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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 

Explaining the Drift Behavior of Caffeine and Glucosamine After Addition of Ethyl Lactate in the Buffer Gas of an Ion Mobility Spectrometer
Roberto Fernandez-Maestre*, Andres Reyes Velasco, Herbert H. Hill
Dopants, Ethyl lactate glucosamine, Caffeine, Ion mobility spectrometry, Theoretical calculations
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.
1023 - 1028
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