ISO INTERNATIONAL STANDARD 10136-4 First edition 1993-07-01 Glass and glassware - Analysis of extract solutions - Part 4: Determination of aluminium oxide by molecularabsorption spectrometry Verre et verrerie -Analyse des solutions d'attaque Partie 4: Dosage de I'oxyde d'aluminium par spectrometrie d'absorption moléculaire Reference number ISO 10136-4:1993(E) ISO 10136-4:1993(E) Foreword IsO (the International Organization for Standardization) is a worldwide technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be and non-governmental, in liaison with IsO, also take part in the work. IsO (IEC) on all matters of electrotechnical standardization. avote. International Standard ISO 10136-4 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 spectrometricmethods Part 3: Determination of calcium oxide and magnesium oxide by flame atomic absorption spectrometry 一 Part 4: Determination of aluminium oxide by molecular absorption spectrometry Part 5: Determination of iron(lll) oxide by molecular absorption spectrometry and flame atomic absorption spectrometry Part 6: Determination of boron(lll) 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, including photocopying and microfim, without per- mission in writing from the publisher. nternationalOrganizationforStandardization Case Postale 56 · CH-1211 Geneve 20 · Switzerland Printed in Switzerland ii IS010136-4:1993(E) Introduction The amounts of aluminium oxide (Al2O3) extracted from most glasses by methods normally used for measuring the hydrolytic resistance are ex- tremely small, therefore very sensitive analytical methods are needed for sis, of the International Commission on Glass (ICG), examined the problem (see [6] in annex A) and decided that the most widely applicable approach would probably be via a molecular absorption spectrometic method, al- though flame atomic absorption spectrometry was also studied. A considerable number of reagents are available for producing colour complexes with aluminium but none is particularly outstanding. Three were selected for the round-robin examination in which eleven laboratories collaborated and they were chromazurol S, eriochrome cyanine and 8-hydroxyquinoline. The results obtained suggested that the chromazuro! at the low concentrations of aluminium oxide expected in extract sol- utions, is probably as accurate as any other generally available method. In a later investigation, the determination of very low concentrations of aluminium oxide in extract solutions by flame atomic absorption spec- flame atomic absorption spectrometric method is not suitable for the de- termination of low concentrations of aluminium oxide in extract solutions. The results of investigations on turbidities, especially in grain test sol- utions, showed that acidification to dissolve possible hydroxides and/or strongly acidic, or by addition of acids. ii