Analysis of anthocyanins in strawberries and elderberries. A comparison of capillary zone electrophoresis and HPLC

Abstract

Anthocyanins in strawberry and elderberry extracts were separated by reverse phase HPLC at pH 1.8, and compared with separations achieved by capillary zone electrophoresis using a standard silica capillary and pH 8.0 running buffer. HPLC separated all the anthocyanins in both extracts, although the similar characteristics of the anthocyanins in the elderberry extract made this the more difficult separation. CZE separation of strawberry anthocyanins was of a quality comparable with results obtained with a standard anthocyanin mixture. Elderberry pigments gave a poorer electropherogram, possibly due to additional interfering compounds in the extract. A greater sample concentration (87 times) was required for equivalent CZE response compared with HPLC, due mainly to the much smaller introduction volume, the shorter detector cell path-length and the small proportion of coloured anthocyanin species present at pH 8.0. The results indicate that under these conditions, HPLC has more advantages, but CZE has potential, particularly if methodology for working with strongly acidic buffers becomes available.