Reagents and standards
HPLC grade methanol and acetonitrile were purchased from
Carlo Erba (Italy). Formic and hydrochloric acid were of analytical
grade and obtained from Panreac (Barcelona, Spain). Trifluoroacetic
acid was purchased from Sigma Chemical Co. (St. Louis, MO,
USA). Cyanidin 3-glucoside used as standard was isolated and
characterised in our laboratory.