Voltammetric Study of the Influence of Various Phosphate Anions on Silver Nanoparticle Oxidation.

The antibacterial properties of silver are strongly controlled by the redox couple of silver/silver(I). This work reports the influence of phosphate anions on silver nanoparticle oxidation, which is important given the abundance of phosphate species in biological systems. The three different species of anions were found to have a varying degree of influence on silver oxidation with the order PO4 (3-)>HPO4 (2-)>H2PO4 (-). It was found that in the presence of phosphate anions, the silver oxidation potential shifts to a less positive value, which indicated the increasing ease of the oxidation reaction of silver. Given that the interplay between silver and its cation is crucial to its antibacterial properties and significant concentrations of the HPO4 (2-) anion are present at biological pH (near neutral), it is essential that the influence of the dibasic anion (HPO4 (2-)) on silver oxidation dynamics be considered for biological systems.