Cu2+-BTC based metal–organic framework: a redox accessible and redox stable MOF for selective and sensitive electrochemical sensing of acetaminophen and dopamine

Abstract

A Cu²⁺ plus benzenetricarboxylate (BTC) based ‘3D’ metal–organic framework HKUST-1 was synthesized via a facile microwave assisted route. The structure and morphology of the framework were characterized by XRD, FTIR, SEM, and TEM and its thermal stability tested with TGA. The thermal studies reveal the stability of the framework up to 300 °C with the collapsing of the material in the temperature range of 300–400 °C. The kinetics of decomposition reveals that the HKUST-1 decomposition follows first order kinetics with the energy of activation 198.01 kJ mol⁻¹. The redox stability and accessibility of the MOF were explored via voltammetric investigations carried out with a HKUST-1 modified glassy carbon electrode (HKUST-1/GCE). HKUST-1/GCE was also tested for its potential towards electrochemical sensing of acetaminophen (AC) and dopamine (DA) wherein the analytes were observed to result in concentration dependent faradaic signals appreciably separated over the voltammetric scale. Linear correlations were found between the oxidation peaks and the concentrations of acetaminophen and dopamine, in the concentration ranges of 12.5–375 μM and 12.5–175 μM, respectively. HKUST-1/GCE was observed to exhibit excellent stability, reproducibility and detection limits as low as 0.092 nM and 0.11 nM for AC and DA, respectively. The presented results clearly establish the redox stability, redox accessibility and suitability of HKUST-1 as a potential electrode material for sensitive electrochemical sensing of AC and DA.