ISO 23696-1:2023

Water quality — Determination of nitrate in water using small-scale sealed tubes — Part 1: Dimethylphenol colour reaction

This document specifies a method for the determination of nitrate as NO₃-N in water of various origin such as natural water (including groundwater, surface water and bathing water), drinking water and wastewater, in a measuring range of concentration between 0,10?mg/l and 225?mg/l of N0₃-N using the small-scale sealed tube method. Different measuring ranges of small-scale sealed tube methods can be required.

The measuring ranges can vary depending on the type of the small-scale sealed tube method of different manufacturers.

It is up to the user to choose the small-scale sealed tube test with the appropriate application range or to adapt samples with concentrations exceeding the measuring range of a test by preliminary dilution.

NOTE?1?? The results of a sealed-tube test are most precise in the middle of the application range of the test.

Manufacturers’ small-scale sealed tube methods are based on dimethylphenol colour reaction depending on the typical operating procedure of the small-scale sealed tube used, see Clause?9.

NOTE 2?? Laws, regulations or standards can require that the data is expressed as NO₃– after conversion with the stoichiometric conversion factor 4,426?81 in Clause?11.

NOTE?3?? In the habitual language, use of sewage treatment and on the displays of automated sealed-tube test devices, NO₃ without indication of the negative charge has become the common notation for the parameter nitrate and especially for the parameter nitrate-N. This notation is adopted in this document even though not being quite correct chemical nomenclature.

Edition	2023
Standard Part No	1
Published Date	2023
Published By	International Standardization Organisation
Page Count	8