Abstract: A micellar electrokinetic chromatography-mass spectrometric method based on laurel acyl malic acid ester (LMAE) for the separation and determination of coptisine, berberine, jatrorrhizine, phellodendrine and ligustrazine in Niuhuang Shangqing Tablets was established. The baseline separation of the five compounds was attained within 18 min by an uncoated capillary (88 cm×50 μm) on the operating voltage of 25 kV using 7.5 mmol/L LMAE-15 mmol/L ammonia-50 mmol/L ammonium acetate mixture (pH=7.0) containing 12.5% (v/v) acetonitrile as the electrophoretic medium and 50% 2-propanol aqueous solution (containing 3 mmol/L acetic acid) as the sheath liquid. The peak area of each component to its concentration showed a good linear relationship. The relative standard deviations of migration times and peak areas of the five components were less than 5% and the recoveries were between 96.0% and 105%. The developed method is simple, rapid, accurate and is suitable for the routine analysis of the five alkaloid components in Niuhuang Shangqing Tablets.

Key words: alkaloids, electrospray ionization-mass spectrometry (ESI-MS), laurel acyl malic acid ester, Niuhuang Shangqing Tablets, micellar electrokinetic chromatography (MEKC)