Question

Explain what would happen if the hexane was added to the top of the column immediately after adding the sample. This is for isolation of chlorophyll and carotenoid pigments from spinach

Answer 1

Chlorophylls and carotenes do not dissolve very well in water, but they dissolve like crazy in hexane. The other compounds do not dissolve well in hexane, but dissolve well in water. if the hexane was added to the top of the column immediately after adding the sample without using a small bed of adsorbent or cotton to protect the sample flowing upward and downward above the column the chlorophyll and carotenoids are soluble in hexane along with hexane soluble organic impurities and goes down to bottom of the column. during this process some heat is evolved (you can feel it by touching the column).

The structures of the compounds dissolves in hexane are

in TLC plate after devoloping you may cross check the compounds as