Suppose you are given a pure sample of every known plant pigment. How could you use thin layer chromatography to identify which pigments are found in spinach leaves.

By obtaining spectrographs of all known pigments and matching it with the spectrographs obtained from individual components of spinach leave.

Explanation:

Chromatography refers to the separation of the components of a substance into its constituents by passing a mobile phase containing the mixture through a stationary phase. Chromatography was coined from two Greek words; 'Chroma' meaning colour and 'graphien' meaning to write. Hence chromatography literarily means 'colour writing'. This comes from the fact that chromatography often separates various components of a substance leaving a chromatogram showing different colours.

If I have a pure sample of all plant pigments, I will pass them through a mass spectrometer, UV-visible spectrometer and Infrared spectrometer to identify the components chemically.

When this is done, I will now carry out a separation of the components of spinach leaves via thin layer chromatography and obtain the chromatogram. Then each component is also passed through all the spectroscopic analysis listed above and the results are matched with the database of the spectrographs not all known plant pigments. By so doing, the chemical identity of the components of spinach leaves can be discovered. The matching of spectrographs can be done by an automated system.