Eletrodo impresso com estêncil utilizando tinta condutora à base de grafite para a determinação eletroquímica de paracetamol em fármaco

Abstract

Paracetamol (PAR) is a widely used pharmaceutical compound with analgesic and antipyretic properties and is considered safe and effective when administered within the recommended dosage. However, excessive intake may lead to severe toxic effects, such as hepatotoxicity and nephrotoxicity, which makes the development of reliable analytical methods for its monitoring essential. In this context, this study presents the development of electrochemical sensors fabricated by serigrafia using a conductive ink composed of graphite powder and alkyd varnish (30:70% ratio) for the detection of PAR by differential pulse voltammetry (VPD). The electrochemical behavior of PAR was investigated with different pH values (4.0–8.0) using cyclic voltammetry (VC) and a 0.1 mol L−1 phosphate buffer, with pH 8.0 identified as the optimal condition. The instrumental parameters of the technique were optimized, resulting in a pulse amplitude of 60 mV, a potential step of 6 mV, and a modulation time of 30 ms. The developed method exhibited a good linear working range from 4.34 to 21.0 μmol L−1, with limits of detection and quantification of 1.34 μmol L−1 and 4.16 μmol L−1, respectively. In addition, repeatability studies (n = 10, RSD < 3%) demonstrated excellent precision, while recovery rates ranging from 87% to 95% at two fortification levels (7.5 and 12.5 μmol L−1) in pharmaceutical samples confirmed the accuracy of the method. Therefore, the developed procedure proved to be suitable for the quantification of PAR in pharmaceutical formulations, highlighting the use of a sensitive electrochemical method with simple instrumentation and low cost.