ISO INTERNATIONAL STANDARD 9964-2 First edition 1993-05-01 Water quality - Determination of sodium and potassium - Part 2: Determination of potassium by atomic absorption spectrometry Qualité de I'eau -Dosage du sodium et du potassium : Partie 2: Dosage du potassium par spectrometrie d'absorption atomique Reference number ISO9964-2:1993(E) ISO 9964-2:1993(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, governmental and non-governmental, in liaison with IsO, aliso take part in the work. Iso collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. ISO/TC 147. Water quality. Sub-Committee SC 2, Physical, chemical, biochemical methods. IsO 9964 consists of the following parts, under the general title Water quality Determination of sodium and potassium: - Part 1: Determination of sodium by atomic absorption spectrometry - Part 2: Determination of potassium by atomic absorption spec- trometry -- Part 3: Determination of sodium and potassium by flame emission spectrometry ISO1993 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without per- mission in writing from the publisher. international Organization for Standardization Case Postale 56 . CH-1211 Geneve 20 · Switzerland Printed in Switzerland ii 1SO 9964-2:1993(E) INTERNATIONAL STANDARD Water quality -- Determination of sodium and potassium Part 2: Determination of potassium by atomic absorption spectrometry Scope SO5667-1:1980. Water quality Sampling 1 Part 1: Guidance on the design of sampling pro- grammes. 1.1 Field of application ISO 5667-2:1991, Water quality Sampling Part 2: Guidance on sampling techniques. This International Standard specifies a method for the determination of dissolved potassium by flame atomic absorption spectrometry (AAS). It is intended for the 3 Principle analysis of raw and drinking waters. The method is applicable to water samples with a Addition of caesium chloride solution to the sample mass concentration of potassium in the range from as an ionization suppressant. Aspiration of the sample 5 mg/l to 50 mg/l. This range can be extended to directly into the airjacetyiene flame of an atomic ab- lower or higher limits if dilution factors are chosen sorptionspectrometer. Measurement of which are different from the factor specified in absorbance at a wavelength of 766,5 nm. clause 8. 4 Reagents 1.2 Interferences During the anatysis, use only reagents of recognized analytical grade and only deionized water or water of The ions normally present in raw and drinking waters do not interfere with the determination of potassium equivalent purity. by atomic absorption spectrometry. 4.1 Hydrochloric acid, c(HCl) ~ 11 mol/l, p = 1,18 g/ml. 2 Normative references 4.2 Nitric acid, c(HNO3) ~ 16 mol/l, p = 1,41 g/ml The following standards contain provisions which, through reference in this text, constitute provisions 4.3 Caesium chloride, (CsCl), solution. of this part of ISO 9964. At the time of publication, the editions indicated were valid. All standards are subject Dissolve 25 g of caesium chloride in a solution of to revision,and parties to agreements based on this 50 ml of hydrochloric acid (4.1) and 450 ml of water, part of ISO 9964 are encouraged to investigate the and dilute