New Micron-Ring-Disk Electrodes: Fabrication, Characterization, and Applications

Traditional electrochemical analysis with single-working-electrode systems is effective for targeting individual reactions or species but falls short in simultaneously analyzing multiple analytes. Two-working-electrode systems, such as the rotating ring-disk electrode, address this limitation but suffers from several drawbacks, such as low collection efficiency, high background noise, and bulky size, which significantly limit its use toward a wider range. In this study, we proposed the design and fabrication of a simple, low-cost, compact, and user-friendly two-working-electrode system: the micro-ring-disk electrodes (MRDEs). The fabrication process reliably produces high-performance MRDEs using various materials, with disk and ring sizes ranging from 5 to19 μm. Taking advantage of the unique dual-working-electrode structure, the MRDEs enable in situ detection with multiple targets. To demonstrate this capability, the selective detection of dopamine (DA) was performed in the presence of ascorbic acid (AA), a common interference. By holding the microring electrode at a constant potential to oxidize AA, DA was accurately detected at the microdisk electrode, even when AA interference was present at four times the concentration of DA. This work not only provides a practical solution for the easy fabrication of two-working-electrode systems but also offers valuable insights into their application of selective and multitarget detection in complex environments.