Infrared and Nuclear Magnetic Resonance Spectrometry of Caffeine in Roasted Coffee Beans after Separation by Preparative Supercritical Fluid Chromatography

Abstract

The isolation of caffeine from coffee powder was performed using supercritical fluid extraction (SFE) and preparative supercritical fluid chromatography (SFC). Two grams of roasted coffee bean powder gave 0.49g of extract using supercritical carbon dioxide (40°C, 200kg/cm2) as an extractant. This extract was mixed with 0.6ml of methanol and after decantation, 0.2ml of the supernatant was subjected to preparative SFC. Fractionation was carried out with referring to the retention time of the standard caffeine. After evaporation of ethanol added as a modifier from the collected fraction, a 7-8mg of needle-like crystals was obtained. This crystal was identified to be caffeine by FTIR and by FT-NMR, respectively.