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.