Analysis of 22 free amino acids in honey from Eastern Europe and Central Asia using LC-MS/MS technique without derivatization step

Abstract

This study aimed to investigate the presence of 22 free amino acids (FAAs) in six honey types from Belarus (BY), Kazakhstan (KZ) and Poland (PL), for the first time. A short sample preparation step based on extraction by formic acid/water/methanol system and a relatively simple and easy clean-up stage with graphitized carbon black sorbent were performed. Using a HILIC (hydrophilic interaction liquid chromatography) column, the separation of 22 FAAs was successfully carried out. Liquid chromatography coupled with mass spectrometry detectors (LC–MS/MS) were used in 22 FAAs analysis without a derivatization step. Eighty one samples of honey from 6 types and 3 origins with 13 combinations: honeydew (16), multifloral (18), rape (16), linden (8), buckwheat (9) and dandelion (5) contained FAAs from 127.7 mg/kg (dandelion, PL) to 1523.2 mg/kg (multifloral herbs, KZ). Proline ranged from 70.8 to 461.4 mg/kg, tyrosine was characteristic for KZ honey (429 mg/kg), and cystine was present only in PL linden honey (0.1 mg/kg). Summarized results confirm presence and the diversity of FAAs in honey of different types and origin. Honey samples were classified using chemometric methods based on the amino acid concentration. Amino acid profiling of honey is useful, additional tool, expanding standard quality and melissopalynological analysis.