Square Wave Voltammetric Determination of Caffeine in Coffee
No Thumbnail Available
Date
2005-07
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa Universty
Abstract
A carbon paste electrode was utilized for monitoring caffeine using square wave
voltammetry (SWV). This method was applied to determine the caffeine levels in some
coffee samples. Optimal experimental conditions for the analysis were found to be as
follows: pH value of 6 for the suporting electrolyte, SW frequency of 30 Hz, SW
amplitude of 40 mV, and step potential of 7 mV. Having these optimum conditions a
linear range was observed with in the concentration of 0 ~ 250 mg/L. For caffeine
concentration of 50 mg/L, the detection limit three times the standard deviation in
measured concentration (n=6) was found to be (10.67μg/mL). This method was applied
for the determination of the caffeine levels in Ethiopian green coffee samples. The
caffeine content of Ethiopian green coffee samples ranged from 0.9 - 1.16 % on dry mass
basis. The quantities are in good agreement with those reported in the literature for
Coffea arabica. The results are also in good agreement with values determined by HPLC
method.
Key words: Square Wave Voltammetry, Coffee, Caffeine and Carbon Paste Electrode
Description
Keywords
Square Wave Voltammetry, Coffee, Caffeine and Carbon Paste Electrode