C118 Laboratory Determination of Iron in Total Cereal Worksheet – 25 Points Name________________________ Lab Partner___________________ 1. (1 pt.) An adequate supply of minerals (ions or inorganic compounds) is essential for good health. List some of the functions of iron in the body. 2. (2 pts.) What is the difference between heme and nonheme sources of iron? Refer to chemical structures as well as differences in absorption in your answer. 3. (2 pts.) What other minerals are present in Total cereal? List their functions in the body. What form of these minerals are present in the cereal? 4. (2 pts.) Record observations from the various steps in the experiment. a) Appearance of Teflon stir bar after it has been removed from cereal slurry. b) Addition of concentrated aqueous HCl (during and after dissolution of iron) c) After addition of color forming agent 2,2 dipyridyl to standards and sample5. (2 pts.) Give the purpose of adding the following to the sample and Fe2+ standards 2 drops of 1.0 M HCl 6 drops of 2.0 M sodium acetate 0.50 mL of 10% hydroxylamine 6. (2 pts.) Describe how a 6 ppm Fe2+ standard can be prepared from a 10 ppm Fe2+ stock solution using a 10 mL graduated pipet and 10 mL volumetric flask. Show any relevant calculations. 8. (4 pts.) Attach a plot of a calibration curve of absorbance vs. concentration of your standards. Were any data points discarded? Include the equation for the straight line and the R2 value. What can be inferred about the accuracy and precision of the experiment from the R2 value? Do you feel the R2 value is adequate for providing accurate results? 9. (1 pt) Calculate the concentration of Fe2+ in the solution analyzed from the calibration curve. 10. (2 pts.) Based on your answer in number 9, calculate the amount of Fe (s) in the total cereal sample. Report your answer in units of mg (Fe)/g of cereal. 11. (2 pts.) Calculate the amount of iron in one serving of cereal. (Use the serving size listed on the box). How does your analysis compare with the reported value?12. (2 pts.) Calculate the amount of iron you would ingest in the amount of Total cereal that you would normally eat? Compare this amount to the RDA for iron for you. 13. (3 pts.) Evaluate the form of iron used in Total cereal for fortification. Do you feel that this iron will be readily absorbed and utilized by your
View Full Document
Unlocking...