Separation and Determination of Phenylpropanoid Glycosides in Rhodiola by Microemulsion Electrokinetic Chromatography

A novel microemulsion electrokinetic chromatography (MEEKC) method for the simultaneous separation and quantitative determination of phenylpropanoid glycosides in Rhodiola L. was developed. The effects of many parameters influencing separation characteristics were optimized. Retention factor met rosarin<rosavin<rosin at the same 2-propanol concentration. Both selectivity and resolution of rosarin and rosavin increased with increasing 2-propanol content. The similar chemical structure led to a small difference in theoretical plates. The resolution of rosarin and rosavin showed greater improvements than rosavin and rosin with increasing buffer pH. According to the separation characteristics, the optimal running buffer was determined: 80 mmol/L sodium dodecyl sulfate, 1.0% n-heptane, 7.5% 1-buatnol, 22.5% 2-propanol, and 10 mmol/L sodium borate buffer at pH 9.25. Validation showed that this simple MEEKC method possesses feasible accuracy and precision. Furthermore, the developed method successfully quantified three phenylpropanoid glucosides in the Rhodiola rosea sample extracts and three oral liquids.