场放大样品进样-压力辅助毛细管区带电泳测定饮用水中的百草枯

1 引 言 百草枯属有机杂环类季铵盐除草剂,由于它具有优良的除草效果,已广泛应用于多种作物的杂草防治.百草枯具有极强的水溶性,极易迁移至水体环境中,从而对饮用水的质量安全构成潜在威胁.目前,百草枯的残留检测方法主要有分光光度法1]、液相色谱-质谱联用法2]、气相色谱质谱联用法3]和毛细管电泳法(CE) 4～6].采用分光光度法测定百草枯,不仅操作繁琐费时,而且灵敏度低.采用气相色谱法测定百草枯,通常需要衍生化,应用较少3].采用液相色谱法测定百草枯,通常需要在流动相中添加离子对试剂2].毛细管电泳具有分离效率高,分析速度快等优点,已被广泛用于水样中百草枯残留的测定.然而,毛细管电泳灵敏度不高,极大地限制了其在实际样品分析中的应用.场放大样品进样(FASI)是一种简单有效的在线富集方法,其富集倍数可达1000倍7],可有效提高毛细管电泳技术的灵敏度,因此应用较为广泛.本实验建立了场放大样品进样-压力辅助毛细管区带电泳法(CZE),用于测定饮用水中百草枯的残留量.

Rapid, Simple and Ultrasensitive Analysis of Paraquat in Drinking Water by Field-Amplified Sample Injection Combined with Pressure-Assisted Capillary Zone Electrophoresis

Field-amplified sample injection(FASI) combined with pressure-assisted capillary zone electrophoresis(CZE) was developed for the determination of paraquat in drinking water.High reproducibility in FASI-CZE process could be attained with constant pressure applied at both ends of capillary.Compared with conventional hydrodynamic injection,the enrichment factor of 1174 was achieved for paraquat by FASI.Several parameters including length of water plug,injection time and composition of sample solution were systematically optimized.Linearity,sensitivity,precision and accuracy were investigated to validate the proposed method.The result showed that the calibration curve was linear at the concentration of 1.0-100 μg/L with a correlation coefficient of 0.9975.The limit of detection was 0.039 μg/L(S/N=3).Mean recovery of paraquat was ranged from 78.4% to 94.5% with relative standard deviation ranging from 3.0% to 10.4%.Finally,the method proposed was applied for the determination of paraquat in real drinking water.