Makarychev-Mikhailov Sergey, Shvarev Alexey, Bakker Eric
Department of Chemistry, Auburn University, Auburn, Alabama 36849, USA.
J Am Chem Soc. 2004 Sep 1;126(34):10548-9. doi: 10.1021/ja047728q.
Ion-selective electrode membranes based on hydrophobic materials doped with chemically selective host molecules are an attractive sensing technology but normally suffer from a limited sensitivity, given by the Nernst equation, and a direct reliance on the reference electrode potential, which makes miniaturization difficult. These fundamental problems are addressed here by imposing a multipulse electrochemical excitation signal onto ion-selective membranes that lack ion-exchange properties. Current pulses are responsible for the generation of ion fluxes in the direction of the membrane, which give reproducible super-Nernstian response slopes that originate from depletion processes at the membrane surface. Membranes may also be measured at zero current after this pulse, giving super-Nernstian response regions at lower concentrations. Difference potentials obtained from subsequent pulses give about 10-fold higher sensitivities than predicted on the basis of the Nernst equation.
基于掺杂化学选择性主体分子的疏水材料的离子选择电极膜是一种有吸引力的传感技术，但通常受限于能斯特方程给出的有限灵敏度，以及对参比电极电位的直接依赖，这使得小型化变得困难。本文通过将多脉冲电化学激励信号施加到缺乏离子交换特性的离子选择膜上来解决这些基本问题。电流脉冲负责在膜的方向上产生离子通量，从而产生可重复的超能斯特响应斜率，这源于膜表面的耗尽过程。在该脉冲之后，膜也可以在零电流下进行测量，从而在较低浓度下给出超能斯特响应区域。后续脉冲获得的差分电位比基于能斯特方程预测的灵敏度高约10倍。
