Circular ments

Sample sheets of 100 x 50 x 4 millimeter were prepared with the wet deposition technique. Two rectangular TMA samples and one circular TMA sample were machined from these sheets. The rectangular samples, 10 x 7 x 4 mm, were taken in the length (X) direction and in the width (Y) direction of the sample sheet. The circular sample, diameter 5 mm, was used to measure the l.e.c. in the Z direction. The samples, placed in a TMA 7, were measured from -20°C to 120°C with a heating rate of 2°C/minute. Subsequently, the sample was cooled with the same rate and heated again for the real measuring scan. The first heating scan was ment to remove the frozen-in stresses which influence the thermal expansion behaviour (see 3.1.2). 

In contrast to B sectors, E sectors utilize the component of Equation 3.27. Such instm-ments select ions according to their kinetic energy rather than momentum (as in B sectors). The radius of the circular ion path formed in the static electric sector can be derived by combining centrifugal force (Equation 3.28) with electric force, similar to Equation 3.29 but by replacing with Fg, to give ... 

Whereas the importance of the various modes of develr ment is well known for analytical TLC, linear development is the only method widely used for preparative CPLC. Remarkably this is also the only development mode reported for preparative OHjC. In contrast, until now all RPC separations have been performed in the circular development mode. A new possibility in RPC is the planar column (75), where in contrast to the centrifugal force, the flow is accelerated linearly, giving linear development. The advantage of anticircular CPLC was clearly demonstrated by Traitler and Studer (37), and the applicability of this development mode has also been reported for on-line RPC. As already mentioned, anticircular and circular development are also possible for on-line OPLC separations using separation distances of 20 or 40 cm (12,81). 

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