Abstract: A pressurized capillary electochromatography with gradient elution for simultaneous separation of five active anthraquinone compounds in Chinese herb rhubarb extracts has been proposed. The experimental results show that under the optimal conditions the five anthraquinone compounds of Rhein, Aloe-emodin, Chrysophanol, Emodin and Physcion in Chinese herb Rhubarb extracts can be completely separated in 22 min. The column efficiency obtained by capillary electrochromatography with gradient elution is 4.6 times that by μ-HPLC with gradient elution, and the latter is 6.63 times that by μ-HPLC with isocratic elution. The developed method hasthe advantages of higher separation capacity, faster separation rate and less consumption of samples and solvents compared with previously reported HPLC and CE methods, and thus may be applied to the separation and determination of active components in complex matrix systems.

Key words: Capillary electrochromatography, Gradient elution, Chinese herb Rhubarb, Anthraquinone compounds