For many years the Winkler method with its various modifications has been the accepted procedure to determine the dissolved oxygen (D. O.) in fresh and saline waters (Amer. Public Health Ass., 1946). The accuracy of this volumetric test has proven itself in the laboratory where proper facilities and apparatus are available for such determinations. However, this test is too awkward and elaborate to be utilized in the field for sanitary and biological studies.
Lieber, Maxim, and Rolf Eliassen. 1949. "The use of the amidol test for dissolved oxygen in sea water." Journal of Marine Research 8, (2). https://elischolar.library.yale.edu/journal_of_marine_research/708