Electrospray and tandem mass spectroscopy as tools for anthocyanin characterization

The utility of electrospray and tandem mass spectroscopy (ES-MS and MS-MS) in anthocyanin characterization was tested using different anthocyanin extr acts. Anthocyanins were semipurified by using a C-18 resin, washed with aci dified water followed by ethyl acetate, and recovered with acidified methan ol. Samples were directly injected into a mass spectrometer in either aqueo us or methanolic solutions. The positive charge of anthocyanins favored fas t and effective ES-MS detection of intact molecular ions. Little interferen ce from other compounds was observed when the ethyl acetate cleaning proced ure was used. Tandem mass spectroscopy provided clear and characteristic fr agmentation patterns. The voltage used affected only the proportions at whi ch these fragments were present. ES-MS may be used as a fast procedure for identification of anthocyanins requiring minimal sample preparation. In com bination with HPLC, ES-MS and MS-MS could be very powerful tools for anthoc yanin characterization and monitoring the authenticity of anthocyanin-conta ining fruit juices and vegetable extracts.