Analyzing VitaminC 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, KIO3, H2SO4, and H2O • Prepared a solution containing: Ascorbic acid and H2O • 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
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. http://nutritiondata.self.com/ (accessed November 14, 2012). • Zelman, Kathleen M., Web MD. The Benefits of Vitamin C:What can vitamin C do for your health? http://www.webmd.com/diet/features/the-benefits-of-vitamin-c (accessed December 8, 2012).