Question

What is the principle of paper chromatography? Why can be the mixtures of dyes be separated using this method?

Answer 1

Paper chromatography is an analytical method that is used to separate coloured chemicals or substances, especially pigments.

the principle involved is partition chromatography where in the substances are distributed or partitioned between to liquid phases.

Chromatography is used to separate mixtures of substances into their components.

They all have a stationary phase (a solid, or a liquid supported on a solid) and a mobile phase (a liquid or a gas). The mobile phase flows through the stationary phase and carries the components of the mixture with it. Different components travel at different rates.

In paper chromatography, the stationary phase is a very uniform absorbent paper. The mobile phase is a suitable liquid solvent or mixture of solvents.

Like all chemicals, dyes have different physical properties like boiling points, melting points, and color. These properties also can include the affinity of a dye to a particular chemical. If a chemical “sticks” to another, it has a high affinity. If a chemical doesn’t want to stick to another, it has a low affinity. If we have several dyes with different affinities to a single liquid, we can separate them using technique of paper chromatography