Determination Of Vitamin C Concentration By Titration Using Potassium Iodate
Vitamin C is an essential nutrient that plays a crucial role in maintaining good health. It is a powerful antioxidant that helps protect the body against damage caused by free radicals. The human body cannot produce vitamin C, which means that it must be obtained through diet or supplements. However, not all sources of vitamin C are equal in terms of their concentration and bioavailability. Therefore, it is important to accurately determine the concentration of vitamin C in different sources.
What Is Titration?
Titration is a common laboratory technique used to determine the concentration of a substance in a solution. It involves adding a known volume of a solution of known concentration (the titrant) to a solution of the substance being analyzed (the analyte) until the reaction is complete. The point at which the reaction is complete is known as the endpoint, and it is usually detected using an indicator or by monitoring a physical property of the solution, such as pH or conductivity.
Titration Of Vitamin C With Potassium Iodate
Vitamin C can be titrated with potassium iodate, which reacts with the ascorbic acid in the presence of an acid catalyst to produce iodine. The iodine is then titrated with a standard solution of sodium thiosulfate until the endpoint is reached. The concentration of vitamin C in the sample can then be calculated using the stoichiometry of the reaction.
Preparation Of Reagents
The reagents required for the titration of vitamin C with potassium iodate are as follows:
- Potassium iodate solution
- Sodium thiosulfate solution
- Starch solution
- Sulfuric acid solution
- Vitamin C sample
The potassium iodate solution should be standardized against a primary standard, such as sodium thiosulfate, before use. The sodium thiosulfate solution should be standardized against a primary standard, such as potassium dichromate, before use. The starch solution should be freshly prepared before use.
Titration Procedure
The titration procedure for vitamin C with potassium iodate is as follows:
- Weigh out a sample of the vitamin C and dissolve it in 50 ml of distilled water.
- Add 5 ml of 1M sulfuric acid to the solution and mix well.
- Add 10 ml of potassium iodate solution to the solution and mix well.
- Allow the mixture to stand for 5 minutes to allow the reaction to proceed.
- Add starch solution to the mixture and titrate with sodium thiosulfate solution until the blue color disappears.
- Repeat the titration until consistent results are obtained.
Calculation Of Vitamin C Concentration
The concentration of vitamin C in the sample can be calculated using the following formula:
Concentration of vitamin C (mg/ml) = (volume of sodium thiosulfate solution × concentration of sodium thiosulfate solution × 176.12) ÷ (weight of vitamin C sample × 1000)
Where:
- Volume of sodium thiosulfate solution is the volume required to reach the endpoint
- Concentration of sodium thiosulfate solution is the known concentration of the standard solution
- Weight of vitamin C sample is the weight of the sample used in the titration
Conclusion
The determination of vitamin C concentration by titration using potassium iodate is a simple and reliable method that can be used to accurately determine the concentration of vitamin C in different sources. By knowing the concentration of vitamin C in different sources, we can make informed decisions about our diet and supplement intake to ensure that we are getting enough of this essential nutrient for optimal health.