A novel electrochemical sensor was developed by modifying a glassy carbon electrode (GCE) with a hybrid nanocomposite composed of a polyoxometalate (POM), CoW11O39CpFe(H2O), immobilized within the Zr-based metal-organic framework (MOF) UiO-66, and phosphorus-doped electrochemically reduced graphene oxide (P@ERGO). The resulting CoW11CpFe@UiO-66/P@ERGO nanocomposite was comprehensively characterized, and its electrochemical behavior was evaluated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and amperometry. The modified electrode enabled the simultaneous detection of dopamine (DA) and uric acid (UA) with well-resolved oxidation peaks. Two linear response ranges were obtained for DA (40–300 µM and 350–1500 µM, LOD: 0.48 µM) and UA (200–900 µM and 950–2700 µM; LOD: 0.58 µM), as determined by DPV, with an exceptional peak potential separation (ΔEsep) of 0.18 mV. The sensor exhibited high repeatability (RSD: 3.01% for UA and 4.43% for DA), good reproducibility (RSD: 3.61% for UA, 4.71% for DA), and excellent stability and long-term stability over 30 days (RSD = 3.15%). Selectivity studies confirmed negligible interference from common biological compounds, including ascorbic acid. These results indicate that the proposed sensor offers a reliable, selective, and stable platform for real-time, simultaneous detection of multiple analytes in complex biological samples, highlighting its potential for clinical and biomedical applications.
Kochebaghi et al. (Sun,) studied this question.