Comparison of a 2D/3D imidazole-based MOF and its application as a non-enzymatic electrochemical sensor for the detection of uric acid

Abstract

This work reports on the effect of the morphology of ZIF-67 on its performance as a non-enzymatic electrochemical uric acid sensor. Three different structures were prepared using a simple co-precipitation method with different solvents. The characterization studies on ZIF-67 were carried out by several techniques including X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The characterization results showed that ZIF-67 which was prepared using methanol, water, and a mixture of methanol and water displayed dodecahedral, microplate, and irregular shapes, respectively. The three different structures are denoted as Me-ZIF-67, W-ZIF-67, and M-ZIF-67, respectively. The uric acid sensor performances were evaluated by conducting Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV) measurements in PBS solution with a pH of 7.4 containing uric acid. The test results show that W-ZIF-67 has the highest electrocatalytic activity compared to the other two materials possessing the highest current and the lowest overpotential. As a uric acid sensor, W-ZIF-67 has a sensitivity of 0.0377 μA μM⁻¹ cm⁻² with a relatively wide linear detection range of 20–1000 μM, and a detection limit of 3.04 μM. W-ZIF-67 also has good reproducibility and is stable against interfering species such as urea, glucose, ascorbic acid, and NaCl.