•Prefer if K is constant over conc. range
•If not constant we can work in a narrow range where it is constant
•This is linear chromatography
•
•Example of non-linear chromatography
–Pour aqueous solution of A & B on column
–Allow water to drain out, both A & B stick
–Wash column with 50% MeOH, A removed
–Wash column with 100% MeOH, B removed
•Used extensively for sample cleanup in GC