Determination Of Vitamin C Concentration By Redox Titration
Ascorbic acid, commonly known as Vitamin C, is a water-soluble vitamin that is essential for the growth and repair of tissues in the human body. It is also an antioxidant that helps to protect cells from damage caused by free radicals. A deficiency in Vitamin C can lead to a number of health problems, including scurvy, anemia, and weakened immunity.
It is important to determine the concentration of Vitamin C in various foods and supplements to ensure that individuals are getting the recommended daily intake. One common method for determining Vitamin C concentration is redox titration.
What Is Redox Titration?
Redox titration is a type of titration that involves a reduction-oxidation (redox) reaction. In this type of reaction, electrons are transferred from one molecule to another. During a redox titration, a solution containing the analyte (the substance being analyzed) is titrated with a solution containing a known concentration of an oxidizing or reducing agent.
In the case of determining Vitamin C concentration, the oxidizing agent used is typically iodine, while the reducing agent is the Vitamin C in the solution being analyzed.
The Procedure
The procedure for determining Vitamin C concentration by redox titration involves several steps:
- Dilute the sample: The sample of the substance being analyzed is typically a food or supplement. To prepare the sample for analysis, it must be diluted with distilled water to a known volume.
- Add indicator: A small amount of indicator solution is added to the sample. The indicator used in this procedure is typically starch. The addition of the indicator causes the solution to turn blue-black.
- Titrate the solution: A solution of iodine is slowly added to the sample until the blue-black color of the solution changes to a light yellow color.
- Record the volume of iodine solution used: The volume of iodine solution used to reach the endpoint is recorded.
- Calculate the concentration of Vitamin C: The concentration of Vitamin C in the sample can be calculated using the volume of iodine solution used and a known equation.
The Equation
The equation used to calculate the concentration of Vitamin C in the sample is:
Vitamin C (mg/mL) = [(Volume of Iodine Solution Used) x (Iodine Concentration) x (Molecular Weight of Vitamin C)] / [(Volume of Sample) x 1000]
Possible Sources Of Error
There are several possible sources of error in the redox titration method for determining Vitamin C concentration. These include:
- Incorrect dilution of the sample
- Presence of other reducing agents in the sample
- Incorrect addition of the indicator
- Incomplete reaction between the iodine and Vitamin C
Conclusion
Determining the concentration of Vitamin C in various foods and supplements is essential to maintaining good health. The redox titration method is a reliable and accurate way to determine Vitamin C concentration. However, it is important to be aware of possible sources of error and to take steps to minimize them.