A Cu(II)-BTC Metal-Organic Framework Modified Carbon Paste Electrode and Its Application as Electrochemical Sensor for Methanol Determination

This work presents a novel electrochemical sensor for methanol, based on a Cu(II) Metal-Organic Framework. The copper (II) benzenetricarboxylic metal-organic framework (Cu-BTC) was synthesized in mild condition at room temperature, and the obtained crystals were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The obtained Cu-BTC was incorporated at different ratios (7, 15, 30 wt%) in carbon paste electrodes to determine its electrocatalytic activity in the absence and the presence of methanol. The electrodes were characterized by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). An anodic peak response toward methanol was observed at 1.25 V using 0.1 M NaOH as supporting electrolyte, with a maximum current density of 10 mA. Also, the oxidation signal of methanol in the presence of ethanol was studied by DPV. The quantitative analysis of methanol in the presence of ethanol using the modified electrode presented a LOD, LOQ and sensitivity values of 0.0511 mM, 0.1549 mM, and 19.8 mA mM−1 cm−2, respectively. The results demonstrated the high potential of Cu-BTC as part of electrochemical sensors for the determination of methanol in actual samples.