Dissolved Oxygen

Methodology

The basis of the Winkler procedure is that the oxygen in a sea water sample is made to oxidize iodide ion to iodine quantitatively (in the presence of an alkaline solution of manganese (II) ion); and the amount of iodine generated in this fashion is determined by titration with a standard thiosulfate solution. The end-point is located using starch as a visual indicator for the presence of iodine. The amount of oxygen present in the original sample can then be computed from the titrator.

Reference

Dickson, A. (1996). Determination of dissolved oxygen in sea water by Winkler titration, WHP Operations and Methods.