Method for determining dissolved oxygen in water

The invention relates to a method for determining the concentration of dissolved oxygen in a liquid water sample comprising the steps: a) providing a liquid water sample of predetermined volume, the oxygen content of which is to be determined; b) mixing additives with the liquid water sample to form a mixture, the additives comprising an oxidizable metal salt comprising a metal cation and an anion selected from an inorganic anion or an organic anion which, with the cation, results in a water soluble oxidizable metal salt, at least one water soluble alkali metal compound selected from an alkali metal oxide, or an alkali metal hydroxide or a salt of an alkali metal and a weak acid; and at least one oxidation-reduction indicator capable of a color change upon oxidation of the oxidizable metal salt during contact with dissolved oxygen in the liquid sample to a color indicative of the concentration of dissolved oxygen in the liquid sample; c) preventing any substantial contact of the mixture with atmospheric oxygen; and d) determining the concentration of dissolved oxygen in the liquid sample by comparing the color of the mixture to a predetermined color indicative of the concentration of dissolved oxygen in the water sample. (author)