Practical : Comparison of the vitamin c content of
1: Label six test tubes 1-6.
2: Use a 2cm syringe to put 1cm DCPIP solution into each tube .
3: Use a fresh syringe to draw up 2cm of 0.1% ascorbic acid solution.
4: Squeeze plunger of syringe carefully so you add one drop of ascorbic acid solution to the DCPIP in tube 1.Shake tube and continue adding ascorbic acid until blue dye turns to a colourless liquid.
5: Note the position of plunger in syringe and subract reading from 2.0. This will tell you volume of ascorbic acid solution you have added.
6:Write volume in appropriate space in table.
7:Wash syringe and repeat with one of the fruit juices , using DCPIP in tube 2 .
*Note:the acid in fruit juice may turn DCPIP from blue to red but it is the point which the dye becomes colourless that counts.
The less drops needed , the more vitamin c present