Solid-phase extraction and reversed-phase high-performance liquid chromatography of free phenolic acids in some Echinacea species

A new method is described combining solid-phase extraction (SPE) and reversed-phase high-performance liquid chromatography (RP-HPLC) for the isolation, purification as well as qualitative and quantitative determination of free phenolic acids in six Echinacea species. Plant extracts were purified and phenolic acids isolated on octadecyl and quaternary amine Bakerbond SPE columns; final eluates were analysed by RP-HPLC. Significant differences in the composition and amount of phenolic acids within Echinacea genus have been shown. The method can be used for quick screening analysis of the content of phenolic acids in plant material.