ISO INTERNATIONAL STANDARD 11083 Firstedition 1994-08-15 Water quality -- Determination of chromium(Vi) -- Spectrometric method using 1,5-diphenylcarbazide Qualité de I'eau -- Dosage du chrome(Vi) --- Methode par spectrométrie d'absorption moleéculaire avec la 1,5-diphénylcarbazide ISO Reference number ISO 11083:1994(E) Copyright International Organization for Standardizatior No reprodu Not for Resale ISO 11083:1994(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. 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 collaborates closely with the Internationai Electrotechnical Commission (lEC) 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 11083 was prepared by Technical Committee ISO/TC 147. Water. quality. Sub-Committee SC 2. Physical, chemical, biochemical methods. ?ISO1994 Ail rights reserved. Unless otherwise specified, no part of this pubtication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfim, without permission in writing from the publisher. International Organization for Standardization Case postale 56 · CH-1211 Geneve 20 · Switzerland Printed in Switzerland ii Copyright Intermational Organization for Standardization Not for Resale ISO 11083:1994(E) INTERNATIONAL STANDARD ISO Water quality Determination of chromium(Vl) - Spectrometric method using 1,5-diphenylcarbazide Scope 3.2 Sodium hydroxide solution. 1 Dissolve 20 g of sodium hydroxide (Na0H) in 100 ml ThisInternationalStandardspecifiesaspectrometric method for determination of chromium(Vl) in water. of water. Themethodisapplicabletothedeterminationof dissolved chromium(Vl) in waters in the concentration 3.3 Phosphoric acid solution A. range of 0,05 mg/l to 3 mg/l. The application range may be extended by dilution of the sample. Dilute 10 ml of phosphoric acid (H3PO4, p = 1,71 g/ml) to 100 m! with water. 3.4 Phosphoric acid solution B. 2 Principle Dilute 700 ml of phosphoric acid (H3PO4, p = 1,71 g/ml) to 1 000 ml with water. After sample pretreatment (which aims at stabilizing the valency states of chromium(Vl) and chromium(ll1), if present) chromium(Vl) reacts with 1,5-diphenyl- 3.5 Aluminium sulfate solution. carbazide to form a red-violet chromium-1,5-diphenyl- carbazone complex. The absorbance of this complex Dissolve 247 g of aluminium suffate [Al2(SO4)3.18H2Ol in isthenmeasuredatawavelengthbetween540nm 1 000 ml of water. and 550 nm, the exact wavelength being given in the test report. 3.6 Sulfite solution. Dissolve 11,8 g of sodium sulfite (Na2SO3) in water and dilute to 100 ml. 3 Reagents This solution is stable for about a week. Use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 3.7 Sulfite test paper. Commercially available reagents with guaranteed 3.8 1,5-diphenylcarbazide solution. concentrations may also be used. Dissolve 1 g of 1,5-diphenylcarbazide (C13H14N4O) in 100 m! of propanone (acetone). C3HgO, and acidify 3.1 Phosphate buffer solution, pH = 9.0 ± 0,2 with one drop of glacial acetic acid. Dissolve 456 g of dipotassium hydrogen phosphate Stored in a brown glass bottle in a refrigerator at 4 °C. (K2HPO4.3H20O) in 1 000 mt of water. Check the pH this solution is stable for two weeks. Discard the and adjust if necessary. solution if it becomes discoloured. 1 networking permitted without license from IHS Not for Resale