High temporal resolution of fast-scan cyclic voltammetry (FSCV) is widely appreciated in fundamental and applied electrochemistry to quantitatively investigate rapid dynamics of electron transfer and neurotransmission using ultramicroelectrodes (UMEs). Faster potential scan, however, linearly increases the background current, which must be subtracted for quantitative FSCV. Herein, we numerically simulate fast-scan nanogap voltammetry (FSNV) for quantitative detection of diffusing redox species under quasi-steady states without the need of background subtraction while maintaining high temporal resolution of transient FSCV. These advantages of FSNV originate from the use of a parallel pair of cylindrical UMEs with nanometer-wide separation in contrast to FSCV with single UMEs. In FSNV, diffusional redox cycling across the nanogap is driven voltammetrically at the generator electrode and monitored amperometrically at the collector electrode without the transient background. We reveal that the cylindrical collector electrode can reach quasi-steady states ~104 times faster than the generator electrode with identical sizes to allow for fast scan. Double-microcylinder and nanocylinder UMEs enable quasi-steady-state FSNV at hundreds volts per second as practiced for in-vivo FSCV and megavolts per second as achieved for ultra-FSCV, respectively. Rational design and simple fabrication of double-cylinder UMEs are proposed to broaden the application of nanogap voltammetry.

中文翻译：

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双柱超微电极快速扫描纳米间隙伏安法的模拟

快速扫描循环伏安法 (FSCV) 的高时间分辨率在基础和应用电化学中得到广泛认可，用于使用超微电极 (UME) 定量研究电子转移和神经传递的快速动力学。然而，更快的电位扫描会线性增加背景电流，定量 FSCV 必须减去背景电流。在这里，我们数值模拟了快速扫描纳米间隙伏安法 (FSNV)，用于在准稳态下定量检测扩散氧化还原物质，而无需背景减法，同时保持瞬态 FSCV 的高时间分辨率。与具有单个 UME 的 FSCV 相比，FSNV 的这些优势源于使用具有纳米级间隔的平行圆柱 UME 对。在 FSNV 中，跨越纳米间隙的扩散氧化还原循环在发生器电极处以伏安法驱动，并在集电极处以电流法监测，没有瞬态背景。我们发现圆柱形集电极可以比具有相同尺寸的发生器电极快 104 倍达到准稳态，以实现快速扫描。双微柱和纳米柱 UME 分别在体内 FSCV 和超 FSCV 所达到的每秒数百伏和兆伏的情况下实现准稳态 FSNV。提出了双圆柱UME的合理设计和简单制造，以拓宽纳米间隙伏安法的应用。我们发现圆柱形集电极可以比具有相同尺寸的发生器电极快 104 倍达到准稳态，以实现快速扫描。双微柱和纳米柱 UME 分别在体内 FSCV 和超 FSCV 所达到的每秒数百伏和兆伏的情况下实现准稳态 FSNV。提出了双圆柱UME的合理设计和简单制造，以拓宽纳米间隙伏安法的应用。我们发现圆柱形集电极可以比具有相同尺寸的发生器电极快 104 倍达到准稳态，以实现快速扫描。双微柱和纳米柱 UME 分别在体内 FSCV 和超 FSCV 所达到的每秒数百伏和兆伏的情况下实现准稳态 FSNV。提出了双圆柱UME的合理设计和简单制造，以拓宽纳米间隙伏安法的应用。