Publication
Title
Cation selectivity of natural and synthetic ionophores probed with laser-induced liquid beam mass spectrometry
Author
Abstract
The novel laser desorption method laser-induced liquid beam ionization/desorption (LILBID) is applied to the mass spectrometric examination of selective ion binding by natural and synthetic ionophores in methanol solutions. The ions are desorbed from a liquid jet with an IR laser pulse and then extracted perpendicularly into a reflectron time-of-flight (RE-TOF) analyzer. LILBID studies on the natural ion carriers valinomycin and monensin A are presented, as well as those on the synthetic crown ethers 18-crown-6, diaza-18-crown-6, and benzo-15-crown-5. No fragment ions are detected, and the measured ion selectivity is in good qualitative agreement with published stability constants of the complexes. The observed specific recognition of silver ions by diaza-18-crown-6 can be rationalized by the principle of hard and soft acids and bases, which predicts stable complexes when the polarizabilities of Lewis acid and base are similar. Weak, noncovalent interactions like those in the sandwich complex between two benzo-15-crown-5 molecules with one potassium ion are detected with LILBID. Their preservation during the process of ion desorption depends on the laser intensity. A comparison with spectra obtained by using electrospray ionization (ESI) and matrix assisted laser desorption/ionization (MALDI) shows that LILBID can potentially become a sensitive tool for the screening of weak but specific molecular interactions.
Language
English
Source (journal)
Analytical chemistry. - Washington, D.C., 1948, currens
Publication
Washington, D.C. : 1997
ISSN
0003-2700 [print]
5206-882X [online]
Volume/pages
69:17(1997), p. 3587-3594
ISI
A1997XU10100032
Full text (Publisher's DOI)
UAntwerpen
Faculty/Department
Publication type
Subject
External links
Web of Science
Record
Identification
Creation 01.07.2011
Last edited 05.08.2017