Application of carboxyl functionalized graphene oxide as mimetic peroxidase for sensitive voltammetric detection of H2O2 with 3,3′,5,5′-tetramethylbenzidine

A sensitive electrochemical method for H2O2 determination was proposed with carboxyl functionalized graphene oxide (GO-COOH) as mimetic peroxidase and 3,3′,5,5′-tetramethylbenzidine (TMB) as substrate. GO-COOH exhibited intrinsic peroxidase-like activity that could catalyze the oxidation of TMB with H2O2. The generated product exhibited a sensitive second order derivative linear sweep voltammetric reduction peak at − 0.93 V (vs. Ag/AgCl) in Britton–Robinson buffer. Under the optimal conditions the reduction peak current was proportional to H2O2 concentration in the linear range from 0.006 to 0.8 μmol L− 1 with the detection limit of 1.0 nmol L− 1 (3σ). This proposed method was further applied to determine H2O2 content in fresh milk samples with satisfactory results.

► A carboxyl functionalized graphene oxide (GO-COOH) was used as mimetic peroxidase.
► GO-COOH can catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine with H2O2.
► Linear sweep voltammetric peak of the oxidation product appeared at − 0.93 V.
► A sensitive electrochemical method for H2O2 determination was proposed.