Normal-phase high-performance liquid chromatographic separation of procyanidins from cacao beans and grape seeds

[EN ]An HPLC method using a normal-phase silica column and a gradient of dichloromethane-methanol-formic acid-water mixtures as the eluent was developed to separate procyanidins on a molecular mass basis, without derivatization. It was successfully applied to the analysis of procyanidin extracts from cacao beans and grape seeds. The monomers and major dimers were resolved as discrete peaks. Oligomeric and polymeric components were eluted in order of increasing degree of polymerization, as confirmed by determining the average molecular mass of successive fractions collected from the normal-phase column using gel permeation chromatography, after acetylation