Sensing interface based on electrodeposited Cu-BTC microporous film for electrochemical detection of the painkiller paracetamol

Abstract

The use of metal–organic framework materials in electrochemical sensors has been gaining more attention in the last few years due to their highly porous structure and electrocatalytic activity. In this work, a novel paracetamol electrochemical sensor based on a Cu-BTC microporous film electrochemically grown onto glassy carbon electrode was introduced. The Cu-BTC film was deposited directly onto the electrode surface via an electrochemical approach using a Et₃N probase to accelerate the growth of Cu-BTC. The fast growth enables the formation of a microporous structure with better adsorption of targeted molecules. The two-dimensional arrangement of units made of dimeric copper cations coordinated to carboxylate anions helped to improve the electrochemical conductivity and electron transfer rate at the electrode surface (charge transfer resistance was dramatically decreased from 2173 Ω to 86 Ω). The electrocatalytic activity of copper ion centers in Cu-BTC was studied with peak separation between oxidation and reduction peaks of pseudo-redox paracetamol molecules much shortened (from 629 mV to 87 mV). Consequently, the sensing parameters (sensitivity and detection limit) of the as-prepared paracetamol sensor were considerably improved. Further works need to be conducted on tailoring ligand structure in order to much improve the electrical conductivity of metal–organic frameworks for sensing purposes.