The methods used to analyze the products, data, and results will be provided in the sections below. Experimental: The entire experiment is based on the results from the calibration curve. The calibration curve is used to generate an equation that is then used to calculate malarial. This value is then converted to the desired unit, milliards. So, to obtain the calibration curve data, two students began by preparing two solutions. The first was 100 ml of 1. 0 x 10-3 M Fee(NON)3, and the second was 100 ml of 0. 10 M SKIN. Both solutions were made in 1. 0 HON… The former solution was prepared using 0. 404 grams of Fee(NON)OH on an analytical balance (calculations below). The latter solution was prepared using 0. 97 grams of SKIN on a top loading balance (calculations below). Then, 1. 0 ml of the iron nitrate solution was added to 100 ml of the SKIN solution and mixed. Being that the spectrophotometer (the instrument being used to measure absorbency) was already zeroed by the teaching assistant, the construction of the calibration curve could begin. To start, the cavetti was filled with the current mixture, placed into the spectrophotometer, and the absorbency was recorded.
The cavetti was then emptied back into the beaker containing the entire solution, as not to skew the overall volume, and therefore the concentration. Then, another 1. 0 ml of the iron nitrate solution was added to the original mixture, and used to rinse the cavetti 3 times. The cavetti was again filled with solution, placed in the spectrophotometer, and its absorbency was recorded. Again, the solution was returned to the same beaker, and another 1. 0 ml of iron nitrate was added to the beaker. This process was repeated until 10 different concentrations were measures for absorbency, each containing 1. L more iron nitrate than the previous trial. The resulting data is then used to produce a Beers-Lambert Plot where absorbency is a function of concentration. The scatter plot yielded, is then curve-fitted, and an equation is produced that is then used in the subsequent steps of this experiment. The plot of the data, or calibration curve, is below in the results section. In order to apply the calibration curve, the next step in the experiment was the cereal extraction. To do this, 32. 0 grams of [email protected] cereal was weighed out on a top loading balance. Then, in a sealed plastic freezer bag, it was finely crushed. Next, 30. Grams of the crushed cereal was measured out on a top loading balance, placed in a 600 ml beaker. A Teflon magnet and 250 ml of De-unionized water are then added to the beaker. The beaker was then stirred on a stirring plate for 15 minutes. After, the magnet is removed it contained small iron filaments. To remove the filaments, the magnet was placed into a beaker with 50 ml of 1. 0 M HON… This beaker was warm and swirled for about 10 minutes, until all of the iron was removed. The magnet was then rinsed with with 2-3 ml of 1. 0 M HON… The magnet was then placed back into the cereal slurry and tiered for another 15 minutes.
Again, the magnet was removed, placed into the beaker with the 1. 0 M HON.. And warm and swirled in order to remove the iron. This process was repeated until the magnet comes out of the slurry without any iron. After this, the magnet was rinsed a final time with 1. 0 M HON.., making sure to pour the rinses into the same beaker that collected the previous rinses. The rinse beaker was put into a 100. 00 ml volumetric flask then filled to the mark with 1. 0 M HON… Next, 100 ml of 0. MM SKIN was prepared in a 100. 00 ml volumetric flask using 1. 0 M HON… This solution was then poured into a 250 ml eager and 1. 0 ml of the cereal sample solution is pipettes in. The absorbency of this solution was then measured and recorded (results below). The final step of this experiment was the Iron Tablet extraction. To perform this step, a 325 MGM iron tablet was placed into a 25 ml Erlenmeyer flask and 20 ml of 5 M HON.. Was added. This solution was then stirred and warmed for 10 minutes, or enough time to allow the tablet to be crushed. Once crushed, the solution was heated again for 10 minutes. Next, the liquid was decanted into a 100 ml volumetric flask. The remaining solid was then washed 4 times with 15 L of ODL water.
However, to construct the calibration curve, only Curt’s calibration curve data (me) was used so as standardize the results for this particular report. Other than that, the cereal extraction results and the iron tablet results were all averaged to produce one absorbency value to be used in the calculation for that particular section (cereal/iron tablet). The calibration curve data was graphed and curve-fitted, producing the equation: y = 6318. Xx – 0. 0465. The average of all 8 cereal extractions produced an absorbency value of . 294 and the average of all 4 iron tablet extractions produced an absorbency value of . 224.
For the cereal extraction calculation, . 294 was plugged in for Y’ in the calibration curve equation. When the equation is solved in terms of “x”, it produces a value of 5. 39 x 10-5. This equates to the malarial of Fee and then a simple geochemistry equation produces a value in milliards from this. The geochemistry was possible because there were known values for the amount of solution (SKIN + cereal sample) and the molar mass of BE. For the cereal sample, it was found that 30. 4 MGM of iron were present. The ERDA for Fee is reported at 8 MGM. The cereal box claimed to have 100% of ERDA for Fee in one serving size of 30. Rams, which was the exact amount used in the experiment. For the iron tablet extraction calculation, . 224 was plugged in for “Y’ in the calibration curve equation. When the equation is solved in terms of “x”, it produces a value of 4. 28 x 10-5 . This equates to the malarial of Be and then a simple geochemistry equation produces a value in milliards from this.. For the cereal sample, it was found that 241 MGM of iron were present. The tablet used claimed to have 361% of the ERDA value for Fee, which would mean it contains 28. 88 MGM of Fee. However, the experiment, produced a much higher iron concentration.
These values could have been affected by a plethora of errors made during the experiment. Contamination of the solutions, incorrect measuring of substances or not correctly zeroing instruments all play a factor in the data. Avery likely culprit in this particular experiment could be that there were not a sufficient number of magnet rinses, therefore, there might have still been some iron in the cereal that was not extracted out. An error could very well have been made when decanting the liquid during the iron tablet extraction as well. Finally, if the calibration curve was incorrectly constructed, then the results loud surely be skewed.
It should also be noted that the particular forms of iron in both the cereal and the tablet are different. As explained in the lab manual, the form of iron in the iron tablets is ferrous sulfate. This means the iron is Fee+. This is different than the iron that is present in the cereal, which is in elemental form, again, according to the lab manual. Both of these forms of iron act differently in terms of how the human body takes each kind in. The elemental iron in the cereal is absorbed by the body much slower than it absorbs the Fee+ form of iron in the ferrous sulfate f the iron tablet.
So, it is more advantageous for the body if it receives the iron tablet. Conclusion This lab was aimed towards highlighting a certain method, utilizing a calibration curve to analyze extraction data, to ascertain iron concentration values in different substances. To briefly summarize, a calibration curve, using the Beers- Lambert plot was constructed using known values of known substances to produce a fitted-line equation. Iron was then extracted from the cereal and iron tablets and their absorption values were put into the calibration curve equation o find the malarial of the substance.
Then, using known values and geochemistry, the malarial was converted to milliards. This value was then comparable to the values listed on the two products. Although, the FDA speculated that the iron concentrations in both the cereal and iron tablets were lower than reported, the results of the lab showed that they were actually higher than reported. However, as explained in the discussion section, many errors that may have been made during the experiment, could have contributed to the results and therefore would skew the comparisons.