Neethu Kalloor Sadanandhan. Molji Cheriyathuchenaaramvalli, Sudha J Devaki* A. R. Ravindranatha Menon
We have developed PEDOT – reduced graphene oxide – silver hybrid nanocomposite (PEDOTNTs/rGO/Ag NPs) modified electrode as a transducer for the detection of serotonin. Structure and properties of the nanocomposites were characterized by XPS, XRD, SEM, TEM, FT-IR, UV–Visible, and Raman spectroscopy. The electrochemical impedance spectroscopic (EIS) results showed a very low charge transfer resistance (198 Ω) for the modified electrode and its sensing performance towards serotonin studied by various electrochemical techniques such as cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry (CA). PEDOTNTs/rGO/AgNPs/GCE showed better performance by DPV with a lower detection limit of 0.1 nM with high operational stability, reproducibility (inter- and intra-electrode – 2.3%) response time (8 s) and sensitivity (14.304 μA mM-1/cm2). It also showed a liner range from 1 nM to 0.5 mM (linear regression equation y = 6.33 e-6x + 0.153 e-6). The kinetics of serotonin oxidation was studied by chronoamperometry and the catalytic rate constant calculated as 1.647 × 103 mol-1Ls-1. Later, the modified electrode demonstrated as a transducer for the selective detection of serotonin in the presence of ascorbic acid, uric acid and tyrosine. Real sample analysis and interference studies suggested the modified electrode can be exploited in pharmaceutical and medical fields.
Journal of Electroanalytical Chemistry, 794, 2017, 244-253