Analysis of natural anthocyanins by capillary zone electrophoresis in acidic media

Four natural glycosylated anthocyanins were detected at 520 nm, in their colored flavylium cation form using the capillary zone electrophoresis mode in acidic media. For analyses, 0.25 mM cetyltrimethylammoniumbromide in 160 mM NaH2PO4/H3PO4 as running buffer was used in a 72 cm x 50 mu m internal diameter fused silica capillary column. The pH of the electrophoretic media was of the order of 2.1. It is demonstrated that hydrophobic interactions between the chromophore and the alkyl chain of the surfactant on one hand and influence of the positive charge of the surfactant on the capillary wall on the other hand, are responsible for the detection of the colored flavylium cation form of anthocyanins in acidic media.