Our Steps

Materials:

Procedure
Part One-collecting the water sample:

1. Rince the water samle bottle with the samle water.
2. Tighly cap the bottle, and submerge it to the disierd depth .
3. Remove the cap and allow the bottle to fill.
4. Tap the sides of the bottle to disloge any air bubbles.
5. Replace the cap wile the bottle is still submerged .
6. Retreave the bottle and make sure that no air bubbles are trapped inside .

Part Two-adding the reageants:

1. Remove the cap from the bottle. (note:becarefull not to introduse air ino the sample wile adding the reageants.)

2. Emediatly add 8 drop's of manganous sulfate solution and add 8 drop's of alkaline potassium iodide azide.

3. Tap the bottle and mix by inverting several times. A precipitate will form

4. Allow the persipitit to settle bellow the sholder of the bottle

5. Immediately use the 1.0 g. spoon to add one level measure of sufamic acid powder

6. Cap and gently invert the bottle to mix the content's untill the precipitate and the reagent's have totally dissolved. The solution will be clear yellow to orange if the sample contain's dissolved oxygen(Note: at the poin the sample has been "fixed" and contact between the sample and the atmospere will not affect the test result's. Sample's may be hled a the point at titrated later.)

Part Three-the titration

1. Fill the titration tube to the 20ml line with the fixed sample, Cap the tube.

2.Depress plunger of the titrator.

3. Insert the titrator into the plug in the top of the Sodium Thiosulfate, titrating solution.

4. Invert the bottle and slowly with draw the plunger until the bottom of the plunger is opposite the zero mark on the scale. (Note: If the air bubble's appear in the titrator barrel, exple them by partially filling the barrel and pumping the titration soulution back into the reagent container. Repeat untill bubbles disappear.)

5.Turn the bottle upright and remove the titrator. (Note:If the sample is a very pale yellow, go to step 9.

6.Insert the tip of the titrator into the opening of the titration tube cap

7. Slowly depress the plunger to dispense the titrating solution until the yellow-brown color change's to a very pale yellow. Gently swirl the tube during the titrationn to mix the content's.

8. Carefully remove the titratop and cap. Do not to disturb the titrator plunger.

9. Add 8 drops of Starch Indicator Solution, The sample should turn blue.

10. Cap the titration tube. Insert the tip of the Titraor into the opening of the titration tube cap.

11. Continue titrating until the blue.

12. Record the test result's were the titrator tip meet's the scale. Record the ppm D.O. Each minor division on the titrator scale equal's 0.2 ppm.

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