Improving the compatibility of contact conductivity detection with microchip electrophoresis using a bubble cell.
Improving the compatibility of contact conductivity detection with microchip electrophoresis using a bubble cell.
复制标题
使用气泡池提高接触电导检测与微芯片电泳的兼容性。
DOI：
10.1021/ac8013862
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发表时间：
2008
影响因子：
7.4
通讯作者：
C. Henry
中科院分区：
文献类型：
--
作者：
S. Noblitt;C. Henry
提出了一种提高接触电导检测与微芯片电泳兼容性的新方法。接触电导率传统上受到分离电压与检测电极的相互作用的限制，因为施加的场在电极之间产生电压差，导致不希望的电化学反应。为了最小化导电电极之间的电压降，从而提高兼容性，设计了一种新的气泡池检测区。气泡池允许更高的分离场强（600 V/cm），并通过最小化不需要的电化学反应来降低背景噪声。通过在电泳期间成像荧光素来测量气泡池对分离效率的影响。四倍于分离通道宽度的气泡池导致检测点处的分离效率仅降低3%。增加气泡室宽度引起分离效率的较大降低，并且4倍膨胀提供了分离效率损失和保持较高场强之间的最佳折衷。使用商业色谱电导检测器（Dionex CD 20）来评价与气泡池接触电导检测的性能。质量检测限（S/N = 3）低至89 +/- 9阿莫尔，门控进样时浓度检测限低至71 +/- 7 nM。测量的线性范围大于2个数量级，对于氨基磺酸盐为1.3至600 μ M。气泡池改善了微芯片电泳中接触电导检测的兼容性和适用性，并且类似的设计可以在电化学检测中具有更广泛的应用，因为除了减少分离场效应之外，扩展的检测区还提供了增加的电极表面积和降低的分析物速度。
A new approach for improving the compatibility between contact conductivity detection and microchip electrophoresis was developed. Contact conductivity has traditionally been limited by the interaction of the separation voltage with the detection electrodes because the applied field creates a voltage difference between the electrodes, leading to unwanted electrochemical reactions. To minimize the voltage drop between the conductivity electrodes and therefore improve compatibility, a novel bubble cell detection zone was designed. The bubble cell permitted higher separation field strengths (600 V/cm) and reduced background noise by minimizing unwanted electrochemical reactions. The impact of the bubble cell on separation efficiency was measured by imaging fluorescein during electrophoresis. A bubble cell four times as wide as the separation channel led to a decrease of only 3% in separation efficiency at the point of detection. Increasing the bubble cell width caused larger decreases in separation efficiency, and a 4-fold expansion provided the best compromise between loss of separation efficiency and maintaining higher field strengths. A commercial chromatography conductivity detector (Dionex CD20) was used to evaluate the performance of contact conductivity detection with the bubble cell. Mass detection limits (S/N = 3) were as low as 89 +/- 9 amol, providing concentration detection limits as low as 71 +/- 7 nM with gated injection. The linear range was measured to be greater than 2 orders of magnitude, from 1.3 to 600 microM for sulfamate. The bubble cell improves the compatibility and applicability of contact conductivity detection in microchip electrophoresis, and similar designs may have broader application in electrochemical detection as the expanded detection zone provides increased electrode surface area and reduced analyte velocity in addition to the reduction of separation field effects.