A biochemical test to detect cholesterol in solution.
When cholesterol solution is mixed with concentrated sulphuric acid without disturbing the layers, a red ring is formed at the interface of the two layers. The red colour is due to the formation of Dicholestadiene, a condensation product between two cholesterol molecules with removal of one molecule of water.
- Cholesterol solution
- Concentrated sulphuric acid
- Separate the egg yolk (yellow part) of a boiled egg and grind it with about 50 ml of chloroform in a mortar.
- Filter the suspension through a filter paper.
- The filtrate is the cholesterol solution. The egg yolk is the rich source of cholesterol.
- Take 1 ml of cholesterol solution contained in a dry test tube.
- Add 0.5 ml of concentrated sulphuric acid through the wall without shaking.
- Stand it for sometime, see the development of red ring at the junction of two layers.
- Appearance of red ring at the junction of two layers indicates presence of cholesterol in solution.