Dithizone Modified Gold\nNanoparticles Films for Potentiometric Sensing

Abstract

For the first time, application of a membrane composed\nof gold nanoparticles decorated with complexing ligand for potentiometric\nsensing is shown. Gold nanoparticles drop cast from a solution form\na porous structure on a substrate electrode surface. Sample cations\ncan penetrate the gold nanoparticles layer and interact with ligand\nacting as a charged ionophore, resulting in Nernstian potentiometric\nresponses. Anchoring of complexing ligand on the gold surface abolishes\nthe necessity of ionophore application. Moreover, it opens the possibility\nof preparation of potentiometric sensors using chelators of significantly\ndifferent selectivity patterns further enhanced by the absence of\npolymeric membrane matrix. This was clearly seen, for example, for\ngold nanoparticles stabilizing the applied ligand–dithizone–thiol\nconformation leading to a high potentiometric selectivity toward copper\nions, much higher than that of ionophores typically used to induce\nselectivity for polymeric ion-selective membranes.