Analysis of oligosaccharides in beer using MALDI-TOF-MS

Oligosaccharides in four different brands of beer (Cass, Hite, Budweiser, Miller) were systematically analysed with three different dihydroxybenzoic acid (DHB) isomer matrices (2,4-DHB, 2,5-DHB, and 2,6-DHB) using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS). Different experimental conditions, such as dilution (up to 1000-fold) and cationisation agents (sodium chloride or sodium trifluoroacetate) were analysed. No ionised peaks of oligosaccharides were observed with 2,4-DHB matrix. 2,6-DHB was more effective than 2,5-DHB in most of the investigated concentration ranges. 2,6-DHB with 4-fold dilution was the most effective. In certain cases, a cationisation agent was necessary to detect the signals of the oligosaccharides, and sodium chloride provided greater ionisation than sodium trifluoroacetate.