高效液相色谱法同时检测稻田样品中5种除草剂的残留量

Simultaneous determination of five herbicides residue in paddy soil samples by high performance liquid chromatography

建立一种高效液相色谱法同时检测稻田土壤、稻田水和糙米中二甲四氯、2,4,5–T、高效氟吡甲禾灵、精吡氟禾草灵和精喹禾灵5种除草剂残留的方法。土壤样品用0.05%磷酸溶液和乙腈混合液（体积比为1∶2）提取,水样品用乙酸乙酯萃取,糙米样品用0.04 mol/L Na OH提取,用弗罗里硅土柱净化。采用带紫外检测器的高效液相色谱仪测定,以乙腈与水为流动相梯度洗脱,在紫外波长229 nm下检测,用外标法定量。结果表明,5种除草剂在质量浓度0.05~5.00 mg/L的线性关系良好,相关系数（R）达0.999 7~0.999 9;土壤和糙米中添加水平为0.05~1.00 mg/kg时,5种除草剂的平均回收率为78.8%~107.8%,相对标准偏差（RSD≤7.5,n=5）为1.1%~9.2%;当水中添加水平为0.01~0.50 mg/L时,平均回收率为86.2%~109.2%,相对标准偏差（RSD≤6.5,n=5）为1.2%~6.5%。5种除草剂的检出限为0.01~0.02 mg/kg。方法在土壤、糙米和水样中的定量限分别为0.05、0.05 mg/kg和0.01mg/L。该方法的前处理过程简单,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。

To simultaneously determine residues of five herbicides, namely MCPA,2,4,5-T, haloxyfop-p-methyl,quizafol-p-thyl and fluazifop-p-butyl in paddy soil, water and coarse rice, a new method was developed using highperformance liquid acid and aetonitrile chromatography. The residues in soil was extracted with mixed solution of 0.05% ortho-phosphoric （volume ratio of 1 ： 2）, and those in water was extracted with ethyl acetate, while in coarse rice was dissolved by 0.04 mol/L sodium hydroxide aqueous, then purified by a florisil column. Five herbicides were detected at uv wavelength of 229 nm with acetonitrile-water （pH 3） as mobile phase through gradient elution in HPLC, external standard was adopted as the quantification method. The linearity was good （r〉0.999 7） in concentration range of 0.05 to 5.00 mg/L .Mean recoveries of five herbicides in soil and coarse rice were between 78.8% and 107.8% （RSD≤ 7.5, n=5） at fortification levels of 0.05 to 1.00 mg/kg, while they were between 86.2% and 109.2%（RSD≤6.5, n-5）in water at levels from 0.01 to 0.50 mg/kg. Under these optimal condition, The limit of detection for the five ingredients were between 0.01 to 0.02 mg/kg, and the limit of quantification in soil, coarse rice and water were 0.05 mg/kg, 0.05 mg/kg, and 0.01 mg/L respectively. Pre-treatment process of the method was simple, and sensitivity and accuracy of the method meet the technical requirement for the analysis and detection of pesticide residues.