高效液相色谱法同时测定稻田中苄嘧磺隆和苯噻酰草胺残留

建立了同时测定稻田(稻田土壤、水和植株)中苄嘧磺隆和苯噻酰草胺残留量的高效液相色谱(HPLC)分析方法。稻田水样品用二氯甲烷直接萃取;稻田土壤样品用碱性乙腈-二氯甲烷(1:1, v/v)混合液直接提取;水稻植株样品用碱性二氯甲烷提取后,二氯甲烷提取液经弗罗里硅土柱净化。上述样品溶液采用C18不锈钢色谱柱(150 mm×4.6 mm, 5 μm)分离,流动相为水-甲醇(30:70, v/v),流速为0.5 mL/min,柱温为30 ℃,紫外检测波长为238 nm,外标法定量。苄嘧磺隆和苯噻酰草胺在0.05～5.00 mg/L范围内的线性关系均很好(r＞0.9999)。在稻田水、土壤和水稻植株中添加3个水平(0.05, 0.10, 1.00 mg/kg)的苄嘧磺隆和苯噻酰草胺,两者的回收率均在85.39%～113.33%之间,相对标准偏差为0.91%～10.24%。这表明该方法的灵敏度、准确度和精密度均符合农药残留测定的技术要求。

Simultaneous determination of bensulfuron-methyl and mefenacet residues in paddy field using high performance liquid chromatography

An analytical method of high performance liquid chromatography (HPLC) was established for the simultaneous determination of bensulfuron-methyl and mefenacet residues in paddy field (paddy water, soil and rice plant). The residues in the paddy water was extracted with methylene chloride, and the soil with alkaline mixed solution of acetonitrile-methylene chloride (1:1, v/v). The rice plant was extracted with alkaline methylene chloride which was cleaned up by a Florisil column. The separation was performed on a stainless steel C18 column (150 mm x 4.6 mm, 5 microm) at 30 degrees C by HPLC with an ultraviolet detector (UVD) at 238 nm, and water-methanol (30:70, v/v) as the mobile phase at a flow rate of 0.5 mL/min. The quantification was performed by external standard. The calibration curves were linear between the peak area and the concentration in the range of 0.05-5.00 mg/L for bensulfuron-methyl and mefenacet, and the correlation coefficients were more than 0.999 9. The average recoveries of the two herbicides spiked in the paddy water, soil and rice plant at the three concentration levels of 0.05, 0.10 and 1.00 mg/kg ranged from 85.39% to 113.33% with the relative standard deviations of 0.91%-10.24%. The method is characterized by simplicity, sensitivity and accuracy.