Matrix-assisted laser desorption/ionization mass spectrometry of carbohydrates

This review describes the application of matrix-assisted laser desorption/i onization (MALDI) mass spectrometry to carbohydrate analysis and covers the period 1991-1998. The technique is particularly valuable for carbohydrates because it enables underivatised, as well as derivatised compounds to be e xamined. The various MALDI matrices that have been used for carbohydrate an alysis are described and the use of derivatization for improving mass spect ral detection limits is also discussed. Methods for sample preparation and fbr extracting carbohydrates from biological media prior to mass spectromet ric analysis are compared with emphasis on highly sensitive mass spectromet ric methods. Quantitative aspects of MALDI are covered with respect to the relationship between signal strength and both mass and compound structure. The value of mass measurements by MALDI to provide a carbohydrate compositi on is stressed, together with the ability of the technique to provide fragm entation spectra. The use of in-source and post-source decay and collision- induced fragmentation in this context is described with emphasis on ions th at provide information on the linkage and branching patterns of carbohydrat es, The use of MALDI mass spectrometry: linked with exoglycosidase sequenci ng, is described for N-linked glycans derived from glycoproteins, and metho ds for the analysis of O-linked glycans are also covered. The review ends w ith a description of various applications of the technique to carbohydrates found as constituents of glycoproteins, bacterial glycolipids, sphingolipi ds, and glycolipid anchors. (C) 1999 John Wiley & Sons, Inc.