A novel electrochemical imprinted sensor for acetylsalicylic acid based on polypyrrole, sol-gel and SiO2@Au core-shell nanoparticles

A new nanocomposite imprinted electrochemical sensor was developed for sensitive and selective determination of acetylsalicylic acid (ASA), based on a gold electrode modified with one-step electropolymerization of the molecularly imprinted polymer (MIP) composed from polypyrrole (ppy), sol-gel, Silica@Gold core-Shell nanoparticles (SiO2@AuNPs) and acetylsalicylic acid. SiO2@AuNPs were introduced into the polymer matrix for the enhancement of electrical response of [Fe(CN)6]3−/[Fe(CN)6]4− redox pair which was used as an electrochemical active probe. The SiO2@AuNPs, were synthesized chemically by using a modified Stober method and they were characterized by UV-Vis spectrophotometry, Fourier transform infrared (FT-IR) spectrometry, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Under the optimized experimental conditions, two linear concentration ranges from 1.0 to 10.0 nM and 10.0-100.0 nM with a limit of detection (LOD) of 0.2 nM was obtained. The effects of interfering species on the determination of ASA were investigated and it was found that the proposed sensor has a high recognition capacity towards the ASA in the presence of interfering species in solutions. Moreover, the reproducibility, repeatability and stability of the imprinted sensor were all found to be satisfactory. Finally, the modified electrode was successfully applied for determination of ASA in tablet and urine samples.