▎ 摘　　要

A novel electrochemical biosensor was developed using GdTiO3 (GTO) perovskite prepared by sol-ge l(S) and hydrothermal (H) methods and decorated on few layered graphene for simultaneous sensing and quantification of dopamine (DA) and acetaminophen (ACE). The physical and structural characterization of the perovskites and composites were done using XRD, Raman, FTIR, XPS, and TEM analysis. Electrochemical characterization indicates higher activity for the GTO(S)-Gr composite modified electrode than the individual graphene, GTO(S) and GTO(H) component modified electrodes towards DA and ACE sensing. Simultaneous sensing in physiological buffer under optimized conditions exhibited wide linear ranges from 72 nM to 1.5 mu M with lowest detection limit (LOD) 96.89 nM for DA and 50 nM to 1.5 mu M with LOD 58.85 nM for ACE. The estimated sensitivity values are 3.357 x 10(-5) A/nM and 2.177 x 10(-5) A/nM, respectively for DA and ACE being higher than that of the literature reported for the graphene based metal oxide and perovskite sensors. The sensor showed high selectivity towards DA and ACE in the presence of co-interfering components like ascorbic acid, uric acid which may oxidize at the same potential. The binary composite was validated for DA and ACE sensing in practical applications using blood serum, tablet and urine samples and observed good signal recovery. The fabricated sensor was stable and showed good reproducibility. (C) 2021 Elsevier B.V. All rights reserved.