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1、INTERNATIONAL STANDARD ISO 14403 First edition 2002-03-01 Reference number ISO 14403:2002(E) ISO 2002 Water quality Determination of total cyanide and free cyanide by continuous flow analysis Qualit de leau Dosage des cyanures totaux et des cyanures libres par analyse en flux continu Copyright Inter
2、national Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/18/2007 20:29:55 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 14403:2002(E) ii ISO 2002 All rights reserved PDF disclaim
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5、ile; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. ISO 2002 All right
6、s reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the
7、requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.ch Web www.iso.ch Printed in Switzerland Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standard
8、s 1/9972545001 Not for Resale, 04/18/2007 20:29:55 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 14403:2002(E) ISO 2002 All rights reserved iii Contents Page 1Scope . 1 2Normative references . 1 3Terms and definitions 1 4Interferences . 2 5Principle 2 6Reagents 3 7App
9、aratus . 5 8Sampling and sample preparation 9 9Procedure . 10 10Calculation 12 11Precision and accuracy 13 12Test report 13 Annexes ADetermination of the actual cyanide concentration in potassium cyanide stock solution 14 BExample for the determination of total cyanide and free cyanide by continuous
10、 flow analysis (CFA) with gas diffusion and amperometric detection. 15 CResults of the interlaboratory trial for cyanide determination 17 Bibliography. 18 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 No
11、t for Resale, 04/18/2007 20:29:55 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 14403:2002(E) iv ISO 2002 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies).
12、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-g
13、overnmental, 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. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3
14、. 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. Attention is drawn to the possibility that some of the elements of this
15、 International Standard may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. International Standard ISO 14403 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2, Physical, chemical, biochemical methods. An
16、nex A forms a normative part of this International Standard. Annexes B and C 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, 04/18/2007 20:29:55 MDTNo reproduction
17、 or networking permitted without license from IHS -,-,- ISO 14403:2002(E) ISO 2002 All rights reserved v Introduction Methods using flow analysis automate wet chemical procedures and are particularly suitable for the processing of many analytes in water in large sample series at a high analysis freq
18、uency. Analysis can be performed by flow injection analysis (FIA) or continuous flow analysis (CFA). In this International Standard the latter is specified. The CFA method shares the feature of an automatic dosage of the sample into a flow system (manifold) where the analytes in the sample react wit
19、h the reagent solutions on their way through the manifold. The sample preparation may be integrated in the manifold. The reaction product is measured in a flow detector (e.g. flow photometer). It is absolutely essential that the test described in this International Standard be carried out by suitabl
20、e qualified staff. It should be investigated whether and to what extend particular problems will require the specification of additional marginal conditions. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001
21、 Not for Resale, 04/18/2007 20:29:55 MDTNo reproduction or networking permitted without license from IHS -,-,- Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/18/2007 20:29:55 MDTNo repr
22、oduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARDISO 14403:2002(E) ISO 2002 All rights reserved 1 Water quality Determination of total cyanide and free cyanide by continuous flow analysis WARNING Persons using this International Standard should be familiar with n
23、ormal laboratory practice. This International Standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions.
24、1Scope This International Standard specifies methods for the determination of cyanide in various types of water (such as ground, drinking, surface, leachate and waste water) with cyanide concentrations usually above expressed as cyanide ions. The CFA method is applicable to a mass concentration rang
25、e from to . The range of application may be changed by varying the operation conditions. NOTESeawater may be analyzed with changes in sensitivity and adaptation of the reagent and calibration solutions to the salinity of the samples. 2Normative references The following normative documents contain pr
26、ovisions 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 this International Standard are encouraged to investi
27、gate 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 valid International Standards. ISO 3696:1987, Water f
28、or analytical laboratory use Specification and test methods ISO 5725-2:1994, Accuracy (trueness and precision) of measurement methods and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method ISO 8466-1:1990, Water quality Calibratio
29、n and evaluation of analytical methods and estimation of performance characteristics Part 1: Statistical evaluation of the linear calibration function 3Terms and definitions For the purposes of this International Standard, the following terms and definitions apply. 3.1 total cyanide sum of some orga
30、nically bound cyanides, free cyanide ions, complex compounds and cyanide bound in simple metal cyanides, with the exception of cyanide bound in cobalt complexes and of thiocyanate 3g/l 10g/l100g/l Copyright International Organization for Standardization Provided by IHS under license with ISO License
31、e=NASA Technical Standards 1/9972545001 Not for Resale, 04/18/2007 20:29:55 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 14403:2002(E) 2 ISO 2002 All rights reserved 3.2 free cyanide easily liberatable cyanide sum of cyanide ions and the cyanide bound in simple metal
32、 cyanides as determined in accordance with this International Standard NOTEOrganic cyanides are not included. 4Interferences 4.1Interferences by oxidizing agents Oxidizing agents such as chlorine decompose most of the cyanides. If oxidizing agents are suspected, test for their presence as given in c
33、lause 8. 4.2Interferences by sulfides Sulfide concentrations affect the colorimetric procedure. If sulfide is suspected, carry out tests for its presence as given in clause 8. 4.3Other interferences When using in-line distillation for separation of the hydrogen cyanide, salt concentrations higher th
34、an can cause clogging of the distillation coil. Dilute these samples prior to measurement in order to overcome this problem. Under the given distillation conditions aldehydes can transform cyanide to nitrite. Aldehydes can be removed by adding silver nitrate to the sample. NOTEThe addition of AgNO3
35、can alter the ratio of the concentrations of free and total cyanide. The user should evaluate this procedure. Particulate matter in the sample may lead to clogging of the transport tubes and will interfere with the photometric measurement. Particles should be removed by filtration. Thiocyanate can s
36、lightly interfere and lead to positive bias (9.3.2). Significant interferences can arise from cyanide impurities in thiocyanate or from inappropriate distillation procedures (7.1). 5Principle 5.1Determination of total cyanide concentration Complex bound cyanide is decomposed by UV light in a continu
37、ous flow at a pH of 3,8. A UV-B lamp () and a decomposition spiral of borosilicate glass is used to filter off UV light with a wavelength of thus preventing the conversion of thiocyanate into cyanide. Alternatively it is possible to use a long wavelength UV lamp (), which does not emit light below a
38、nd which is equipped with a decomposition spiral of quartz glass or polytetrafluoroethylene (PTFE). The hydrogen cyanide present at pH 3,8 is separated by on-line distillation at or by gas diffusion at across a hydrophobic membrane. The hydrogen cyanide is then determined photometrically by the reac
39、tion of cyanide with chloramine-T to cyanogen chloride. This reacts with pyridine-4- carbonic acid and 1,3-dimethylbarbituric acid to give a red dye. 60 mg/l 10 g/l 0,1 mm 312 nm 290 nm 351 nm 290 nm 125 C 30 C Copyright International Organization for Standardization Provided by IHS under license wi
40、th ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/18/2007 20:29:55 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 14403:2002(E) ISO 2002 All rights reserved 3 5.2Determination of free cyanide concentration The UV lamp is switched off when determi
41、ning the free cyanide content. During distillation at pH 3,8 for separation of the hydrogen cyanide present, a zinc sulfate solution is added to the sample flow in order to precipitate any iron cyanides present as the zinc-cyanoferrate complex. For detection see 5.1. 6Reagents WARNING KCN, K2Zn(CN)4
42、, and their solutions and wastes are toxic. Waste containing these substances shall be removed appropriately. Use only reagents of recognized analytical grade. 6.1Water, grade 1 according to ISO 3696. 6.2Hydrochloric acid I, . 6.3Hydrochloric acid II, . 6.4Hydrochloric acid III, . 6.5Sodium hydroxid
43、e solution I, . 6.6Sodium hydroxide solution II, . 6.7Sodium hydroxide solution III, . 6.8Sodium hydroxide solution IV, . 6.9Surfactant, polyoxyethylene lauryl ether, OH-(CH2CH2-O)n-C18H37. Add of polyoxyethylene lauryl ether in small quantities to of water (6.1) and mix well. Alternatively use a co
44、mmercially available solution of the surfactant. 6.10Citric acid monohydrate, C6H8O7H2O. 6.11Zinc sulfate heptahydrate, ZnSO47H2O. 6.12Potassium hydrogenphthalate, KHC8H4O4. 6.13Chloramine-T trihydrate, C7H7ClNNaO2S3H2O. 6.141,3-Dimethylbarbituric acid, C6H8N2O3. 6.15Pyridine-4-carboxylic acid, C6H5
45、NO2. 6.16Potassium thiocyanate, KSCN. 6.17Potassium hexacyanoferrate(III), K3Fe(CN)6. 6.18Cyanide standards. 6.18.1Potassium cyanide stock solution, (see annex A). Dissolve of potassium cyanide, KCN, in sodium hydroxide solution IV (6.8) in a graduated flask and make up to volume with sodium hydroxi
46、de solution IV (6.8). c(HCl)=12 mol/l c(HCl)=1 mol/l c(HCl)=0,1 mol/l c(NaOH)=2,5 mol/l c(NaOH)=1,0 mol/l c(NaOH)=0,1 mol/l c(NaOH)=0,01 mol/l 30 g100 ml KCN,(CN)=100 mg/l 250 mg1 mg1 000 ml Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA
47、 Technical Standards 1/9972545001 Not for Resale, 04/18/2007 20:29:55 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 14403:2002(E) 4 ISO 2002 All rights reserved Alternatively, a potassium tetracyanozincate solution (6.18.2) may be used. 6.18.2Potassium tetracyanozinca
48、te solution, K2Zn(CN)4, . Commercially available. 6.18.3Cyanide solution I, . Pipette of the potassium tetracyanozincate solution I (6.18.2) or of the potassium cyanide stock solution (6.18.1) into a graduated flask and bring to volume with sodium hydroxide solution IV (6.8). This solution is stable for 1 week if stored at room temperature. 6.18.4Calibration solutions. Prepare at least five calibration solutions with cyanide