INTERNATIONAL ISO STANDARD 10136-2 First edition 1993-07-01 Glass and glassware -- Analysis of extract solutions - Part 2: Determination of sodium oxide and potassium oxide by flame spectrometric methods Verre et verrerie - Analyse des solutions d'attaque spectrométrie d'émission deflamme Referencenumber ISO 10136-2:1993(E) ISO 10136-2:1993(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, also 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. International Standard ISO 10136-2 was prepared by Technical Committee ISO/TC _48. Laboratory glassware and related apparatus, Sub-Committee SC 5, Quality of glassware. IsO 10136 consists of the following parts, under the general title Glass and glassware -- Analysis of extract solutions: Part 1: Determination of silicon dioxide by molecular absorption spectrometry Part 2: Determination of sodium oxide and potassium oxide by flame spectrometric methods Part 3: Determination of calcium oxide and magnesium oxide by flame atomic absorption spectrometry Part 4: Determination of aluminium oxide by molecular absorption spectrometry - Part 5: Determination of iron(ll) oxide by molecular absorption spectrometry and flame atomic absorption spectrometry Part 6: Determination of boron(l) oxide by molecular absorption spectrometry Annex A of this part of ISO 10136 is for information only. ISO1993 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, inciuding'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 SO10136-2:1993(E) Introduction and in the various pharmacopoeia, have relied for many years on a titration of extract solutions with a diluted mineral acid. Such solutions may contain not only the alkali metal oxides (sodium and potassium), 'but also the al- kaline earth oxides (calcium and magnesium), which are also titrated by acid. Thus, the determination is actually of the total alkalinity of the extract recent years, with the advent of more modern techniques, such as flame more. Therefore, the specific determination of sodium and potassium in extract solutions is possible, and this is of interest for many general in- vestigations on the durability of glasses. The procedure was established and applied to simulated or actual dura- of the International Commission on Glass (ICG). In these round robins, up to 21 analysts from 15 laboratories collaborated. The final results of the round robin were that for the very low concentrations in extract solutions, e.g. from borosilicate glasses, no spectrochemical buffer needs to be added, and that for other aqueous extract solutions the addition of only caesium chloride is sufficient (see [5] in annex A). The flame spectrometric methods described in this part of ISO 10136 are durability extract solutions. The results of investigations on turbidities, especially in grain test sol- utions, showed that acidification to dissolve possible hydroxides and/or achieved by using spectroscopic buffer solutions, which are normally strongly acidic, or by addition of acids. ili