DHB Matrix with Additives for Direct MALDI Mass Spectrometry of Carbohydrates and Glycoconjugates

Matrix-assisted laser desorption/ionization (MALDI) is one of the soft ionization methods in mass spectrometry (MS). Its analyte compatibility with a matrix can improve analyte-selective ionization efficiency and control the fragmentation properties of the product ions. 2,5-dihydroxybenzoic acid (DHB) is a versatile matrix that can be used for various molecular species. Although DHB is commonly used as the matrix of first choice for MALDI MS of glycans, many attempts to optimize DHB for glycan analysis using additives have also been reported. This mini-review will present additives of the DHB-based matrix that promote direct analysis of carbohydrates and glycoconjugates by MALDI MS.