Thin Layer Chromatography

Purpose:

The purpose of this experiment is to identify the contents of four samples,
therefore determining the purity with the use of thin-layer chromatography.


Theory:

Chromatography is a separation method that relies on differences in partitioning
behavior between a moving phase and a stationary phase to separate the components in a
mixture. In thin-layer chromatography, the moving phase is a solvent and the stationary
phase is a solid adsorbent on a plate (sheet of glass, metal, or plastic) coated with a thin
layer of a solid adsorbent. The solvent used in today’s experiment is chloroform which is
a polar liquid and the solid adsorbent is a silica gel which attracts polar molecules.

A small amount of the mixture to be analyzed is spotted near the bottom of this
plate. The plate is then placed in a shallow pool of the chloroform in a developing
chamber so that only the very bottom of the plate is in the liquid. The chlor...