▎ 摘　　要

Single step sol-gel synthesized TiO2 and Mn2O3 decorating the pristine graphene (Gr) and graphene oxide (GO), by traditional physical mixing, for selective dopamine (DA) sensing in the presence of its potential interferences in PBS buffer (pH 5). Resulted binary and ternary composites were characterized by XRD, FTIR, UV-DRS, Raman, FE-SEM and TEM techniques. The ternary (TiO2-Mn2O3-Gr (TMGr)) composite showed higher electrochemical activities compared to the binary (TiO2-Gr (TGr), Mn2O3-Gr (MGr) and TiO2-Mn2O3 (TM)) composite in the presence of K-3[Fe(CN)(6)]/K-4[Fe(CN)(6)] redox probe. The same was observed for dopamine (DA) sensing at pH 5. Due to the presence of intrinsic (hydroxyl, acid and epoxide) functional groups with lesser sp(2) hybridized carbon network, the GO-metal oxide composites showed poor electrochemical activity than the Gr-metal oxide composite. Concentration studies by differential pulse voltammetry (DPV) revealed a wide linear range from 0.02 to 100 nM with the lowest detection limit 0.026 nM. The ternary composite was validated for DA sensing by injecting commercial dopamine into the blood serum and urine samples and observed >= 98% signal recovery. The developed sensor showed good stability and reproducibility. (C) 2019 Elsevier Ltd. All rights reserved.