在线净化/固相萃取-高效液相色谱法测定饮用水和环境水体中的百草枯和敌草快

摘要

An on-line solid phase extraction (SPE) system was used to eliminate the interferences sufficiently and fulfill the simple and sensitive determination of diquat and paraquat in tap and pond water. This on-line SPE system used two SPE cartridges. One was an Acclaim Mixed-Mode WAX-1 cartridge for the elimination of anionic interferences; the other one was an Acclaim Mixed-Mode WCX-1 cartridge for the enrichment of diquat and paraquat and the elimination of co-enriched cationic interferences. The baseline separation of diquat and paraquat was achieved on an Acclaim Trinity PI column. A dual-gradient high performance liquid chromato-graphic (HPLC) system provided an efficient platform to fulfill the on-line SPE and separation, and the system operated under automatic control of chromatography data system software. The complete analysis only required 16 min, and the detection limits of the method were 0. 12μg/L for diquat and 0. 10μg/L for paraquat. The method is simple, rapid and sensitive, and can be applied to the determination of diquat and paraquat in drinking water and environmental water.%建立了在线净化/固相萃取(SPE)-高效液相色谱(HPLC)快速、准确测定饮用水和环境水体中的两种痕量除草剂百草枯和敌草快的方法.样品用大体积自动进样器注入在线净化小柱并流经固相萃取小柱,通过双梯度高效液相色谱系统中的上样泵实现净化和富集后,通过阀切换将固相萃取小柱切换至分析流路中;用分析泵将待测物从富集柱冲洗至分析柱进行测定.上样泵流速和分析泵流速分别为0.7和0.6 mL/min,采用等度洗脱方式完成两种除草剂的分离和检测.检测波长分别为260 nm(百草枯)和311 nm(敌草快),进样体积为2.5 mL,整个分析时间为16 min.该方法在1.0～ 20 μg/L范围内线性关系良好,两种除草剂的线性相关系数均大于0.998 0,检出限分别为0.10和0.12 μg/L(S/N=3).该方法前处理简单,快速,可用于饮用水和环境水体中痕量除草剂的测定.