ISO INTERNATIONAL STANDARD 10530 First edition 1992-09-15 Water quality -- Determination of dissolved sulfide -- Photometric method using methylene blue Qualité de I'eau -- Dosage des sulfures dissous -- Methode photometrique au bleu de methylene Reference number ISO 10530:1992(E) Copyright International Organization for Standardization I by IHS under licen No reproduction or networking permitted without license from IHS Not for Resale 1SO 10530:1992(E) Foreword IsO (the International Organization for Standardization) is a worldwide federation of national standards bodies (isO member bodies). The work of preparing International Standards is normally carried out through IsO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with Iso, also take part in the work. Iso collaborates closely with the International Electrotechnical Commission (IEC) on ail matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Inter- national Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard IsO 10530 was prepared by Technical Committee ISO/TC 147, Water quality, Sub-Committee SC 2, Physical. chemical, biochemical methods. AnnexAforms anintegral part ofthisinternational Standard ISO 1992 or by any means, electronic or mechanical, including photocopying and microfilm, withoul permission in writing from the publisher. International Organization for Standardization Case Postale 56 ·CH-1211 Geneve 20 · Switzerland Printed in Switzerland ii working permitted without license from IHS Not for Resale ISO 10530:1992(E) INTERNATIONAL STANDARD Water quality Determination of dissolved sulfide Photometric method using methylene blue Scope Normative reference 1 2 The following standard contains provisions which, 1.1 Application range through reference in this text, constitute provisions of this International Standard. At the time of publi- This international Standard specifies a photometric cation, the edition indicated was valid. All standards method for the determination of dissolved suifide in are subject to revision, and parties to agreements water. The method is applicable to the determi- based on this international Standard are encour- nation of dissoived sulfide in a mass concentration aged to investigate the possibility of applying the range from 0,04 mg/l to 1,5 mg/l. most recent edition of the standard indicated below. Members of IEC and ISO maintain registers of cur- Higher concentrations may be determined by re- rently valid international Standards. ducing and subsequently diluting the volume of the water sample used. SO5667-3:1985, Water quality Sampling Part 3: Guidance on the preservation and handling The method is applicable to waste water and natural of samples. waters requiring filtration. Interferences Principle 1.2 The following ions do not interfere with the method Filtration of the water sample in order to separate the suspended matter and sulfides of low solubility. as long as the mass concentrations specified below are not reached or exceeded: Conservation of the sulfide in the filtrate by addition of ascorbate solution. Stripping of the sulfides from Cyanide 2 mg/l the filtrate using nitrogen and transfer into a receiv- ing flask containing an aqueous zinc acetate sol- lodide 20 mg/1 ution. 900 mg/l Thiosulfate Formation of leukomethylene blue in the receiving ftask on the addition of acid dimethyl-p-phenyl- 900 mg/1 Thiocyanate endiamine solution and oxidation to methylene blue Suifite 700 mg/l by addition of iron(ll) ions. Measurement of the absorbance of this complex at a wavelength of When applying this procedure, the determination of 665 nm. the sulfide portion from polys