Test For Vitamin C

Ascorbic acid can be detected by using the dye dichlorophenolindophenol (DCPIP). The blue DCPIP is decolourised on reduction by ascorbic acid. 1. Using a syringe or pipette, place exactly 2 cm3 of 1% DCPIP in a clean test tube. 2. Using a clean syringe, add 0.1% solution of ascorbic acid (1mg per cm3) to the DCPIP, one drop at a time, until the blue colour disappears. Shake after every drop. 3. Record the number of drops of ascorbic acid needed to decolorise the DCPIP. 4. Obtain juices of raw fruits, such as orange, lemon and grapefruit, and repeat the test with the same volume of DCPIP. Count the number of drops needed for each juice. 5. Tabulate your results as shown below 6. From your results, calculate the actual concentration of ascorbic acid in the juices tested in mg cm-1 , assuming that 1 cm3 of ascorbic acid solution has 1 mg ascorbic acid.