ISO DIS 23695
Water quality — Determination of ammonium nitrogen in water — Small-scale sealed tube method
|Publication Date:||11 January 2021|
|ICS Code (Examination of water for chemical substances):||13.060.50|
This document specifies a method for the determination of ammonium nitrogen (NH4-N) in drinking water, groundwater, surface water, wastewater, bathing water and mineral water using the small-scale sealed tube method. The result can be expressed as NH4 or NH3 or NH3 or NH3-N.
This method is applicable to (NH4-N) concentration ranges from 0,01 mg/l to 1 800 mg/l of NH4-N. The measuring ranges of concentration can vary depending on the type of small-scale sealed tube method of different manufacturers. Concentrations even slightly higher than the upper limit indicated in the manufacturers manual relating to the small-scale sealed tube method used, cannot be reported as accurate results. Appropriate preliminary dilution of the sample shall be performed or a small-scale sealed-tube method with a different application measuring range shall be used.
All manufacturers' methods are based on the Berthelot reaction and its modifications to develop indophenol blue colour. Reagents mixtures could differ slightly based on manufacturers small-scale sealed tube method, see Clause 8. This method is applicable to direct determination of samples by using small-scale sealed tubes for the determination of drinking water, groundwater, surface water, wastewater and on preserved samples. The method is applicable after separation of suspended materials by filtration.