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1、 Reference number ISO 22743:2006(E) ISO 2006 INTERNATIONAL STANDARD ISO 22743 First edition 2006-04-15 Water quality Determination of sulfates Method by continuous flow analysis (CFA) Qualit de leau Dosage des sulfates Mthode par analyse en flux continu (CFA) Copyright International Organization for
2、 Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 03:06:06 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22743:2006(E) PDF disclaimer This PDF file may contain embedded typefaces. In accor
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5、ing. 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 2006 All rights reserved. Unless otherwise specified, no part of this p
6、ublication 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 requester. ISO copyright office Case postale 56 CH-1211 G
7、eneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2006 All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not fo
8、r Resale, 04/20/2007 03:06:06 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22743:2006(E) ISO 2006 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references. 1 3 Interferences . 1 4 Principle. 2 5 Reagents 2 6 Apparatus 3 7 Sa
9、mpling and sample pretreatment 4 8 Procedure 4 9 Calculation of results . 6 10 Expression of results . 6 11 Test report . 7 Annex A (informative) Example of a CFA system for the determination of sulfate. 8 Annex B (informative) Precision and accuracy. 9 Bibliography. 10 Copyright International Organ
10、ization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 03:06:06 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22743:2006(E) iv ISO 2006 All rights reserved Foreword ISO (the Internat
11、ional 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 bee
12、n 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 stand
13、ardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for
14、 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 document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all
15、 such patent rights. ISO 22743 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2, Physical, chemical and biochemical methods. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001
16、Not for Resale, 04/20/2007 03:06:06 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22743:2006(E) ISO 2006 All rights reserved v Introduction Methods using flow analysis automate wet chemical procedures and are particularly suitable for the processing of many analytes i
17、n water in large sample series at a high analysis frequency. Analysis can be performed by flow injection analysis (FIA) 1, 2 or by continuous flow analysis (CFA) 3. Both methods share the feature of an automatic dosage of the sample into a flow system (manifold) where the analytes in the sample reac
18、t with the reagent solutions on its 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). The detector produces a signal from which the concentration of the parameter is calculated. It is necess
19、ary to examine whether and to what extent particular problems will require the specification of additional marginal conditions. In this International Standard, only the CFA procedure is described. Copyright International Organization for Standardization Provided by IHS under license with ISO License
20、e=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 03:06:06 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
21、 Resale, 04/20/2007 03:06:06 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISO 22743:2006(E) ISO 2006 All rights reserved 1 Water quality Determination of sulfates Method by continuous flow analysis (CFA) WARNING Persons using this International Sta
22、ndard should be familiar with normal laboratory practice. This 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 regula
23、tory conditions. IMPORTANT It is absolutely essential that tests conducted according to this standard be carried out by suitably trained staff. 1 Scope This International Standard specifies a continuous flow analysis (CFA) method for the determination of sulfate in various types of water (such as gr
24、ound water, drinking water and waste water). The method is applicable to samples with a sulfate (SO4) mass concentration from 30 mg/l to 300 mg/l. Other concentration ranges are applicable, provided they cover exactly one decade of concentration units (e.g. 100 mg/l to 1 000 mg/l). 2 Normative refer
25、ences The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 3696, Water for analytical laboratory u
26、se Specification and test methods ISO 5667-3, Water quality Sampling Part 3: Guidance on the preservation and handling of water samples ISO 8466-1, Water quality Calibration and evaluation of analytical methods and estimation of performance characteristics Part 1: Statistical evaluation of the linea
27、r calibration function ISO 8466-2, Water quality Calibration and evaluation of analytical methods and estimation of performance characteristics Part 2: Calibration strategy for non-linear second-order calibration functions 3 Interferences Calcium-, magnesium-, iron- and aluminium ions interfere with
28、 the determination of sulfate (negative bias). Treatment with a cation exchange resin will reduce the interferences. Sulfide, sulfite, phosphate and tannic acids may lead to a positive bias, but concentrations of these substances which cause measurable interferences are usually not found in real sam
29、ples. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 03:06:06 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22743:2006(E) 2 ISO 2006 All rights r
30、eserved 4 Principle Sulfate reacts in an acidic solution with barium chloride to form barium sulfate. The excessive barium chloride reacts with methylthymol blue in an alkaline solution to a chelated barium methylthymol blue. The absorbance of the free non-chelated methylthymol blue is measured at 4
31、60 nm 10 nm in a flow through detector. Other metals, such as calcium, magnesium, iron and aluminium, are removed by an ion exchange column prior to the reactions with barium. 5 Reagents Use analytical grade chemicals, unless otherwise specified, and check the blank value of the reagents. 5.1 Water,
32、 complying with grade 1 as defined in ISO 3696. 5.2 Barium chloride dihydrate, BaCl22H2O. 5.3 Concentrated hydrochloric acid, c(HCl) = 12 mol/l, (HCl) = 1,19 g/ml. 5.4 Methylthymol blue, (C37H40N2O13SNa4 or C37H43N2O13SNa). 5.5 Surfactant, polyoxyethylene-23-laurylether (C12H25(OCH2CH2)23OH), a mass
33、 fraction of 30 % solution in water. 5.6 Sodium hydroxide, (NaOH). 5.7 Ethylenedinitrilotetracetic acid tetrasodium salt, Na4-EDTA, (C10H12N2Na4O8). 5.8 Ammonium chloride, (NH4Cl). 5.9 Ammonia solution, 25 % solution, c(NH3H2O) = 14 mol/l, (NH3H2O) = 0,91 g/ml. 5.10 Ethanol, C2H5OH, a volume fractio
34、n of 96 %, = 0,79 g/ml, food grade or pure grade. 5.11 Sodium sulfate, (Na2SO4), dried for 2 h at 105 C. 5.12 Cation exchange resin, DOWEX 50W-X81), particle size 0,3 mm to 0,8 mm in H+ form. 5.13 Barium chloride solution In a 1 000 ml volumetric flask, dissolve 917 mg 1 mg of barium chloride dihydr
35、ate (5.2) in about 500 ml of water (5.1) and make up to volume with water (5.1). When stored at 2 C to 6 C, the solution is stable for 1 month. 5.14 Diluted hydrochloric acid, c(HCl) = 1 mol/l. In a 1 000 ml volumetric flask, dilute 82 ml of concentrated hydrochloric acid (5.3) in about 800 ml of wa
36、ter (5.1) and make up to volume with water (5.1). 1) DOWEX 50W-X8 is a trade name. This information is given for the convenience of users of this International Standard and does not constitute an endorsement by ISO of this product. Copyright International Organization for Standardization Provided by
37、 IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 03:06:06 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22743:2006(E) ISO 2006 All rights reserved 3 5.15 Methylthymol blue solution In a 1 000 ml volumetric flask, di
38、ssolve 160 mg 1 mg of methylthymol blue (5.4) in 50 ml of barium chloride solution (5.13). Add 4 ml of concentrated hydrochloric acid (5.3) and 360 ml of ethanol (5.10). Make up to volume with water (5.1). Add 1 ml of surfactant (5.5). When stored at 2 C to 6 C, the solution is stable for 1 week. 5.
39、16 Buffered Na4-EDTA solution, pH = 10,5. In a 1 000 ml volumetric flask, dissolve 6,75 g of ammonium chloride (5.8) and 40,0 g of Na4-EDTA (5.7) in about 500 ml of water (5.1). Add 57 ml of ammonia solution (5.9) and make up to volume with water (5.1). 5.17 Sodium hydroxide solution, c(NaOH) = 0,25
40、 mol/l. In a 1 000 ml volumetric flask, dissolve 10,0 g of sodium hydroxide (5.6) in about 500 ml of water (5.1). Make up to volume with water (5.1). 5.18 Sulfate stock solution, (SO4) = 3 000 mg/l. In a 1 000 ml volumetric flask, dissolve (4 436 1) mg of sodium sulfate (5.11) in about 500 ml of wat
41、er (5.1). Make up to volume with water (5.1). 5.19 Sulfate spiking solution, (SO4) = 6 mg/l. In a 1 000 ml volumetric flask, dilute 2,00 ml of sulfate stock solution (5.18) in about 800 ml of water (5.1). Make up to volume with water (5.1). Add 1 ml of surfactant (5.5). NOTE The sulfate solution is
42、added to achieve better linearity in the lower measuring part of the calibration curve. In respect to the sulfate concentration in the blank or the quality of the methylthymol blue (5.4), the added sulfate amount can be slightly altered. Without the sulfate addition, this lower part will not be line
43、ar. 5.20 Calibration solutions Prepare at least five calibration solutions by diluting the sulfate stock solution (5.18). Table 1 gives examples for the preparation of 10 calibration solutions in the range of 30 mg/l to 300 mg/l. Table 1 Example for preparation of 10 calibration solutions for the su
44、lfate (SO4) range 30 mg/l to 300 mg/l Volume in ml of sulfate stock solution (5.18) diluted to 100 ml 1 2 3 4 5 6 7 8 9 10 Sulfate (SO4) concentration of calibration solution in mg/l 30 60 90 120150 180 210 240 270 300 6 Apparatus 6.1 Continuous-flow analysis (CFA). The system generally consists of
45、the following components (see Figure A.1 in Annex A). 6.1.1 Sampler or other device, for reproducible sample introduction. 6.1.2 Reagent containers. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for
46、Resale, 04/20/2007 03:06:06 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22743:2006(E) 4 ISO 2006 All rights reserved 6.1.3 Low pulse pump, with chemical resistant pump tubes. 6.1.4 Inlet connector, made of glass, or chemical resistant material, with reproducible air
47、-, sample- and reagent segmentation. 6.1.5 Photometer, with flow cell, optical path length, e.g. 10 mm, wavelength range 450 nm to 470 nm. 6.1.6 Data acquisition and display unit, such as a PC, recorder, printer or plotter. 6.2 Graduated flasks, nominal capacity 100 ml and 1 000 ml. 6.3 Graduated pi
48、pettes, nominal capacity 1 ml, 2 ml, 3 ml, 4 ml, 5 ml, 6 ml, 7 ml, 8 ml, 9 ml, 10 ml and 50 ml. 6.4 Cation exchange column. Glass tube with a length of at least 10 cm and an internal diameter of approximately 2 mm. Suspend the cation exchange resin in water (5.1) and fill the tube with this mixture. Close both sides of the tube with approximately 5 mm of glass wool. 7 Sampling and sample pretre