Development and Optimization of UPLC-ESI-MS/MS Method for the Determination of Free Aminoacids in Honey

Normally the traditional method to determine the floral origin of the honey is pollen recognition. even if many studies have proposed markers of botanical origin for honey, based on aroma compounds, sugar or flavonoid profile as well as organic acids or isotopic relations and, finally, protein and amino acid compositions. Amino acids, in particular, appear to be the best option as markers for honey fingerprintings. European Community food laws establish compositional and quality parameters for honey but these parameters have no relationship to botanical or geographical origin of honey. About amino acid even if the occurrence of more than 30 amino acids in honey has been confirmed in literature, in European Union laws only proline amount is specified. Proline is the major contributor of the total amino acids and come mainly from the honeybee during the conversion of nectar into honey. Its amount in honey has been proposed as an indicator of honey ripeness. The other amino acids and their relative proportions, depending on honey origin (nectar or honeydew), could be characteristic of botanical origin and may be used for authentication. A method for free amino acids analysis by Ultra Performance Liquid Chromatography with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/ MS) has been developed and optimized. A total of 17 amino acids have been optimized according with the precursor (m/z), product (m/z), dwell time (msec), Q1 (V), Q3 (V) and collision energy (V). The sample preparation was kept only on an extraction and separation of metabolite without derivatization or solid phase extraction steps. The performance of this method has been validated for each amino acid.