Non-enzymatic amperometric sensor for hydrogen peroxide detection based on a ferrocene-containing cross-linked redox-active polymer

Abstract

Herein, we report a novel redox-active polymer-based amperometric hydrogen peroxide sensor constructed by physical entrapment of ferrocene carboxylic acid (FcA) into a cross-linked amino-polyethersulfone film (denoted as FcAPS) in a single-step process. The strategy of design was simple yet original allowing the simultaneous achievement of two tasks: i) easy FcA immobilization and ii) in situ polymer crosslinking reaction directly at a glassy carbon electrode surface (GCE). The FcAPS/GCE system shows a good redox behavior, pertaining to the ferrocene/ferrocenium redox couple. The APS-based immobilization was highly effective avoiding the entrapped FcA leaching and thus stabilizing its electrochemical response. The sensing platform, best operated at an optimal voltage of +0.6 V (vs. SCE), was found to exhibit good electrocatalytic activity towards H2O2 oxidation with a detection limit of 2.07 μM (at S/N = 3) and a wide linear range of 10 μM to 10 mM. The enzyme-free sensor, endowed with satisfactory performances, was successfully used to detect H2O2 in processed cow’s milk samples with very good recoveries.