Electrochemical sensing platform for L-CySH based on nearly uniform Au nanoparticles decorated graphene nanosheets

•Both the density and the size of Au NPs could be tuned by the grafted PVP content.•Au NPs showed strongly catalytic behavior toward the electrooxidation of L-CySH.•The performance of L-CySH sensor depended on the density and the size of Au NPs.•The L-CySH sensor exhibited a low detection limit and a satisfactory recovery.

In this study, Au nanoparticles decorated graphene nanosheets were prepared using poly(vinylpyrrolidone) (PVP) covalently functionalized graphene oxide and chloroauric acid as template and Au precursor, respectively. Both the density and the size of Au nanoparticles deposited on the surface of graphene could be adjusted by the PVP grafting density. The graphene–Au hybrid nanosheets were then applied to fabricate a highly sensitive l-cysteine (L-CySH) electrochemical sensing platform. The cyclic voltammetry results showed that the modified glassy carbon electrode with graphene–Au hybrid nanosheets exhibited strong catalytic activity toward the electrooxidation of L-CySH. The current exhibited a widely linear response ranging from 0.1 to 24 μM with a low detection limit under the optimized conditions. The detection limit of L-CySH could reach as low as 20.5 nM (S/N = 3). The enhanced electrochemical performance of the fabricated sensor was attributed to the combination of the excellent conductivity of graphene and strong catalytic property of uniform Au nanoparticles.

Graphical abstractNearly monodisperse Au nanoparticle decorated graphene nanosheets showed excellent catalytic capability toward the electrooxidation of L-CySH.Figure optionsDownload full-size imageDownload as PowerPoint slide