高效液相色谱法测定稻田样品中3种新烟碱类杀虫剂残留

采用带紫外检测器的高效液相色谱仪(HPLC-UV),建立了同时检测呋虫胺、吡虫啉和啶虫脒在稻田水、稻田土壤、水稻植株、稻秆、稻壳和糙米中残留量的检测方法。稻田水、稻田土壤、水稻植株、稻秆、稻壳样品用乙腈提取,糙米样品用V(乙腈)∶V(水)=1∶1混合溶液提取。稻田水无需净化,其余样品用弗罗里硅土柱净化。HPLC-UV测定,流动相为V(甲醇)∶V(水)=30∶70,流速采用梯度流速,紫外检测波长为254 nm。结果表明:在0.05~10 mg/L范围内,3种农药的质量浓度与其相对应的色谱峰面积之间呈良好的线性关系,线性方程分别为呋虫胺:y=62.55x+4.039 2(R2=0.999 2);吡虫啉:y=99.968x+7.525 1(R2=0.998 6);啶虫脒:y=97.084x+6.072(R2=0.999 4)。在0.05~2 mg/kg添加水平下,样品中呋虫胺、吡虫啉和啶虫脒的平均回收率在81%~99%之间,相对标准偏差(RSD,n=5)在1.2%~7.9%之间。该方法的前处理过程较简单,且准确度、精密度和灵敏度均符合农药残留分析的技术要求。

Determination of 3 neonicotinoid pesticide residues in paddy field with high performance liquid chromatography

A method of determining dinotefuran, imidacloprid and acetamiprid in paddy water, paddy soil, rice plant, rice stem, hull and brown rice was established by high performance liquid chromatography with ultraviolet detector. The samples of paddy water, paddy soil, rice plant, rice stem, and hull were extracted with acetonitrile, and rice samples were extracted with mixture of acetonitrile and water(1:1, V/V). Samples were cleaned up with Florisil columns except paddy water, and determined by high performance liquid chromatography with ultraviolet detector. Methanol and water (30:70, V/V) was used as mobile phase at a gradient flow rate, and ultraviolet absorption wavelength was set at 254 nm. It was shown that the calibrations were linear, and the equation and the determination coefficient (R²) was as followed: dinotefuran: y=62.55x+4.039 2(R²=0.999 2); imidacloprid: y=99.968x+7.525 1(R²=0.998 6); acetamiprid: y=97.084x+6.072(R²=0.999 4). The average recoveries of samples ranged from 81% to 99% at spiked levels of 0.05-2 mg/kg, and relative standard deviation (RSD, n=5) was in the range of 1.2%-7.9%. Pre-treatment process of the method was simple, and the sensitivity and accuracy of the method met with the technical requirements for pesticide residue analysis.