Gold nanoparticle/charged silsesquioxane films immobilized onto Al/SiO2 surface applied on the electrooxidation of nitrite

In this work, gold nanoparticles lower than 10?nm were prepared in an aqueous medium using two charged silsesquioxanes, the propylpyridinium chloride and propyl-1-azonia-4-azabicyclo2.2.2]octane chloride, as stabilizer agents which revealed to be water-soluble. This stabilization method is innovative allowing thin films containing gold nanoparticles to be obtained, and it was used for the first time in the preparation of carbon paste electrodes (CPEs). The charged silsesquioxanes were characterized by liquid ¹³C NMR. The gold nanoparticle/silsesquioxane systems were characterized by ultraviolet–visible spectroscopy (UV–Vis) and transmission electron microscopy. In sequence, they were immobilized on silica matrix coated with aluminum oxide. The resulting solid materials designated as Au-Py/AlSi and Au-Db/AlSi were characterized by infrared spectroscopy and N₂ adsorption/desorption isotherms. The results showed that the gold nanoparticle/silsesquioxane systems are strongly adhered to the surface-forming thin films. The Au-Py/AlSi and Au-Db/AlSi materials were used to prepare CPEs for the electrooxidation of nitrite (NO ₂ ^? ) using cyclic voltammetry and differential pulse voltammetry. The Au-Py/AlSi and Au-Db/AlSi CPEs showed high sensitivity and detection limits of 71.87 and 53.66?μA?mmol^–1?L and 1.3 and 3.0?μmol?L^–1, respectively.