A sensitive electrochemiluminescence glucose biosensor based on graphene quantum dot prepared from graphene oxide sheets and hydrogen peroxide

Abstract

Graphene quantum dots (GQDs) with a size of <10nm were generated from graphene oxide sheets by exploiting the scissor cut effect after sono- and photo-chemical treatment. During this process, hydrogen peroxide was added as the only chemical reagent. A strong cathodic electrochemiluminescence (ECL) signal was generated by applying a cyclic voltammetry scanning on glassy carbon electrode in a mixture of GQD and potassium persulfate. The ECL properties of GQD/K2S2O8 coreactant system were studied in detail and a possible mechanism was proposed which revealed that the ECL signal was mainly dependent on the presence of the reduction of GQD and dissolved oxygen. Furthermore, the ECL signal was found to be quenched by H2O2, a product of enzymatic oxidation of glucose. Therefore, an ECL glucose biosensor was prepared by decorating a film consisting of glucose oxidase, chitosan and GQD on a glassy carbon electrode. Under the optimized conditions, the ECL decreased linearly in the 1.2 to 120pmol·L−1 glucose concentration range, and the detection limit was as low as 0.3pmol·L−1.