Presentation on theme: "Real World: Calcium in Milk By: Chealsa Mooney and Christina Robinson."— Presentation transcript:
Real World: Calcium in Milk By: Chealsa Mooney and Christina Robinson
To determine how much calcium was in different types of milk and comparing them to their known values. Using two different types of indicators and comparing the results they produce. Purpose
Procedure One Calmagite Indicator 1.Weighed out EDTA, dissolved in 1000mL. Resulted in 0.0361M EDTA solution 2.Created ammonia buffer 3.In 250mL Erlenmeyer flask put 50mL of milk, 3mL ammonia buffer and small amount of calmagite indicator. 4.Titrated with EDTA solution.
Procedure Two Patton-Reeder 1.Used same solution of EDTA. 2.In 250mL Erlenmeyer flask put 10mL of milk, 40mL distilled water, and 4mL of 8M NaOH. 3.Allowed solution to sit for 5 minutes for precipitate to form. 4.Added 0.05g of Patton-Reeder indicator when precipitate formed. 5.Titrated with EDTA solution.
Spike Procedure 1.In 250mL Erlenmeyer flask put 10mL of milk, 3mL ammonia buffer, 1mL spike and small amount of calmagite indicator. 2.Titrated with EDTA solution. 3.To test without the spike to see if it produced the same result we put in a 250mL Erlenmeyer flask 10mL of milk, 3mL ammonia buffer and small amount of calmagite indicator. 4.Titrated with EDTA solution.
Data Types of milkPercentage of Calcium 1% milk 60% 2% milk 30% Nonfat skim milk 25% Lactose milk 50% Skim milk 45%
Data Calmagite Indicator Ex: Soy milk Aver: 0.02082g mL of EDTACa2+ conc. (g) Trial 116.8mL0.02327g Trial 215.2mL0.02105g Trial 313.1mL0.01814g
Calculations EX: 1% milk Ca2+ concentration in milk L EDTA x M EDTA x 1mol Ca 2+ x molar mass Ca 2+ 1mol EDTA 0.0771 L x 0.0361 M x 1mol Ca 2+ x 40.078 g/mol Ca 2+ =0.11155 1mol EDTA Grams of Calcium per serving grams Ca 2+ x vol vol sample serving 0.11155 g x 240mL = 0.53544 g 50mL serving serving
Calculations cont. Grams of Calcium per serving based on 2,000 calorie diet mg Ca 2+ (needed daily) x 1 g x %Ca 2+ in milk 1000 mg 11oo mg x 1 g x 60% = 0.66g Ca 2+ 1000mg Percent Difference Actual - Experimental x 100% Actual 0.66 - 0.5354 x 100% = 18.9% 0.66
Conclusion - The calmagite indicator took a lot more EDTA to reach the endpoint -Overall, the Patton-Reeder indicator produced better results although the lowest percent difference came from the Lactose milk using the Calmagite indicator. (7.68% difference) -Calmagite indicator with the skim milk produced the highest percent difference (102%) -The spike test produced good results. It took about that same amount of EDTA to titrate samples with and without the CaCO3
Sources of error: - misreading the buret - Some trials might have needed to be titrated more (blue endpoint but then after a minute it would go back to purple)
References Determination of Calcium Ion Concentration. College of Science. University of Canterbury, n.d. Web. 12 Dec. 2012. http://www.outreach.canterbury.ac.nz/chemistry/docume nts/calcium.pdf Harris, Daniel C. Quantitative Chemical Analysis, 8th ed.; W.H. Freeman and Company: New York, 2010, page 240.