What are the types of titration for vitamin C?

Answer 1

You titrate samples exactly the same as you did your standard. Record the initial and final volume of iodine solution required to produce the color change at the endpoint.

Titrating Juice Samples

1. Add 25.00 ml of juice sample to a 125 ml Erlenmeyer flask.
2. Titrate until the endpoint is reached. (Add iodine solution until you get a color that persists longer than 20 seconds.)
3. Repeat the titration until you have at least three measurement that agree to within 0.1 ml.

Titrating Real Lemon

Real Lemon is nice to use because the maker lists vitamin C, so you can compare your value with the packaged value.

1. Add 10.00 ml of Real Lemon into a 125 ml Erlenmeyer flask.
2. Titrate until you have at least three measurements that agree within 0.1 ml of iodine solution.

Other Samples

• Vitamin C Tablet - Dissolve the tablet in ~100 ml distilled water. Add distilled water to make 200 ml of solution in a volumetric flask.
• Fresh Fruit Juice - Strain the juice through a coffee filter or cheese cloth to remove pulp and seeds, since they could get stuck in the glassware.
• Packaged Fruit Juice - This also may require straining.
• Fruits & Vegetables - Blend a 100 g sample with ~50 ml of distilled water. Strain the mixture. Wash the filter with a few milliliters of distilled water. Add distilled water to make a final solution of 100 ml in a volumetric flask.

Titrate these samples in the same way as the juice sample described above.

Answer 2

The two common types of titration used for vitamin C are iodometric titration and dye-based titration. In iodometric titration, vitamin C is titrated with an iodine solution using a starch indicator. In dye-based titration, a redox indicator dye is used to determine the endpoint of the titration.