Improving the performance of electrochemical sensors by means of synergy. Combinations of gold nanoparticles and phthalocyanines

Abstract

Voltammetric sensors chemically modified with combinations of two electrocatalytic materials: tetraoctylammonium bromide capped gold nanoparticles (AuNPNBr) and a sulphur containing zinc phthalocyanine derivative (ZnPcRS) are reported. The electrocatalytic effects in the detection of catechol have been analyzed in sensors obtained by direct mixing (AuNPNBr/ZnPcRS) and in sensors modified with an adduct where both components are linked covalently (AuNPNBr-S-ZnPcR). Results demonstrate that the nature of the interaction between both components modifies the electrocatalytic properties. The AuNPNBr/ZnPcRS mixture improves the electron transfer rate of the catechol reduction, with limits of detection of 10−6 M. The covalent adduct AuNPNBr-S-ZnPcR enhances the response rate of the oxidation of the catechol with limits of detection of 10−7 M.