Development of an Electrochemical Dopamine Sensor Using Nitrogen-Rich Sulfur Dual-Doped Reduced Graphene Oxide

In the present work, we report on developing an electrochemical dopamine sensor using a novel material of nitrogen-rich sulfur dual-doped reduced graphene oxide (N-rich SRGO). Nitrogen and sulfur heteroatoms were incorporated into graphene sheets through a one-step, cost-effective hydrothermal approach to synthesize N-rich SRGO. Experimental investigations were carried out to compare the electrochemical properties of N-rich SRGO with nitrogen sulfur-doped reduced graphene oxide (NSRGO), nitrogen-doped reduced graphene oxide sheets (NRGO), and reduced graphene oxide (RGO) by modifying the glassy carbon electrode. Electrochemical studies demonstrated that N-rich SRGO exhibited a notably higher oxidation current ( 345~\mu A) compared to NSRGO ( 219~\mu A), NRGO ( 173~\mu A), and RGO ( 160~\mu A). We developed a dopamine sensor by utilizing the superior chemical reactivity and enhanced charge carrier density of the proposed N-rich SRGO-modified electrode. Experimental results reveal a high sensitivity of 142 \mu A/mM, with a limit of detection of 9.3~\mu M and a wide dynamic range of 150- 350~\mu M. This N-rich SRGO-based sensor displayed excellent repeatability and selectivity, even in the presence of other electroactive interferents, showcasing its potential for practical applications.