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Characteristic pH and electrolyte concentration dependences of 2‐aminopyridine‐derivatized oligosaccharides (N‐glycans) in sonic‐spray ionization mass spectrometry
Author(s) -
Deguchi Kisaburo,
Takegawa Yasuhiro,
Hirabayashi Atsumu,
Nakagawa Hiroaki,
Nishimura ShinIchiro
Publication year - 2005
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.2063
Subject(s) - chemistry , electrolyte , ion , mass spectrometry , analytical chemistry (journal) , ionization , analyte , ammonium acetate , 2 aminopyridine , electrospray ionization , chromatography , organic chemistry , high performance liquid chromatography , electrode
The intensities of ion signals from neutral oligosaccharides (N‐glycans) derivatized with 2‐aminopyridine (PA) were analyzed by ion trap mass spectrometry with a sonic‐spray ionization (SSI) source, in both positive‐ and negative‐ion modes, while varying the pH and concentration of ammonium acetate buffer solution. Two characteristic results are reported and discussed. The first characteristic is the pH dependence of the ion intensities; on increasing the solution pH from 4.3 to 8.6, positive ion intensities increase and negative ion intensities decrease. The second characteristic concerns the dependence of ion intensities on electrolyte concentration; on increasing the electrolyte concentration, the SSI efficiency for the PA N‐glycans first increases and then decreases. Assuming that the SSI mechanism essentially conforms to the statistical charging model and the charge residue model, a new model that focuses a great deal of attention on the counter (electrolyte) ion distribution surrounding the solvated analyte (PA N‐glycan) is proposed, in particular to rationalize the characteristic pH dependence. Copyright © 2005 John Wiley & Sons, Ltd.