Department of Chemistry and Biochemistry , Queens College , Flushing , New York 11367 , United States.
The Graduate Center of CUNY , New York , New York 10016 , United States.
Anal Chem. 2019 May 7;91(9):5530-5536. doi: 10.1021/acs.analchem.9b00426. Epub 2019 Apr 23.
Ion transport controlled by electrostatic interactions is an important phenomenon in biological and artificial membranes, channels, and nanopores. Here, we employ carbon-coated nanopipets (CNPs) for studying permselective electrochemistry in a conductive nanopore. A significant accumulation (up to 2000-fold) of cationic redox species and anion depletion inside a CNP by diffuse-layer and surface-charge effects in a solution of low ionic strength were observed as well as the shift of the voltammetric midpeak potential. Finite-element simulations of electrostatic effects on CNP voltammograms show permselective ion transport in a single conducting nanopore and semiquantitatively explain our experimental data. The reported results are potentially useful for improving sensitivity and selectivity of CNP sensors for ionic analytes.
静电相互作用控制的离子传输是生物和人工膜、通道和纳米孔中的重要现象。在这里，我们采用涂覆碳的纳米管（CNP）研究低离子强度溶液中扩散层和表面电荷效应在导电纳米孔中对选择透过性电化学的影响。我们观察到阳离子氧化还原物种在 CNP 内的显著积累（高达 2000 倍）和阴离子耗尽，以及伏安峰中值电位的偏移。静电效应对 CNP 伏安图的有限元模拟显示在单个导电纳米孔中的选择透过性离子传输，并半定量地解释了我们的实验数据。所报道的结果可能有助于提高 CNP 传感器对离子分析物的灵敏度和选择性。
