A NOVEL AND RAPID METHOD FOR THE SPECTROFLUOROMETRIC DETERMINATION OF CURCUMIN IN CURCUMIN SPICES AND FLAVORS

A sensitive and rapid spectrofluorometric method for determination of microamounts of curcumin in curcumin spices and related flavors has been developed. It involves dissolving curcumin samples in dry acetone, irradiating the resulting clear solution at λE = 424 nm, and measuring the stable intense green-yellow fluorescence at λF = 504 nm. The fluorescent solution shows no change in λE or λF or in fluorescence intensity for at least 1 month under ambient conditions. Beer's law is followed over the range 0.0-500 ppb of curcumin. The sensitivity and detection limit ( S N = 2) are 4.7 and 0.34 ppb of curcumin per fluorescence unit, respectively. The RSD and recovery for a series of concentrations (0.01-0.3 ppm) are 1.13-2.03 and 98.96-100%, respectively. Temperature control is needed; pH adjustment and O2 removal from test solution are unnecessary. Under the specified conditions, water is the only quencher for curcumin fluorescence. Direct calibration determination is satisfactory and therefore there is no need to use a rather lengthy standard additions technique. © 1992.