Analysis of antioxidants from orange juice obtained by countercurrent supercritical fluid extraction,using micellar electrokinetic chromatography and reverse-phase liquid chromatography

Antioxidants from orange juice were determined by the combined use of countercurrent supercritical fluid extraction (CC-SFE) prior to reverse-phase liquic chromatography (RP-LC) or micellar electrokinetic chromatography (MEKC). The separation of antioxidants found in the SFE fractions was achieved by using a new MEKC method and a published LC procedure, both using diode array detection. The characterization of the different antioxidants was further done by LC-mass spectrometry. Advantages and drawbacks of LC and MEKC for analyzing the antioxidants found in the different orange extracts are discussed. Although LC yields higher peak area and slightly better reproducibility than MEKC, the latter technique provides information about the CC-SFE extracts in analysis times 7 times faster than by LC. This analysis advantage can be used for the quick adjustment of CC-SFE conditions, thus providing a fast way to obtain orange fractions of specific composition.