Materials: 4 Winkler bottle samples 125 mL Erlenmeyer flask 1 x 10 mL syringe Pipette dropper Safety goggles Plastic tote Manganous Sulfate solution in a dropper bottle Potassium Iodide solution in dropper bottle Sulfamic Acid and scoop Starch indicator solution Sodium Thiosulfate solution Procedure Pour 100 ml of water from the Winkler bottle to be tested into the 125 ml flask. Pour gently to avoid adding oxygen to your sample. Add 8 drops Manganous Sulfate solution, then 8 drops Potassium Iodide solution. Gently swirl the flask to mix. A cloudy precipitate should form. Let sit for 5. Add 1 g of Sulfamic Acid (using 1 g scoop) to the flask. Swirl to mix. Make sure all of the Sulfamic Acid dissolved. This may take several minutes of swirling Add three drops of starch indicator solution. Swirl to mix. Solution should turn dark blue/brown. Fill 10 ml syringe with sodium thiosulfate. This is your titrating solution. While gently swirling the flask, slowly add the sodium thiosulfate until the water becomes colorless. Go slowly! The number of ml of sodium thiosulfate solution added to your flask equals the ppm of oxygen present in your sample.
Materials: 4 Winkler bottle samples 125 mL Erlenmeyer flask 1 x 10 mL syringe Pipette dropper Safety goggles Plastic tote Manganous Sulfate solution in a dropper bottle Potassium Iodide solution in dropper bottle Sulfamic Acid and scoop Starch indicator solution Sodium Thiosulfate solution Procedure Pour 100 ml of water from the Winkler bottle to be tested into the 125 ml flask. Pour gently to avoid adding oxygen to your sample. Add 8 drops Manganous Sulfate solution, then 8 drops Potassium Iodide solution. Gently swirl the flask to mix. A cloudy precipitate should form. Let sit for 5. Add 1 g of Sulfamic Acid (using 1 g scoop) to the flask. Swirl to mix. Make sure all of the Sulfamic Acid dissolved. This may take several minutes of swirling Add three drops of starch indicator solution. Swirl to mix. Solution should turn dark blue/brown. Fill 10 ml syringe with sodium thiosulfate. This is your titrating solution. While gently swirling the flask, slowly add the sodium thiosulfate until the water becomes colorless. Go slowly! The number of ml of sodium thiosulfate solution added to your flask equals the ppm of oxygen present in your sample.