Optical And Thermal Properties Of Coffee And Caffeine

In this project, the thermal and optical propeliies of coffee and caffeine are investigated.rnCharacteristics involved are solvatochromic effect, fluorescence, chemical structures (bonds) andrnthermal propeliies of both coffee and caffeine. The UVNis absorption band of caffeine inrndifferent solvents shows very small solvatochromic effect, indicating only local transitions ofrnelectrons. This founding is similar to that found for QM-calculations. Fluorescencernmeasurements revealed no fluorescence emission by caffeine, but deactivation of fluorescienrnfluorescence intensity. However, simple correlation between the deactivation produced byrncaffeine and coffee on the fluorescence of fluorescein could not be drawn with out the detailedrnknowledge of other components. From FT-IR results, the fluorescence deactivation mechanismrnis found to incorporate carbonyl groups of both caffeine and coffee. The observed thermalrn(TGA) results showed coffee is thermally unstable and decomposes steadly.This shows therninherent discrepancy of the temperature dependent measurement, which makes exactrnmeasurement of caffeine at various temperature intervals unrealistic. The DSC result showsrncrystallization, heat absorption melting and heat release of coffee at various temperature regionsrnKey Words: Coffee, Caffeine, Fluorescence, Solventochromism, Thermal, UVNis

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