Simultaneous electrochemical sensing of dihydroxy benzene isomers at cost-effective allura red polymeric film modified glassy carbon electrode

A simple and simultaneous electrochemical sensing platform was fabricated by electropolymerization of allura red on glassy carbon electrode (GCE) for the interference-free detection of dihydroxy benzene isomers. The modified working electrode was characterized by electrochemical and field emission scanning electron microscopy methods. The modified electrode showed excellent electrocatalytic activity for the electrooxidation of catechol (CC) and hydroquinone (HQ) at physiological pH of 7.4 by cyclic voltammetric (CV) and differential pulse voltammetric (DPV) techniques. The effective split in the overlapped oxidation signal of CC and HQ was achieved in a binary mixture with peak to peak separation of 0.102 V and 0.103 V by CV and DPV techniques. The electrode kinetics was found to be adsorption-controlled. The oxidation potential directly depends on the pH of the buffer solution, and it witnessed the transfer of equal number of protons and electrons in the redox phenomenon. The limit of detection (LOD) for CC and HQ was calculated to be 0.126 μM and 0.132 μM in the linear range of 0 to 80.0 μM and 0 to 110.0 μM, respectively, by ultra-sensitive DPV technique. The practical applicability of the proposed sensor was evaluated for tap water sample analysis, and good recovery rates were observed. Electrocatalytic interaction of ALR/GCE with dihydroxy benzene isomers.