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

Navolotskaya DV, Toh HS, Batchelor-McAuley C, Compton RG - ChemistryOpen (2015)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Saint Petersburg State University Universitetskaya nab.7-9, Saint Petersburg, 199034, Russia.

ABSTRACT
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.

No MeSH data available.


The oxidation of silver in 0.1 m NaNO3 at a scan rate of 0.05 V s−1. Black: Silver-nanoparticle-modified glassy carbon electrode. Red: A silver macro electrode. Inlay: A close up of the voltammogram.
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fig01: The oxidation of silver in 0.1 m NaNO3 at a scan rate of 0.05 V s−1. Black: Silver-nanoparticle-modified glassy carbon electrode. Red: A silver macro electrode. Inlay: A close up of the voltammogram.

Mentions: In order to ensure information on silver oxidation is easily obtained, a silver-nanoparticle-modified glassy carbon electrode is used instead of a silver macro electrode. As seen in Figure 1 (black line), in the absence of phosphate ions, a silver macro electrode oxidised in sodium nitrate gives a large current that increases indefinitely. However, with a silver-nanoparticle-modified electrode, a clear silver oxidation signal is seen at 0 V versus mercury/mercurous sulfate reference electrode (MSE) because the amount of silver is limited.10 Therefore, all experiments are performed with silver-nanoparticle-modified electrodes with similar silver coverages to ensure the ease of determining the silver oxidation peak potential. With the information on oxidation potential, the influence of phosphates on silver oxidation can be studied. In addition, the usage of silver nanoparticles also ensures a large surface area for silver–phosphate interaction to take place.


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

Navolotskaya DV, Toh HS, Batchelor-McAuley C, Compton RG - ChemistryOpen (2015)

The oxidation of silver in 0.1 m NaNO3 at a scan rate of 0.05 V s−1. Black: Silver-nanoparticle-modified glassy carbon electrode. Red: A silver macro electrode. Inlay: A close up of the voltammogram.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4608526&req=5

fig01: The oxidation of silver in 0.1 m NaNO3 at a scan rate of 0.05 V s−1. Black: Silver-nanoparticle-modified glassy carbon electrode. Red: A silver macro electrode. Inlay: A close up of the voltammogram.
Mentions: In order to ensure information on silver oxidation is easily obtained, a silver-nanoparticle-modified glassy carbon electrode is used instead of a silver macro electrode. As seen in Figure 1 (black line), in the absence of phosphate ions, a silver macro electrode oxidised in sodium nitrate gives a large current that increases indefinitely. However, with a silver-nanoparticle-modified electrode, a clear silver oxidation signal is seen at 0 V versus mercury/mercurous sulfate reference electrode (MSE) because the amount of silver is limited.10 Therefore, all experiments are performed with silver-nanoparticle-modified electrodes with similar silver coverages to ensure the ease of determining the silver oxidation peak potential. With the information on oxidation potential, the influence of phosphates on silver oxidation can be studied. In addition, the usage of silver nanoparticles also ensures a large surface area for silver–phosphate interaction to take place.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Saint Petersburg State University Universitetskaya nab.7-9, Saint Petersburg, 199034, Russia.

ABSTRACT
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.

No MeSH data available.