Yin Xue-Bo
Central Laboratory, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin, China.
Electrophoresis. 2004 Jun;25(12):1837-42. doi: 10.1002/elps.200405815.
An on-line preconcentration method was developed for capillary electrophoresis (CE) with hydride generation-atomic fluorescence spectrometric (HG-AFS) detection of arsenite, arsenate, dimethylarsenic acid, and monomethylarsenic acid. These arsenic species were negatively charged in the sample solution with high pH. When the potential was applied to the electrophoretic capillary, the negatively charged analyte ions moved faster and stacked at the boundary of sample and CE buffer with low pH. So, high sample pH in combination with low buffer pH allowed the injection of large sample volumes (approximately 1100 nL). Comparison of the preconcentration of analyte solution, prepared with doubly deionized water and that prepared with lake or river water, indicated that preconcentration was independent on the original matrix. With injection of approximately 1100 nL sample, an enrichment factor of 37-50-fold was achieved for the four species. Detection limits for the four arsenic species ranged from 5.0 to 9.3 microg.L(-1). Precisions (RSDs, n = 5) were in the range of 4.9-6.7% for migration time, 4.7-11% for peak area, and 4.3-7.1% for peak height, respectively. The recoveries of the four species in locally collected water solution spiked with 0.1 microg.mL(-1) (as As) ranged from 83 to 109%.
开发了一种在线预富集方法，用于毛细管电泳（CE），结合氢化物发生-原子荧光光谱法（HG-AFS）检测亚砷酸盐、砷酸盐、二甲基砷酸和一甲基砷酸。这些砷物种在高pH值的样品溶液中带负电荷。当向电泳毛细管施加电势时，带负电荷的分析物离子移动得更快，并在低pH值的样品和CE缓冲液的边界处堆积。因此，高样品pH值与低缓冲液pH值相结合允许进样大体积的样品（约1100 nL）。比较用双去离子水制备的分析物溶液和用湖水或河水制备的分析物溶液的预富集情况，表明预富集与原始基质无关。进样约1100 nL样品时，这四种物种的富集因子达到37至50倍。这四种砷物种的检测限范围为5.0至9.3 μg·L⁻¹。迁移时间的精密度（相对标准偏差，n = 5）在4.9 - 6.7%范围内，峰面积的精密度在4.7 - 11%范围内，峰高的精密度在4.3 - 7.1%范围内。在当地采集的水溶液中加入0.1 μg·mL⁻¹（以As计）时，这四种物种的回收率在83%至109%之间。
