Phenolic profiles of raw mono- and polyfloral honeys from Latvia

Abstract

The phenolic compound profiles of 393 raw mono- and polyfloral Latvian honey samples were investigated using a targeted ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) method. This strategy allowed simultaneous determination of the content of 11 phenolic acids, 18 flavonoids, 2 plant hormones, and 3 water-soluble vitamins in honey samples of botanically diverse origin, including buckwheat (Fagopyrum esculentum), heather (Calluna vulgaris), linden (Tilia cordata), and rapeseed (Brassica napus). Honey samples were collected directly from the beekeepers and were analyzed in their natural, raw form. A selective high-throughput analysis was implemented using sugaring-out assisted liquid-liquid extraction (SULLE) combined with the pentafluorophenyl (PFP) stationary phase. The robustness of the method was evaluated by using the design of experiments (DoE) approach and validated. Pooled quality control (QC) samples allowed monitoring of the method performance across the analysis sequences and principal components analysis (PCA) of QC samples resulted in a small amount of total variance in the total projection, indicating that the data were of good quality. The acquired occurrence data were compiled and compared with other studies. To the best of our knowledge, this study is the first of this scale and purpose, providing unique insights into the phenolic compound composition of fresh, regional European honey.