《ISO-15587-2-2002.pdf》由会员分享，可在线阅读，更多相关《ISO-15587-2-2002.pdf（22页珍藏版）》请在三一文库上搜索。
1、 Reference number ISO 15587-2:2002(E) ISO 2002 INTERNATIONAL STANDARD ISO 15587-2 First edition 2002-03-01 Water quality Digestion for the determination of selected elements in water Part 2: Nitric acid digestion Qualit de leau Digestion pour la dtermination de certains lments dans leau Partie 2: Di
2、gestion lacide nitrique Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 03:27:58 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 15587-2:2002(E) PDF
3、 disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, par
4、ties accept therein the responsibility of not infringing Adobes licensing policy. The ISO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative
5、 to the file; 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
6、All rights 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 countr
7、y of the 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
8、with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 03:27:58 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 15587-2:2002(E) ISO 2002 All rights reserved iii Contents Page Foreword.iv 1 Scope1 2 Normative references1 3 Term and definition
9、.2 4 Principle2 5 Reagents.2 6 Apparatus.2 7 Sampling.3 8 Procedure.3 9 Test report5 Annex A (informative) Digestion in an open system using electrical heating6 Annex B (informative) Digestion in an open system using microwave-assisted heating.8 Annex C (informative) Digestion in a closed system usi
10、ng microwave assisted heating.10 Annex D (informative) Digestion in a closed system using an autoclave.14 Annex E (informative) Performance checks.16 Bibliography17 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/997
11、2545001 Not for Resale, 04/19/2007 03:27:58 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 15587-2:2002(E) iv ISO 2002 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO memb
12、er 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 been established has the right to be represented on that committee. International organizations, government
13、al 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 standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Direct
14、ives, 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 bodie
15、s casting 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 15587-2 was prepared by Technical Committee ISO/TC 147, Water quality,
16、 Subcommittee 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
17、 15587 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, 04/19/2007 03:27:58 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL
18、STANDARD ISO 15587-2:2002(E) ISO 2002 All rights reserved 1 Water quality Digestion for the determination of selected elements in water Part 2: Nitric acid digestion WARNING Persons using this part of ISO 15587 should be familiar with normal laboratory practice. This part of ISO 15587 does not purpo
19、rt 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. 1 Scope This part of ISO 15587 specifies a method for extracting trac
20、e elements from a water sample using nitric acid as a digestion agent. The method is applicable to all types of waters with a suspended solids concentration of less than 20 g/l and a total organic carbon (TOC) concentration expressed as carbon of less than 5 g/l. The nitric acid digestion method is
21、empirical and it might not necessarily release elements completely. However, for most environmental applications the result is fit for purpose. Nitric acid digestion is suitable for the release of: Al*, As, B, Ba*, Be*, Ca, Cd, Co, Cr*, Cu, Fe*, Hg, K, Mg*, Mn, Mo, Na, Ni, P, Pb, Se, Sr, Tl, V*, Zn
22、(asterisk indicates a possible lower recovery compared to aqua regia digestion method specified in ISO 15587-1, see reference 1). It is suitable for the release of Ag only if the sample is stabilized immediately after digestion. Nitric acid digestion is not suitable for Sb, Sn and for the digestion
23、of refractory compounds such as SiO2, TiO2 and Al2O3. The method is generic and may be implemented using a wide variety of equipment provided the digestion composition is unchanged, the digestion temperature is known, and the digestion duration is in accordance with this temperature. 2 Normative ref
24、erences The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of ISO 15587. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this p
25、art of ISO 15587 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 valid Inter
26、national Standards. ISO 3696:1987, Water for analytical laboratory use Specification and test methods ISO 5667-3:1994; Water quality Sampling Part 3: Guidance on the preservation and handling of samples Copyright International Organization for Standardization Provided by IHS under license with ISO L
27、icensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 03:27:58 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 15587-2:2002(E) 2 ISO 2002 All rights reserved 3 Term and definition For the purposes of this part of ISO 15587, the following term and defi
28、nition applies. 3.1 wet digestion treatment with 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 subs
29、equent analysis. Some analytical methods require the element in solution 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 pai
30、d to the presence of chemically stable organometals 4. 4 Principle The test portion is digested with nitric acid 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 diges
31、tible fraction is 120 min. The maximum duration is set at four times the minimum duration. By convention, both the required minimum and maximum duration are assumed to halve with every 15 C increase in temperature above the boiling point (see Figure 1). After digestion the digest is clarified, if ne
32、cessary. 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 used if it meets the purity requirements f
33、or the subsequent analysis. 5.2 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) = 1,42 kg/l, approximately 69 % by mass. Both are suitable. 5.3 Antifoaming agent, for instance n-dodecane (C12H26). 5.4 Ammonia s
34、olution, approximately 25 % by mass. 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 shall be inert and shall not release substances to the digest in excess of the
35、 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 with the vapour shall be inert and shall meet the purity requirements of the su
36、bsequent analysis. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 03:27:58 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 15587-2:2002(E) ISO 2002
37、 All rights reserved 3 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 condensation equipment or equipment to absorb these species in nitric acid or aqu
38、a 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 Filter paper, cellulose-based ashless type, with a median pore size adap
39、ted 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 negligible impact on trueness of the analytical result. 6.6 Anti-bumpin
40、g granules or roughened glass beads, having a diameter of 2 mm to 3 mm and acid-washed for instance with warm nitric acid (5.2) diluted to 10 % by volume with water (5.1). 6.7 Volumetric flask, usually of nominal capacity 50 ml or 100 ml. 6.8 Graduated pipettes or dispensers. 7 Sampling Handle and p
41、reserve 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 sample. Any test portion larger than 20 ml is allowed, provided that the volume of nitric acid is modified proportion
42、ally. 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 volume from the determination of its mass, possibly corrected for the mass and density of solids. Report the uncertaint
43、y of the volume if it is higher than 0,1 ml for a volume of 25 ml. 8 Procedure 8.1 Preparation Carefully acid-wash digestion equipment in contact with the digestion solution and volumetric ware for instance with warm nitric acid (5.2) diluted to 10 % by volume with water (5.1) and rinse with water (
44、5.1). Add a test portion of 25,0 ml 0,1 ml to the digestion vessel (6.1). Add 6,25 ml 0,1 ml of nitric acid (5.2). The boiling point of this mixture is equal to 103 C. If excessive foaming occurs, add one or more drops of antifoaming agent (5.3). Swirl and allow the mixture to stand until any visibl
45、e reaction has stopped. If the digestion vessel is of the open type, proceed with 8.2. If not, proceed with 8.3. Examples of digestion in an open system are given in annexes A and B. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technic
46、al Standards 1/9972545001 Not for Resale, 04/19/2007 03:27:58 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 15587-2:2002(E) 4 ISO 2002 All rights reserved 8.2 Digestion in an open system Connect the digestion vessel (6.1) to the vapour recovery system (6.2). Connect t
47、he 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. Maintain boiling for at least 120 min. As the boiling point decreases
48、with altitude add 20 min to the minimum duration for every 1 000 m above sea level. The maximum allowed duration equals four times the minimum duration. Once the digestion period is completed, allow the digestion vessel to cool. If silver is an analyte, add 30 ml of ammonia solution (5.4) to the digestion vessel immediately after cooling. If the volatile species trap (6.3) is used, add the contents to the digestion vessel. Rinse the trap and/or the condenser with water (5.1), for insta