Spectrophotometric Determination of Iron in Vitamin Tablets Essay Example
Lab 2: Spectrophotometric Determination of Iron In Vitamin Tablets
Objectives:
- To determine the amount of iron in a generic vitamin tablet on a per tablet (in grams) basis.
- To prepare standards using a pre-made iron solution to help determine the iron content in our generic vitamin tablets
- Determine absorbances of our vitamin tablets and standards using the spectrophotometer
Method:
1. Mass three vitamin tablets that contain iron
2. Place each vitamin in a 125-mL Erlenmeyer flask with 25 mL of 6M HCl
3. Do the same as above with no vitamin (This will be the reagent blank)
4. In the hood, simmer until the vitamin completely dissolves plus an additional 3 minutes.
5. After vitamin dissolves, allow to cool and then filter to a 100-mL volumetric flask.
6. Be sure to wash original beaker with water to allow for a quantitative transfer
7. Dilute to the mark on the beaker and mix well
8. Use citrate solution to determine how many drops are needed to make 0.5 mL of the vitamin extract to pH ~ 3.5, using the pH paper. (Count the drops; Only need to do this once)
9. Using a micropipette take 0.5 mL of originally diluted solution (vitamin extract) and place into a new 100 mL volumetric flask.
10. Add number of drops determined before of citrate solution
11. Add 2 mL of hydroquinone solution
12. Add 3 mL of o-phenanthroline solution
13. Dilute to the mark again and mix well.
14. Let color develop for 20 minutes
Standards:
1. Use a pipet to place 10 mL of 0.04 mg/mL iron solution into a beaker.
2. Measure the pH and add citrate solution until pH ~ 3.5 is reached (Count the drops)
3. Use a pipet to place a fresh 10 mL of the 0.04 mg/mL iron solution into a 100 mL volumetric flask
4. Add number of drops determine previously of citrate solution
5. Add 2 mL of hydroquinone
6. Add 3 mL of o-phenanthroline solution
7. Dilute to the mark using water and mix well
8. Do the same to make standard solutions using 5, 2 and 1 mL of the 0.04 mg/mL Fe
Objectives:
- To determine the amount of iron in a generic vitamin tablet on a per tablet (in grams) basis.
- To prepare standards using a pre-made iron solution to help determine the iron content in our generic vitamin tablets
- Determine absorbances of our vitamin tablets and standards using the spectrophotometer
Method:
1. Mass three vitamin tablets that contain iron
2. Place each vitamin in a 125-mL Erlenmeyer flask with 25 mL of 6M HCl
3. Do the same as above with no vitamin (This will be the reagent blank)
4. In the hood, simmer until the vitamin completely dissolves plus an additional 3 minutes.
5. After vitamin dissolves, allow to cool and then filter to a 100-mL volumetric flask.
6. Be sure to wash original beaker with water to allow for a quantitative transfer
7. Dilute to the mark on the beaker and mix well
8. Use citrate solution to determine how many drops are needed to make 0.5 mL of the vitamin extract to pH ~ 3.5, using the pH paper. (Count the drops; Only need to do this once)
9. Using a micropipette take 0.5 mL of originally diluted solution (vitamin extract) and place into a new 100 mL volumetric flask.
10. Add number of drops determined before of citrate solution
11. Add 2 mL of hydroquinone solution
12. Add 3 mL of o-phenanthroline solution
13. Dilute to the mark again and mix well.
14. Let color develop for 20 minutes
Standards:
1. Use a pipet to place 10 mL of 0.04 mg/mL iron solution into a beaker.
2. Measure the pH and add citrate solution until pH ~ 3.5 is reached (Count the drops)
3. Use a pipet to place a fresh 10 mL of the 0.04 mg/mL iron solution into a 100 mL volumetric flask
4. Add number of drops determine previously of citrate solution
5. Add 2 mL of hydroquinone
6. Add 3 mL of o-phenanthroline solution
7. Dilute to the mark using water and mix well
8. Do the same to make standard solutions using 5, 2 and 1 mL of the 0.04 mg/mL Fe