Highly sensitive electrochemical sensor based on xylan-based Ag@CQDs-rGO nanocomposite for dopamine detection

Although polysaccharide-based carbon quantum dots (CQDs) are widely used in the field of detection, most of the CQDs-based sensors only take advantage of their optical properties. In this work, considering the selectivity to target substance and reducibility of xylan-based CQDs, a high-sensitive sensor based on greenly synthesized CQDs-based nanocomposite was fabricated for dopamine (DA) detection. First, the CQDs prepared from xylan were used as the reductant and stabilizer to quickly synthesize silver nanoparticles (Ag NPs) and reduced graphene oxide (rGO), and then Ag@CQDs-rGO nanocomposite was obtained and loaded on glassy carbon electrode (GCE) to fabricate electrochemical sensor. The electrochemical sensing of DA is of great significance for studying and treating neurochemical diseases due to its potential feasibility in diagnostics. Under optimal conditions, the linear range for monitoring DA was from 0.1 to 300 mu M with a limit of detection of 1.59 nM (S/N = 3). Finally, this sensor was successfully applied to detect DA in dopamine hydrochloride injection and bovine serum solution samples. The proposed strategy may broaden the application of polysaccharide-based CQDs and this sensor may provide a discriminative and sensitive analytical platform for DA clinical diagnostics and drug screening.