Electroanalysis at Ultramicro and Nanoscale Electrodes: A Comparative Study

In this paper, we compare emerging nanowire electrodes (100 nm wide × 50 nm high × 45 μm long) against state-of-the-art commercial ultramicroelectrodes (12.5 μm diameter) in terms of improvements in current density and also compatibility with rapid electroanalysis. Analyte diffusion profiles at ultramicrodisc and nanowire electrodes were simulated for a variety of scan rates (50–5000 mV.s−1) and corresponding experimental measurements were undertaken. Significant enhancements in applied voltage scan rate (up to 300 fold increase) were observed (permitting analysis times as low as 30–50 milliseconds) while still maintaining steady-state conditions, when using nanowire electrodes. Nanowire electrodes also exhibited a tenfold improvement in current densities when compared to the ultramicrodisc electrodes.