Page 195 - Multidimensional Chromatography

188 Multidimensional Chromatography

Figure 8.17 Schematic diagram of a cross-section (a) through the clamped plates, and
views from above (b–d) of coupled plates serially connected to achieve multidimensional
separation with stationary phases with different characteristics (hatched lines, glass plate;
light shading, stationary phase A; dark shading, stationary phase B; wavy lines, stationary
phase C).

samples, ready for development in the second direction. By use of a mobile phase of
appropriate selectivity (S T2 ; S V2 ) an effective multidimensional planar chromato-
graphic separation can be observed (Figure 8.16(f)).
Figure 8.17 depicts MD-PC performed on three different types of stationary
phase (6). The three grafted chromatographic plates (Figure 8.17(a)) are clamped in
lap-joint fashion with the edges of their stationary phases in close contact. The man-
ner in which the three plates are prepared and the separation which can theoretically
be achieved are also apparent from the schematic diagrams in Figures 8.17(b–d), in
which the most polar stationary phase is phase ‘A’ and the least polar is stationary
phase ‘C’.

8.12 SERIALLY CONNECTED MULTILAYER
FORCED-FLOW PLANAR CHROMATOGRAPHY

Mincsovics and co-workers (36) found that OPLC is suitable for the development of
several chromatographic plates simultaneously if the plates were specially prepared.
With this multilayer technique many samples can be separated during a single chro-
matographic run. On the basis of this concept, Botz et al. (32, 33) proposed a novel
OPLC technique with a significantly increased separation efficiency, in which the
separation distance can be increased as a result of special arrangement of the
chromatographic plates. This category of multilayer FFPC, linear development