SHIELDED 



FLUORESCENT 



8 W LAMP 



SHIELDED 



FLUORESCENT 



8 W,LAMP 



INSIDE OF BOX 

 IS PAINTED 

 WHITE 



Figure J-6. Titration box (Micro) Winkler method (after J. H. Carpenter) . 



900 ml. of the boiled water, contained in a 1,000 

 ml. volumetric flask. 



Step 3. Add 1 gram of sodium carbonate, and 

 dilute to 1.000 ml. with the boiled wn+er. 



Step 4. Store the solution in a 1,000 ml. poly- 

 ethylene bottle. Label bottle, indicating concen- 

 tration. 



J-15 Treating Oxygen Samples. — As soon 

 as the O2 samples are drawn (instructions for 

 drawing O2 samples are given in chapter F, 

 Taking an Oceanographic Station) , they should 

 be taken to the ship's laboratory and treated 

 immediately. NOTE ; Two separate O2 samples 

 should be drawn from each Nansen bottle for 

 the (Micro) Winkler titration method, and the 

 sample flask numbers etched on the flask should 

 be used as the sample bottle numbers on the A 

 sheet. To treat the sample, perform the follow- 

 ing steps : 



Step 1. Remove the glass stopper from the 

 sample flask, and with a rapid delivery pipette 



1/4 inch below the surface of the liquid, add 1 ml. 

 of manganous solution. 



Step 2. Add 1 ml. of NaOH-Nal solution in 

 the same manner as step 1. 



Step 3. Seat the stopper securely without 

 trapping bubbles, and shake thoroughly to mix 

 the precipitate. 



Step 4. Repeat steps 1, 2, and 3 with other 

 oxygen samples; then, after approximately 5 

 minutes, reshake each sample again to mix the 

 precipitate thoroughly. 



Step 5. Wlien the precipitate has settled ap- 

 proximately two-thirds of the way to the bot- 

 tom of the sample flask, add 1.0 ml. of ioN 

 H2S04, restopper the flask, and shake thor- 

 oughly until all precipitate is dissolved. The in- 

 troduction of tlie acid may cause the liberation 

 of CO2 and N2 ; however, this does not affect the 

 titration results. 



Samples are now ready to be titrated, and 

 they should be titrated within a 4-hour period. 



J-9 



