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A GC separation, like extraction, involves a partitioning of solutes
between phases. In the case of GC, one phase in stationary and the
other is mobile. The more a solute is partitioned in the mobile phase,
the more it moves; in other words, the partitioning between the stationary
and mobile phases affects the time required for a solute to travel
through the instrument.
This is essentially the same for all types of chromatography (thin
layer, paper, liquid-liquid, etc). Gas chromatography is more precisely
described as gas-liquid chromatography.
- A solute that interacts very little with the stationary phase (via
van der Waals forces such as dispersion, dipole-dipole interactions,
etc.) moves relatively quickly through the column. Such a solute is
not retained by the stationary phase material.
- A solute with strong interactions with the stationary phase is retained
by that phase; such a solute will take longer to travel through the
John S. Riley, DSB Scientific Consulting