simple methodology to tell which test tube contains which combination of starch,protein or lipids. material:3 solutions,water bottle,NaOH,KI,CuSO4,Ethanol,test tube & rack,wax pencil,syringe
In the rack mark tubes for each test solution using wax pencil. Add approximately 2cm (in height) of water to all test tubes. Firstly, you can detect the availability of proteins in an unknown solution with the CuSO4 in the presence of NaOH. In this case, a violet staining will occur.Secondly, the starch detection in the solution is based on the reaction with KI. In the presence of starch the mixture will have form violet to black color. Finally, lipid containing is tested by adding ethanol using a syring. Lipids are almost insoluble in ethanol. Therefore the drops of the added ethanol to the test solution will look still as the drops on the surface of the solution with the lipids.