COD is a titration test. COD stands for Chemical Oxygen Demand. It is a method for assessing water pollution post-treatment, with higher values indicating increased organic pollution.

Unlike Biological Oxygen Demand, COD is suitable for toxic water and non-biodegradable organic matter in effluent treatment plants. COD determination is quicker than BOD testing, offering efficient analysis of chemically digestible matter in water samples.


No calibration is required for this test.


This test uses the COD reagents.

  • Take 10 ml of the water sample into a round bottom reflex flask.
  • Add some glass beads to prevent the solution from bumping into the flask while heating.
  • Add 1 ml of Reagent A to the flask and mix by swirling the flask.
  • Add 5 ml of Reagent B to the flask.
  • Now slowly and carefully add 15 ml of Reagent C.
  • Connect the reflex condenser and digest the contents using a hot plate for 2 hours.
  • After digestion, cool the flask and rinse the condenser with 25 ml of distilled water collecting in the same flask.
  • Add 2-4 drops of Reagent D to the flask and titrate with the titrant to the endpoint.
  • From the home screen choose Titration Test > Water > Dissolved Oxygen and enter the titration result.
  • This should give you the result in mg/L.