Chromatographic separation
was performed on a Synergi 4 lm MAX RP C12 column
(250 mm 2.0 mm i.d.) equipped with a 5 lm C12 guard column
(4.0 mm 2.0 mm i.d.), both from Phenomenex (Torrance, CA,
USA), with mobile phases consisting of A; formic acid/water (2/
98, v/v) and B; acetonitrile. The phenolic compounds were identified
based on their UV–vis spectra (220–600 nm), mass spectra and
retention times relative to external standards and comparison with
previous results