Potential of Capillary Electrophoresis for the Profiling of Propolis

Abstract

The usefulness of capillary electrophoresis (CE) with diode array detection for the profiling of Propolis, a hive product, is investigated. Water extracts of Propolis were analyzed with both capillary zone electrophoresis (CZE) at pH 7.0 and 9.3, and micellar electrokinetic chromatography (MEKC) with sodium dodecyl sulfate at pH 9.3. Characteristic profiles were obtained and several organic acids and preservatives could be identified by means of library comparison of the recorded UV spectra combined with addition of reference compounds to the extracts. The selectivity of the CZE and MEKC system differed considerably but the information obtained with both methods was similar. The dry residues of the water extraction were extracted with ethanol-water (70 : 30, v/v) and analyzed with the MEKC system to enable the separation of the more hydrophobic constituents of the Propolis samples. Complex profiles containing various well separated peaks were obtained allowing the identification of some interesting flavonoids. On the basis of the recorded CZE and MEKC profiles, the Propolis samples could be divided into two clearly different groups which are probably from a different origin.