Partition Chromatography

Two Liquid Phases

In Partition Chromatography, both the stationary phase and the mobile phase are liquids, and separation of the mixture's components happens through continuous differential partitioning of each component between these two liquid phases.

Paper Chromatography, as an Example

A common example of partition chromatography is Paper Chromatography, which uses a special-quality paper called Whatman paper number 1. The water trapped within the fibres of this paper itself acts as the stationary phase. The mixture's solution is spotted, using a glass capillary, onto a strip of the chromatography paper about $2\,cm$ from one end, and the paper is then suspended inside a chamber containing the mobile phase, with care taken that the spot itself does not dip into the mobile-phase liquid. The mobile phase then rises up the paper by capillary action and flows over the spot, and as it does, the components partition themselves differently between the stationary phase (the water held in the paper) and the mobile phase, so that different solutes are retained at different positions along the paper according to how they partition between the two phases. The developed paper strip is called the chromatogram; as with TLC, coloured components show up as coloured spots directly, while colourless ones are seen under UV light or with a spraying agent.

Retention Factor (Rf) …