Nitrogen (Total) in Effluents

Prove InstrumentsPhotometric determination after decomposition with potassium peroxodisulfate with the thermoreactor


Wastewaters generally contain various physical forms of nitrogen. The total nitrogen household is determined by measuring the parameters ammonium, nitrite, and nitrate nitrogen. The measurement of organically bound nitrogen requires the additional decomposition of the sample according to Kjeldahl.

The content of total nitrogen can be rationally measured after decomposition according to the Koroleff method in the thermoreactor with alkaline peroxodisulfate solution. The method is restricted by the content of organic compounds, expressed as the COD content. For the decomposition of samples in the thermoreactor, the maximum COD concentration must not exceed 300 mg/l. Very slightly oxidizable N compounds are only partly measured.

Sample Preparation

Thermoreactor with 120 °C digestion temperature.

The sample, pH 5 - 9, with a COD value smaller than 300 mg/l is treated as per the instructions of the Spectroquant® Nitrogen Cell Test given. The sample is digested in a closed round-cell in the thermoreactor. After digestion the sample must be checked, as specified, for freedom from peroxides; any peroxides present must be destroyed with sodium sulfite.


Determine with the below mentioned test kits.


Nitrogen (total) content in mg/l N = analysis value in mg/l N



Products 100613 and 114763 not compatible with Move 100.