Paper chromatography is a useful technique in the separation and identification of
different plant pigments.
In this technique, the mixture containing the pigments to be separated is first
applied as a spot or a line to the paper about 1.5 cm from the bottom edge of the paper.
The paper is then placed in a container with the tip of the paper touching the
solvent. Solvent is absorbed by the paper and moves up the paper by capillary action.
As the solvent crosses the area containing plant pigment extract, the pigments
dissolve in and move with the solvent.
The solvent carries the dissolved pigments as it moves up the paper. The
pigments are carried along at different rates because they are not equally soluble.
Therefore, the less soluble pigments will move slower up the paper than the more
soluble pigments. This is known as developing a chromatogram.
There are various methods. The one described here uses Thin layer
chromatography (TLC) on specially prepared strips instead of paper. It is a
chromatography technique for analyzing mixtures by separating the compounds in the
mixture. TLC can be used to help determine the number of components in a mixture, the
identity of compounds, and the purity of a compound. During chromatography, a mobile
phase (eluent) distributes the compounds present in a mixture over a stationary phase
(adsorbent).
Video TLC
https://www.youtube.com/watch?v=CmHFVxTxkGs
https://www.youtube.com/watch?v=rbp_Qc4jMAc