Merck, 1.11107, Oxygen Test

General description
Method: titrimetric, acc. to Winkler, with titration pipette MQuant®
The sustainability of biological processes in natural waters is essentially depended on a sufficient oxygen content. The oxygen present in water is also consumed by chemical processes and by microorganisms. This MQuant® Oxygen test (formally MColortest®) is suitable for the titrimetric determination using a graduated syringe.
It can be used in:
Groundwater, drinking water, and surface water, seawater
Aquarium water, waters from aquaculture
Industrial water and wastewater
Boiler water and boiler feed water
Beverages

Method
In alkaline solution, dissolved oxygen oxidizes manganese(II) ions to form manganese(IV) hydroxides (“oxygen fixation”). In strongly acidic solution these yield manganese(III) ions, which in turn oxidize iodide ions to form iodine. This is then titrated with sodium thiosulfate solution against starch as the indicator until the solution becomes entirely colorless. The oxygen concentration is determined from the consumption of titration solution (iodometric determination acc. to Winkler). The oxygen consumption is calculated as the difference between the oxygen content measured immediately after sampling and that measured after n days (n = 2 to 5).
Legal Information
MCOLORTEST is a registered trademark of Merck KGaA, Darmstadt, Germany
MQUANT is a registered trademark of Merck KGaA, Darmstadt, Germany