Analyzing Vitamin C Content in Varieties of Fruit Kristen Eccleston Melinda Kitts Drew Landerman Tim Abell Nick Reichart

Purpose  The purpose of this lab was to take different types of fruits and titrate them with standardized iodine solution over a period of 3 weeks. We wanted to see if time affected the vitamin C content in each fruit.

Importance  Vitamin C is crucial to the body  Daily intake of Vitamin C is necessary

Procedure  Prepared a solution containing: KI, KIO 3, H 2 SO 4, and H 2 O  Prepared a solution containing: Ascorbic acid and H 2 O  Made starch indicator daily  Used 25mL of juice sample and 10 drops of starch indicator  Titrated with standardized iodine solution

Solution Standardization  Used prepared iodine solution  Standardized the solution using an ascorbic acid solution

Sample Preparation  Approximately 100g of fruit prepared  Juice extracted  Juice diluted to 100mL with DI water  25mL aliquots with 10 drops starch indicator prepared  Three trials prepared

Titration procedure  Buret filled with iodine solution  Each sample titrated to uniform and consistent color  Amount of iodine solution added recorded

Data

Error Discussion  Did not spike before titration  Fruit juice did not mix thoroughly when diluted with distilled water  Overshot titration because unknown color change  Didn’t re-standardize iodine solution daily  Juicer may not have completely extracted the juice from the fruit

Summary  Expected to decrease over time  Source stated that after fruit is picked, Vitamin C content stays somewhat constant over time  Some worked better than others

Works Cited  Self Nutrition Data. Nutrition Facts. (accessed November 14, 2012).  Zelman, Kathleen M., Web MD. The Benefits of Vitamin C:What can vitamin C do for your health? e-benefits-of-vitamin-c (accessed December 8, 2012). e-benefits-of-vitamin-c