Question

Find out a qualitative test for proteins, fats and oils, amino acids and test any fruit juice, saliva, sweat and urine for them.

Answer 1

Biuret Test: Biuret test is done for protein. Appearance of violet colour in the solution confirms the presence of protein. Biuret (H₂NCONHCONH₂) reacts with copper ion in a basic solution and gives the violet colour. 

Liebermann-Burchard Test: This test is done for cholesterol. The reagent is a mixture of acetic anhydride and sulphuric acid. Appearance of green colour confirms the presence of cholesterol. 

Grease Test: This test is done for certain oils. This is a simple test which involves rubbing the given sample on cloth or paper. Appearance of a translucent spot shows the presence of oil.