LC-DAD-ESI/MS analysis of flavonoids and abscisic acid with chemometric approach for the classification of Slovenian honey

The flavonoid profiles of seven types of Slovenian honey were analysed. The flavonoids are phenolic compounds that have health-related properties, and their presence in honey is attributed to the plants visited by the bees. The flavonoids were extracted from honey samples by solid-phase extraction and analysed by liquid chromatography, with diode array detection and electrospray ionisation mass spectrometry (LC-DAD-ESI/MS). The honey samples had similar, but quantitatively different, flavonoid profiles. The flavonoids myricetin, luteolin, quercetin, naringenin, apigenin, kaempferol, pinocembrin, chrysin and galangin were identified using reference standards, while pinobanksin was tentatively identified through its retention time, m/z, UV spectrum and MS/MS data. Two non-phenolic compounds were also identified; cis–trans-abscisic acid and, tentatively, trans–trans-abscisic acid. The analysis did not show any specific compounds to use as markers for determination of the botanical origins of these different types of Slovenian honey. Further analyses of more honey samples with additional standards are needed to identify such potential markers, although linear discriminant analysis correctly classified 85% of these honey samples according to their botanical origins.