Laser-activated screen-printed carbon electrodes for enhanced dopamine determination in the presence of ascorbic and uric acid

Abstract Commercial screen-printed carbon electrodes have been treated with a CO2 laser energy of 12.8 mJ cm−2 in air. This thermal treatment resulted in an increase in the crystallinity of the graphite and an enhancement in electron transfer rates, determined by Raman spectroscopy and cyclic voltammetry, respectively. Laser treatment also facilitated the introduction of oxygen groups by anodization at a potential of 1.55 V vs Ag, which was highly beneficial for the simultaneous detection of dopamine (DA), even in the presence of ascorbic acid (AA), and uric acid (UA) by differential pulse voltammetry (DPV). Anodized laser-treated electrodes were much better at resolving the oxidation peaks of these three substances compared to the as-received commercial electrodes. A linear response from 0.34 to 1.6 µM and a detection limit of 80 nM were obtained for DA in the presence of 20 µM uric acid and 160 µM ascorbic acid. This work demonstrates a suitable method to improve sensitivity in carbon-based printable sensors for the simultaneous analysis of oxygen surface-sensitive substances.