Anthraquinone Functionalized Ionic Liquid Based Disposable Electrochemical Sensor for the Enzyme-Free Detection of Hydrogen Peroxide

A simple and selective enzyme-free electrochemical sensor for H₂O₂ has been designed and fabricated using ionic liquid (IL) tagged anthraquinone (AQ) modified electrode (AQ-PF₆-IL). This newly synthesized AQ-PF₆-IL has been systematically characterized, after which it has been immobilized over a screen-printed electrode to produce AQ-PF₆-IL/SPE. The electrochemical investigation of AQ-PF₆-IL/SPE displayed a set of distinct redox peaks attributable to the anthraquinone/anthrahydroquinone redox pair. Interestingly, AQ-PF₆-IL/SPE has shown enhanced peak current at reduced formal potential for AQ, when compared to AQ/SPE. Further, the electrocatalytic activity of AQ-PF₆-IL/SPE towards the reduction of H₂O₂ was investigated with the sequential addition of H₂O₂. A rapid and appreciable enhancement in cathodic peak currents was observed and thus demonstrating the excellent electrochemical reduction of H₂O₂ at the newly developed sensor. Besides, AQ-PF₆-IL/SPE established a good linear behaviour over a concentration range of 10-1228 μM with a high sensitivity of 0.281 μA μM⁻¹ cm⁻² and low detection limit of 2.87 μM. The fabricated sensor displayed excellent stability, good anti-interference ability, along with acceptable reproducibility. The superior properties of the developed sensor could be attributed to the newly designed AQ-PF₆-IL, wherein the redox characteristics of AQ mediator are integrated with the high stability and conductivity of IL.