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1、 Reference number ISO 15587-1:2002(E) ISO 2002 INTERNATIONAL STANDARD ISO 15587-1 First edition 2002-03-01 Water quality Digestion for the determination of selected elements in water Part 1: Aqua regia digestion Qualit de leau Digestion pour la dtermination de certains lments dans leau Partie 1: Dig
2、estion leau rgale Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/18/2007 23:52:17 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 15587-1:2002(E) PDF discl
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6、ghts 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 t
7、he 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 ii ISO 2002 All rights reserved Copyright International Organization for Standardization Provided by IHS under license with I
8、SO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/18/2007 23:52:17 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 15587-1:2002(E) ISO 2002 All rights reserved iii Contents Page Foreword.iv 1 Scope1 2 Normative references1 3 Terms and definitions .2 4
9、 Principle2 5 Reagents.3 6 Apparatus.3 7 Sampling.4 8 Procedure.4 9 Test report6 Annex A (informative) Digestion in an open system using electrical heating7 Annex B (informative) Digestion in an open system using microwave-assisted heating.9 Annex C (informative) Digestion in a closed system using m
10、icrowave-assisted heating 11 Annex D (informative) Digestion in a closed system using an autoclave.15 Annex E (informative) Performance checks.17 Bibliography18 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545
11、001 Not for Resale, 04/18/2007 23:52:17 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 15587-1:2002(E) iv ISO 2002 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member b
12、odies). 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 a
13、nd 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 standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives
14、, Part 3. 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 voting. Publication as an International Standard requires approval by at least 75 % of the member bodies ca
15、sting a vote. Attention is drawn to the possibility that some of the elements of this part of ISO 15587 may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 15587-1 was prepared by Technical Committee ISO/TC 147, Water quality, Sub
16、committee SC 2, Physical, chemical and biochemical method. ISO 15587 consists of the following parts, under the general title Water quality Digestion for the determination of selected elements in water: Part 1: Aqua regia digestion Part 2: Nitric acid digestion Annexes A to E of this part of ISO 155
17、87 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 23:52:17 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STAN
18、DARD ISO 15587-1:2002(E) ISO 2002 All rights reserved 1 Water quality Digestion for the determination of selected elements in water Part 1: Aqua regia digestion WARNING Persons using this part of ISO 15587 should be familiar with normal laboratory practice. This part of ISO 15587 does not purport to
19、 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. 1 Scope This part of ISO 15587 specifies a method for extracting trace ele
20、ments from a water sample using aqua regia as a digestion agent. The method is applicable to all types of waters with a suspended solids mass concentration of less than 20 g/l and a mass concentration of total organic carbon (TOC) expressed as carbon of less than 5 g/l. The aqua regia digestion meth
21、od is empirical and it might not release elements completely. However, for most environmental applications, the result is fit for purpose. Aqua regia digestion is suitable for the release of: Ag, Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, Ni, P, Pb, Sb, Se, Sn, Sr, Tl, V, Zn.
22、It is not suitable for the digestion of refractory compounds such as SiO2, TiO2 and Al2O3. The presence of chloride in the digestion solution may limit the application of analytical techniques. The method is generic and may be implemented using a wide variety of equipment provided the digestion comp
23、osition is unchanged, the digestion temperature is known, and the digestion duration is in accordance with this temperature. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of ISO 15587. For dated r
24、eferences, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part of ISO 15587 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated refe
25、rences, 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 for analytical laboratory use Specification and test methods ISO 5667-3:1994, Water quality Sampling Part 3: Guidance o
26、n the preservation and handling of samples Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/18/2007 23:52:17 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO
27、15587-1:2002(E) 2 ISO 2002 All rights reserved 3 Terms and definitions For the purposes of this part of ISO 15587, the following terms and definitions apply. 3.1 aqua regia solution obtained by mixing one volume of nitric acid with three volumes of hydrochloric acid 3.2 wet digestion treatment with
28、reactive liquid chemicals with the aim of bringing analytes into solution so as to be suitable for subsequent analysis NOTE The degree to which analytes are brought into solution suitable for subsequent analysis may depend on the principle of the subsequent analysis. Some analytical methods require
29、the element in solution to be independent of its chemical state, others require a specific valence or a specific ionic species, for instance hydride atomic spectrometry, photometry and electrochemical methods. For the latter, special attention should be paid to the presence of chemically stable orga
30、nometals 5. 4 Principle The test portion is digested with aqua regia at a defined temperature. The temperature is at least the boiling point (103 C at 101,3 kPa) and at most 175 C. At the boiling point (101,3 kPa), the minimum duration to release the digestible fraction is 120 min. The maximum durat
31、ion is set at four times the minimum duration at that temperature. By convention, both the required minimum and maximum duration is assumed to halve with every 15 C increase in temperature above the boiling point (see Figure 1). After digestion the digest is clarified, if necessary. Figure 1 Range o
32、f permitted digestion temperature and duration Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/18/2007 23:52:17 MDTNo reproduction or networking permitted without license from IHS -,-,-
33、ISO 15587-1:2002(E) ISO 2002 All rights reserved 3 5 Reagents During analysis, use only reagents of recognized analytical grade that meet the purity requirements of the subsequent analysis. Verify their purity by performing a blank test. 5.1 Water, complying with grade 1 of ISO 3696. Grade 2 may be
34、used if it meets the purity requirements for the subsequent analysis. 5.2 Hydrochloric acid, c(HCl) = 12,0 mol/l, = 1,2 kg/l, approximately 37 % by mass. 5.3 Nitric acid, c(HNO3) = 15,8 mol/l, = 1,4 kg/l. Nitric acid is available both as (HNO3) = 1,40 kg/l, approximately 65 % by mass and (HNO3) = 1,
35、42 kg/l, approximately 69 % by mass. Both are suitable. 5.4 Antifoaming agent, for instance n-dodecane (C12H26). 6 Apparatus 6.1 Digestion vessel, temperature- and pressure-resistant and capable of containing the mixture of sample and digest solution. If a closed vessel is applied, its inner wall sh
36、all be inert and shall not release substances to the digest in excess of the purity requirements of the subsequent analysis. 6.2 Vapour recovery system, capable of recovering the evaporated digest during open digestion (e.g. reflux condenser) and designed to minimize losses. Materials in contact wit
37、h the vapour shall be inert and shall meet the purity requirements of the subsequent analysis. 6.3 Volatile species trap, in an open digestion system capable of trapping one or more volatile measurement species which may pass through the vapour recovery system (6.2). This trap may comprise condensat
38、ion equipment or equipment to absorb these species in nitric acid or aqua regia. Materials in contact with the vapour shall be inert and shall meet the purity requirements of the subsequent analysis. 6.4 Heating device, capable of maintaining the target temperature for the required time period. 6.5
39、Filter paper, cellulose-based ashless type, with a median pore size adapted to the apparatus used for analysis. It shall not be able to release substances to the digest in excess of the purity requirements of the subsequent analysis and shall not absorb substances from the digest beyond the level of
40、 negligible impact on trueness of the analytical result. 6.6 Anti-bumping granules or roughened glass beads, having a diameter of 2 mm to 3 mm and acid-washed for instance with warm nitric acid (5.3) diluted to 10 % by volume with water (5.1). 6.7 Volumetric flask, usually of nominal capacity of 50
41、ml or 100 ml. 6.8 Graduated pipettes or dispensers, of appropriate volume for the task. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/18/2007 23:52:17 MDTNo reproduction or networking
42、permitted without license from IHS -,-,- ISO 15587-1:2002(E) 4 ISO 2002 All rights reserved 7 Sampling Handle and preserve the water sample in accordance with ISO 5667-3. The digestion procedure (see clause 8) is based on a test portion of 25,0 ml 0,1 ml taken from a well-shaken homogeneous water sa
43、mple. Any test portion larger than 20 ml is allowed, provided that the volume of aqua regia is modified proportionally. If suspended solids make it impossible to deliver a representative test portion of a known volume, deliver the test portion otherwise, for instance by weighing. Calculate the volum
44、e from the determination of its mass, possibly corrected for the mass and density of solids. Report the uncertainty of the volume if it is higher than 0,1 ml for a volume of 25 ml. To lower the limit of detection, the preserved sample may be concentrated by evaporation. Evaporation is carried out af
45、ter addition of nitric acid (5.3) and before addition of hydrochloric acid (5.2). However, the concentrated water sample shall meet the requirements of clause 1. Evaporation is not allowed if volatile analyte species might be present. 8 Procedure 8.1 Preparation Carefully acid-wash digestion equipme
46、nt in contact with the digestion solution and volumetric ware for instance with warm nitric acid (5.3) diluted to 10 % by volume with water (5.1) and rinse with water (5.1). Add a test portion of 25,0 ml 0,1 ml to the digestion vessel (6.1). Add 6,0 ml 0,1 ml of hydrochloric acid (5.2) followed by 2
47、,0 ml 0,1 ml of nitric acid (5.3). The boiling point of this mixture is equal to 103 C. The volume ratio sample to aqua regia is equal to approximately three. A volume ratio up to four is allowed. If excessive foaming occurs, add one or more drops of antifoaming agent (5.4). Swirl and allow the mixt
48、ure to stand until any visible reaction has stopped. If the digestion vessel is of the open type, proceed with 8.2. If not, proceed with 8.3. 8.2 Digestion in an open system Connect the digestion vessel (6.1) to the vapour recovery system (6.2). Connect the volatile species trap (6.3) so as to prevent volatile measurement species from passing through the vapour recovery system. Place the digestion vessel in the heating device (6.4). Increase the temperature to the boiling point. M