Analysis of iridoid glycosides from Picrorhiza kurroa by capillary electrophoresis and high performance liquid chromatography - Mass spectrometry

A micellar electrokinetic chromatography (MEKC) method was applied to the a nalysis of iridoid glycosides of Picrorhiza kurroa ROYLE EX BENTH. Baseline separation was achieved within 16 min using a fused silica capillary and a berate buffer solution (100 mM, pH 8.60) containing 30 mM SDS and 1% aceto nitrile. The applied voltage was 25 kV,the thermostating temperature was ke pt constant at 30 degreesC. Injection was performed in the pressure mode fo r 2 s, the detection wavelength was 205 nm. For optimization of the CE meth od an iridoid-containing fraction of a methanolic extract of Fl kurroa was injected. The impact of the electrolyte composition, the pH value, the ioni c strength, the concentration of SDS, the influence of organic additives, t he voltage and the temperature on resolution of adjacent peaks was studied. The optimized method was used for quantitative determination of the main i ridoids in crude methanolic extracts of Fl kurroa. Analysis was also performed by HPLC-MS using an electrospray ionization (ES I) interface. Conditions were optimized both for efficient HPLC and for the MS system. Mass spectra of all HPLC peaks showed one dominant signal corre sponding to [M+Na](+). The good agreement of quantitative CE results with t hose obtained by LC clearly demonstrated the applicability of the presented methods.