Transcript Determining the Iron Content in Vitamins

Determining the Iron Content in
Vitamins
Rachel Warehime & John Siller
Purpose
• Use two different methods
▫ Gravimetric determination
▫ Spectrometry determination
• Various vitamins
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One A Day (Women’s and Men’s)
Prenatal Vitamins
General Complete Multivitamin
Kids Chewable Tablet
Senior Vitamins
Procedure #1
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Fired crucibles and weighed until mass was reproduced.
Weigh out 0.5 gram sample of each vitamin
Dissolve in 3M HCl, add 5 mL 6M HNO3, boil for 2 minutes.
Dilute to 200 mL, add 3M ammonia until basic, and boil for 5
minutes.
Decant supernatant through ashless filter paper and wash the solid
with 1 % NH4NO3.
Allow filter paper to dry for 24 hours.
Place filter paper with solid in weighed crucibles and ignite the
paper in the 900◦C oven and put the lid on the crucible.
Let the crucibles cool for 15 minutes and then weigh them to
determine the weight of iron left in the crucibles.
Data
• Men’s (A&G)
▫ A = 0.5010 g
• Women’s (B&H)
▫ B = 0.5010 g
• Senior (C&I)
▫ C = 0.5040 g
G = 0.5022 g
H = 0.5001 g
I = 0.5012 g
• Kids (D&J)
▫ D = 0.5008 g
J = 0.5023 g
• Prenatal (E&K)
▫ E = 0.5019 g
K = 0.5008 g
• General (F&L)
▫ F = 0.5022 g
L = 0.5003 g
Milligrams of Fe found in vitamins
• Men’s (A&G)
▫ A = 1.61 mg (0.0012 g)
• Women’s (B&H)
▫ B = 18.67 mg (0.0132 g)
• Senior (C&I)
▫ C = 27.8 mg (0.02 g)
G = 4.13 mg (0.003 g)
H = 18.05 mg (0.0129 g)
I = 24.1 mg (0.0174 g)
• Kids (D&J)
▫ D = 8.8 mg (0.0063 g)
J = 7.41 mg (0.0053 g)
• Prenatal (E&K)
▫ E = dropped lid
K = 23.7 mg (0.017 g)
• General (F&L)
▫ F = 132.9 mg (0.0958 g)
L = 214.5 mg (0.1534 g)
Comparison
• Men’s
▫ Actual = 0 mg
Experimental = 1.61 mg & 4.33 mg
• Women’s
▫ 18 mg
Experimental = 18.67 mg & 18.05 mg
• Senior
▫ 8 mg
Experimental = 27.8 mg & 24.1 mg
• Kids
▫ 15 mg
Experimental = 8.8 mg & 7.41 mg
• Prenatal
▫ 28 mg
Experimental = dropped lid & 23.7 mg
• General
▫ 18 mg
Experimental = 132.9 mg & 214.5 mg
Procedure #2
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Place one tablet in a flask with 25 mL of HCl and boil for 15 minutes.
Filter the solution once cooled and dilute 5 mL to 100 mL in flask.
From this solution, we made 4 more solutions.
Pipet 10 mL, 5 mL, 2 mL, and 1 mL into different flasks and dilute
them all to 100 mL with distilled water.
• Measure the absorbance of these solutions at a wavelength of 265
nm
Data
• Mass of tablets
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Men’s
Women’s
Senior
Kids
Prenatal
General
1.4974 g
1.7850 g
2.2343 g
1.1538 g
1.1063 g
1.5455 g
Absorbance Graphs
0.3
0.5
Men's
Women's
0.45
0.25
0.4
0.35
0.2
0.3
0.15
0.25
Series1
0.2
Series1
0.1
0.15
0.1
0.05
0.05
0
0
5
10
15
0
0
2
4
6
8
10
12
Absorbance Graphs
0.3
Senior
0.35
Kids
0.3
0.25
0.25
0.2
0.2
0.15
Series1
Series1
0.15
0.1
0.1
0.05
0.05
0
0
0
5
10
15
0
5
10
15
Absorbance Graphs
0.35
Prenatal
0.3
0.3
General
0.25
0.25
0.2
0.2
0.15
Series1
0.15
Series1
0.1
0.1
0.05
0.05
0
0
0
5
10
15
0
2
4
6
8
10
12
Discussion
• First procedure was successful
• Second procedure was not
▫ Human error
▫ Better procedure
▫ Not using certain chemicals listed
 Were not available