Simultaneous determination of alpha, beta and gamma cyclodextrins by LC

Cyclodextrins (CDs) can be synthesized from starch by cyclodextrin glycosyl transferase (CGTase). This enzyme produces alpha-, beta- and gamma-CDs in v arying proportions. In the production of cyclodextrins, purity as well as y ield are important factors. A precise and reproducible method was developed and validated for the simultaneous determination of alpha-, beta-, and gam ma-CDs. Optimum separation between the three CDs was achieved using a Finep ak amino column with a mobile phase consisting of acetonitrile-water (70.30 , viv) at a flow rate of 1 mi/min. Detection was carried out using a differ ential refractive index detector. The developed method gave good chromatogr aphic resolution of the three components with retention times of 13.16, 16. 83 and 21.74 min for alpha-, beta- and gamma-CDs, respectively. The polynom ial regression data for the calibration plots exhibited good linear relatio nship (coefficient of correlation r = 0.9987 for alpha, r = 0.9986 for beta and r = 0.9998 for gamma-CDs) over a concentration range of 2-10 mg/ml. St atistical analysis proves that the proposed LC method is precise, reproduci ble and accurate for the estimation of alpha-, beta- and gamma-cyclodextrin s. The method can be employed for determination of percent purity as well a s estimation of process yields of the cyclodextrins during the enymatic pro duction. (C) 2000 Elsevier Science B.V. All rights reserved.