In-depth cannabis fatty acid profiling by ultra-high performance liquid chromatography coupled to high resolution mass spectrometry

Industrial hemp (Cannabis sativa L.) represents an important plant, used for a variety of uses including pharmaceutical and nutraceutical purposes. As such, a detailed characterization of the composition of this plant could help future research to further exploit the beneficial effects of hemp compounds on the human health. Among the many compounds of hemp, fatty acids represent an interesting class of minor components, which has been overlooked so far. In this work, an untargeted approach based on liquid-chromatography coupled to a high-resolution mass spectrometry and a dedicated structure-based workflow for raw data interpretation was employed for the characterization of fatty acids from hemp inflorescences. A simple method, without any chemical derivatization, was developed for extraction and characterization of fatty acids leading to the tentative identification of 39 fatty acid species in the five hemp samples. A quantitative analysis on the untargeted data was initially performed, using peak areas as surrogate of analyte abundance for relative quantitation. Five fatty acids resulted the most abundant in all hemp samples, with ca. 90% of the total peak area. For these compounds a targeted quantitative method was validated, indicating that the most abundant ones were linolenic acid (1.39-7.95 mg g-1) and linoleic acid (1.04-7.87 mg g-1), followed by palmitic acid (3.74-6.08 mg g-1), oleic acid (0.91-4.73 mg g-1) and stearic acid (0.64-2.25 mg g-1).