Identification of polysaccharides DP12-19 in honey by liquid chromatography high resolution mass spectrometry

The complex composition of honey imposes the specific identification of several markers useful for characterizing various adulterants. The most common type of honey adulteration is the fraudulent addition of syrups from various row matter as corn, rice, wheat, etc.: more, the analytical profile of sugar syrups can be very complex making difficult the identification of markers. At today polysaccharides are considered as potential detection markers of honey adulteration,[1] and the saccharide content is considered a potential identity card of saccharides for each floral source. [2] Various analytical systems are adopted to highlight honey adulteration: infrared spectroscopy, nuclear magnetic resonance spectroscopy, carbon isotope ratio method, quadrupole time-of flight mass spectrometry, and the application of analytical methods in authentication and adulteration of honey is described in bibliography. [3] This work offers a contribution concerning the identification of polysaccharides DP 12 – 19 by a not conventional analytical technique, the Liquid Chromatography - High Resolution Mass Spectrometry (LC-HRMS). Using Q Exactive Focus Orbitrap LC-MS/MS, the peak of polysaccharides resolved in an Isotopic Ratio Mass Spectrometry (IRMS) is studied and single polysaccharides from DP 12 to DP 19 are identified by the exact mass of ion [M - 2H]2-; this technique is an alternative to Ultra High-Performance Liquid Chromatography/Quadrupole Time of Flight Mass Spectrometry (UHPLC/Q-TOF-MS). For example, maltododecaose (DP 12) is identified by m/z 980.3140 [M - 2H]2- and maltononadecaose (DP 19) is identified by m/z 1547.5007 [M - 2H]2-. Examples of application are shown. [1] Megherbi, M; Herbreteu, B.; Faure, R.; Salvador, A. J. Agric. Food Chem. 2009, 57, 2105-2011. [2] Consonni, R.; Cagliani, L. R.; Cogliati, C. J. Agric. Food Chem. 2012, 18, 4526-4534. [3] Siddiqui, A. J.; Musharraf, S. G.; Choudhary, M. I.; Rahman, A. Food Chem. 2017, 217, 687-698.