Rf Values

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Rf Values

Chromatography

can be used to separate mixtures of coloured compounds – mixtures that are

suitable for separation by chromatography include inks, dyes and colouring

agents in food…

Simple

chromatography is carried out on paper – a spot of the mixture is placed near

the bottom of a piece of chromatography paper and the paper is then placed

upright in a suitable solvent.

Simple

chromatography is carried out on paper – a spot of the mixture is placed near

the bottom of a piece of chromatography paper and the paper is then placed

upright in a suitable solvent.

Different

chromatograms and the separated components of the mixtures can be identified by

calculating the Rf

value

Rf = distance

moved by the compound ÷ distance

moved by the solvent

The

Rf value of a particular compound is

always the same – if the chromatography has been carried out in the same way.

This

allows industry to use chromatography to identify compounds in mixtures

(precisely).