ISO INTERNATIONAL STANDARD 10359-2 First edition 1994-10-15 Water quality - Determination of fluoride Part 2: Determination of inorganically bound total fluoride after digestion and distillation Qualité de I'eau - Dosage des fluorures Partie 2: Dosage des fluorures totaux liés inorganiquement apres digestion et distillation ISO Reference number ISO10359-2:1994(E) ISO 10359-2:1994(E) Foreword ISO (the International Organization for Standardization) is a worldwide of preparing International Standards is normally carried out through IsO 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, also take part in the work. isO collaborates closely with the International Electrotechnical Commission (lEC)onallmattersofelectrotechnicalstandardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International a vote. ISO/TC147. Water quality, Subcommittee sc 2, Physical, chemical, biochemical methods. quality --Determination offluoride: Part 1: Electrochemical probe method for potable and lightly polluted water Part 2: Determination of inorganically bound total fluoride after di- gestion and distillation Annex A of this part of ISO 10359 is for information only. ISO 1994 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanicai, inciuding photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case Postale 56 . CH-1211 Geneve 20 · Switzerland Printed in Switzerland ii @ ISO IS010359-2:1994(E) Introduction centration depends primarily on the hydrogeological conditions and is generally below 1 mg/l. Certain industrial waste waters may also contain fluoride ions in higher concentrations. The fluoride concentration is also dependant on the type and concentration of cations present at the same time in water, such as Ca?+, Mg2+, Ai3+ or Fe3+, which may form sparingly soluble compounds with fluoride ions or complexes of low dissociation grade. In addition, stable boron-fluoride complexes exist. Several different methods are available for determining as follows. a） Direct measurement using fluoride ion selective electrodes. This method is suitable for the determination of fluoride in drinking and surface water. It is included in ISO 10359-1. b) Determination of inorganically bound total fluoride using decompo- sition, distillation and potentiometric measurement. This method is included in this part of iSO 10359. ili