7. FAQ's and Knowledgebase / Biochemical Oxygen Demand

How much water do I need to add to my COD vials?

A chemical oxygen demand (COD) test is used to measure the amount of organic compounds in a water sample. It measures the capacity of water to consume oxygen during the decomposition of organic matter and the oxidation of inorganic chemicals such as Ammonia and nitrate. You can see a video on the common method of testing COD with vials in our video here.

COD Vials

The start of the COD testing method requires a specified volume of sample to be pipetted into the COD vials, here are the volumes you should use for the corresponding COD range:

Low range Camlab Water COD vials 0-150mg/l – add 2ml of your sample

Medium range Camlab Water COD vials 0-1500mg/l – add 2ml of your sample

High range Camlab Water COD vials 0-15000mg/l – add 0.2ml of your sample

Make sure to prepare a blank by using deionised water instead of the sample, this follows the same volumes as above. Replace the caps tightly and invert several times to mix the contents. This is then ready to add to a reactor to be digested at high temperature, 150°C  for 120mins,  left to cool and finally measured in an colorimeter to give a result of COD mg/L.

For more information on COD testing or water testing in general please get in touch with one of our technical team on 01954233120 email us support@camlab.co.uk or fill in the form below.