A Layered Electrochemical Sensor for Epinephrine Based on a Nitrogen‐Doped Reduced Graphene Oxide‐ZnFe <sub>2</sub> O <sub>4</sub> /β‐Cyclodextrin‐Modified Platinum Electrode
Arya Sethu Madhavan, Jishnu Kakkaraparambil Vijayan, Leena Rajith
Abstract
Abstract A novel nanocomposite of nitrogen‐doped reduced graphene oxide‐ZnFe 2 O 4 /β‐cyclodextrin (NRGO‐ZnFe 2 O 4 /β‐CD) was synthesised for electrocatalytic applications on platinum electrode. The structural and morphological characterisation of the synthesised nanocomposite was carried out using FTIR, XRD, EDAX, FESEM, HRTEM etc. The electrochemical characterisation was performed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). NRGO‐ZnFe 2 O 4 /β‐CD proved to be an excellent electrocatalyst for the electrochemical detection of epinephrine on platinum electrode and the optimum pH for the response was found to be 7. The electrochemical characteristics of the oxidation of epinephrine was found to be quasi reversible and diffusion controlled with charge transfer coefficient and diffusion coefficient of 0.55 and 1.03×10 −5 cm 2 /s respectively. Detection limit in the micromolar range of epinephrine was achieved with specific recognition in presence of other structurally similar catecholamines like norepinephrine and dopamine even in their ten‐fold excess concentration at β‐CD/NRGO‐ZnFe 2 O 4 /Pt electrode and the electrode exhibited good repeatability, excellent reproducibility and stability for the oxidation of epinephrine. Recognition of epinephrine with high selectivity could be attained in presence of other common substances present in biological fluids.