UHPLC-DAD Multi-Method for Determination of Phenolics in Aromatic Plants

The aim of this paper was to develop and validate a method of ultra high-performance liquid chromatography coupled with diode array detector (UHPLC-DAD), which allows quantifying simultaneously 19 phenolic compounds in aromatic plants. Twenty-one fresh and dried aromatic plants were extracted with methanol before their UHPLC-DAD analysis. The method was validated regarding specificity, working range, linearity, limit of detection (LOD) and quantification (LOQ), precision, and accuracy. The developed method allows detecting and quantifying the phenolic compounds at low concentrations (LOD < 0.15 μg/mL, except for carnosol and carnosic acid). The relative standard deviation obtained was lower than 5.73 and 8.75%, for repeatability and intermediate precision, respectively. The proposed method is straightforward and sensitive, with good precision and accuracy. Dried thyme presented the highest diversity of phenolic compounds and rosmarinic acid was present in most of the samples. This analytical tool is a valid alternative to conventional methods to quantify phenolic compounds in aromatic plants or in their extracts.This study was funded by the Foundation for Science and Technology (FCT) (PTDC/AGRTEC/3366/2012), COMPETE Program (FCOMP-01-0124-FEDER-028015), and the Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES) (BEX 8754/14-4).