Assay Analysis of Ferrous Fumarate by Titration Method
Introduction:
In pharmaceutical and food industries, it is essential to determine the potency or concentration of active ingredients in products. Assay analysis plays a crucial role in ensuring the quality and efficacy of these substances. In this blog post, we will focus on the assay analysis of Ferrous Fumarate, a commonly used iron supplement, using the titration method. We will provide a step-by-step guide along with an example and calculations.
Understanding Ferrous Fumarate:
Ferrous Fumarate is an iron salt with the chemical formula FeC4H2O4. It is widely used as a dietary supplement to treat iron deficiency anemia. Assaying Ferrous Fumarate helps determine the iron content accurately, ensuring its potency and effectiveness.
Titration Method for Assay Analysis:
Titration is a widely used analytical technique for determining the concentration of a substance in a sample. In the case of Ferrous Fumarate, we can employ a titration method using a strong oxidizing agent, such as potassium permanganate (KMnO4), to react with the iron ions present in the sample solution.
Required Chemicals and Glassware:
Before proceeding with the assay analysis, ensure that you have the following chemicals and glassware readily available:
Chemicals:
1. Ferrous Fumarate sample
2. Potassium permanganate (KMnO4) - Analytical grade
3. Sulfuric acid (H2SO4) - Dilute solution
4. Phenolphthalein or potassium dichromate - Indicator
Glassware:
1. Analytical balance
2. Burette
3. Conical flask
4. Pipette or measuring cylinder
5. Volumetric flask
6. Beakers
7. Graduated cylinders
Standardization of Potassium Permanganate Solution (0.01 N) :
Before performing the assay analysis, it is crucial to standardize the potassium permanganate (KMnO4) solution to determine its exact concentration. Follow these steps for standardization:
Step 1: Preparation of Standard Solution:
Weigh accurately around 0.2-0.3 grams of pure primary standard-grade oxalic acid (C2H2O4·2H2O). Dissolve it in distilled water in a volumetric flask to obtain a known concentration solution, typically around 0.1 N.
Step 2: Titration Procedure:
Take a measured volume, usually 10 mL, of the oxalic acid solution in a conical flask. Add a few drops of phenolphthalein indicator. Phenolphthalein changes from colorless to pink at the endpoint.
Step 3: Titration Process:
Slowly add the potassium permanganate (KMnO4) solution from the burette into the conical flask containing the oxalic acid solution while continuously swirling the flask. The pink color of the solution will disappear as the oxidation reaction occurs.
Step 4: Endpoint Detection:
The endpoint is reached when a persistent pale pink color is observed, indicating the complete oxidation of oxalic acid.
Step 5: Recording the Volume:
Note the final volume reading on the burette. The difference between the initial and final volume readings represents the volume of KMnO4 solution required to react with the known concentration of oxalic acid.
Step 6: Calculation and Standardization:
Using the known concentration of the oxalic acid solution, calculate the exact concentration of the potassium permanganate (KMnO4) solution by applying the stoichiometry of the reaction.
Assay Analysis of Ferrous Fumarate:
Now that we have a standardized potassium permanganate (KMnO4) solution, we can proceed with the assay analysis of Ferrous Fumarate. Follow these steps for the assay analysis:
Step 1: Preparation of Sample Solution:
Weigh an accurately known amount, typically around 1-2 grams, of Ferrous Fumarate sample using an analytical balance. Dissolve the sample in a suitable solvent, such as water or dilute sulfuric acid, in a volumetric flask or beaker. Ensure complete dissolution of the sample.
Step 2: Titration Setup:
Prepare a standardized solution of potassium permanganate (KMnO4) of known concentration. This solution will serve as the titrant. Fill a burette with the KMnO4 solution and note the initial volume.
Step 3: Titration Procedure:
Take a measured volume, usually 10 mL, of the prepared Ferrous Fumarate sample solution in a conical flask using a pipette or measuring cylinder. Add a few drops of a suitable indicator, such as phenolphthalein or potassium dichromate, to the solution in the conical flask.
Step 4: Titration Process:
Start adding the KMnO4 solution from the burette into the conical flask containing the Ferrous Fumarate sample solution. Swirl the flask gently while adding the KMnO4 solution to ensure proper mixing. The KMnO4 solution will react with the ferrous ions in the Ferrous Fumarate, oxidizing them to ferric ions.
Step 5: Endpoint Detection:
Continue adding the KMnO4 solution until a persistent color change is observed. For example, in the case of phenolphthalein indicator, the solution turns from colorless to a pale pink color at the endpoint. The color change indicates that all the iron ions in the sample solution have reacted with the KMnO4.
Step 6: Recording the Final Volume:
Note the final volume reading on the burette. The difference between the initial and final volume readings represents the volume of KMnO4 solution required to react with the iron content in the Ferrous Fumarate sample.
Calculation of Assay:
The assay of Ferrous Fumarate can be calculated using the following formula:
Assay (%) = [(Volume of KMnO4 solution used) × (Normality of KMnO4) × (Molecular weight of iron)] / (Weight of Ferrous Fumarate sample) × 100
Example Calculation:
Let's consider an example where 0.5 grams of Ferrous Fumarate sample was dissolved, and 2.4 mL of 0.01 N KMnO4 solution was required to reach the endpoint.
Assuming the molecular weight of iron as 55.85 g/mol:
Assay (%) = [(1.9 mL) × (0.01 N) × (55.85 g/mol)] / (1.114 g) × 100
Assay (%) = (106.12) / 1.114
Assay (%) ≈ 95.3 %
In this example, the assay analysis indicates that the Ferrous Fumarate sample contains approximately 187.8% of the expected iron content.
Conclusion:
The assay analysis of Ferrous Fumarate by the titration method provides valuable information about its iron content. By following the step-by-step procedure and performing the necessary calculations, you can accurately determine the potency of Ferrous Fumarate, ensuring its quality and effectiveness as a dietary supplement. Proper standardization of the potassium permanganate.
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