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4.0 DISCUSSION
Vitamin C can be determined by acid-base reaction or oxidation-reduction reaction. 2,6-dichlorophenolindophenol, DCPIP solution can be used as an indicator for vitamin C [11]. DCPIP is used as a good indicator because ascorbic acid has two protons that can accept from ascorbic acid and also ascorbic acid has two protons which can donate to DCPIP. The C=O from DCPIP accepts to protons to eventually become C-OH and the C=O is a good proton acceptor because the C=O is very reactive. If vitamin C, which is a good reducing agent. DCPIP solution is a weak oxidizing agent, so that it will not oxidize substances other than the ascorbic acid in the sample of fruit juice. In present, the blue dye, which turns pink in acid conditions, is reduced to a colourless compound by ascorbic acid. The following reactions give a brief description of the overall reaction