高效液相色谱法测定噻唑锌在水、土壤及黄瓜中的残留

Determination of zinc-thiazole residues in water,soil and Cucumis sativus L. by high performance liquid chromatography

建立了采用高效液相色谱-二极管阵列检测器(HPLC-DAD)测定水、土壤和黄瓜中噻唑锌残留的方法。在碱性条件下先将噻唑锌转化为噻二唑(AMT),采用外标法通过测定噻二唑的量未进行噻唑锌的定量分析。样品在40℃恒温振荡条件下,依次经Na_2S转化及乙腈提取;过滤后调节混合液pH值至3,经乙酸乙酯液-液分配后,用HPLC-DAD及BDS Hypersil-C_(18)色谱柱,以V(乙腈):V(0.1%乙酸)=10:90为流动相,在313 nm波长下测定样品中的噻唑锌残留。结果表明:噻二唑在0.10~10 mg/L、噻唑锌在0.20~5.0 mg/L的质量浓度范围内线性关系良好(R^2>0.999 5),噻二唑的检出限(LOD)为0.05 mg/L。在0.2、1和5 mg/L添加水平下,噻唑锌在水中的平均回收率为100%~110%,相对标准偏差(RSD)为0.90%~6.4%;在0.05、0.5和5 mg/kg添加水平下,噻唑锌在土壤中的平均回收率为81%~98%,RSD为0.70%~2.8%;在0.05、0.5和2 mg/kg添加水平下,噻唑锌在黄瓜中的平均回收率为95%~102%,RSD为1.3%~4.2%。噻唑锌在水、黄瓜和土壤中的定量限(LOQ)分别为0.03 mg/L、0.05 mg/kg和0.05mg/kg。本方法简单、准确、可靠,能满足农药残留分析的要求。

A new residue determination method for zinc-thiazole in water, soil and Cucumis sativus L. samples has been developed and validated by high performance liquid chromatography with diode array detection. Zinc-thiazole （bis-（2-amino-5-mercapto-1,3,4-thiadiazole）zinc） was converted into AMT （2- amino-5-mercapto-1,3,4-thiadiazole） in the alkaline solution. The quantitative analysis of zinc-thiazole was then achieved by the determination of AMT. Samples were reacted with sodium sulfide, and extracted with acetonitrile at 40℃. The mixture was filtered and the pH of the filtrate was adjusted to 3. The filtrate clean-up was conducted by liquid-liquid extraction （LLE） using ethyl acetate. The determination was carried out using HPLC-DAD （313 nm） with BDS Hypersil C18 column and V （acetonitrile） ： V （0.1% acetic acid） = 10 ： 90 were used as the mobile phase. The analyte was quantified by external standard method. The results showed that the linear range of this method was 0.1-10 mg/L for AMT, 0.2-5 mg/L for zinc-thiazole. And the correlation coefficients were above 0.999 5. The limits of detection （LODs） for AMT was 0.05 mg/L. The average recovery of zinc-thiazole in water, soil and C. sativus at three spiked levels （0.05-5 mg/kg） were 81%- 110% with relative standard deviations （RSDs, n=5） ranged from 0.7% to 6.4%. The limit of quantification （LOQs） of zinc-thiazole in water, C. sativus and soil samples were 0.03, 0.05 and 0.05 mg/kg, respectively. This method is simple, accurate and reliable, which is suitable for the determination of zinc-thiazole in water, soil and C. sativus.