Combined use of supercritical fluid extraction, micellar electrokinetic chromatography, and reverse phase high performance liquid chromatography for the analysis of antioxidants from rosemary (Rosmarinus officinalis L.)

Antioxidants from rosemary were determined by the combined use of supercrit ical fluid extraction (SFE) prior to reverse-phase high-performance liquid chromatography (RP-HPLC) or micellar electrokinetic chromatography (MEKC). The separation of antioxidants found in the SFE fractions was achieved by u sing a new MEKC method and a published HPLC procedure, both with diode arra y detection. The characterization of the different antioxidants was further done by HPLC-mass spectrometry. Advantages and drawbacks of HPLC and MEKC for analyzing the antioxidants found in the different extracts are discusse d. From the results it is concluded that HPLC renders higher peak area and is better in its reproducibility than MEKC; both techniques provide similar analysis time reproducibility. The main advantage of MEKC is its much high er separation speed, which is demonstrated to be useful for the quick adjus tment of SFE conditions, allowing rosemary fractions of higher antioxidativ e power to be obtained quickly. Moreover, the possibilities of this approac h for following the degradation of antioxidants are discussed.