DETERMINATION OF CURCUMOL IN THE VOLATILE OIL OF CURCUMA AROMATICA

A method for the determination of curcumol in the volatile oil of Gurcuma aromatica by thin-layer chromatography coupled with infrared spectrophotometry is reported. The volatile oil is chromatographed on a silica gel G plate with petroleum ether (30～60℃)-acetone (96:4) as the developer. Under this condition, interfering substances with lower polarity than curcumol-are carried farther from the origin while curcumol is retained near the origin. The curcumol zone, which can be ascertained by its predetermined R_f value, is scraped off from the plate and eluted with CHCl₃. For the quantitative determination of curcumol by infrared spectophotometry, use is made of the absorption peak of vinylidene group in the molecule(out-of-plane bending vibration, 890 cm^-1, 11.24μm) with GCl₄ as the solvent. Since the vinylidene band is specific for curcumol, a complete separation of curcumol from other non-interfering components. is not required. The method is simple and gives accurate and reproducible results. The statistical results show that the average relative deviation of eight determinations is less. than 2%.