Simultaneous determination of pharmacologically active ingredients in Rhodiola by capillary chromatography with electrochemical detection

Rhodiola, in which there are abundant pharmacologically active ingredients, is one of the functional adaptogenic agent that aid specific bodily functions to adapt to the changes and stress of life in addition to being tonic. In an attempt to qualitatively and quantitatively determine the pharmacologically active ingredients in Rhodiola, a new method based on capillary electrophoresis with electrochemical detection (CE-ED) has been developed. The effects of working electrode potential, pH and concentration of running buffer, separation voltage, applied potential and injection time on CE-ED were investigated. Under the optimum conditions, the analytes could be well separated within 24 min at the separation voltage of 18 kV in a 80 mmol L−1 borax running buffer (pH 9.0). Good linear relationship was established between peak current and concentration of analytes over two orders of magnitude with detection limits (S/N = 3) ranged from 3.16 × 10−7 to 1.11 × 10−7 g mL−1 for all target ingredients. This proposed method has been successfully applied for the analysis of real samples, with satisfactory results.