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Journal of Analytical Methods in Chemistry - Volume 2017 2017, Article ID 3979068, 8 pages - https:-doi.org-10.1155-2017-3979068

Research ArticleBahir Dar University, P.O. Box 79, Bahir Dar, Ethiopia

Correspondence should be addressed to Meareg Amare

Received 20 January 2017; Accepted 5 March 2017; Published 23 April 2017

Academic Editor: Sibel A. Ozkan

Copyright © 2017 Meareg Amare and Senait Aklog. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Lignin film was deposited at the surface of glassy carbon electrode potentiostatically. In contrast to the unmodified glassy carbon electrode, an oxidative peak with an improved current and overpotential for caffeine at modified electrode showed catalytic activity of the modifier towards oxidation of caffeine. Linear dependence of peak current on caffeine concentration in the range to  mol L

with determination coefficient and method detection limit LoD = 3 s-slope of 0.99925 and  mol L

, respectively, supplemented by recovery results of 93.79–102.17% validated the developed method. An attempt was made to determine the caffeine content of aqueous coffee extracts of Ethiopian coffees grown in four coffee cultivating localities Wonbera, Wolega, Finoteselam, and Zegie and hence to evaluate the correlation between users preference and caffeine content. In agreement with reported works, caffeine contents w-w% of 0.164 in Wonbera coffee; 0.134 in Wolega coffee; 0.097 in Finoteselam coffee; and 0.089 in Zegie coffee were detected confirming the applicability of the developed method for determination of caffeine in a complex matrix environment. The result indicated that users’ highest preference for Wonbera and least preference for Zegie cultivated coffees are in agreement with the caffeine content.





Autor: Meareg Amare and Senait Aklog

Fuente: https://www.hindawi.com/



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