Electrochemically polymerized glutamine-activated graphite paste surface as a green biosensor for sensitive catechol detection in water samples

In the current research work, an electrochemically polymerized glutamine-clustered graphite paste electrode surface was developed for the electrochemical detection of hazardous catechol (CL) molecules. The cyclic voltammetric (CV) method was operated for the detection of redox activities of CL in phosphate buffer solution (PBS) of pH 7.0 on the surface of polymerised glutamine (GN) modified graphite (GP) paste electrode (P(GN)MGPPE). The electrochemical impedance (EI), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDXS), and CV methods were used to elucidate the surface behaviours and morphology of the prepared electrode materials. The P(GN)MGPPE provides a well-defined and highly sensitive electrochemical redox peak for CL based on an adsorption-controlled reaction approach compared to the bare graphite paste electrode (BGPPE) surface. The activated electrochemical sensor provides good linear relation among the concentrations, and the corresponding reduction peak currents of CL ranging from 2.0 to 200.0 μM and the calculated detection limit (DL) and quantification limit (QL) are found to be 0.045 µM and 0.151 µM, respectively. The activated electrode surface reveals high electrocatalytic activity with good reproducibility, repeatability, and stability. Finally, the P(GN)MGPPE surface was operated for the detection of CL in water samples with a fine recovery ranging from 99.23 to 100.42%.