Determination of Flavonoids and Phenolic Acids in Plant Materials Using SLE-SPE-UHPLC-MS/MS Method

Today, great emphasis is placed on the search for and dissemination of native plant materials in various industries, with particular emphasis on food, cosmetics, dietary supplements, and as livestock feed and a source of biomass. Solid-liquid extraction (SLE), solid phase extraction (SPE), and ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) methods were developed for the simultaneous determination of 30 flavonoids and phenolic acids in plant materials (lucerne (Medicago sativa L.), goldenrod (Solidago virgaurea L.), phacelia (Phacelia tanacetifolia Benth.), buckwheat (Fagopyrum esculentum), licorice (Glycyrrhiza glabra), and lavender (Lavandula spica L.)). Different SLE methods were tested to evaluate their applicability for the isolation of polyphenols from plants. Then extracts were purified with a C18 reversed-phase SPE cartridge. After extraction, samples were analyzed by UHPLC-MS/MS. The SLE-SPE-UHPLC-MS/MS assay method has been fully validated. For the most compounds, good recoveries and RSDs (<10%) were obtained. Limits of quantification range from 0.4 to 20ng/mL. The main phenolic acids in the studied plants have been found to be 3-(4-hydroxyphenyl)propionic acid, 4-hydroxybenzoic acid, and 3,4-dihydroxybenzoic acid. Quercetin, rutin, glabridin, and naringenin are the major flavonoids detected in the analyzed samples. The obtained scientific data can be useful to select plant materials with high nutritional value and the presence of many biologically active ingredients, as well as selecting samples used as a plant biomass, as food, and as a component of dietary supplements.