Chromatography was first developed as a separation technique using coloured substances (the name means "colour writing". If the substances are colourless, they may be coloured after their separation by suitable chemical reactions.

Separation of substances by chromatographic methods may be on a tiny scale (for analysis) or on a large scale (for industrial production). It is not necessary to use paper and water - the stationary phase may be many sorts of surface, even liquids, and the mobile phase may be liquid or gas.

Physics and chemistry

See: Gas Chromatography

Things you can try yourself

No problem doing this at home! Paper tissue or toilet paper will do. Draw a circle with a felt tip pen, drip water slowly into the centre of the circle and watch the colours separate.

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