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Summary: Magnetic Resonance Microimaging and Numerical
Simulations of Velocity Fields Inside Enlarged
Flow Cells Used for Coupled NMR
Microseparations
Xiaofeng Zhang and Andrew G. Webb*
Department of Electrical and Computer Engineering; and Beckman Institute for Advanced Science and Technology,
University of Illinois at UrbanasChampaign, Urbana, Illinois 61801
The coupling of various chemical microseparation meth-
ods with small-scale NMR detection is a growing area in
analytical chemistry. The formation of enlarged flow cells
within the active volume of the NMR detector can signifi-
cantly increase the coil filling factor and hence the signal-
to-noise ratio of the NMR spectra. However, flow cells can
also lead to deterioration of the separation efficiency due
to the development of complex flow patterns, the form of
which depend on the particular geometry of the flow cell
and the flow rate used. In this study, we investigated the
flow characteristics in different flow cell geometries rel-
evant to the coupling of capillary liquid chromatography
and NMR. Computational fluid dynamics was used to
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