Electrochemical resolution of purine metabolite overlap using a synthesis-assisted Fe₂O₃-RGO heterointerface

An advanced electrochemical sensor was successfully fabricated by modifying a glassy carbon electrode (GCE) with a composite of Fe₂O₃ nanoparticles and reduced graphene oxide (RGO). The resulting Fe₂O₃-RGO/GCE was characterized, and its performance was evaluated for the simultaneous determination of uric acid (UA), xanthine (XA), and hypoxanthine (HX). The oxidation peaks of UA, XA, and HX were clearly separated at approximately +0.3 V, +0.7 V, and +1.2 V, respectively. This remarkable separation, attributed to a synergistic effect between the highly conductive RGO and the catalytic Fe₂O₃, overcomes a significant analytical challenge presented by the overlapping signals of these coexisting purine metabolites. The sensor exhibited a low detection limit of 0.003 µM for UA within a linear range of 0.01 µM to 1.99 µM. Furthermore, the electrode's selectivity was confirmed; common biological interferents, such as ascorbic acid, dopamine, glucose, and urea, did not cause significant signal interference. The method's practical utility was confirmed through the analysis of real urine samples, with results showing high recovery rates and statistical agreement with the standard HPLC method. Additionally, this work provides a sustainable and scalable solution to the persistent challenge of purine metabolite overlap, offering a robust platform for the rapid, low-cost, and decentralised monitoring of metabolic disorders in clinical settings.