土壤中六种新烟碱类农药残留的分离及光谱研究

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 TM C18 色谱柱(4.6 mm×250 mm，5 μm)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0.05，0.1，1.0 mg·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1.4～7.0%。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。

Simultaneous Determination of 6 Neonicotinoid Residues in Soil Using DLLME-HPLC and UV

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 nitenpyram. The soil sample was produced by dispersive liquid-liquid micro-extraction (DLLME) after extracted by the mixed solution of acetonitrile and CH₂Cl₂ (2∶1, φ). The analytes were separated by HPLC with Alltima TMC₁₈ column (4.6 mm×250 mm，5 μm) and detected by PDA at 260 nm. External standard method was used for quantification. The results showed that good linearity 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 0.003 μg· 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 1.4%～7.0%. 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.