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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 method for the determination of zinc thiazide in water, soil and cucumber using HPLC-DAD was established. Under basic conditions, the thiazole zinc was firstly converted to thiadiazole (AMT), and the quantitative analysis of zinc thiazole was not carried out by measuring the amount of thiadiazole using the external standard method. After the sample was heated at 40 ° C under constant shaking, it was sequentially converted to Na 2 S and extracted with acetonitrile. After filtration, the pH of the mixture was adjusted to 3, and the mixture was partitioned by ethyl acetate and analyzed by HPLC-DAD and BDS Hypersil-C 18 chromatography Column with V (acetonitrile): V (0.1% acetic acid) = 10: 90 as the mobile phase at 313 nm wavelength was determined thiazole zinc residues in the sample. The results showed that the detection limit (LOD) of thiadiazole was within the range of 0.10 ~ 10 mg / L and that of zinc thiazole was 0.20 ~ 5.0 mg / L (R ~ 2> 0.999 5) 0.05 mg / L. The average recoveries of zinc thiazole in water ranged from 100% to 110% and the relative standard deviations (RSDs) were 0.90% ~ 6.4% at the concentrations of 0.2, 1 and 5 mg / L. At 0.05, 0.5 and 5 mg / kg The average recovery of zinc in the soil was 81% -98% and the RSD was 0.70% -2.8% at the additive level. The average recoveries of zinc in the cucumber at 0.05, 0.5 and 2 mg / kg 95% ~ 102%, RSD 1.3% ~ 4.2%. The limit of quantitation (LOQ) of zinc for thiazole in water, cucumber and soil were 0.03 mg / L, 0.05 mg / kg and 0.05 mg / kg, respectively. The method is simple, accurate and reliable, and can meet the requirements of pesticide residue analysis.