INFRARED AND NUCLEAR-MAGNETIC-RESONANCE SPECTROMETRY OF CAFFEINE IN ROASTED COFFEE BEANS AFTER SEPARATION BY PREPARATIVE SUPERCRITICAL FLUID CHROMATOGRAPHY

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 0.49 g of extract using supercritical carbon dioxide (40-degrees-C, 200 kg/cm2) as an extractant. This extract was mixed with 0.6 ml of methanol and after decantation, 0.2 ml 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 7-8 mg of needle-like crystals was obtained. This crystal was identified to be caffeine by FTIR and by FT-NMR, respectively.