This experiment used EDTA titration to determine and compare the calcium concentrations in orange juices from Augsburg and St. Thomas cafeterias. The results found that Augsburg orange juice contained 76.49 mg of calcium per 8 fluid ounces, which was slightly higher than the 72.32 mg of calcium found in 8 fluid ounces of St. Thomas orange juice. Atomic absorption spectroscopy analysis by another researcher found similar results. Both methods provided comparable data on the higher calcium content of Augsburg orange juice.

1. Determination of Calcium in Orange Juice via EDTA Titration
Chris Myers, Chm 353 Quantitative Analysis Final Project
Introduction
• The purpose of this experiment was to determine calcium
concentrations between orange juices taken from Augsburg’s
cafeteria and St. Thomas’s cafeteria.
• Another purpose of this experiment was to examine and compare
methods of calcium determination as both EDTA titration and AAS
were used.
• Calcium is the most abundant mineral in the body and is extremely
important in bone and tooth strength.
• The Institute of Medicine of the National Academy of Sciences
found that many Americans are not meeting there daily
requirements of calcium (1000 mg daily).
• Foods rich in calcium are milk, yogurt, cheese, cabbage, kale,
spinach, broccoli, calcium fortified juices, breads, and cereals.
• So who cares more about our health; Augsburg or St. Thomas? Lets
see.
Results & Discussion
• Since the EDTA and mole ratios
were 1:1 calcium concentration
was then calculated off of data
collected from EDTA titration
and standardization
• What was found was that
Augsburg orange juice had
76.49 mg calcium in 8 fluid oz
and St. Thomas had 72.32 mg calcium in 8 fluid oz.
• When comparing this data to the AAS data collected by Dave
Bergstrand, a correlation was found as AAS data also showed
Augsburg OJ having a higher calcium content (82.42mg vs 79.95mg).
Methods
• This experiment used EDTA titration to calculate
calcium concentration.
• Each orange juice solution was prepared by
filtration and then a 1:1 dilution with 0.1M HCl.
• An ammonia buffer (pH 10) was used along with
a calmagite indicator to calculate endpoint
during titration (wine red to blue).
• Lastly the EDTA solution was standardized by a
CaCO3 0.1 M HCl solution.
References
Office of Dietary Supplements. Dietary Supplement Fact Sheet:
Calcium.
http://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/
(accessed Apr 23, 2013)
Conclusion
• What was found from both EDTA titration and AAS was that Augsburg
had orange juice with a higher calcium concentration than St. Thomas
did.
• It was also found that both methods worked and had similar results.
• The accuracy of the methods couldn’t be calculated due to literature
values being absent from dispenser.
Acknowledgement (optional)
• Dave Bergstrand who performed AAS
Augsburg Orange Juice St. Thomas Orange Juice
Trial 1 Vol 3.7 ml Trial 1 Vol 3.4 ml
Trial 2 Vol 3.6 ml Trial 2 Vol 3.5 ml
Trial 3 Vol 3.7 ml Trial 3 Vol 3.4 ml
Average Vol 3.67 ml Average Vol 3.47 ml
Trial 1 mol 0.000041 Trial 1 mol 0.000037
Trial 2 mol 0.000040 Trial 2 mol 0.000039
Trial 3 mol 0.000041 Trial 3 mol 0.000039
Average mol 0.000040 Average mol 0.000038
Calcium (mg) 1.62 per 5 ml Calcium (mg) 1.53 per 5 ml
8 Fluid oz = 76.49 mg calcium 8 Fluid oz = 72.32 mg calcium