7150/1 International Standard (TSO INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEXAYHAPOAHA OPTAHW3ALMA IO CTAHAAPTM3ALMM-ORGANISATION INTE RNATIONALE DE NORMALISATION Water quality -- Determination of ammonium Part 1 : Manual spectrometric method QualitedeI'eau-DosagedeI'ammonium-Partie1:Methodespectrométriquemanuelle First edition -- 1984-06-01 ISO 7150/1-1984 (E) UDC 543.342 : 543.42 Ref.No.ISO7150/1-1984 (E) Descriptors : water, quality, chemical analysis, determination of content, ammoniacal nitrogen, ammonium ion, spectrophotometric analysis, water pollution. Price based on 7 pages Copyright International Organization for Standardizatio networking permitted without license from IHS Not for Resale Foreword ISo (the International Organization for Standardization) is a worldwide federation of national standards bodies (IsO member bodies). The work of developing International Standards is carried out through Iso technical committees. Every member body interested ina subject for which atechnical committee hasbeen authorized has the andnon-governmental,inliaison withIsO,alsotakepart inthework. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the iso Council. International Standard ISO 7150/1 was developed by Technical Committee ISO/TC 147, Water quality, and was circulated to the member bodies in February 1983. It has been approved by the member bodies of the following countries : Australia Hungary Norway Austria India Poland Belgium Iran Romania Canada Iraq South Africa, Rep. of Chile Italy Spain Czechoslovakia Korea, Dem. P. Rep. of Sweden Denmark Korea, Rep.of Switzerland Finland Mexico Thailand France Netherlands United Kingdom Germany, F.R. New Zealand USSR The member body of the following country expressed disapproval of the document on technical grounds : Japan ? International Organization for Standardization, 1984 Printed in Switzerland Copyright International Organization for Standardization No reproduction or networking permitted without license from IHS Not for Resale INTERNATIONALSTANDARD ISO7150/1-1984 (E) Water quality - Determination of ammonium Part 1: Manual spectrometric method 1 Scope and field of application 3 Principle 1.1 Substance determined Spectrometric measurement at about 655 nm of the blue compound formed by reaction of ammonium with salicylate This part of ISo 7150 specifies a manual spectrometric method and hypochlorite ions in the presence of sodium nitrosopenta- for the determination of ammonium in water. cyanoferrate(l) (sodium nitroprusside). NOTE - An automated spectrometric method for the determination of Hypochlorite ions are generated in situ by the alkaline ammoniumwill form the subjectof IS07150/2. hydrolysis of N, N'-dichloro-1,3,5-triazine-2,4,6 (1H, 3H, 5H)-trione, sodium salt (sodium dichloroisocyanurate). Reac- 1.2 Type of sample tion of the chloramine with sodium salicylate takes place at pH12,6inthepresence of sodium nitroprusside. Any The method is applicable to the analysis of potable water, and chloramines present in the sample are quantitatively de- mostrawandwastewaters.Applicationtoexcessivelycoloured termined as a consequence.Sodium citrate is incorporated in or saline waters shall be preceded by distillation (see clause 10). the reagent tomask interferencefrom cations,notablycalcium and magnesium. For interferences, see clause 9. 1.3 Range t Reagents An ammonium nitrogen concentration, on of up to 1 mg/l, using the maximum test portion of 40 ml, can be determined. During the analysis, use only reagents of recognized analytical Much higher concentrations can be determined by taking grade and only water prepared as described in.4.1. smallertest portions. 1.4 Limit of detection1) 4.1 - Water, ammonium-free, prepared by one of the follow- ing methods. When using cells of optical path length 40 mm and a 40 ml test portion, the limit of detection lies within