气液微萃取技术快速净化大葱中25种农药残留研究

Study on the rapid purification of 25 kinds of pesticide residues in green onion by gas-liquid micro extraction

目的建立气液微萃取技术快速、高效净化大葱中25种农药残留的方法。方法对气液微萃取技术的加热温度、萃取时间及萃取溶剂进行优化。结果气液微萃取最佳加热温度为300℃,萃取时间为5min,萃取溶剂为二氯甲烷:丙酮:乙酸乙酯(1:1:1,V:V:V),此方法 5min内完成净化,无需浓缩可直接进样分析。25种农药0.001~1mg/kg浓度范围内线性关系良好,相关系数在0.9991~1.0000,平均回收率为76.2%~117.1%(n=7),相对标准偏差(relative standard deviation, RSD)在1.1%~7.0%之间。结论该净化方法高效、快速、准确度高、重现性好,能够有效减少基质干扰现象。

Objective To establish a rapid and efficient method for purification of 25 kinds of pesticide residues in green onion by gas–liquid micro extraction (GLME). Methods The heating temperature, extraction time and extraction solvent of GLME were optimized. Results The optimal extraction temperature of GLME was 300 ℃, the extraction time was 5 min and the extraction solvent was dichloromethane:acetone:ethyl acetate (1:1:1, V:V:V). This method could completed purification within 5 minutes, and the sample could be directly injected without concentration. The 25 kinds of pesticides had good linear relationship in the concentration range of 0.001?1 mg/kg, with correlation coefficient of 0.9991?1.0000, the average recoveries were 76.2%?117.1%(n=7), and the relative standard deviation (RSD) were 1.1%?7.0%. Conclusion This purification method is efficient, rapid, accurate, and has good reproducibility, which can effectively reduce matrix interference.