Conductivity detection cell for capillary zone electrophoresis with a solution mediated contact of the separated constituents with the detection electrodes
Conductivity detection cell for capillary zone electrophoresis with a solution mediated contact of the separated constituents with the detection electrodes
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DOI：
10.1016/s0021-9673(00)01070-0
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发表时间：
2001-05-04
影响因子：
4.1
通讯作者：
Masár, M
中科院分区：
文献类型：
--
作者：
Bodor, R;Kaniansky, D;Masár, M
本文研制了一种毛细管区带电泳（CZE）接触式电导率检测池（ESMC cell），通过电解质溶液介导分离组分与检测电极的接触。这种CZE电导率传感的新方法旨在消除由于电极反应和分离成分与检测电极直接接触时的吸附而引起的检测干扰。当载体电解质溶液介导检测电极与分离成分的电接触时，电池的检测性能达到最佳。介质和载体电解质溶液的不同组成导致检测信号的较大漂移。在这种情况下，用ESMC细胞进行的等速电泳实验显示，这些漂移的起源是在细胞中检测室和检测电极之间的传输过程（扩散和电迁移）中。这些过程在一定程度上也影响了当前结构的ESMC电池的其他分析相关性能参数[例如，检测浓度限（lod），电池对能带拓宽的贡献]。例如，在最佳操作条件下，ESMC电池提供的测试分析物的浓度lod比在相同工作条件下使用的当前柱上电导率电池高3-4倍。另一方面，这些LOD值（25-150 nmol/l）仍然比参考实验估计的非接触式电导率检测器低20-5倍。碘化物的CZE实验是在导致该阴离子在电流电导率电池的检测电极上发生电化学反应的工作条件下进行的，而在ESMC电池中没有发生。此外，与参考接触电导率电池相反，该电池不需要特殊的处理（例如，通过化学或电化学手段清洁检测电极的表面），以保持其可靠的长期性能。由ESMC电池提供的电导率检测器监测自来水和矿泉水样品的阴离子CZE分析表明，这种检测方法在分析高离子强度样品基质中存在的离子成分时具有实际适用性和一定的局限性。(C) 2001 Elsevier Science B.V.版权所有
A contact conductivity detection cell for capillary zone electrophoresis (CZE) with an electrolyte solution mediated contact of the separated constituents with the detection electrodes (ESMC cell) was developed in this work. This new approach to the conductivity sensing in CZE is intended to eliminate detection disturbances due to electrode reactions and adsorption of the separated constituents when these are coming into direct contact with the detection electrodes, An optimum detection performance of the cell was achieved when the carrier electrolyte solution mediated the electric contact of the detection electrodes with the separated constituents. Different compositions of the mediator and carrier electrolyte solutions led to large drifts of the detection signals. Isotachophoresis experiments performed in this context with the ESMC cell revealed that origins of these drifts are in transport processes (diffusion and electromigration) between the detection compartment and the detection electrodes in the cell. These processes affected, to some extent, other analytically relevant performance parameters of the ESMC cell of the present construction as welt [e.g., concentration limits of detection (LODs), a contribution of the cell to the band broadening]. For example, the ESMC cell gave, under optimum operating conditions, 3-4 times higher concentration LODs for the test analytes than a current on-column conductivity cell employed under identical working conditions. On the other hand, these LOD values (25-150 nmol/l) were still 20-5 times lower than those estimated from reference experiments for a contactless conductivity detector. CZE experiments with iodide, carried out under working conditions leading to electrochemical reactions of this anion on the detection electrodes of current conductivity cells, did not occur in the ESMC cell. In addition, this cell, contrary to a reference contact conductivity cell, required no special carl (e.g., cleaning of the surfaces of the detection electrodes by chemical or electrochemical means) to maintain its reliable long-term performance. Anionic CZE analyses of tap and mineral water samples monitored by the conductivity detector provided with the ESMC cell demonstrated a practical applicability and certain limitations of this detection approach in the analysis of ionic constituents present in high ionic strength sample matrices. (C) 2001 Elsevier Science B.V. AII rights reserved.