A new voltammetric method for a direct determination of gold nanoparticles, based on adsorption and electrochemical detection of colloidal gold, is described. In this protocol, the absorption of gold nanoparticles onto the rough surface of graphite-epoxy composite electrode is followed by their electrochemical oxidation in 0.1 M HCl medium at a potential of +1.25 V. The resulting tetrachloroaurate ions generated near the electrode surface are detected by differential pulse voltammetry (DPV). The DPV response is linear in the range from 4.7 × 108 to 4.7 × 1011 nanoparticles cm-3 with a limit of detection of 1.8 × 10 8 gold nanoparticles cm-3. The surface characteristics of the composite electrode are investigated and the parameters that affect the complete analytical detection process of gold nanoparticles are optimized.
Bibliographical noteFunding Information:
This work was financially supported by MEC (Madrid) (projects BIO2004-02776, MAT2004-05164), by the Spanish “Ramón Areces” foundation (project ‘Bionanosensores’) and the “Ramón y Cajal” program of the Ministry of Science and Technology (Madrid) that supports A. Merkoçi and C. Mills. M.P. acknowledges the support from the NATO NSF.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)