Characterization of the gold-catalyzed deposition of silver on graphite screen-printed electrodes and their application to the development of impedimetric immunosensors |
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Authors: | Attila Vig,Xavier Muñ oz-Berbel,Antonio Radoi,Jean-Louis Marty |
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Affiliation: | a Department of Biochemistry, College of Károly Eszterházy, Eger, Leányka u. 6, 3300, Hungary b IMAGES EA 4218 Université de Perpignan Via Domitia, 52 avenue Paul Alduy, 66860 Perpignan Cedex, France |
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Abstract: | This paper describes the characterization of the gold-catalyzed deposition of silver on graphite screen-printed electrodes (SPEs) using electrochemical impedance spectroscopy (EIS) and the application of this approach to the development of impedimetric immunosensors. After applying −0.1 V for 45 s, the amount of electrodeposited silver quantitatively changes the magnitude of two elements of the electrical equivalent circuit: the interface capacitance, Ci, and the charge-transfer resistance, RCT. Better correlations have been found when considering the RCT since this parameter is almost exclusively dependent on the amount of deposited silver under these experimental conditions. This approach has been successfully applied to the development of an impedimetric immunosensor for aflatoxin M1. The RCT magnitude shows good correlation with the amount of gold immobilized on the electrode surface after a competitive assay and thus, with the toxin concentration. This approach has been found sensitive in a wide range of concentrations, from 15 to 1000 free-AFM1 ppt with a limit of detection of 12 ppt. |
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Keywords: | Impedance spectroscopy Immunosensor Colloidal gold nanoparticles Silver deposition Screen-printed electrodes Toxins |
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