ISO INTERNATIONAL STANDARD 21793 First edition 2020-08 Water quality Determination of total organic carbon (TOC), dissolved organic carbon (DOC), total bound nitrogen (TNp), dissolved bound nitrogen (DNp), total bound phosphorus (TPp) and dissolved bound phosphorus (DPb) after wet chemical catalysed ozone hydroxyl radical oxidation (COHR) Qualite de I'eau-Détermination ducarbone organique total (COT),du carbone organique dissous (COD), de I'azote total lie (TN),de I'azote dissous lie (DN), du phosphore total lie et du phosphore dissous lié (DP) apres oxydation par I'ozone avec des radicaux hydroxyles et catalyseur en milieux aqueux (COHR) Referencenumber IS0 21793:2020(E) ISO @IS02020 IS021793:2020(E) COPYRIGHTPROTECTEDDOCUMENT ISO2020 All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may below or ISo's member body in the country of the requester. ISO copyright office CP 40i : Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone: +41 22 749 01 11 Email: copyright@iso.org Website: www.iso.org Published in Switzerland ii IS02020-Allrights reserved IS021793:2020(E) Contents Page Foreword V Introduction .vi 1 Scope. .1 2 Normativereferences .1 3 Terms and definitions .1 4 Principle. .2 5 Interferences .3 5.1 General. 3 5.2 TOC 3 TN 5.3 3 5.4 TP. .4 6 Reagents .4 7 Solution preparations 5 7.1 Blank solution 5 7.2 Sample oxidation solutions.. 5 7.2.1 Sulfuric acid TIC and catalyst solution 5 7.2.2 Base oxidation solution. 7.2.3 TP solution. 5 7.2.4 TP hydrolysis solution 5 7.3 Calibration stock solutions. 6 7.4 Individual calibrationstandard solutions 6 7.4.1 TOC 6 7.4.2 TN. 6 7.4.3 TP 7 7.4.4 Combined calibration standard solutions. 7 7.5 System check stock solutions 7 7.5.1 TOC and TN stock solution 7 7.5.2 TP stock solution 7 7.6 Particle processing control solution 7 7.7 Gases. 8 8 Apparatus .8 9 Qualityrequirementsfortheanalyticalsystem .8 9.1 System check. 8 9.2 Recovery andvariation of replicatedeterminations forparticleprocessingcontrol for TOC, TNb, and TPb 9 10 9 Sampling and sample preparation 10.1 Samplingand sampleinjection .9 11 Procedure. .9 11.1 General. 9 11.2 Calibration 10 11.3 Validity check of the calibration function 10 11.4 Measurement 10 11.4.1 General. .10 11.4.2 Determination .10 12 Evaluation .11 13 Expression of results .11 14 Test report. .11 @ IS0 2020 - All rights reserved iii