New voltammetric sensing technique for determination of paracetamol by l-phenylalanine based carbon paste electrode

In this work, the carbon paste electrode was electro-polymerized using l-phenylalanine in 0.2 M phosphate buffer solution of pH 8.0. This l-phenylalanine modified carbon paste electrode (PLPAMCPE) was used for the study of paracetamol (PCL). The modified electrode was characterized by cyclic voltammetry, differential pulse voltammetry (DPV), scanning electron microscopy, and electrochemical impedance spectroscopy. The PLPAMCPE showed an excellent current response towards the oxidation of PCL. During the pH study ranging from 5.0 to 8.0 pH, pH 6.0 showed high peak current hence considered as the optimum pH. The scan rate study showed that the reaction was adsorption-controlled reaction. Further study i.e., by varying concentration of PCL in the linear range of 1.2 µM to 12 µM, the current increases linearly. The limit of quantification of 18.2 μM and the limit of detection of 5.4 μM was obtained for the DPV method. The study also showed that the presence of different metal ions did not hinder the PCL analysis. The developed electrode showed good repeatability, stability, and reproducibility. Simultaneous study of PCL with dopamine shows good selectivity for PCL. This method is desirable due to its quickness, low cost, ease of handling, and its applicability to real sample.