Electron capture negative ion mass spectra of some typical matrix-assisted laser desorption/ionization matrices.
A series of seven typical matrix-assisted laser desorption/ionization (MALDI) matrices has been investigated by means of electron capture negative ion mass spectrometry (ECNI-MS). It has been shown that the most effective matrices form deprotonated negative ions predominantly in the low-energy region. Relative dissociative cross sections have been measured for all molecules under investigation. The relative integrated abundance of [M - H](-) ion formation in the series changes by four orders of magnitude. It has been shown that 2,5-DHB (gentisic acid), one of the most effective MALDI matrices, has maximal relative intensity of [M - H](-) formation at the energy approximately equal 0.8 eV. This result is in accordance with a finding of Frankevich and Zenobi [Book of Abstracts, Workshop-school "Mass spectrometry in chemical physics, bio-physics and environmental sciences", Zvenigorod, Russia, April, 25-26, 2002, p. 40] that a probable origin of negative ions in MALDI is the process of low-energy (0.5-1 eV) dissociative electron capture by matrix molecules.
Institute of Physics of Molecules and Crystals, Ufa Research Center of RAS, October Prospect 151, Ufa 450075, Russia. nail@anrb.ru
N L
NL
Asfandiarov
S A
SA
Pshenichnyuk
A I
AI
Fokin
V G
VG
Lukin
V S
VS
Fal'ko
D000465:Algorithms; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D011522:Protons; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
D004364:Pharmaceutical Preparations; D011522:Protons