Gold nanoparticles stabilized by sulfonated imidazolium salt for the manufacture of modified electrodes in order to electrochemical detection of indomethacin

Abstract

Modified carbon paste electrode (MCPE) was manufactured employing gold nanoparticles (Au-NPs) stabilized by 1-(3-sulfonatopropyl)imidazolium. The modification of carbon paste electrode (CPE) was carried out -quickly and simply- without separating the Au-NPs from the reaction medium. The Au-NPs were characterized by routine techniques such as UV–visible spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS) and, zeta potential (ZP). The Au-NPs obtained are quasi-spherical with a size of around 10 nm and a high surface area which made excellent NPs with catalytic properties. The MCPE was used as an electrochemical sensor for commercial indomethacin (Ind) detection. Under optimum conditions, the sensor presented a linear response in the 1.0 × 10-7 – 1.0 × 10-4 M concentration range, good detection sensitivity and, a low detection limit of 0.68 nM of Ind. The proposed sensor -with good stability and sensitivity- was also employed in capsules and injectables of commercial origin with excellent percentage recoveries. The electrochemical sensor modified by employing Au-NPs have a high confidence level and this was simple to make, convenient, cost-effective, and traceable as an alternative method for the determination of Ind in commercial samples.