ISO-9174-1998.pdf
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1、A Reference number ISO 9174:1998(E) INTERNATIONAL STANDARD ISO 9174 Second edition 1998-07-15 Water quality Determination of chromium Atomic absorption spectrometric methods Qualit de leau Dosage du chrome Mthodes par spectromtrie dabsorption atomique Copyright International Organization for Standar
2、dization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:41:28 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 9174:1998(E) ISO 1998 All rights reserved. Unless otherwise specified, no part of this publ
3、ication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case postale 56 CH-1211 Genve 20 Switzerland Internetisoiso.ch Printed i
4、n Switzerland ii ContentsPage 1Scope 1 2Normative references .1 3Determination of chromium by flame atomic absorption spectrometry1 4Determination of chromium by electrothermal atomization atomic absorption spectrometry 5 Annex A (informative) Pretreatment and digestion of sludge and sediment sample
5、s8 Annex B (informative) Precision data.9 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:41:28 MDTNo reproduction or networking permitted without license from IHS -,-,- ISOIS
6、O 9174:1998(E) iii 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 su
7、bject 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
8、(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 S
9、tandards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. International Standard ISO 9174 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2, Physical, chemical, biochemical methods. This second edition cancels and replaces the first edi
10、tion (ISO 9174:1990), which has been technically revised. Annexes A and B of this International Standard are for information only. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007
11、 02:41:28 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 9174:1998(E) ISO iv Introduction Chromium occurs in water in the oxidation states III and VI. The two methods described in this International Standard determine chromium in both oxidation states, either as acid-s
12、oluble chromium or as water-soluble chromium, depending on the sample pretreatment. The method chosen depends on the concentration of chromium in the water to be examined. Annex A provides information on pretreatment and digestion of chromium from sludges and sediments. Copyright International Organ
13、ization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:41:28 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISOISO 9174:1998(E) 1 Water quality Determination of
14、chromium Atomic absorption spectrometric methods 1 Scope This International Standard specifies two methods for the determination of chromium in water by atomic absorption spectrometry. The two methods are covered in separate clauses as follows: Clause 3: Determination of chromium by flame atomic abs
15、orption spectrometry; Clause 4: Determination of chromium by electrothermal atomization atomic absorption spectrometry. Clause 3 is applicable to the analysis of water and waste water when the concentration range is between 0,5 mg/l and 20 mg/l of chromium. When the concentration is below 0,5 mg/l,
16、the determination can be carried out after carefully evaporating an acidified sample to small volume, taking care to avoid the formation of a precipitate. NOTE The use of evaporation will increase the effect of interfering substances and therefore for concentrations below 0,1 mg/l the method in clau
17、se 4 is given. Clause 4 is applicable to the analysis of water and waste water when the concentration range is between 5 mg/l and 100 mg/l of chromium by injecting a sample volume of 20 ml. It is applicable to the determination of higher concentrations by using a smaller sample volume. 2 Normative r
18、eferences The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on
19、 this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently
20、 valid International Standards. ISO 5667-2 : 1991, Water quality Sampling Part 2: Guidance on sampling techniques. ISO 5667-3 : 1994, Water quality Sampling Part 3: Guidance on the preservation and handling of samples. 3 Determination of chromium by flame atomic absorption spectrometry 3.1 Principle
21、 The method is based on the atomic absorption spectrometric measurement of the chromium content of the acidified sample in a nitrous oxide/acetylene flame. Measurement at a wavelength of 357,9 nm. Addition of lanthanum salt to reduce matrix interferences is necessary. 3.2 Reagents All reagents shall
22、 be of recognized analytical grade. Use deionized water or water distilled from an all-glass apparatus. The water used for blank tests and for preparing reagents and standard solutions shall have a chromium content that is negligible compared with the smallest concentrations to be determined in the
23、samples. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:41:28 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 9174:1998(E) ISO 2 3.2.1 Hydrochlo
24、ric acid, HCl, r 1,18 g/ml. 3.2.2 Nitric acid, HNO3, r 1,42 g/ml. 3.2.3 Nitric acid, c(HNO3) = 1,5 mol/l. Introduce about 500 ml of water into a 1 000 ml volumetric flask, add 100 ml of nitric acid (see 3.2.2) and dilute to the mark with water. 3.2.4 Hydrogen peroxide, H2O2, 30 % mass fraction solut
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