Molina Daniel E, Medina Adan Schafer, Beyenal Haluk, Ivory Cornelius F
The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington 99163, USA.
J Electrochem Soc. 2019;166(2):B125-B132. doi: 10.1149/2.0891902jes.
A microfluidic platform for hydrodynamic electrochemical analysis was developed, consisting of a poly(methyl methacrylate) chip and three removable electrodes, each housed in 1/16" OD polyether ether ketone tube which can be removed independently for polishing or replacement. The working electrode was a 100-μm diameter Pt microdisk, located flush with the upper face of a 150 μm × 20 μm × 3 cm microchannel, smaller than previously reported for these types of removable electrodes. A commercial leak-less reference electrode was utilized, and a coiled platinum wire was the counter electrode. The platform was evaluated electrochemically by oxidizing a potassium ferrocyanide solution at the working electrode, and a typical limiting current behavior was observed after running linear sweep voltammetry and chronoamperometry, with flow rates 1-6 μL/min. While microdisk channel electrodes have been simulated before using a finite difference method in an ideal 3D geometry, here we predict the limiting current using finite elements in COMSOL Multiphysics 5.3a, which allowed us to easily explore variations in the microchannel geometry that have not previously been considered in the literature. Experimental and simulated currents showed the same trend but differed by 41% in simulations of the ideal geometry, which improved when channel and electrode imperfections were included.
开发了一种用于流体动力电化学分析的微流控平台，它由一个聚甲基丙烯酸甲酯芯片和三个可拆卸电极组成，每个电极都装在外径为1/16英寸的聚醚醚酮管中，该管可独立拆卸以进行抛光或更换。工作电极是直径为100μm的铂微盘，与一个150μm×20μm×3cm微通道的上表面齐平，比之前报道的这类可拆卸电极更小。使用了一种商用无泄漏参比电极，对电极是一根盘绕的铂丝。通过在工作电极上氧化亚铁氰化钾溶液对该平台进行电化学评估，在流速为1 - 6μL/min的情况下进行线性扫描伏安法和计时电流法测量后，观察到了典型的极限电流行为。虽然之前曾使用有限差分法在理想的三维几何结构中对微盘通道电极进行过模拟，但在此我们使用COMSOL Multiphysics 5.3a中的有限元方法预测极限电流，这使我们能够轻松探索文献中以前未考虑过的微通道几何结构变化。实验电流和模拟电流显示出相同的趋势，但在理想几何结构的模拟中两者相差41%，当考虑通道和电极的缺陷时，这种差异有所改善。
