双水相萃取-高效液相色谱法分析红小豆中酰胺除草剂

建立以硫酸铵-乙醇为基础的双水相萃取法，在红小豆中萃取分离富集乙草胺、丁草胺、敌稗、异丙甲草胺4 种酰胺类除草剂的方法。采用高效液相色谱法对4 种除草剂进行分析测定。在双水相萃取过程中，上相富醇溶液的极性更接近于同一有机溶剂中除草剂的极性。下相盐溶液能有效沉淀蛋白质和脂肪。考察前处理条件，最终选择硫酸铵-乙醇体系双水相体系类型、25%乙醇、28%硫酸铵、35 ℃、1 min超声萃取时间为最佳前处理条件。由于避免了有毒有机溶剂，本方法是一种环境友好的方法。乙草胺、丁草胺、敌稗、异丙甲草胺的检测限分别为3.5、7.1、4.6、5.8 μg/kg。在加标量为10 μg/kg和100 μg/kg水平下，4 种酰胺除草剂的平均回收率范围为86.1%～95.9%，相对标准偏差≤4.5%。

Analysis of Acetanilide Herbicide Residues in Adzuki Beans (Vigna angularis) by Aqueous Two-Phase Extraction Coupled with High Performance Liquid Chromatography

A method for the determination of four acetanilide herbicides including acetochlor, butachlor, propanil, and metolachlor in adzuki beans was established using ammonium sulfate-ethanol-based aqueous two-phase extraction combined with high performance liquid chromatography. In the aqueous two-phase extraction, the polarity of the alcohol-rich upper phase was more similar to that of the herbicides in the same organic solvent. The salt solution of the lower phase could effectively precipitate protein and fat. Based on the recoveries of the herbicides, the optimal pretreatment conditions were determined as follows: aqueous two-phase system containing 25% ethanol and 28% ammonium sulfate, and ultrasonic extraction for 1 min at 35 ℃. Avoiding the use of toxic organic solvents, the current method was environmentally friendly. The detection limits for acetochlor, butachlor, propanil, and metolachlor were 3.5, 7.1, 4.6 and 5.8 μg/kg, respectively. The average recoveries at spiked concentrations of 10 and 100 μg/kg ranged from 86.1% to 95.9%, with relative standard deviation equal to or lower than 4.5%.