Examining Elements in Cereals A Real World Project By Nicole Dixon and Amanda Lagace

Purpose The purpose of our experiment was to analyze the mineral content in cereal products in order to make a comparison to the reported values. The content analyses of sodium, potassium, magnesium, calcium, copper, iron, and zinc were performed by the ICP-OES, and the analyses of iron and zinc were performed again using the AA. We analyzed the content using a calibration curve made from standards of various concentrations, and the cereal products we analyzed were Cheerios, Total, Oatmeal Crisp, and Cocoa Puffs.

Method We began this procedure by creating 1L of 0.1M nitric acid to use as a solvent. We then created standards for the experiment. We made standards from the sodium, potassium, magnesium, calcium, copper, iron, and zinc stock solutions in concentrations of 10ppm, 20ppm, 30ppm, 40ppm, and 50ppm in 100mL volumetric flasks with nitric acid. We also set aside a blank of nitric acid for analysis. We then created our cereal samples for analysis. We first crushed 0.1g of cereal with a mortar and pestle and dissolved it in 100mL of nitric acid. We used a stir plate for several minutes in order to dissolve most of the sample. What could not be dissolved we filtered out of the solution with filter paper. We ran the blank, standards, and samples on the ICP for the presence of the seven elements. We used the information from the standard to create a calibration curve in order to determine the concentration of the elements in the samples. We then ran the blank, standards, and samples on the AA for the presence of zinc and iron, using the information from the standards again to create a calibration curve to determine the sample concentrations. We used the concentration determined by experimentation to compare to the reported values on the cereal boxes and we calculated the percent difference between the two.

Data Cereal Samples Massed Out Cheerios0.101 g Total g Oatmeal Crisp g Cocoa Puffs g

Data-AA AA Data SampleAbsorbance 10 ppm ppm ppm ppm ppm0.850 Oatmeal Crisp0.162 Cheerios0.260 Total0.021 Cocoa Puffs0.019 SampleAbsorbance 10 ppm ppm ppm ppm ppm1.917 Oatmeal Crisp1.732 Cheerios0.183 Total0.080 Cocoa Puffs0.117 Iron Zinc Iron: Zinc

AA Calibration Curves

Data-ICP SampleCa Int. (c/s)Cu Int. (c/s)Fe Int. (c/s)K Int. (c/s)Mg Int. (c/s)Na Int. (c/s)Zn Int. (c/s) 10 ppm ppm ppm ppm ppmN/A Oatmeal Crisp Cheerios Total Cocoa Puffs

ICP Calibration Curves

ICP Calibration Curves (cont)

Even More Data CheeriosTotalOatmeal CrispCocoa Puffs Sodium160mg140mg125mg150mg Potassium170mg90mg190mg70mg Calcium100mg1000mg20mg100mg Iron6.75mg15mg7.5mg3.75mg Zinc3.75mg15mgNot reported3.75mg Magnesium35mg21mg35mg14mg CopperNot reported 0.04mg Reported values of elements in one serving of each cereal product: CheeriosTotalOatmeal CrispCocoa Puffs Sodium5.771ppm4.965ppm2.108ppm5.644ppm Potassium6.132ppm3.192ppm3.205ppm2.634ppm Calcium3.607ppm35.467ppm0.3373ppm3.763ppm Iron0.2435ppm0.532ppm0.1265ppm0.1411ppm Zinc0.3527ppm0.532ppm0.5903ppm0.1411ppm Magnesium1.2625ppm0.7448ppmNot reported0.5268ppm CopperNot reported ppm Calculated theoretical values of elements in 0.1g of cereal in 100mL of solvent based on reported values

Sample Calculations Example Calculations of Theoretical Values:

Calculations Used ICP (Calibration Curves from Instrument Nay= x Ky= x Cay= x Fey= x Mgy= x Zny= x Cuy= x AA (Calibration Curves from Excel) Fey= x Zny= 0.027x

Results Cheerios – ICP ElementConcentration (ppm) % Difference Na % K % Ca % Fe % Mg % Zn % Cu Cheerios – AA ElementConcentration (ppm) % Difference Fe % Zn %

Results Total - ICP ElementConcentration (ppm) % Difference Na % K % Ca % Fe % Mg % Zn % Cu Total - AA ElementConcentration (ppm) % Difference Fe % Zn %

Results Oatmeal Crisp - ICP ElementConcentration (ppm) % Difference Na % K % Ca % Fe % Mg % Zn Cu Oatmeal Crisp - AA ElementConcentration (ppm) % Difference Fe % Zn

Results Cocoa Puffs - ICP ElementConcentration (ppm) % Difference Na % K % Ca % Fe % Mg % Zn % Cu % Cocoa Puffs - AA ElementConcentration (ppm) % Difference Fe % Zn %

Conclusions The best results came from Potassium. The cereal with the lowest percent differences overall was Cheerios. The cereal with the worst numbers was Oatmeal Crisp. The worst results elementally was iron. Most of the elements with higher percent differences were those with lower reported concentrations in the cereals.

What Went Wrong (Possibly) Dissolving the flaky cereals. Filtering the cereals. Concentrations of standards. Low concentration of cereal in the samples. (Used 0.1g in 100 mL) Difference between ICP and AA.