What is the difference between thin-layer and paper chromatography?

Thin-layer chromatography uses a thin layer of adsorbent material on a flat plate, while paper chromatography uses filter paper as the stationary phase.

Thin-layer chromatography (TLC) and paper chromatography are both techniques used in the laboratory to separate mixtures into their individual components. However, they differ in the materials used for the stationary phase and the nature of the separation process.

In TLC, a thin layer of an adsorbent material, such as silica gel or alumina, is spread on a flat plate, usually made of glass, plastic or aluminium. The sample is applied to the plate and a solvent, known as the mobile phase, is allowed to rise up the plate by capillary action. As the solvent moves, it carries the sample with it. Different components in the sample move at different rates, depending on their affinity for the adsorbent material and the solvent, resulting in separation.

On the other hand, paper chromatography uses filter paper as the stationary phase. The sample is applied to the paper and a solvent is allowed to rise up the paper by capillary action. The separation of components is based on their different affinities for the paper and the solvent.

In terms of sensitivity, TLC is generally more sensitive than paper chromatography, meaning it can detect smaller amounts of material. It also offers a wider choice of adsorbents and solvents, allowing for more flexibility in separating different types of mixtures. However, paper chromatography is simpler and cheaper, making it a good choice for quick, preliminary separations.

IGCSE Chemistry Tutor Summary: Thin-layer chromatography (TLC) uses a flat plate covered with an adsorbent material, like silica, for separating mixtures, while paper chromatography employs filter paper. TLC is more sensitive, offering better separation and flexibility with different mixtures due to a variety of adsorbents and solvents. However, paper chromatography is simpler and less expensive, ideal for basic, initial separations.