Transcript Real World Project: Determination of Vitamin C in Fruit Juices

Real World Project: Determination
of Vitamin C in Fruit Juices
Brian Gillease
And
Lauren Burns
Objective
•
•
•
•
Calculate vitamin C in a Vitamin C tablet
Titrate fruit juices
Calculate amount of vitamin C in each juice
Compare juices to tablet
Importance
• Vitamin C –
– antioxidant; binds with carbon, hydrogen, oxygen;
oxidizes easily
– Safe and efficient nutrient, helps protect body
against cardiovascular disease, eye disease, and
other diseases
Procedures - Errors
• Juicer
– too much pulp
• Filtration
– pulp too thick
• Strawberry Juice
– red color of juice
Picture Perfect!
Data
Clementine
Juice
30 mL filtered, digested soln. + 50 mL KIO3
soln. + KI + 10 mL H2SO4 + starch indicator
Trial
1
2
3
Initial Vol. Final Vol.
Vol.
Grams
Mass KI Na2S2O3 Na2S2O3 Na2S2O3 Consumed Moles I3- Ascorbic
(g)
(mL)
(mL)
Added Moles I3- Present
Acid
% Difference
2.0013
2.0009
2.0022
0
0
0
Moles I3- 0.0014046
Formed
66
Manufacture
r's Claim
0.176
26
28.1
29.5
26
0.0011110 0.0002935 0.0517059
92
74
62
70.62161244
28.1
0.0012008 0.0002038 0.0359000
34
32
91
79.60222108
29.5
0.0012606 0.0001440 0.0253628
62
04
43
85.5892935
0.0376562
Average
99
78.60437568
grams per
fruit
Clementine
Juice Spike
30 mL filtered, digested soln. + 50 mL
KIO3 soln. + KI + 10 mL H2SO4 +
starch indicator
Trial
Final
Total Initial Vol. Vol.
Vol.
Consume Moles
Grams
Mass Mass Mass Na2S2O3 Na2S2O Na2S2O3 d Moles
I3Ascorbic
%
KI (g) AA (g) AA (g) (mL)
3 (mL) Added
I3Present
Acid
Difference
1
0.003 0.020
2.0056 1
7
2
0.003
2.015 4 0.021
0
18.5
18.5
3
0.004 0.021
2.0015 2
8
0
20.25
20.25
Moles I3Formed
0.0014
04666
Manufacturer's
Claim
0.0176
0
22
22
0.001574 0.00016 0.0298915 244.403800
384
9717
87
1
0.001323 8.07527 0.0142226 32.2732466
914
E-05
18
8
0.001449 4.44824 0.0078344 135.938000
149
E-05
84
9
0.0078344 137.538349
Average
84
2
Papaya
Juice
30 mL filtered, digested soln. + 50 mL KIO3 soln.
+ KI + 10 mL H2SO4 + starch indicator
Trial
1
2
Initial Vol. Final Vol.
Mass KI Na2S2O3 Na2S2O3
(g)
(mL)
(mL)
2.0009
2.0022
3
2.0014
Moles I3Formed
0.00140
4666
0
0
0
Manufacturer's
grams per
Claim
0.0956
fruit
22.2
21.4
23.2
Vol.
Na2S2O3 Consumed Moles I3Added
Moles I3Present
Grams
Ascorbic
Acid
%
Difference
22.2
0.00094870 0.00045596 0.08030706 100.097215
2
5
2
1
21.4
0.00091451 0.00049015 0.08632834
4
2
7
93.7988006
23.2
0.00099143
0.07278045 107.970233
6
0.00041323
7
2
0.07980528 16.5216645
Average
9
7
Papaya
Juice
Spike
30 mL filtered, digested soln. + 50 mL
KIO3 soln. + KI + 10 mL H2SO4 + starch
indicator
Trial
1
2
3
Moles I3Formed
Manufacturer's
Initial
Vol.
Na2S2 Final Vol. Vol.
Grams
%
Mass Mass Total Mass O3 Na2S2O3 Na2S2O Consumed Moles I3- Ascorbic Differenc
KI (g) AA (g) AA (g)
(mL)
(mL) 3 Added Moles I3- Present
Acid
e
2.0021 0.0029
2.009 0.0032
2.0029 0.0036
0.0014
04666
0.0985
0.0988
0.0992
0
0
0
20
18.2
19.3
20
0.0014312 2.65916E 0.004683 104.7547
58
-05
47
914
18.2
0.0013024 0.000102 0.018003 81.77749
45
222
836
418
19.3
0.0013811 2.35024E 0.004139 95.82724
64
-05
371
659
0.005819 94.11984
Average
913
407
Orange Juice
30 mL filtered, digested soln. + 50 mL KIO3 soln. +
KI + 10 mL H2SO4 + starch indicator
Trial
1
2
Initial Vol. Final Vol.
Na2S2O3 Na2S2O3
Mass KI (g) (mL)
(mL)
2.005
2.0067
3
2.0039
Moles I3Formed
0.0014046
66
Manufacturer's
Claim
0.0511
0
0
0
31.1
30.3
30
Vol.
Na2S2O3 Consumed Moles I3Added
Moles I3- Present
%
Difference
31.1
0.0013290 7.56294E- 0.0133202 73.932925
37
05
75
83
30.3
0.0012948 0.0001098 0.0193415 62.149590
49
17
59
67
30
0.0012820 0.0001226 0.0215995 57.730839
29
37
41
99
Average
grams per
fruit
Grams
Ascorbic
Acid
0.0180871 64.604452
25
17
Orange
Juice Spike
30 mL filtered, digested soln. + 50 mL
KIO3 soln. + KI + 10 mL H2SO4 + starch
indicator
Trial
1
2
3
Moles I3Formed
Initial
Consum
Total
Vol. Final Vol. Vol.
ed
Moles Grams
%
Mass Mass AA Mass Na2S2O Na2S2O Na2S2O Moles
I3Ascorbic Differenc
KI (g)
(g)
AA (g) 3 (mL) 3 (mL) 3 Added
I3Present Acid
e
2.0105 0.004 0.0551
2.0008 0.0039 0.055
2.0065 0.0037 0.0548
0.0014
04666
Manufacturer's
Claim
0.0511
0
0
0
21
19.35
18.55
21
0.00150 9.81545 0.01728 131.374
2821
E-05
7528
8241
19.35
0.00138 1.99242 0.00350 93.6196
4742
E-05
9168
9371
18.55
0.00132 7.71746 0.01359 75.1963
7492
E-05
2415
225
6.19815 100.063
Average E-05
6134
Grapefruit
Juice
30 mL filtered, digested soln. + 50 mL KIO3
soln. + KI + 10 mL H2SO4 + starch indicator
Trial
1
2
Initial Vol. Final Vol.
Mass KI Na2S2O3 Na2S2O3
(g)
(mL)
(mL)
2.0022
1.995
3
2.0039
Moles I3Formed
0.00140
4666
0
0
0
Manufacturer's
grams
Claim
0.0384 per fruit
30.1
33.8
30.5
Vol.
Na2S2O3 Consumed Moles I3Added
Moles I3- Present
Grams
Ascorbic
Acid
%
Difference
30.1
0.0012863 0.0001183 0.0208468 45.711249
03
64
8
4
33.8
0.0014444 -3.97532E- 0.0070015 118.23322
2
05
6
79
30.5
0.0013033 0.0001012 0.0178362 53.551463
96
7
38
28
Average
0.0105605 72.498646
2
85
Grapefruit
Juice
Spike
30 mL filtered, digested soln. + 50 mL KIO3
soln. + KI + 10 mL H2SO4 + starch indicator
Trial
1
2
Total Initial Vol. Final Vol.
Vol.
Grams
Mass KI Mass AA Mass AA Na2S2O3 Na2S2O3 Na2S2O3 Consumed Moles I3- Ascorbic
%
(g)
(g)
(g)
(mL)
(mL)
Added Moles I3- Present
Acid
Difference
2.0056
2.015
3
2.0015
Moles I3Formed
0.00140
4666
Manufacturer's
Claim
0.0384
0.0037
0.0033
0.0037
0.0421
0.0417
0.0421
0
0
0
19
18.5
19.5
19
0.0013596 4.49713E- 0.0079205 81.186249
95
05
89
55
18.5
0.0013239 8.07527E- 0.0142226 65.893001
14
05
18
92
19.5
0.0013954 9.1898E- 0.0016185 96.155440
77
06
6
19
0.0079205 81.078230
Average
89
55
Strawberry
Juice
30 mL filtered, digested soln. + 50 mL KIO3
soln. + KI + 10 mL H2SO4 + starch indicator
Initial
Vol.
Final Vol.
Mass KI Na2S2O3 Na2S2O3
Trial
(g)
(mL)
(mL)
1
2
2.0012
1.9992
3
2.0003
Moles I3Formed
0.001404
666
Manufacturer's
Claim
0.0071
0
0
0
37
28.7
25.5
Vol.
Na2S2O3 Consumed Moles I3Added
Moles I3- Present
%
Difference
37
0.0015811 0.0001765 0.0310866 537.84079
69
03
97
67
28.7
0.0012264 0.0001781 0.0313841 342.02996
75
92
28
76
25.5
0.0010897 0.0003149 0.0554692 681.25725
25
42
65
02
Average
grams
per fruit
Grams
Ascorbic
Acid
0.0185888 161.81547
99
37
Strawberry
Juice Spike
30 mL filtered, digested soln. + 50 mL
KIO3 soln. + KI + 10 mL H2SO4 + starch
indicator
Trial
1
2
3
Moles I3Formed
Initial
Vol.
Total Na2S2 Final Vol. Vol. Consume
Grams
%
Mass Mass Mass AA O3 Na2S2O3 Na2S2O3 d Moles Moles I3- Ascorbic Differenc
KI (g) AA (g)
(g)
(mL)
(mL)
Added
I3Present
Acid
e
2.0034 0.0031 0.0102
2.0021 0.0038 0.0109
2.0018 0.0035 0.0106
0.0014
04666
Manufacturer's
Claim
0.0071
0
0
0
18.4
19.1
20.2
18.4
0.001316 8.7909E- 0.015483 51.79435
757
05
024
343
19.1
0.001366 3.7815E- 0.006660 38.89740
851
05
183
287
20.2
0.001445 4.09042E 0.007204 167.9649
571
-05
281
177
0.004979 86.21889
Average
642
134
Error Source
• Over titrated thiosulfate
• Not enough KI
– Wasn’t an excess of KI to react with
• Refrigerate
– Juices were not refrigerated
• Solutions degrade
– KIO3 degraded; did not work