Bottle, polyethylene, with tubulature. 



Bottle, reagent storage, amber glass or black 

 painted, capacity : 500 and 8,000 ml. 



Burette, auto-zero, three-way stopcock, grad- 

 uated in 0.05 ml. increments, capacity: 

 0-10 ml. 



Pipette, automatic, A.B.A. type, capacity : up 

 to 2 ml. 



Pipette, automatic zero, acid type, capacity : 

 50 ml. 



Pipette, volumetric, transfer type Class "A", 

 capacity : 5 and 10 ml. 



J-5 Setting up the Apparatus. — Figures J-1 

 and J-2 show schematic arrangements for the 

 automatic 50-ml. pipette and the burette. 



Step 1. Clamp the glassware to the support 

 rods that are rigidly attached to the titration 

 bench. 



Step 2. Attach the filter pump, or aspirator, 

 to the salt water tap and connect it to the pipette 

 with rubber tubing. If a salt water tap is not 

 available, a small electric vacuum pump of the 

 portable laboratory type may be used m place 

 of the aspirator. 



Step 3. Attach the magnetic stirrer below the 

 burette. 



Step 4. Secure sea racks to the top of the table 

 to hold three 500-ml. reagent bottles, the starch 

 solution dropping bottle, the sample bottle, and 

 several Erlenmeyer flasks. 



Step 5. Above the sea racks, secure a rack to 

 hold the various small pipettes. 



Step 6. Rig a fluorescent titration lamp behind 

 the burette. 



PRESSURE BULB 



Figure J-1. Automatic pipette assembly. 



Figure J-2. Automatic self zero- 

 ing (0-10 ml.) burette assembly. 



J-6 Preparing the Reagents. — Several days 

 before oxygen samples are to be analyzed, the 

 following reagents must be prepared for the 

 (Macro) Winkler titration process: (1) Man- 



fanous reagent (2) Sodium Iodide-Sodium Hy- 

 roxide solution (3) Starch solution (4) Potas- 

 sium lodate (orBiiodate) solution (5) Sodium 

 Thiosulfate solution and (6) ION Sulfuric acid. 



1. Manganous reagent. 



Step 1. Dissolve 600 grams of MnCU -41120 in 

 about 500 ml. of distilled water. An electric mag- 

 netic stirrer and heat will hasten solution of the 

 salt. 



Step 2. Dilute to one liter, and for conven- 

 ience, split solution into two 500-ml. polyethyl- 

 ene bottles. 



2. Sodium Iodide-Sodium Hydroxide solu- 

 tion. 



Step 1. Pour 600 ml. of cold distilled water 

 into a 1,000 ml. beaker, and place the beaker 

 in a pan or feink of cold water. 



Step 2. Put on safety goggles while preparing 

 the solution. 



Step 3. Slowly add 320 grams of NaOH pel- 

 lets, stirring all the while until all pellets are 

 dissolved. Cool to room temperature. This tech- 

 nique prevents overheating and boiling of the 

 solution. 



Step 4. Add 600 grams of NaT to the above 

 beaker and stir until dissolved. 



Step 5. Pour into a graduated cylinder, and 

 dilute to 1 liter. 



Step 6. Transfer the liter of NaOH-Nal solu- 

 tion to a beaker. Stir until well mixed. 



J-2 



