Electrochemical Sensing of Paracetamol Using Functionalized MWCNTs: Integrating Computational and Experimental Methods

An electrochemical sensing platform for the detection of paracetamol is proposed in this work. The sensor (Asp-MWCNTs/IL/ITO) is based on Indium Tin Oxide (ITO) electrode loaded with asparagine functionalised Multi Walled Carbon Nanotubes (MWCNTs) and Ionic Liquid (IL). Initially, in-silico studies were performed to check the favourable interaction of the drug with the nanocomposite. The potential energy surface of Asp-MWCNTs and paracetamol complexes were explored using density functional theory and single-point energy coupled cluster calculations. The analysis of non-covalent interactions showed hydrogen bonding interactions predominantly stabilising the complex. The interaction process between Asp-MWCNTs and paracetamol is spontaneous due to negative value of binding energy (-0.75 eV). The functionalised MWCNTs were characterised through different techniques. Asp-MWCNTs/IL/ITO electrode showed good sensitivity with a linear range from 20-300 mu gL-1 and limit of detection of 0.0194 mu M for paracetamol in phosphate buffer as supporting electrolyte. The sensor showed excellent repeatability and reproducibility with a relative standard deviation of 1.45 % at 60 mu gL-1 concentration. The chemical functionalization resulted in providing extra stability as it retained 95 % of its signal response even after 45 days. The sensor's applicability was tested in real water samples with the help of spiking study which showed good recovery >95 %."