基于十八烷基三甲基溴化铵修饰的磁性粒子在线磁性固相萃取-高效液相色谱法测定水样中磺酰脲类农药

采用溶胶-凝胶法制备表面修饰了十八烷基三甲基溴化铵的磁性粒子作为萃取剂,研制了一种在线磁性固相萃取(on-line MSPE)装置,建立了on-line MSPE与高效液相色谱联用测定水样中两种磺酰脲类农药(氯磺隆、苄嘧磺隆)的方法。实验优化了在线磁性固相萃取条件并进行方法学考察,证明该方法具有良好的线性关系(两种目标物的线性相关系数均≥0.999 7)和较低的检出限(两种目标物的检出限分别为0.32和1.12μg/L)。将此法用于3种环境水样中两种磺酰脲类农药的检测,水样中均检出氯磺隆,均未检出苄嘧磺隆。两种目标物加标回收率为70.0%～113.4%。该方法高效、简便,在分离富集环境水样中磺酰脲类农药方面有一定的应用前景。

Determination of sulfonylurea herbicides in water samples by high performance liquid chromatography coupled with on-line magnetic solid phase extraction using trimethylstearylammonium-bromide-modified magnetic particles

A magnetic particle with a trimethylstearylammonium-bromide-modified surface was prepared as an adsorbent by a sol-gel method. An on-line magnetic solid phase extraction (MSPE) device was established and used for extraction and preconcentration of two sulfonylurea herbicides (SUHs) (chlorsulfuron and bensulfuron-methyl) in water samples prior to high-performance liquid chromatography. On-line MSPE parameters were optimized, including desorption conditions, adsorbent dose, pH of the sample solution, and injection flow rate. Under the optimum conditions, satisfactory linearity was obtained (correlation coefficients ≥ 0.9997). The limits of detection (LODs) of chlorsulfuron and bensulfuron-methyl were 0.32 and 1.12 μg/L, respectively. The method was successfully applied to determine two sulfonylurea herbicides in three types of environmental water samples. The recoveries of sulfonylurea herbicides were in the range of 70.0%-113.4%. The results confirmed that this method is efficient and simple and has a wide application potential in separation and enrichment of sulfonylurea herbicides in environmental water samples.