Capillary electrophoresis separation of rosemary antioxidants from subcritical water extracts

In this work, the possibilities of the combined use of subcritical water extraction (SWE) and capillary electrophoresis (CE) are established through the separation of antioxidants from rosemary (Rosmarinus officinalis L.). A new CE method is developed that allows the separation of different antioxidants found in the SWE fractions. The CE method is reproducible, efficient and fast, allowing the analysis of complex rosemary extracts in less than 16 min. The CE method is compared with a published reversed-phase high-performance liquid chromatography (RP-HPLC) procedure, both using diode-array detection. The main advantages of CE compared with HPLC are its higher resolving power and its different selectivity, which is demonstrated to be useful for the detection of some very polar compounds that cannot be analyzed by RP-HPLC. Moreover, the possibilities of the CE approach for following the degradation of antioxidants is also demonstrated. To our knowledge, this is the first work showing the high potential of the combined use of SWE and CE.