Electrochemical investigation of paracetamol at Congo red modified carbon paste electrode: a voltammetric study

This work illustrates the modification of carbon paste electrode (CPE) by electropolymeri­zation of Congo red. The poly(Congo red) modified CPE (Congo red/MCPE) was used to study the electrochemical behaviour of paracetamol (PA) by cyclic voltammetry. Compared to bare CPE, Congo red/MCPE exhibited better electrocatalytic activity towards the oxidation of PA, with an enhanced oxidation peak current in phosphate buffer solution at neutral pH and a sweep rate of 100 mV s-1. The effect of analyte concentration changes at Congo red/MCPE was studied by varying the concentration of PA and the limit of detection was found to be 1.1 µM. The proposed approach was successfully applied to the simultaneous measurement of paracetamol and dopamine, with the modified electrode exhibiting relatively high sensitivity, selectivity, and stability. The applicability of the developed method to determine the drug in pharmaceutical samples (tablets) is also illustrated.