LC–MS analysis of anthocyanins from purple corn cob

Liquid chromatography coupled with diode array spectrophotometry and mass spectrometry detection (LC–DAS–MS) has been applied to the study of the anthocyanin composition of a commercial extract from purple corn cob used as a colourant additive in the food industry. Nine different anthocyanins were isolated using semipreparative HPLC and identified by LC–MS and hydrolytic techniques. Useful information for the identification of compounds was also obtained from their fragmentation patterns (MS–MS spectra). Six of these anthocyanins seem to be present in the original cob, namely cyanidin‐3‐glucoside, pelargonidin‐3‐glucoside, peonidin‐3‐glucoside and their respective malonyl derivatives. The other three are produced during the industrial extraction process and have been identified as the corresponding ethylmalonyl derivatives. © 2002 Society of Chemical Industry