Document Detail

Negative ion-atmospheric pressure photoionization-mass spectrometry.
MedLine Citation:
PMID:  14766288     Owner:  NLM     Status:  PubMed-not-MEDLINE    
The ionization mechanism in the novel atmospheric pressure photoionization mass spectrometry (APPI-MS) in negative ion mode was studied thoroughly by the analysis of seven compounds in 17 solvent systems. The compounds possessed either gas-phase acidity or positive electron affinity, whereas the solvent systems had different polarities and gas-phase acidities and some of them positive electron affinities. The analytes that possessed gas-phase acidity formed deprotonated ions in proton transfer; in addition, fragments and solvent adducts were observed. The compounds of positive electron affinity formed negative molecular ions by electron capture or charge exchange and substitution products of form [M - X + O](-) by substitution reactions. The efficiency of deprotonation was decreased if the solvent used possessed higher gas-phase acidity than the analyte. Solvents of positive electron affinity captured thermal electrons and deteriorated the ionization of all the analytes. Also, the proportion of substitution products was affected by the solvent. Finally, the performances of negative ion APPI and negative ion APCI were compared. The sensitivity for the studied compounds was better in APPI, but the formation of substitution products was lower in APCI.
Tiina J Kauppila; Tapio Kotiaho; Risto Kostiainen; Andries P Bruins
Related Documents :
990268 - Synthesis, structure determination, spectral properties, and energy-linked spectral res...
16592728 - An improvement in the theory of regular solutions.
17487888 - Quantum-chemical calculations on the electronic circular dichroism of (-)-dibromophakel...
15477158 - Solvatochromic behavior of the electronic absorption spectra of some azo derivatives of...
11384438 - Fano and kondo resonance in electronic current through nanodevices.
24534908 - Optical signatures of silicon-vacancy spins in diamond.
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of the American Society for Mass Spectrometry     Volume:  15     ISSN:  1044-0305     ISO Abbreviation:  J. Am. Soc. Mass Spectrom.     Publication Date:  2004 Feb 
Date Detail:
Created Date:  2004-02-09     Completed Date:  2004-04-21     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9010412     Medline TA:  J Am Soc Mass Spectrom     Country:  United States    
Other Details:
Languages:  eng     Pagination:  203-11     Citation Subset:  -    
Viikki Drug Discovery Technology Center, Department of Pharmacy, University of Helsinki, Helsinki, Finland.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Direct electrospray tandem mass spectrometry of the unstable hydroperoxy bishemiacetal product deriv...
Next Document:  An automated high performance capillary liquid chromatography-Fourier transform ion cyclotron resona...