In this paper, we investigated the fragmentation of the main triterpene acids of apple using an liquid chromatography atmospheric pressure chemical ionization mass spectrometry (LC-APCI-MSn ) approach and high-resolution mass spectrometry (HR-MS) (Q-TOF). Triterpenes were isolated using semipreparative high-performance liquid chromatography, and chemical structures were elucidated by HR-MS and nuclear magnetic resonance spectroscopy. Finally, compounds were used to study MSn behavior in ion trap. Isolated triterpenes present similar structures, bearing carboxyl group linked to C-17 and different substitutions. We observed significant changes in MS2 spectra, which were useful for further compound identification. The observed fragments allowed the discrimination of different derivatives, namely, pomaceic, annurcoic, euscaphic, pomolic, corosolic, maslinic, betulinic, oleanolic, and ursolic acids. The proposed method allows a rapid identification of triterpene acids, and it could be useful for the analysis of these compounds in apple fruits and in other natural sources.
Keywords: APCI; LC-MS; apple; nutraceutical; triterpene acids.
© 2018 John Wiley & Sons, Ltd.