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For the first time, application of a membrane composed of gold nanoparticles decorated with complexing ligand for potentiometric sensing is shown. Gold nanopartides drop cast from a solution form a porous structure on a substrate electrode surface. Sample cations can penetrate the gold nanoparticles layer and interact with ligand acting as a charged ionophore, resulting in Nernstian potentiometric responses. Anchoring of complexing ligand on the gold suthce abolishes the necessity of ionophore application. Moreover, it opens the poss~biity of preparation of potentiometric sensors using chelators of significantly different selectivity patterns further enhanced by the absence of polymeric membrane matrix. This was clearly seen, for example, for gold nanoparticles stabilizing the applied ligand-dithizone-thiol conformation leading to a high potentiometric selectivity toward copper ions, much higher than that of lonophores typically used to induce selectivity for polymeric ion-selective membranes. [ABSTRACT FROM AUTHOR]