Mass spectrometric tools for species identification from leaf bud metabolites

Previous studies have demonstrated that leaf surface metabolites can be used for distinguishing between birch species [1], [2]. In this study, the aim was to develop a rapid LC-MS based fingerprinting method for the leaf bud metabolites other common Finnish trees and shrubs. The extracts were screened for marker candidates using two approaches: 1) UHPLC-ESI-Q-Orbitrap analysis combined with MZmine 2 data processing to obtain unique species-specific markers and 2) UHPLC-ESI-QqQ analysis and selection of main ions from the full scan spectra to obtain species-sensitive markers. Depending on the species, 1 – 6 marker candidates were chosen for further testing. Two competitive fingerprinting methods utilizing selected ion recording were created and tested for specificity and repeatability with 4 – 10 replicates per species.