Simultaneous determination of l-ascorbic acid, dopamine and uric acid with gold nanoparticles–β-cyclodextrin–graphene-modified electrode by square wave voltammetry

Graphene decorated with gold nanoparticles (AuNPs–β-CD–Gra) has been synthesized by in situ thermal reduction of graphene oxide and HAuCl4 with β-cyclodextrin (β-CD) under alkaline condition. The AuNPs–β-CD–Gra product was well characterized by infrared spectroscopy, X-ray powder diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and selected area electron diffraction. This material was used to fabricate an AuNPs–β-CD–Gra-modified glassy carbon electrode (GCE) which showed excellent electro-oxidation of l-ascorbic acid (AA), dopamine (DA) and uric acid (UA) in 0.10 M NaH2PO4–HCl buffer solution (pH 2.0) by square wave voltammetry (SWV). Three well-resolved oxidation peaks of AA and DA and UA were obtained. The AuNPs–β-CD–Gra/GCE exhibits linear responses to AA, DA and UA in the ranges 30–2000, 0.5–150 and 0.5–60 μM, respectively. The detection limits (based on S/N = 3 and preconcentration time = 3.0 min) for AA, DA and UA are 10, 0.15 and 0.21 μM, respectively. The AuNPs–β-CD–Gra/GCE has been successfully applied to determine UA in human urine with satisfactory results. Our work provides a simple, convenient and green route to synthesize AuNPs on Gra which is potentially useful in electroanalysis.