Bodor Róbert, Kaniansky Dusan, Masár Marián, Silleová Katarína, Stanislawski Bernd
Department of Analytical Chemistry, Faculty of Science, Comenius University, Mlynská Dolina CH-2, SK-84215 Bratislava, Slovak Republic.
Electrophoresis. 2002 Oct;23(20):3630-7. doi: 10.1002/1522-2683(200210)23:20<3630::AID-ELPS3630>3.0.CO;2-8.
The use of capillary zone electrophoresis (CZE) on-line coupled with isotachophoresis (ITP) sample pretreatment (ITP-CZE) on a poly(methylmethacrylate) chip, provided with two separation channels in the column-coupling (CC) arrangement and on-column conductivity detection sensors, to the determination of bromate in drinking water was investigated. Hydrodynamic and electroosmotic flows of the solution in the separation compartment of the chip were suppressed and electrophoresis was a dominant transport process in the ITP-CZE separations. A high sample load capacity, linked with the use of ITP in this combination, made possible loading of the samples by a 9.2 microL sample injection channel of the chip. In addition, bromate was concentrated by a factor of 10(3) or more in the ITP stage of the separation and, therefore, its transfer to the CZE stage characterized negligible injection dispersion. This, along with a favorable electric conductivity of the carrier electrolyte solution, contributed to a 20 nmol/L (2.5 ppb) limit of detection for bromate in the CZE stage. Sample cleanup, integrated into the ITP stage, effectively complemented such a detection sensitivity and bromate could be quantified in drinking water matrices when its concentration was 80 nmol/L (10 ppb) or slightly less while the concentrations of anionic macroconstituent (chloride, sulfate, nitrate) in the loaded sample corresponding to a 2 mmol/L (70 ppm) concentration of chloride were still tolerable. The samples containing macroconstituents at higher concentrations required appropriate dilutions and, consequently, bromate in these samples could be directly determined only at proportionally higher concentrations.
研究了在聚甲基丙烯酸甲酯芯片上使用毛细管区带电泳（CZE）与等速电泳（ITP）在线联用进行样品预处理（ITP-CZE），该芯片在柱耦合（CC）配置中有两个分离通道以及柱上电导检测传感器，用于测定饮用水中的溴酸盐。芯片分离室中溶液的流体动力流和电渗流受到抑制，在ITP-CZE分离中电泳是主要的传输过程。与在此组合中使用ITP相关的高样品负载能力，使得通过芯片的9.2微升进样通道加载样品成为可能。此外，在分离的ITP阶段溴酸盐被浓缩了10³倍或更多，因此，其转移到CZE阶段时进样分散可忽略不计。这与载体电解质溶液良好的电导率一起，使得CZE阶段溴酸盐的检测限达到20 nmol/L（2.5 ppb）。集成到ITP阶段的样品净化有效地补充了这种检测灵敏度，当饮用水基质中溴酸盐的浓度为80 nmol/L（10 ppb）或略低，而加载样品中阴离子常量成分（氯离子、硫酸根离子、硝酸根离子）的浓度对应于2 mmol/L（70 ppm）的氯离子浓度时仍可耐受时，溴酸盐可以在饮用水基质中进行定量。含有较高浓度常量成分的样品需要适当稀释，因此，这些样品中的溴酸盐只能在相应较高的浓度下直接测定。
