We present here the detection of dopamine (DA) at nanopipet electrodes with radii of hundreds of nanometers ranging from 160 nm to 480 nm. Dibenzo-18-crown-6 (DB18C6) was employed as an ionophore to facilitate DA transfer, resulting in a half-wave transfer potential, E1/2, DA, of −0.322 (±0.020) V vs. E1/2, TBA. Well-defined steady-state sigmoidal cyclic voltammograms were observed for the transfer of DA. High resolution scanning electron microscopy was used to measure the size and taper angle of the nanopipet electrodes. The detection is linear with concentration of DA ranging from 0.25 mM to 2 mM; calculated diffusion coefficient at nanopipet electrodes with above mentioned sizes is 4.87 (±0.28) × 10−10 m2/s. The effect of the common interferent ascorbic acid on DA detection with nanopipet electrodes was evaluated, where DA detection still shows linear behavior with well-defined sigmoidal CVs with E1/2, DA being −0.328 (±0.029) V vs. E1/2, TBA. The diffusion coefficient for DA transfer in MgCl2 with the presence of 2 mM AA was measured to be 1.93 (±0.59) × 10−10 m2/s on nanoelectrodes with radii from 161 nm to 263 nm, but the physiological concentration of 0.1 mM AA had no effect on DA’s diffusion coefficient.

中文翻译：

---

使用循环伏安法在纳米管电极上通过辅助离子转移对多巴胺进行电化学检测

我们在这里展示了在半径为数百纳米、范围从 160 nm 到 480 nm 的纳米管电极上检测多巴胺 (DA)。DiBenzo-18-crown-6 (DB18C6) 被用作离子载体以促进 DA 转移，导致半波转移电位 E1/2, DA 为 -0.322 (±0.020) V vs. E1/2, TBA 。观察到 DA 转移的明确稳态 S 形循环伏安图。使用高分辨率扫描电子显微镜测量纳米管电极的尺寸和锥角。检测结果与 DA 浓度范围为 0.25 mM 至 2 mM 呈线性关系；计算出上述尺寸的纳米管电极的扩散系数为 4.87 (±0.28) × 10−10 m2/s。评估了常见干扰物抗坏血酸对纳米移液管电极 DA 检测的影响，其中 DA 检测仍然显示线性行为，具有明确的 S 形 CV（E1/2），DA 为 -0.328 (±0.029) V vs. E1/2，待定。在半径为 161 nm 至 263 nm 的纳米电极上，存在 2 mM AA 的 MgCl2 中 DA 转移的扩散系数测得为 1.93 (±0.59) × 10−10 m2/s，但生理浓度为 0.1 mM AA对DA的扩散系数没有影响。