期刊
TALANTA
卷 76, 期 4, 页码 742-746出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.talanta.2008.04.042
关键词
1,4-benzoquinone; modified carbon paste electrode; caffeine; voltammetry
资金
- Department of Chemistry, Addis Ababa University
In this paper a simple and highly sensitive electroanalytical method for the determination of caffeine content using 1,4-benzoquinone modified carbon paste electrode is presented. The method is based on suppression of 1,4-benzoquinone peak current on addition of caffeine. Square-wave and cyclic voltammetric techniques were utilised for the investigation. The 1,4-benzoquinone modified electrode exhibited a well-defined peak with reproducible peak current values for repetitive measurements; and showed a decrease in peak current value with an increase in caffeine content. The result revealed two linear range regions between 0 mmol L(-1) and 0.5 mmol L(-1) and 0.5 mmol L(-1) and 8.0 mmol L(-1), with detection limits of 0.3 mu mol L(-1) and 5.1 mu mol L(-1), respectively. The method was then successfully applied to the determination of caffeine content in coffee samples. The effects of pH, electrode composition, step potential, pulse amplitude and square-wave frequency on the voltammetric responses were also investigated. (C) 2008 Elsevier B.V. All rights reserved.
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