Chemistry Lab Report Determination of Acetylsalicylic Acid in Aspirin Purpose Experimentally verify that the ASA Content of Excedrin Migrane was 250 mg per tablet as indicated on the package. For this laboratory, a series of ASA/and NaOH solutions were prepared by mixing known volumes of ASA with known volumes of NaOH. Four samples of the known ASA/NaOH solution were then diluted with .02 M FE 3+ and labeled A‐D. Each of these known solutions were put into a spectrophotometer and there absorbance was measured and recorded. A sample of Excedrin Migrane (1 tablet), was mixed with 1M NaOH and also diluted with .02 M Fe 3+it’s absorbance was also measured and recorded. A plot of Absorbance to Concentration was prepared and the concentration of the Excedrin Migrane tablet was determined using the results of the linear analysis. Procedure The four known solutions were prepared using 254 mg of acetylsalicylic acid and 10 mL 1M NaOH in a 125 mL Erlenmeyer flask. The solution was then quantitatively transferred to a 250 mL volumetric flask and diluted with distilled water. A 10.00 mL sample of the aspirin solution was then diluted with .02 M Fe 3+ and labeled as solution A. 3 other similar solutions were made with 6.00, 4.00 and 2.00 mL aspirin solutions and labeled B,C and D. A solution then was made using a Excedrin Migrane tablet with a label designation of 250 mg ASA. This tablet was mixed with 10 mL 1M NaOH and diluted with distilled water. A 4 mL sample was diluted with .02 M Fe 3+ and transferred to a 125 mL Erlenmeyer flask. All samples were prepare with volumetric glassware and pipets. All solutions were then inserted into the spectrophotometer and their absorbance was measured and recorded. Data Table 1: Absorbance and concentration of ASA ml ASA solution Absorbance 10 mL known 6 mL known 4 mL known Concentration (ppm) .15 101.6 .08 60.96 .06 40.64 2 mL known .02 20.32 4 mL unknown .058 30.48 Results A linear fit of the data was done using MS Excel. The equation of the best fit line was found to be Y=0.0016x‐0.0097 Or in other words absorbance of the solution = (0.0016)(concentration) ‐0.0097. The absorbance was determined by calculating .0016*concentration + .0097 giving us a absorbance of .058. next the concentration was multiplied by our C2 value of 100 giving us 3048 that was divided by 4 to give us our C1 value of 762 this was then added to our formula 250 x 762/1000 to give us 190.5 mg ASA. This is below the listed 250 mg per tablet on the container of Excedrin Migrane. Discussion This experiment was performed for the purpose of determining ASA in mg content in 1 tablet of Excedrin Migrane. It was accomplished by measuring the solutions absorbance and using a dilution formula to calculate concentration. The Excedrin Migrane was determined to have a concentration of 30.48 ppm and a absorbance of .058 this gave us a solution of 190.5 mg ASA. This is below the stated 250 mg ASA listed on the bottle. Our group does not believe that the package was mislabeled by the difference in the mg ASA could be contributed to errors in the testing procedure. Some possible contributing factors to our number being low was first in the standards samples. While making standard ASA solution we had to dilute the solution in a 250 mL volumetric flask to a mark, This is not precise way to dilute do to the fact that over or under the mark may cause errors in concentration. Also each of the known samples had to be transferred to a 100 mL volumetric flask and again diluted with .02 M Fe 3+ to the mark, this is another area where if to much or not enough .02 M Fe 3+ is added it could cause errors in the report. Another possible error could occur with the unknown sample as stated above the dilution process was repeated with the same possibility for error. These errors were apparent on our linear graph as 3 of our known solutions were not in line on the graph, our 2 mL and 6 mL solution were heavy in concentration and our 4 mL solution was light in concentration. This could be caused by not mixing the standard solution completely causing heavy and light samples of ASA. Conclusion A single tablet of Excedrin Migrane was experimentally determined to have a absorbance of .058 and a concentration of 30.48 (ppm) which correlated to 190.5 mg of ASA, this represents a 13.8% deviation from the 250 mg ASA content per tablet reported on the label. Lab Group This report was completed by [names deletedl.