Sensing of paracetamol in the presence of dopamine using an electrochemically polymerized l-alanine layered carbon nanotube sensor

The current research work introduces the development of a modest and green electrochemical sensor for the analysis of paracetamol (PCA) and dopamine (DA), using a polymerized l-alanine layered carbon nanotube paste electrode [(L-AN)LCNTPE]. The constructed sensor, comparing both (L-AN)LCNTPE and a bare carbon nanotube paste electrode [BCNTPE], enhancing electro-analytical performance. The electrochemical responses of PCA were studied using different methods, including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and scanning electron microscopy (SEM) were employed to study PCA electrochemical responses and characterize the working electrode surface. PCA investigation in 0.2 M phosphate-buffered solution (PBS) at pH 7.0 using the Poly (L-AN)LCNTPE showed high electrocatalytic activity and more active spots compared to BCNTPE. pH variation from 5.5 to 8.0 showed optimum performance at pH 7.0, shows superior current response in a 0.2 M PBS. At pH 7.0, scan rate effects (0.025 to 0.65 V/s) and PCA absorption, along with simultaneous DA detection on (L-AN)LCNTPE, were studied. The results indicated pH-controlled, adsorption-proceeded redox behaviour of PCA on (L-AN)LCNTPE. The sensor detected PCA in the range of 0.2 µM to 100.0 µM, with a low detection limit of 1.0 × 10^–7 M and a low quantification limit of 3.5 × 10^–7 M. The (L-AN)LCNTPE shows good stability, reproducibility, and repeatability, in PCA detection. The applicability in medicinal samples (tablets) was also studied.