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

Tian, Xianqing, Cheng, Changming, Yuan, Hongyan, Du, Juan, Xiao, Dan, Xie, Shunping, Choi, Martin M.F.
Talanta 2012 v.93 pp. 79-85
X-ray diffraction, ascorbic acid, beta-cyclodextrin, detection limit, dopamine, glassy carbon electrode, gold, graphene, humans, infrared spectroscopy, nanogold, oxidation, pH, scanning electron microscopy, transmission electron microscopy, uric acid, urine
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 0.10M 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 0.5–60μM, respectively. The detection limits (based on S/N=3 and preconcentration time=3.0min) for AA, DA and UA are 10, 0.15 and 0.21μM, 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.