Qualitative and Quantitave Determination of Silver in Silverex - Antimicrobial Cream Using Bentonite Modified Carbon Graphite Working Electrode

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Published: 2022-03-14

Page: 151-161


Duke Omondi Orata *

Department of Chemistry, University of Nairobi, P. O. Box 30197-00100, Nairobi, Kenya.

Dorcas Gathoni Ngigi

Department of Chemistry, University of Nairobi, P. O. Box 30197-00100, Nairobi, Kenya.

David Kariuki

Department of Chemistry, University of Nairobi, P. O. Box 30197-00100, Nairobi, Kenya.

*Author to whom correspondence should be addressed.


Abstract

The results presented in this paper shows that surface modified electrode technique can be used to qualitatively and quantitatively detect the presence of silver redox active moiety in silverex a topical broad spectrum antibiotic (SC).

The results indicate that when the silver containing topical cream is spin coated on the carbon graphite working electrode surface, the latter displays the properties of the immobilized SC.

When bentonite a clay montmorillonite characterized by the prescence of octahedral and tetrahedral sites was used as host matrix, the electrochemical signal of the silver in SC was significantly enhanced. The enhanced redox activity is proposed to result from isomorphous substitution of the silver redox moiety in the octahedral layer leading to pre-concentration of the redox active moiety hence enhanced redox signal.

The voltammetric data obtained from bentonite modified carbon graphite working electrode yielded the surface coverage  for the silverex topical in the 20gm tube . From the data there was 0.25g silver in the 20gm silverex ionic gel, corresponding to 0.22% silver compared manufacturers specification of 0.2%.

The results obtained from scan rate variation studies suggest that the STC is neither completely a surface attached species neither is its redox process diffusion controlled.

The p-Aminophenol has been shown to strongly influence the redox properties of STC and is proposed to act as an electro-catalyst by removing the oxidative stress associated with the oxidation –reduction of silver in SC.

The redox properties of SC are shown to be unaffected by change in supporting electrolyte solution pH, therefore does not depend on protonation-deprotonation equilibrium.

Polyaniline as a host matrix suppresses significantly the redox activity of the silver in the SC.

Keywords: Cyclic voltammetry, Surface Modified Electrodes, Electrocatalyst, Host-Matrix, Bentonite, p-Aminophenol


How to Cite

Orata, D. O., Ngigi, D. G., & Kariuki, D. (2022). Qualitative and Quantitave Determination of Silver in Silverex - Antimicrobial Cream Using Bentonite Modified Carbon Graphite Working Electrode. Asian Journal of Pure and Applied Mathematics, 4(1), 151–161. Retrieved from https://globalpresshub.com/index.php/AJPAM/article/view/1499

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