Abstract: A method for Monacolin K determination in red fermented rice based on micellar electrokinetic capillary chromatography has been developed. The assay conditions including pH and the concentration of running buffer, organic additive, the concentration of sodium dodecyl sulfate （SDS）, and the separation voltage were optimized. Under the optimized conditions (20 mmol/L borate buffer (pH 10.6, containing 10%(v/v) methanol, 40 mmol/L SDS), the Monacolin K can be separated within 23 min, with the linear working range of 5.00~100.00 mg/L (r2=0.9976) and a limit of detection (S/N=3) of 0.13 mg/L. It had good recoveries (98.5%~99.5%) and the relative standard deviations lower than 3%. The method is simple, rapid, sensitive, highly reproducible and can be successfully applied in the determination of Monacolin K in red fermented rice.

Key words: Monacolin K, red fermented rice , micellar electrokinetic capillary chromatography (MEKC)