Objective: The purpose of this study was to develop and validate a specific and sensitive liquid chromatography tandem mass-spectrometry method for quantification of usnic acid concentration in the lichen, Cladonia uncialis, suitable for detection of relatively small fluctuations of usnic acid concentration in response to environmental changes.
Results: The resulting method was fully validated according to international guidelines and demonstrated good selectivity and sensitivity with minor levels of a matrix effect and high accuracy.
Keywords: Cladonia uncialis; LC–MS/MS; Lichen; Liquid chromatography tandem mass-spectrometry; Secondary metabolites; Usnic acid.