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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 35, Number 4
BKCSDE 35(4)
April 20, 2014 

 
Title
Explaining the Drift Behavior of Caffeine and Glucosamine After Addition of Ethyl Lactate in the Buffer Gas of an Ion Mobility Spectrometer
Author
Roberto Fernandez-Maestre*, Andres Reyes Velasco, Herbert H. Hill
Keywords
Dopants, Ethyl lactate glucosamine, Caffeine, Ion mobility spectrometry, Theoretical calculations
Abstract
Protonated caffeine (CH+) and glucosamine (GH+) overlapped in an analysis with ion mobility spectrometryquadrupole mass spectrometry. Ethyl lactate vapor (L) at different concentrations from 0 to 22 mmol m−3 was added as a buffer gas modifier to separate these signals. The drift times of CH+ and GH+ increased with L concentration. The drift time increase was associated to clustering equilibria of CH+ and GH+ with one molecule of L and the equilibrium of GH+ was more displaced to the formation of GLH+ than that of CLH+. GH+ clustered more to L than CH+ because GLH+ formed more stable hydrogen bonds (26.30 kcal/mol) than CLH+ (24.66 kcal/mol) and the positive charge in GH+ was more sterically accessible than in CH+. The aim of this work was to use theoretical calculations to guide the selection of a buffer gas modifier for IMS separations of two compounds that overlap in the mobility spectra and predict this separation, simplifying that empirical process.
Page
1023 - 1028
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