Theoretical investigation of low detection sensitivity for underivatized carbohydrates in ESI and MALDI
Citations Over TimeTop 11% of 2016 papers
Abstract
Electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) mainly generate protonated ions from peptides and proteins but sodiated (or potassiated) ions from carbohydrates. The ion intensities of sodiated (or potassiated) carbohydrates generated by ESI and MALDI are generally lower than those of protonated peptides and proteins. Ab initio calculations and transition state theory were used to investigate the reasons for the low detection sensitivity for underivatized carbohydrates. We used glucose and cellobiose as examples and showed that the low detection sensitivity is partly attributable to the following factors. First, glucose exhibits a low proton affinity. Most protons generated by ESI or MALDI attach to water clusters and matrix molecules. Second, protonated glucose and cellobiose can easily undergo dehydration reactions. Third, the sodiation affinities of glucose and cellobiose are small. Some sodiated glucose and cellobiose dissociate into the sodium cations and neutral carbohydrates during ESI or MALDI process. The increase of detection sensitivity of carbohydrates in mass spectrometry by various methods can be rationalized according to these factors. Copyright © 2016 John Wiley & Sons, Ltd.
Related Papers
- → Protonation Sites in Pyrimidine and Pyrimidinamines in the Gas Phase(1997)47 cited
- → Proton Affinities of Dicyanogen Isomers: Is There a Preferred Site of Protonation for CNCN?(1998)13 cited
- → Theoretical proton affinities of α1 adrenoceptor ligands(2005)11 cited
- → Modeling of the Chemico-Physical Process of Protonation of Carbon Compounds(2011)2 cited
- → Abinitio studies on structures and proton affinities of fluorométhanols(1985)5 cited