Determination of oscillator strength of caffeine and caffeine in tea leaves by the integrated absorption coefficient technique at two different temperatures

Abstract

In this paper, oscillator strength of caffeine in dichloromethane, water, chloroform, and ethyl acetate were calculated in the wave number range of 32, 000 to 41,000cm-1. It was found that oscillator strength of caffeine in dichloromethane, water, chloroform, and ethyl acetate were 0.230 ± 0.001, 0.170 ± 0.0003, 0.114 ± 0.001, 0.150 ± 0.001 respectively. Caffeine content of real tea leaves using integrated absorption coefficient method were also calculated for different samples at two different temperatures. The result agrees with that obtained using Beer’s law with a little less in the case of integrated absorption coefficient technique with higher value at the boiling temperature and smaller extraction time. Key words: Tea leaves, integrated absorption coefficient, caffeine, oscillator strength, UV-visible spectroscopy.