Ion Exchange or Ion Chromatography

  This is a type of chromatography that is applied to separate and determine ions on columns that have a low ion exchange capacity. This is based on the equilibrium of ion exchange between the ions in solution and the counter ions to pair with the oppositely charged ions that are fixed to the stationary phase. This stationary phase would either have positive of negative functional groups affixed to it, usually sulfonate (-SO₃^-) or a quaternary amine (-N(CH₃)₃⁺), being a cation and anion exchanger respectively.