SSH EN ISO 20236:2021

Water quality - Determination of total organic carbon (TOC), dissolved organic carbon (DOC), total bound nitrogen (TNb) and dissolved bound nitrogen (DNb) after high temperature catalytic oxidative combustion (ISO 20236:2018)

Scope

This International Standard specifies a method for the determination of total organic carbon (TOC), dissolved organic carbon (DOC), and for the determination of dissolved and particular bound nitrogen (TNb) in the form of free ammonia, ammonium, nitrite, nitrate and organic compounds capable of conversion to nitrogen oxides under the oxidative conditions described. The procedure is carried out instrumentally.
NOTE 1 Generally the method can be applied for the determination of total carbon (TC) and total inorganic carbon (TIC) (see Annex A in the Outline).

The method is applicable for water (e.g. drinking water, raw water, ground water, surface water, sea water or waste water) containing suspended material of ≤ 100 μm of particle size (convention). Reduce particles of > 100 μm of size to pieces of particle size of ≤ 100 μm before injection. The method allows a determination of TOC/DOC ≥ 1 mg/l C and TNb ≥ 1 mg/l N.
NOTE 2 The determination of carbon concentrations > 0,3 mg/l to 1 mg/l is only applicable in special cases, for example drinking water, measured by highly sensitive instruments. Cyanide, cyanate and particles of elemental carbon (soot), when present in the sample, can be determined together with the organic carbon. Volatile or purgeable organic carbon (VOC, POC) is not determined by this method. Dissolved nitrogen gas is not determined by this method. Generally, the working range is restricted by instrument dependant conditions (e.g. injection volume). Higher concentrations may be determined after appropriate dilution.