Analytical Method: Nitrogen (total) in effluents

Instruments and Reagents:

Cat.No. 173016  Spectroquant® VIS Spectrophotometer Prove 100 or

Cat.No. 173017  Spectroquant® UV/VIS Spectrophotometer Prove 300 or

Cat.No. 173018  Spectroquant® UV/VIS Spectrophotometer Prove 600 or

Cat.No. 109748  Spectroquant® Photometer NOVA 30 or

Cat.No. 109751  Spectroquant® Photometer NOVA 60 or

Cat.No. 173632  Spectroquant® Colorimeter Move 100

Cat.No. 114946  Rectangular cells 10 mm and/or

Cat.No. 114947  Rectangular cells 20 mm and/or

Cat.No. 114944  Rectangular cells 50 mm 
Cat.No. 114537  Spectroquant® Nitrogen Cell Test
Cat.No. 100613  Spectroquant® Nitrogen Cell Test*
Cat.No. 114763  Spectroquant® Nitrogen Cell Test*
Thermoreactor with 120 °C digestion temperature
*not compatible with Move 100
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:
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 above mentioned test kits.
Nitrogen (total) content in mg/l N = analysis value in mg/l N


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