ISO 20236:2018

This document specifies a method for the determination of total organic carbon (TOC), dissolved organic carbon (DOC), total bound nitrogen (TNb) and dissolved bound nitrogen (DNb) in the form of free ammonia, ammonium, nitrite, nitrate and organic compounds capable of conversion to nitrogen oxides under the conditions described. The procedure is carried out instrumentally. NOTE Generally the method can be applied for the determination of total carbon (TC) and total inorganic carbon (TIC), see Annex A. The method is applicable to water samples (e.g. drinking water, raw water, ground water, surface water, sea water, waste water, leachates). The method allows a determination of TOC and DOC ≥ 1 mg/l and TNb and DNb ≥ 1 mg/l. The upper working range is restricted by instrument-dependent conditions (e.g. injection volume). Higher concentrations can be determined after appropriate dilution of the sample. For samples containing volatile organic compounds (e.g. industrial waste water), the difference method is used, see Annex A. Cyanide, cyanate and particles of elemental carbon (soot), when present in the sample, can be determined together with the organic carbon. The method is not appropriate for the determination of volatile, or purgeable, organic carbon under the conditions described by this method. Dissolved nitrogen gas (N2) is not determined.