Immobilization of stable catechol form on the SPCE surface to enhance hydrophilicity, reusability, and application for acetaminophen analysis

Abstract

This study presents the development and application of a modified screen-printed carbon electrode (SPCE) incorporating carboxylated multi-walled carbon nanotubes (MWCNT-COOH) and catechol (CA) for the electrochemical analysis of acetaminophen (ACAP). The use of CA, in combination with ultrasonic treatment, significantly improved the dispersion of MWCNT-COOH in aqueous media and promoted the formation of a stable, hydrophilic surface layer on the electrode. This modification not only enhanced the sensitivity of the sensor but also introduced a key advantage: the ability to reuse the SPCE multiple times without surface fouling or performance degradation. Differential pulse voltammetry (DPV) was employed to evaluate the electrochemical behavior of ACAP on the modified electrode, demonstrating a wide linear response range from 0.05 µM to 250 µM, with a detection limit of 15 nM and a quantitation limit of 58 nM. The selectivity of the sensor was confirmed in the presence of common tablet excipients, showing minimal interference. The method was successfully applied to the determination of ACAP content in commercial Tylenol tablets, with results (495.8 ± 1.6 mg) closely matching the declared dosage. These findings establish the modified SPCE/MWCNT-COOH/CA-U platform as a highly promising sensing tool, characterized by its simple preparation procedure, high sensitivity and selectivity, excellent stability, cost-effectiveness, and reusability, offering substantial benefits for routine pharmaceutical analysis.