Standard procedure to determine the Percentage of caffeine in coffee seeds by UV/Vis Spectrophotometer
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Date
2005-07
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Addis Ababa University
Abstract
In this work using UV/Vis spectrophotometer the electronic transition properties of caffeine
are investigated. The molar decadic absorption coefficients of caffeine in water and
dichloromethane are 1112 m2 mole'1, 1010 m2 mole'1 respectively obtained. From the
experimental results the transitional dipole moment of caffeine in water 11.50 xlO'30 C m and
in dichloromethane 10.8OxlO'30 C m respectively calculated . In addition, fast and simple
methods are developed that enable to quantify the contents of caffeine in coffee seeds. The
methods are extracting caffeine from coffee solution by dichloromethane and apply Gaussian
fit to remove the possible interferences with the caffeine spectra . The results obtained using
our teclmiques are compared with HPLC and found to be similar. The methods have a good
application for identifying decaffeinated coffee seeds which are discovered in Ethiopia
Key words: caffeine, extract, absorbance, UV/Vis spectrophotometer
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Keywords
Key words: caffeine, extract, absorbance, UV/Vis spectrophotometer