高效液相色谱法测定土壤中香豆素类灭鼠药残留

建立了测定土壤中杀鼠灵、杀鼠醚、溴敌隆、氟鼠灵、溴鼠隆5种香豆素类灭鼠药残留量的柱后衍生荧光检测高效液相色谱方法。样品在加入内标物氯杀鼠灵后用丙酮-氨水-甲醇(体积比为100∶3∶100)混合液提取,浓缩的提取液用5 mL正己烷-氯仿(体积比为3∶1)混合液溶解,NH2固相萃取小柱净化,用15 mL 50 mmol/L四丁基磷酸二氢铵甲醇溶液洗脱分析物,移除溶剂,用甲醇-0.25%(体积分数)乙酸水溶液(体积比为3∶2)混合液溶解,过滤后,经高效液相色谱分离,以甲醇-氨水-水(体积比为1∶1∶8)混合液为衍生试剂进行柱后衍生,采用荧光检测器检测。杀鼠灵、杀鼠醚、溴敌隆、氟鼠灵、溴鼠隆5种鼠药在0.02~10.00 mg/L范围内线性关系良好,相关系数均大于0.999,定量限(LOQ,S/N=10)为2.2~18.5μg/L。在0.1~0.3 mg/kg添加水平内,5种灭鼠药的回收率为94.6%~118.0%,相对标准偏差(RSD)为0.8%~10.2%(n=3)。实验结果表明该方法灵敏、准确,重复性好。

Determination of coumarin rodenticides in soils by high performance liquid chromatography

A method for the determination of warfarin, coumatetralyl, bromadiolone, flocoumafen and brodifacoum residues in soils with post-column derivatization and fluorescence detection by high performance liquid chromatography (HPLC) was established. The samples were extracted with a mixed solution of acetone, ammonium and methanol (100:3:100, v/v/v) after adding ratilan as internal standard. The extracts were vacuum-concentrated and dissolved in 5 mL mixed solution of hexane and chloroform (3:1, v/v) for solid phase extraction (SPE) clean up on an aminopropyl column. The analytes were eluted from the column using 15 mL of 50 mmol/L tetrabutylammonium dihydrogen phosphate in methanol. The solvent was evaporated and the sample was dissolved in a mixed solution of methanol and 0.25% (v/v) acetic acid aqueous solution (3:2, v/v). The coumarin rodenticides were separated on a C₁₈ column by HPLC and on-line derivatized with a mixed solution of methanol, ammonium and water (1:1:8, v/v/v) and detected with a fluorescence detector. Good linearities of the analytes were achieved over the mass concentration of 0.02-10.00 mg/L, with correlation coefficients above 0. 999. The limits of quantification (LOQ, S/N=10) were 2.2-18.5 μg/L for the five coumarin rodenticides. The recoveries were 94.6%-118.0% at the spiked levels of 0.1-0.3 mg/kg in soil with the relative standard deviations of 0.8%-10.2% (n=3). The results indicated that the method is sensitive and accurate with repeatability.