RESOLUTION OF COMPLEX-MIXTURES OF NONFLAVONOID POLYPHENOLS BY COLUMN-SWITCHING HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY USING OCTADECYLSILICAAND GRAPHITIZED CARBON COLUMNS

Differences in the retention capacity and selectivity of C-18 and grap hitized carbon columns were used to resolve complex mixtures of non-fl avonoid polyphenols by transferring fractions between columns arranged in a serial manner. Separation of mixture components was accomplished in a single switching operation by using mobile phases of the same co mposition but at different eluting strength in both separation steps. The elution conditions used in both columns were simplified by means o f simulation software in order to obtain multiple fractions. The poten tial of this technique was realized by resolving a mixture of 38 very similar species that could not be separated with an isolated column.