MESA+ Institute and Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Anal Chem. 2022 Jul 19;94(28):10168-10174. doi: 10.1021/acs.analchem.2c01503. Epub 2022 Jul 6.
In current-blockade impact electrochemistry, insulating particles are detected amperometrically as they impinge upon a micro- or nanoelectrode via a decrease in the faradaic current caused by a redox mediator. A limit of the method is that analytes of a given size yield a broad distribution of response amplitudes due to the inhomogeneities of the mediator flux at the electrode surface. Here, we overcome this limitation by introducing microfabricated ring-shaped electrodes with a width that is significantly smaller than the size of the target particles. We show that the relative step size is somewhat larger and exhibits a narrower distribution than at a conventional ultramicroelectrode of equal diameter.
在当前的阻断影响电化学中，绝缘颗粒通过减少由于氧化还原介质引起的法拉第电流而在微电极或纳米电极上撞击时被安培检测到。该方法的局限性在于，由于电极表面上介质通量的不均匀性，给定大小的分析物会产生广泛的响应幅度分布。在这里，我们通过引入宽度明显小于目标颗粒尺寸的微制造环形电极克服了这一限制。我们表明，相对阶跃尺寸稍大，并且分布比直径相等的常规超微电极更窄。
