Surfactant-Modified Discharged Battery and Carbon Nanotube Composite Paste Electrode for the Analysis of Paracetamol

An electrochemical technique had been developed in this work for the selective and sensitive detection of paracetamol (PC) and levofloxacin (LF) by modifying a bare discharged battery and carbon nanotube composite paste electrode (BDCNCPE) using surfactant cetyl trimethylammonium bromide (CTAB). The surfactant-modified discharged battery and carbon nanotube composite paste electrode (SMDCNCPE) achieved optimal detection with a quasi-reversible peak in a 0.2 M phosphate buffer solution (PBS) at pH 7.0. Characterization of both the BDCNCPE and SMDCNCPE was carried out using techniques such as scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), linear sweep voltammetry (LSV), RAMAN study, and differential pulse voltammetry (DPV). SEM and EDX analysis of morphological characteristics confirmed surface modification by the development of uniform surfactant layers. CV with K4[Fe(CN)6] and KCl as a redox probe for electrochemical characterization revealed improved electron transfer and a larger electroactive surface area at the modified electrode. The sensor effectively identified possible interferences from different metals and organic compounds, with scan rate analysis indicated an adsorption-controlled process. The effects of pH and concentration variations were also thoroughly investigated. The SMDCNCPE displayed excellent electrochemical properties, showing a linear range from 10 to 320 mu M, with a 0.091 mu M limit of detection (LOD) and a 0.3 mu M limit of quantification (LOQ), as well as good stability, repeatability, and reproducibility.