The principles of IGC are very simple, being the reverse
of a conventional gas chromatographic (GC)
experiment. An empty column is uniformly packed with
the solid material of interest, typically a powder, fibre
or film. A pulse or constant concentration of gas is
injected down the column at a fixed carrier gas flow
rate and the retention behaviour of the pulse or concentration front travelling down the packed column
is then measured by a detector. A series of IGC
measurements with different gas phase probe
molecules allows access to a wide range of phyiscochemical
properties of the solid sample. The
fundamental property measured by IGC from which
most of these properties are derived is known as the
retention volume VN. This is a measure of how strongly
a given gas probe molecule interacts with the solid
sample. From a series of measurements of VN a whole
variety of thermodynamic and kinetic parameters can
be readily calculated.