IDENTIFICATION OF SWEET CHERRY ANTHOCYANINS AND
HYDROXYCINNAMIC ACIDS USING HPLC COUPLED WITH DAD AND MS DETECTOR
Branka Mozetič and Polonca
Trebše
Nova Gorica Polytechnic, Laboratory for Environmental Research,
P.Box. 301, Nova Gorica
5001-SI,
Abstract
In absence of standards, HPLC coupled with DAD offers
identification of polyphenols by scanning UV-Vis spectra of individual components, which spectral
characteristics are unique, but not selective. At the same time HPLC-DAD
determination methods of polyphenols differ in mobile
phase solutions resulting in DAD scanned spectra deviation between different
studies, aggravating the precise identification based on agreement to UV-Vis data from literature. Mass spectrometry (MS) detection
with molar weight determination of the individual components in the sample
enables more precise identification of compounds eluted from the column. Sweet
cherry Petrovka polyphenols
were separated on C18 Hypersil PEP 300 column (250 x
4.6 mm, 5μm) using gradient solvent mixture consisting of methanol, water
and formic acid. MS and UV-Vis spectra of eluted anthocyanins and hydroxycinnamic
acids were recorded. HPLC-MS analyses were performed using a LCQTM
ion trap, Finnigan, MAT mass spectrometer by
atmospheric pressure chemical ionisation (ACPI).
Molecular and fragmented ion masses of sweet cherry hydroxycinnamic
acids and anthocyanins were determined and with UV-Vis spectra, in the range of 190-600 nm, used for
identification of compounds. Electro spray mass spectrum of two hydroxycinnamic acids produced ions with m/z ratios of
353.0 and 337.0, which corresponded to molecular weights of neochlorogenic
acid and 3’-p-coumarylquinic acid. The molecular weights of 5 anthocyanins corresponded to cyanidin-3-glucoside (449.0),
cyanidin-3-rutinoside (595.1), peonidin-3-glucoside (463.1),
pelargonidin-3-rutinoside (579.1) and peonidin-3-rutinoside (609.2).
Key words: sweet
cherries, anthocyanins, hydroxycinnamic
acids, HPLC-DAD/MS