土壤中六种新烟碱类农药残留的分离及光谱研究

摘要

A simple,cheap and rugged method was developed for simultaneous deter mination of 6 neonicotinoid residues in soil,including imidacloprid,acetamiprid,thiamethoxam,thiacloprid,clothianidin and nitenpyrarm.The soil sample was produced by dispersive liquid-liquid micro-extraction (DLLME) after extracted by the mixed solution of acemnitrile and CH2Cl2 (2 ∶ 1,φ).The analytes were separated by HPLC with Alltima TMC18 column (4.6 mm×250 mm,5 μin) and detected by PDA at 260 nm.External standard method was used for quantification.The results showed that good lineadty was obtained with correlation coefficients between 0.998 2 and 0.999 9 in the range of 0.5～200 μg · L-1.The limits of detection (LODs) were in the range between 0.000 5 and 0.003μg · mL-1 (S/N=3).The method was validated with five soil samples spiked at three fortification levels (0.05,0.1,1.0 mg · kg-1) and recoveries were in the range of 55.3％95.6％ with RSD of 1.47.0％.The effect of clean-up was evaluated by UV spectra and demonstrated that the method established is effective.In conclusion,this method is competent for the simultaneous analysis of 6 neonicotinoid residues in soil%建立了一种可同时检测土壤中吡虫啉、啶虫脒、噻虫嗪、噻虫啉、噻虫胺、烯啶虫胺六种新烟碱类农药残留的方法,该方法操作简单、成本低廉且重现性好,符合环境研究过程中实验量大、样品量多的特点.土壤样品经乙腈:二氯甲烷(2:1 (φ))提取后,进一步用分散液液微萃取处理.分析方法采用Alltima TMC18色谱柱(4.6 mm×250 mm,5μm)分离,PDA检测器检测,外标法定量.六种农药在0.5～200 μg·L-1浓度范围内线性关系良好,相关系数为0.998 2～0.999 9,检测限为0.000 5～0.003 μg·mL-1 (S/N=3).以五种土壤为代表,在0.05,0.1,1.0mg·kg-1三个添加水平的平均加标回收率为55.3％～95.6％,相对标准偏差为1.4～7.o％.同时应用紫外分光光度法对净化效果进行考察,证明本实验所建立的方法具有明显的净化作用,因此满足土壤中六种新烟碱类农药残留检测的要求.