Photometric determination of the COD. • Photometric determination of chromium(III) concentration after two hours of oxidation with potassium dichromate/sulphuric acid/silver sulphate at 148 °C. • The chemical oxygen demand of a water is determined by silver-catalysed oxidation with potassium dichromate/sulphuric acid at 148 °C during a two hour period. • Type: tube test 0-12 • Range: 5.0 - 60.0 g/l O2 • Sufficient for: 20 determinations • Sea water suitability: no