Determination of common ginsenosides in Kang'ai injection by aqueous two-phase extraction with deep eutectic solvents and HPLC-UV/DAD

In this work, four kinds of deep eutectic solvents (DESs), composed of choline chloride (ChCl) and several alcohols, were synthesized and characterized by 1H NMR and FT-IR spectra. Based on DES (ChCl and 1,4-butanediol) and inorganic salt solution (dipotassium phosphate, K2HPO4), aqueous two-phase system (ATPS) coupled with high-performance liquid chromatography has been developed and applied. This method was used for the efficient extraction and determination of eight common ginsenosides (including ginsenoside Rg1, Re, Rf, Rg2, Rb1, Rc, Rb2 and Rd) in the traditional Chinese medicine injection named Kang'ai injection. To achieve optimum extraction performance, the experimental conditions were optimized, including type and amount of DES and salt, ultrasound time, temperature and pH value. In the dynamic linearity range, experimental results showed satisfactory recoveries of analytes ranging from 92.7-110.8% with the relative standard deviations (RSDs) ranging from 1.2-3.9%. It has been proved that DES-ATPS has great potential for determination of active ingredients in traditional Chinese medicine injection as well as samples in other analytical science field.