液相色谱法分析龙眼及其种植土壤中的烯酰吗啉残留

紫外扫描确定250 nm作为烯酰吗啉检测波长，优化后选取甲醇+水（V ∶ V=6 ∶ 4）作为流动相不易受样品中杂质峰的干扰且两个组分峰具有较好的分离度。建立了烯酰吗啉标准曲线，0.05～5 mg/kg范围内线性关系良好（R2=0.999 7）。选择乙腈高速匀浆提取后经过佛罗里硅藻土萃取柱净化处理龙眼样品，避免了杂质对目标峰的干扰，回收率77％～97％，变异系数<7％；选择丙酮+水（V ∶ V=1 ∶ 1）作为提取剂采用2种方法（振荡3 h、超声振荡各30 min）提取后土壤样品用二氯甲烷萃取后不经净化直接分析，结果表明对目标物分析无影响，对比2种提取方法选取超声振荡各30 min的方法不仅节约时间，而且回收率较高为83％～96％，变异系数<7％。

Residue Analysis of Dimethomoph in Longan and Soil by HPLC

250 nm was selected as the detection wavelength by the UV spectrophotometer. 60% methanol in water was selected as the mobile phase after optimization. Two peaks with a good separation were detected without interference from the matrix. The standard curve was developed and the linear was good from 0.05 mg/kg to 5 mg/kg. Residue in longan samples were extracted by homogenate in acetonitrile and purified by florisil column, which avoided the matrix interference to the aim peaks. The recovery of the method was 77%-97% with a RSD less than 7%. At the same time, soil samples were extracted using 50% acetone in water solution via two methods, oscillation for 3 hours and ultrasonic for 30 min combined with oscillation for 30 min. Then the residues were extracted using dichloromethane from the extraction solution. Ultrasonic treatment for 30 min combined with oscillation for 30 min had a higher recovery rate 83%-96% with a RSD less than 7%.