Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, U.K.
J Am Chem Soc. 2021 Nov 17;143(45):19199-19206. doi: 10.1021/jacs.1c09743. Epub 2021 Nov 3.
Continuous, real-time ion sensing is of great value across various environmental and medical scenarios but remains underdeveloped. Herein, we demonstrate the potential of redox capacitance spectroscopy as a sensitive and highly adaptable ion sensing methodology, exemplified by the continuous flow sensing of anions at redox-active halogen bonding ferrocenylisophthalamide self-assembled monolayers. Upon anion binding, the redox distribution of the electroactive interface, and its associated redox capacitance, are reversibly modulated, providing a simple and direct sensory readout. Importantly, the redox capacitance can be monitored at a freely chosen, constant electrode polarization, providing a facile means of tuning both the sensor analytical performance and the anion binding affinity, by up to 1 order of magnitude. In surpassing standard voltammetric methods in terms of analytical performance and adaptability, these findings pave the way for the development of highly sensitive and uniquely tunable ion sensors. More generally, this methodology also serves as a powerful and unprecedented means of simultaneously modulating and monitoring the thermodynamics and kinetics of host-guest interactions at redox-active interfaces.
连续实时离子传感在各种环境和医疗场景中具有重要价值，但仍未得到充分发展。在此，我们展示了氧化还原电容光谱学作为一种灵敏且高度适应性的离子传感方法的潜力，以氧化还原活性卤键二茂铁基异酞酰亚胺自组装单层中阴离子的连续流动传感为例。阴离子结合后，电活性界面的氧化还原分布及其相关的氧化还原电容可被可逆调节，提供了一种简单直接的传感读出方式。重要的是，氧化还原电容可在自由选择的恒定电极极化下进行监测，通过这种方式可以轻松地调节传感器的分析性能和阴离子结合亲和力，幅度可达 1 个数量级。在分析性能和适应性方面超越了标准伏安法，这些发现为开发高灵敏度和独特可调离子传感器铺平了道路。更广泛地说，这种方法还为同时调节和监测氧化还原活性界面上主客体相互作用的热力学和动力学提供了一种强大且前所未有的手段。
