A procedure in which parts or all of the separated sample components are subjected
to additional separation steps. This can be done e.g. by conducting a particular fraction
eluting from the column into another column (system) having different separation characteristics.
When combined with additional steps, this may be described as multi-dimensional chromatography
. In planar chromatography
refers to the chromatographic process in which the components are caused to migrate
first in one direction and subsequently in a direction at right angles to the first
one; the two elutions are carried out with different eluents.
PAC, 1993, 65, 819
(Nomenclature for chromatography (IUPAC Recommendations 1993))
on page 827