Dopamine detection via differential pulse voltammetry (DPV)

DPV measurements were conducted with a step size of 0.015 V, a modulation amplitude of 0.05 V, a modulation time of 5 s, and an interval time of 10 s, spanning the potential range from − 0.1 to + 0.8 V. All experiments were conducted in a 0.01 M PBS solution at pH 7.4, using a Pt electrode as the counter electrode (CE) and Ag|AgCl (KCl 3 M) as the reference electrode. To prevent DA polymerization, a stock solution was prepared in 0.01 M PBS, with the pH adjusted to 4. Increasing volumes of this DA stock solution were sequentially introduced and analyzed via DPV to establish the calibration curve, covering the concentration range from 0.25 to 500.0 µM.

The same experimental setup was used to investigate the effect of increasing concentrations of uric acid and ascorbic acid on a constant dopamine concentration. In these tests, dopamine was first added to the PBS solution, followed by the sequential addition of either ascorbic acid or uric acid.