Atmospheric pressure photoionization mass spectrometry. Ionization mechanism and the effect of solvent on the ionization of naphthalenes.

Details

Serval ID
serval:BIB_D72EB6810DAB
Type
Article: article from journal or magazin.
Collection
Publications
Title
Atmospheric pressure photoionization mass spectrometry. Ionization mechanism and the effect of solvent on the ionization of naphthalenes.
Journal
Analytical chemistry
Author(s)
Kauppila T.J., Kuuranne T., Meurer E.C., Eberlin M.N., Kotiaho T., Kostiainen R.
ISSN
0003-2700 (Print)
ISSN-L
0003-2700
Publication state
Published
Issued date
01/11/2002
Peer-reviewed
Oui
Volume
74
Number
21
Pages
5470-5479
Language
english
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Abstract
The ionization mechanism in dopant-assisted atmospheric pressure photoionization and the effect of solvent on the ionization efficiency was studied using 7 naphthalenes and 13 different solvent systems. The ionization efficiency was 1-2 orders of magnitude higher with dopant than without, indicating that the photoionization of the dopant initiates the ionization process. In positive ion mode, the analytes were ionized either by charge exchange or by proton transfer. Charge exchange was favored for low proton affinity solvents (water, hexane, chloroform), whereas the addition of methanol or acetonitrile to the solvent initiated proton transfer. In negative ion mode, the compounds with high electron affinity were ionized by electron capture or by charge exchange and the compounds with high gas-phase acidity were ionized by proton transfer. In addition, some oxidation reactions were observed. All the reactions leading to ionization of analytes in negative ion mode are initiated by thermal electrons formed in photoionization of toluene. The testing of different solvents showed that addition of buffers such as ammonium acetate, ammonium hydroxide, or acetic acid may suppress ionization in APPI. The reactions are discussed in detail in light of thermodynamic data.

Keywords
Atmospheric Pressure, Naphthalenes/analysis, Naphthalenes/chemistry, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods
Pubmed
Web of science
Create date
02/05/2017 13:42
Last modification date
20/08/2019 15:56
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