Multi-walled carbon nanotubes–cobalt phthalocyanine modified electrode for electroanalytical determination of acetaminophen

• A sensor based on MWCNT and CoPc for the detection of ACOP was developed.
• The oxidation mechanism of ACOP was investigated by square-wave voltammetry.
• It was performed a comparison between the proposed methodology and the UV–Vis spectrophotometry.
• The results showed that the electroanalytical methodology is suitable for practical applications.

Here we described the development of a simple methodology for quantification of acetaminophen (ACOP) using square-wave voltammetry (SWV). A glassy carbon electrode modified with gold nanoparticles, functionalized multi-walled carbon nanotubes and cobalt (II) phthalocyanine was prepared and characterized with cyclic voltammetry, SWV and electrochemical impedance spectroscopy. The optimum experimental conditions, such as pH, buffer and square-wave voltammetric parameters were investigated. From the data analysis of the optimization of experimental conditions, the oxidation of ACOP was characterized as a quasi-reversible and proton-dependent process, where the reaction mechanism presents the participation of equal number of protons and electrons (two protons and two electrons) and ks value is equal to 59.0 ± 2.5 s− 1. Under the optimized conditions, calibration curves were linear in the concentration range of 1.49 μmol L− 1 to 47.6 μmol L− 1 and 47.6 μmol L− 1 to 107.0 μmol L− 1 with a limit of detection of 0.135 μmol L− 1. Other analytical parameters such as equations of the analytical curves, correlation coefficients, recovery efficiency and relative standard deviation for repeatability and reproducibility experiments were compared to results obtained by the use of UV–Vis spectrophotometry.