玉米中21种农药残留检测的最佳组合是V(甲苯)∶V(乙腈)=3+1、25mg PSA、25mg C_(18)、15mg GCB。21种农药在0.01~0.8 mg·L^(-1)范围内具有较好的线性关系,相关系数均大于0.997。4个添加水平(0.02、0.05、0.10、0.20 mg·kg^(-1))下,21种农药的加标回收率为76.7%~107.5%。检出限为0.0011~0.0061 mg·kg^(-1),定量限为0.011~0.061 mg·kg^(-1),相对标准偏差范围为3.1%~11.3%。该方法有效、快速、灵敏、可靠,适用于甜玉米基质中21种有机磷类农药残留的测定。

To optimize cleanup of pyrethroid pesticide residues in Sweet corn for QuEChERS. The study was carried out through or-thogonal experimental design, using GC recovery as the guide. Four factors of F（ toluene） ： F（ acetonitrile）, PSA, C18 ,GCB was studied. The optimized conditions for Pretreatment method were toluene＋acetonitrile = 3 ＋1、 25mg PSA、 25mg C18、 1 5mg GCB . The calibration curves of 21 pesticide residues were linear in the range of 0. 01 -0.8 mg ·L-1 with correlation coefficients more than 0. 997. The recoveries for all compounds in Sweet corn at the fortified levels of 0. 02 mg - kg -1 ,0. 05 m g - kg -1 ,0. 10 mg · kg -1 and 0. 20mg · kg -1 were 76. 7% ？-07. 5%.The limits of detection（ LOD） were in the range of 0. 0011 -0. 0061 mg · kg -1,with limits of quantitation（LOQ）of 0. 011-0. 061 mg · kg-1 ,and the RSDs were from 3. 1% - 11. 3 % . The established method is highly effi-cient, rapid, sensitive and reliable,and could meet the requirement for simultaneous determination of 21 pesticide residues in Sweet corn.