Highly Sensitive Electrochemical Sensor for Dopamine and Uric Acid Based on TiO2@C Composite Material Derived from MIL-125

Abstract

TiO2@C material was prepared through the annealing of MIL-125 at 750°C under a nitrogen atmosphere. XRD, SEM, HRTEM, Raman and XPS methods were applied to characterize TiO2@C, and the results showed that Ti-O clusters in MIL-125 were transformed into anatase TiO2, and carbon matrix was evenly covered on the surface of TiO2 in roughly equal proportion with graphite and amorphous states after high-temperature treatment. The synchronous detection ability of TiO2@C modified glassy carbon electrode (denoted as TiO2@C/GCE) for dopamine (DA) and uric acid (UA) was investigated. There are three linear ranges between the detection currents and the concentrations of DA and UA on the TiO2@C/GCE loaded with 3μL 1 mg·mL-1 of TiO2@C, which are 0.2-20, 20-200, 200-800 μM for DA and 0.2-5, 5-50, 50-200 μM for UA, and the minimum detection limits of TiO2@C/GCE for DA and UA are all 0.04 μM. TiO2@C/GCE has high stability, reusability and anti-interference. Even in the presence of ascorbic acid (AA), the current peaks of DA and UA do not interfere with each other. In the detection of actual samples, the recoveries of DA and UA are between 100.19-101.87% and 93.09-105.30%, respectively.