Assay Ferrous Sulfate Tablets 55716e

Name: Mas, Mylyn L.

Date Submitted: 10/01/16

Pharm Chem 135 Section: PH6

Date Performed: 09/23/16

Experiment No. 3 Cerimetry Assay of Ferrous Sulfate Tablets I. DATA AND RESULTS A. Volume/Weighing Measurements Sample 1: Ferrous Sulfate Tablets Weight of 25 tablets: 0.5073 g

Average weight of 25 tablets: 0.5073 g

Weight (Trial 1): 1.3300 g

(Trial 2): 1.3355 g

B. Titration Data Volume of Titrant Used: Volume Reading

Trial 1

Trial 2

Initial Reading

(Over Titrated) 0.00 mL

0.00 mL

Final Reading

42.90 mL

40.28 mL

Total Volume Used

42.90 mL

40.28 mL

Volumetric Solution Used: 0.1 N Ceric Sulfate VS Nf: 0.8016 Calculated % of Active Ingredient: Labelled Claim: 325mg/tab Trial 1: 112.2 % (Overtitrated) Trial 2: 105.4% (Acceptance criteria: 95.0%-110.0%)

Sample: INCONCLUSIVE % Deviation Between Trials:6.31% II. DISCUSSION Twenty-five Ferrous sulfate tablets (Labelled claim: 325 mg/tab) were assayed. Tablets were white in color and rounded in shape and was opened during the week of experiment (September 19-23, 2016). It was stored in a zip lock with a rectangular box as a secondary container and was recently bought from a local pharmacy. Two titration trials for the assay of ferrous sulfate tablets with 0.1 N ceric sulfate VS as the titrant. The first trial with a calculated % A.I of 112.2% was overtitrated with a color change from red to yellow-green which does not change even with addition of titrant. The second trial transitioned from red to pale blue, an acceptable trial, was calculated with a 105.4 % A.I. A % deviation of 6.31 % between trials was calculated. Results are inconclusive since the percent deviation exceeds the standard acceptable criteria of + 3% and one of trials was overtitrated. Two major difficulties were encountered during the experiment. Firstly, the theoretical color change was from red to pale blue. However, the observed change was from red to yellow-green. Titration was continued with the assumption that the pale blue color would still appear. Even with continuous addition of the titrant, however, the color did not change. It was therefore concluded that the sample was already overtitrated. The yellow-green color was due to the combined color of the ferrous ion (yellow) and the pale blue ferric-orthophenantroline complex formed. Another major difficulty encountered was the time it takes to filter the sample. There was only one suction apparatus available for the class and the lead monoxide group also needed to perform gravity filtration. One filtration takes approximately 5-10 minutes, which means that a waiting time of 20 minutes per person was done. The waiting immensely affected the time allotment for every part of the procedure leading to the inability to perform blank determination. The need for a covered burette was a minor difficulty encountered during the titration. It was difficult to cover the burette only to remove it again since the volume cannot be checked with a covered burette. The waiting time for the filtration for 2 trials took up most of the time and titration must be done rapidly so the procedure was time-constraint. The time it took to cover the burette took up the time that should have been intended for the rapid titration and performance of blank determination.

III. CONCLUSION AND RECOMMENDATIONS The results are inconclusive since the % deviation exceeds the acceptable range of the department. In addition, one trial overtitrated which means that the results are also not reliable since there is no acceptable reproducibility of data. It is highly recommended to perform the trials as efficient as possible since the procedures are time-constraint. The procedure also requires a previously boiled and cooled water and in order to boil as fast as possible, use of heater is highly recommended. In addition, the use of freshly prepared orthophenantroline is also highly recommended since its indicating efficiency degrades through time. Lastly, perform the procedures in an area away from light. Ceric sulfate is light sensitive and its oxidizing capacity is degraded when exposed to light causing a decrease in the amount of ceric sulfate that will react with the analyte.