Ali A. Ensafi, Navid Zandi-Atashbar, Zeynab Ahmadi, M. Jafari-Asl, B. Rezaei,

Thionine-functionalized graphene oxide (Th-GO) has been successfully prepared for use as an efficient electrocatalyst in the electrochemical detection of hydrogen peroxide and nicotinamide adenine dinucleotide (NADH), and subsequently characterized by FT-IR spectroscopy, X-ray diffraction, transmission and scanning electron microscopy, and electrochemical methods. Electrochemical studies reveal that the carbon paste electrode modified with Th-GO decreases the working potentials to 0.24 V and 0.00 V towards oxidation of NADH and reduction of H2O2, respectively. Two linear ranges of 2.0–200 μmol L–1 and 200–500 μmol L–1 and a detection limit of 0.43 μmol L–1 have been obtained for NADH analysis. These quantitative data for H2O2 determination are 2.0–3500 μmol L–1 and 1.3 μmol L–1 respectively. Th-GO/CPE shows satisfactory results in terms of repeatability, reproducibility, and selectivity towards NADH and H2O2 analysis in both buffer and real sample.