Winklertitratsioonist

Winklertitratsioon is a method used to determine the amount of dissolved oxygen in a sample, commonly water. It is based on a series of chemical reactions that convert dissolved oxygen into a measurable form. The process begins with the addition of manganese(II) sulfate and an alkaline iodide-azide solution to the water sample. The dissolved oxygen present in the sample oxidizes the manganese(II) ions to manganese(III) hydroxide. In the next step, an acid, typically sulfuric acid, is added. This acid dissolves the precipitate and also liberates iodine from the iodide ions, with the amount of liberated iodine being directly proportional to the original concentration of dissolved oxygen. Finally, the liberated iodine is titrated with a standardized solution of sodium thiosulfate, using starch as an indicator. The volume of sodium thiosulfate solution used allows for the calculation of the dissolved oxygen concentration. This method is widely employed in limnology, oceanography, and environmental monitoring to assess water quality and aquatic ecosystem health. Its accuracy can be affected by the presence of interfering substances, but it remains a standard technique for dissolved oxygen determination.