Biomedical Engineering – From Theory to Applications

Column Coupling Electrophoresis in Biomedical Analysis
ITP preconcentration with GE separation can be a simpler alternative to the membrane
filtration-modified MCE devices for the decreasing of the detectable concentration of
biopolymers as it was demonstrated in section 3.2.1.2.
Fig. 14. Layout and dimensions of the “filter-CE” device (a) and “concentrator-CE” device
(b), these multilayer devices consist of a small piece of nanoporous membrane (gray area)
sandwiched between the upper (dotted line) and lower (solid line) PDMS layers. The
microchannels were about 40 m deep, 100 m or 50 m wide for upper and lower layers,
respectively, and the size of the membrane was about 4 mm x 8 mm. (c) Photograph of the
“concentrator-CE” device. (d) 3-D schematic diagram of the intersection region. The upper
and lower channels are separated by a thin membrane. Reprinted from ref. (Long et al.,
2006), with permission.
4. Performance parameters of column coupling electrophoresis
Limit of detection (cLOD) and limit of quantification (cLOQ) are usually calculated as the
ratio of standard deviations of y-intercepts of regression lines (sa) and the slopes of the
regression lines (b) multiplied by factor 3.3 (cLOD) or 10 (cLOQ). The obtained values of
cLOD and cLOQ by using electrophoretic methods in the column coupling arrangement
clearly indicate significantly higher sensitivity in comparison to the single column CZE and
therefore, favor the use of these hyphenated techniques (comparing with single column
ones) in ultra trace quantitative determination of various analytes present in different
multicomponent matrices.
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