基于动态微波辅助萃取法快速检测西红柿中六种三嗪类除草剂

Rapid detection of six triazine herbicides from tomatoes by dynamic microwave-assisted extraction method

目的：建立简便和快速地萃取西红柿中六种三嗪类除草剂的方法。方法首先,西红柿中三嗪类除草剂通过动态微波辅助萃取法进行萃取之后,利用盐析液液萃取法对萃取物进行快速的富集和净化；之后,将获得的萃取物用氮气吹干,用流动相定容至0.5 mL；最后,采用高效液相色谱-质谱仪对萃取物进行分析。结果实验中对影响动态微波辅助萃取和盐析液液萃取萃取效率的实验条件进行了优化,最优的实验条件为：萃取剂为70%乙腈-水溶液,微波萃取功率为350 W,微波萃取时间为7 min,萃取剂流速为1.0 mL/min,萃取液pH值为8,盐析盐为醋酸铵,用量为2.0 g。六种三嗪类除草剂在1~1000 ng/mL范围内成线性关系,相关系数为0.995~0.998；检出限为0.08~0.33 ng/g；方法的回收率为68%~104%,相对标准偏差为5.0%~7.3%。结论该方法被成功应用于西红柿中三嗪类除草剂的检测,结果令人满意。

Objective A simple and fast sample pretreatment method was proposed for determination of triazine herbicides in tomatoes. Methods The triazine herbicides in tomato samples were extracted by dy-namic microwave-assisted extraction and puritied by salting liquid-liquid extraction method. The extract was evaporated to dryness under a stream of N2, and the residue was then reconstituted with 0.5 mL acetonitrile. Finally, the extract was injected into the LC-MS/MS system for analysis. All the parameters which could affect the extraction effect were investigated. Results The optimized extraction conditions were observed at 70%aqueous acetonitrile, 350 W of microwave forward power, extraction time 7 min, extraction solvent flow-rate 1.0 mL/min, pH 8 of the extract, salting-out reagent ammonium acetate and 2.0 g of addition of ammonium acetate. The linearity ranged from 1 to 1000 ng/mL and correlation coefficient were 0.995~0.998. The limits of detection for the six triazine herbicides were in the range of 0.08~0.33 ng/g. The recoveries of the triazine her-bicides for the spiked samples were in the range of 68%~104%. The relative standard deviations were 5.0%~7.3%. Conclusion This method has been successfully applied to rapid detection of triazine herbicides from tomatoes.