在线大体积进样柱切换-离子色谱法测定茶叶中的微量敌草快和百草枯农药残留

[目的]建立茶叶中的微量敌草快和百草枯农药残留的分析检测方法。[方法]大体积(2 mL)进样后,样品通过在线净化分离,将敌草快和百草枯离子富集在Dionex IonPac SCG短柱中,通过柱切换使目标离子进入分析柱Dionex IonPac SCS进行分离,紫外检测器检测。[结果]敌草快和百草枯的线性范围分别为0.0030～2.5、0.0015～2.5 mg/kg,相关系数分别为0.9991和0.9984,检出限分别为0.75、0.30μg/kg,茶叶样品回收率范围为86.9%～102.9%,精密度(相对标准偏差)小于10.1%。[结论]方法简便、检测快速、重复性良好,在敌草快和百草枯农药残留食品安全监察方面具有很好的应用潜力。

Determination of Low Level Dipaquat and Paraquat Residues in Tea by On-line Column-switching Ion Chromatography

[Aims] Determination of low level dipaquat and paraquat residue in tea was developed. [Methods] After large volume(2 m L) injection of tea sample, the on-line sample clean-up and separation was achieved and then enriched on Dionex IonPac SCG column. After column switching, the separation and determination of dipaquat and paraquat cation ions was performed using Dionex IonPac SCS column and UV detection. [Results] Good linearity in the range of 0.0030-2.5 and 0.0015-2.5 mg/kg was obtained with correlation coefficient(R^2) of 0.9991 and 0.9984 for diquat and paraquat, respectively. Limits of detection(S/N=3) were 0.75, 0.30 μg/kg for diquat and paraquat,respectively. Recoveries ranged from 86.9 to 102.9% and repeatability results were acceptable with relative standard deviation of less than 10.1%. [Conclusions] The proposed method was simple, rapid and reliable and may have the high potential as screening tools for food safety and inspection controls.