Presentation on theme: "Real World: Calcium in Milk"— Presentation transcript:
1Real World: Calcium in Milk By: Chealsa Mooney and Christina Robinson
2PurposeTo 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.
3Procedure One Calmagite Indicator Weighed out EDTA, dissolved in 1000mL. Resulted in M EDTA solutionCreated ammonia bufferIn 250mL Erlenmeyer flask put 50mL of milk, 3mL ammonia buffer and small amount of calmagite indicator.Titrated with EDTA solution.
5Procedure Two Patton-Reeder Used same solution of EDTA. In 250mL Erlenmeyer flask put 10mL of milk, 40mL distilled water, and 4mL of 8M NaOH.Allowed solution to sit for 5 minutes for precipitate to form.Added 0.05g of Patton-Reeder indicator when precipitate formed.Titrated with EDTA solution.
6Spike ProcedureIn 250mL Erlenmeyer flask put 10mL of milk, 3mL ammonia buffer, 1mL spike and small amount of calmagite indicator.Titrated with EDTA solution.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.
13Calculations EX: 1% milk Ca2+ concentration in milk L EDTA x M EDTA x 1mol Ca 2+ x molar mass Ca 2+1mol EDTAL x M x 1mol Ca 2+ x g/mol Ca 2+ =Grams of Calcium per servinggrams Ca 2+ x volvol sample servingg x 240mL = g50mL serving serving
14Calculations cont.Grams of Calcium per serving based on 2,000 calorie dietmg Ca 2+ (needed daily) x g x %Ca 2+ in milk1000 mg11oo mg x g x 60% = 0.66g Ca 2+1000mgPercent DifferenceActual - Experimental x 100%Actualx 100% = 18.9%0.66
16Conclusion- 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
17Sources of error: - misreading the buret - Some trials might have needed to betitrated more (blueendpoint but thenafter a minute itwould go back topurple)-not letting the milk sit long enough to let the magnesium oxide form. (that's what reacted with the indicator)
18ReferencesDetermination of Calcium Ion Concentration. College of Science. University of Canterbury, n.d. Web. 12 Decnts/calcium.pdf•Harris, Daniel C. Quantitative Chemical Analysis, 8th ed.; W.H. Freeman and Company: New York, 2010, page 240.