ISO 21793:2020 PDF

Water quality — Determination of total organic carbon (TOC), dissolved organic carbon (DOC), total bound nitrogen (TNb), dissolved bound nitrogen (DNb), total bound phosphorus (TPb) and dissolved bound phosphorus (DPb) after wet chemical catalysed ozone hydroxyl radical oxidation (COHR)

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Title (English):

ISO 21793:2020

Document status:: Active
Format:: Electronic (PDF)
Number of pages:: 31
Publication date:: September 2, 2020
Edition:: ISO IS 21793 edition 1 version 1
ICS:: 13.060.50

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Description (English):

This document specifies a multi‑parameter method for the determination of total organic carbon (TOC), total nitrogen (TNb) and total phosphorus (TP) in drinking water, raw water, ground water, surface water, sea water, saline water, process water, domestic and industrial wastewater, after a chemical oxidation process. It is applicable to both dissolved and bound suspended materials. The method allows for determination of TOC, TN and TP. The lower and upper working ranges for these parameters are dependent upon instrument conditions (for example sample volume, reaction chemistry amounts) and can be adjusted for a wider range. Typical measurement ranges are shown in Figures C.1 to C.3. The analysis procedure is carried out instrumentally by a single oxidation process. Dissolved nitrogen gas is not included in the TNb measurement in this method. When present in the sample, elemental carbon, cyanate and thiocyanate will be included in the TOC result.

Technical details

Technical committee: ISO/TC 147/SC 2 - Physical, chemical and biochemical methods
SKU: ISO 21793:2020

Abstract

Overview - ISO 21793:2020 (COHR) for water quality

ISO 21793:2020 specifies a multi‑parameter analytical method for determining total organic carbon (TOC), dissolved organic carbon (DOC), total bound nitrogen (TNb), dissolved bound nitrogen (DNb), total bound phosphorus (TPb) and dissolved bound phosphorus (DPb) following a wet chemical catalysed ozone hydroxyl‑radical oxidation (COHR). The procedure uses a single instrumental oxidation step and is applicable to a wide range of matrices - drinking water, ground and surface water, sea and saline water, process water, and domestic and industrial wastewater. Typical measurement ranges depend on instrument settings (sample volume, reaction chemistry) and can be extended as required.

Key technical topics and requirements

Oxidation principle: Wet chemical oxidation by hydroxyl radicals catalysed with ozone (COHR) to convert organic C, N and P into measurable species.
Parameters measured: TOC (includes elemental carbon, cyanate and thiocyanate), DOC, TNb (does not include dissolved N2 gas), DNb, TPb and DPb.
Single‑step instrumental analysis: Enables simultaneous multi‑parameter determination after the COHR treatment.
Detectors and measurement modes:
- TOC (CO2) detection by nondispersive infrared (NDIR) spectrometry.
- Bound nitrogen detection by UV photometric analysis (around 200–220 nm).
- Bound phosphorus detection by colorimetric photometry (approx. 380–470 nm).
Quality and validation: The standard requires calibration, system checks, particle‑processing controls and validation of recovery and repeatability (see informative Annexes B and C for performance/validation data).
Sample scope: Applicable to dissolved and suspended (bound) material; Annex A describes handling when purgeable organic carbon (POC) is included by difference.

Practical applications and users

Water and wastewater laboratories performing compliance testing and process control.
Drinking water utilities and environmental monitoring agencies tracking organic load and nutrient status.
Industrial process water and effluent testing (food, chemical, manufacturing).
Instrument manufacturers and method developers validating COHR‑based multi‑parameter analyzers.
Research groups studying carbon/nitrogen/phosphorus cycling in aquatic systems.

Benefits: simultaneous multi‑parameter data from a single oxidation reduces sample handling, improves throughput and supports integrated water‑quality assessment (TOC/DOC, TNb/DNb, TPb/DPb).

Related standards and references

Normative references cited in ISO 21793: ISO 8245 (TOC/DOC guidance), ISO 5725‑2 (accuracy, repeatability/reproducibility) and ISO 8466‑1 (calibration and evaluation).
Users should consult Annexes A–C of ISO 21793:2020 for procedural variants, performance data and validation guidance.

Keywords: ISO 21793:2020, COHR, TOC, DOC, TNb, DNb, TPb, DPb, water quality, ozone hydroxyl radical oxidation, NDIR, photometric, colorimetric.

Related standards

Standards mentioned in the description

Abstract

Overview - ISO 21793:2020 (COHR) for water quality

Key technical topics and requirements

Oxidation principle: Wet chemical oxidation by hydroxyl radicals catalysed with ozone (COHR) to convert organic C, N and P into measurable species.
Parameters measured: TOC (includes elemental carbon, cyanate and thiocyanate), DOC, TNb (does not include dissolved N2 gas), DNb, TPb and DPb.
Single‑step instrumental analysis: Enables simultaneous multi‑parameter determination after the COHR treatment.
Detectors and measurement modes:
- TOC (CO2) detection by nondispersive infrared (NDIR) spectrometry.
- Bound nitrogen detection by UV photometric analysis (around 200–220 nm).
- Bound phosphorus detection by colorimetric photometry (approx. 380–470 nm).
Quality and validation: The standard requires calibration, system checks, particle‑processing controls and validation of recovery and repeatability (see informative Annexes B and C for performance/validation data).
Sample scope: Applicable to dissolved and suspended (bound) material; Annex A describes handling when purgeable organic carbon (POC) is included by difference.

Practical applications and users

Water and wastewater laboratories performing compliance testing and process control.
Drinking water utilities and environmental monitoring agencies tracking organic load and nutrient status.
Industrial process water and effluent testing (food, chemical, manufacturing).
Instrument manufacturers and method developers validating COHR‑based multi‑parameter analyzers.
Research groups studying carbon/nitrogen/phosphorus cycling in aquatic systems.

Benefits: simultaneous multi‑parameter data from a single oxidation reduces sample handling, improves throughput and supports integrated water‑quality assessment (TOC/DOC, TNb/DNb, TPb/DPb).

Related standards and references

Normative references cited in ISO 21793: ISO 8245 (TOC/DOC guidance), ISO 5725‑2 (accuracy, repeatability/reproducibility) and ISO 8466‑1 (calibration and evaluation).
Users should consult Annexes A–C of ISO 21793:2020 for procedural variants, performance data and validation guidance.

Keywords: ISO 21793:2020, COHR, TOC, DOC, TNb, DNb, TPb, DPb, water quality, ozone hydroxyl radical oxidation, NDIR, photometric, colorimetric.

ISO 21793:2020 PDF

Technical details

Abstract

Overview - ISO 21793:2020 (COHR) for water quality

Key technical topics and requirements

Practical applications and users

Related standards and references

Related standards

Abstract

Overview - ISO 21793:2020 (COHR) for water quality

Key technical topics and requirements

Practical applications and users

Related standards and references

Related standards

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