Polyvinylpyrrolidone-stabilized graphene（PVP-graphene） was synthesized and investigated as a modifier for the determination of ascorbic acid（AA）. With PVP acting as stabilizer and dispersant, the resulting PVP-graphene material could disperse well into water. And the PVP-graphene modified glassy carbon electrode（PVP-graphene-GCE） showed an obvious electrocatalytical activity toward the oxidation of AA in a phosphate buffer solution（PBS, pH=7.0） with an oxidation potential of AA at 0.052 V vs. AglAgCl（sat. KCl）. The calibration curve for APt was linear in a concentration range from 1.0×10^-5 to 5.0×10^-4 mol/L with a correlation coefficient of 0.9998. And the detection limit was found to be 1 μtmol/L. During the oxidation of AA, the π-π interaction of graphene plane with conjugated hexenoic aeid-lactone in AA molecules might play a key role. As a result, an obvious decrease of overpotential was achieved at such a PVP-graphene electrode through a possible adsorption/enrichment process, which will probably trigger potential applications for the electroanalysis of some aromatic and heterocyclic compounds.
HAN Dong-fangSHAN Chang-shengGUO Li-pingNIU LiHAN Dong-xue
