Mass Spectrometry of Biological Molecules
Published Online: 13 JUN 2008
Copyright © 2000 John Wiley & Sons, Ltd. All rights reserved.
Encyclopedia of Analytical Chemistry
How to Cite
Fuchs, B., Arnold, K. and Schiller, J. 2008. Mass Spectrometry of Biological Molecules. Encyclopedia of Analytical Chemistry.
- Published Online: 13 JUN 2008
Mass spectrometric methods may serve as powerful analytical methods in life sciences and medicine. Mass spectrometry (MS) is comparable in sensitivity to techniques based on chromatography or electrophoresis but has superior resolution. Although there are a number of suitable ionization methods, allowing the analysis of biological molecules that are of high molecular weight and low volatility, there are mainly two “soft-ionization” techniques that confer only a minimum of degradation of the analyte: MALDI (matrix-assisted laser desorption/ionization) and ESI (electrospray ionization).
The following article provides a short overview on the advantages and drawbacks of MALDI analysis of biological samples. Whereas most applications of MALDI are in the field of protein analysis, the analyses of carbohydrates and lipids are also comprehensively discussed. It is shown that MALDI is a useful tool especially in the field of lipid analysis, whereas with carbohydrate analysis, still a number of problems have to be solved. MALDI is a rapid and very sensitive (from the low picomolar to the attomolar range) tool that tolerates high amounts of impurities (in contrast to ESI), which are typically present in biological samples. A further advantage is that mainly singly charged ions are formed; this enables MALDI to be applied even to the analysis of crude mixtures although ion yields may differ significantly in dependence on the molecules of interest. In comparison with ESI, MALDI detects compounds of higher molecular weights more sensitively, whereas ESI is more suitable for labile compounds. Therefore, the combination of both methods is, in many cases, the ideal solution for a number of analytical problems.