Rapid and accurate profiling of oligosaccharides in beer by using a reactive matrix via MALDI-TOF MS

Oligosaccharides analysis is crucial for brewing technology. Herein, we reported a rapid and highly reproducible method for profiling of oligosaccharides in beer using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) by employing a reasonably designed reactive-matrix, 2-phenyl-3-(p-aminophenyl) acrylonitrile (PAPAN). The PAPAN enhanced ionization efficiency of oligosaccharides and improved reproducibility comparing to the use of conventional matrix, 2,5-dihydroxybenzoic acid (DHB). After optimization of sample dilution factor and cationization agents, the distributions of maltooligosaccharides in different brands of beers were unambiguously identified. Since the PAPAN selectively reacts with the reducing end of oligosaccharides, the interferences from matrixes are effectively eliminated. Therefore, the method shows potentials for analysis of oligosaccharides in other foods.