How to detect a protein
A few drops of the secret ingredient – and the egg white turns purple!
Attention! All experiments are performed by professionals. Do not attempt!
- chicken eggs;
- copper(II) sulfate solution;
- wooden stick;
- Petri dish;
- sodium hydroxide solution.
A few egg whites are separated from their yolks and a few drops of copper(II) sulfate solution are added. Light blue threads form in the mixture. The mixture is poured into a Petri dish and some sodium hydroxide solution is added – and the mixture turns purple!
Egg white contains ovalbumin protein. Copper(II) sulfate forms an insoluble compound with it, which creates the light blue threads you observe. When sodium hydroxide is added, the copper and ovalbumin compound breaks down into smaller molecules, which give the solution its purple color.
A safer version of this experiment is included in the “Chemistry of eggs” set from the MEL Chemistry subscription.