Investigation Vitamin C

Essay by davidraaamosHigh School, 12th gradeD+, November 2014

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David Ramos Rivero Biology AS


Antioxidants are chemicals that help prevent damage within cells by unstable radicals. Chemical reactions within cells produce radicals. Radicals are oxidising agents Vitamin C is an example of an antioxidant that prevents the damage caused by radicals by providing hydrogen atoms whose electrons pair up with the unpaired electrons in the radicals. Ascorbic acid (Vitamin C) has a chemical structure of C6H8O6. The purpose of this experiment is to investigate the vitamin C content of fruit juice. We will use dichlorophenolindophenol DCPIP solution as an indicator. The reaction between DCPIP and Vitamin will show the amount of Ascorbic acid in each juice.

Structure of Vitamin C


My prediction is that the less volume of solution to cause a colour change of DCPIP solution, then the juice has a greater solution of Vitamin C.

Fair Testing

Independent variable: Fruit Juice - The student should put a certain volume into a clean burette. Also, you should don't get the pulp into the burette as it will obstruct it. Therefore, the student should get the top of the juice and don't shake the juice.

Control Variables:

Use the same type of indicator each time - DCPIP

Same room temperature

Same concentration of DCPIP solution (0.1%) all time

Same volume of DCPIP solution - 1cm3

Dependent Variable: Volume of Juice needed to decolourise 1cm3 of DCPIP.

Reliability, accuracy and precise

Students will need to be careful controlling temperature as it may change the results. Also, they need to control the force when they shake it and the times as if they do it too much It will add oxygen to the DCPIP. Be careful not to lose any solution, changing...