1、BSI Standards PublicationBS ISO 16729:2013Soil quality Digestion ofnitric acid soluble fractions ofelementsBS ISO 16729:2013 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 16729:2013.The UK participation in its preparation was entrusted to TechnicalCommittee E
2、H/4, Soil quality.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2013. Publish
3、ed by BSI StandardsLimited 2013ISBN 978 0 580 74502 7ICS 13.080.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 November 2013.Amendments issued since publicat
4、ionDate Text affectedBS ISO 16729:2013 ISO 2013Soil quality Digestion of nitric acid soluble fractions of elementsQualit du sol Digestion des lments solubles dans lacide nitriqueINTERNATIONAL STANDARDISO16729First edition2013-11-01Reference numberISO 16729:2013(E)BS ISO 16729:2013ISO 16729:2013(E)ii
5、 ISO 2013 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2013All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intra
6、net, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished
7、in SwitzerlandBS ISO 16729:2013ISO 16729:2013(E) ISO 2013 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope . 12 Normative references 13 Principle 24 Interferences and sources of errors . 25 Reagents 26 Apparatus . 37 Digestion procedure . 48 Test report . 5Annex A (informative) R
8、epeatability and reproducibility data . 6Bibliography 8BS ISO 16729:2013ISO 16729:2013(E)ForewordISO (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
9、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-governmental, in liaison with ISO, also take part in the work. ISO coll
10、aborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approv
11、al criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the sub
12、ject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trad
13、e name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Tec
14、hnical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical methods and soil characteristics.iv ISO 2013 All rights reservedBS ISO 16729:2013ISO 16729:2013(E)Introductio
15、nThis method is intended to provide a multi-element digestion of sludge, treated biowaste and soil prior to analysis. It is known that the digestion of environmental samples with nitric acid will not necessarily lead to a complete element breakdown, and that the extract from a test sample may not re
16、flect the total concentrations of the target analytes. However, for most environmental applications the result is fit for the purpose.This International Standard is applicable and validated for several types of matrices as indicated in Table 1 (see also Annex A for the results of the validation).Tab
17、le 1 Matrices for which this International Standard is applicable and validatedMatrix Materials used for validationSludge Municipal sludgeBiowaste CompostSoil Sludge-amended soils ISO 2013 All rights reserved vBS ISO 16729:2013BS ISO 16729:2013Soil quality Digestion of nitric acid soluble fractions
18、of elementsWARNING Persons using this International Standard should be familiar with usual laboratory practice. The reagents used in this International Standard are strongly corrosive and partly very toxic. Safety precautions are absolutely necessary, not only due to the strong corrosive reagents, b
19、ut also to high temperature and high pressure. The use of laboratory-grade microwave equipment with isolated and corrosion-resistant safety devices is required. Domestic(kitchen)-type microwave ovens shall not be used, as corrosion by acid vapours may compromise the function of the safety devices an
20、d prevent the microwave magnetron from shutting off when the door is open, which could result in operator exposure to microwave energy. All procedures shall be performed in a fume hood or in closed force-ventilated equipment. By the use of strong oxidizing reagents, the formation of explosive organi
21、c intermediates is possible, especially when dealing with samples with a high organic content. Do not open pressurized vessels before they have cooled down. Avoid contact with the chemicals and the gaseous reaction products.IMPORTANT It is absolutely essential that tests conducted according to this
22、International Standard be carried out by suitably trained staff.1 ScopeThis International Standard specifies a method for microwave digestion of sludge, treated biowaste and soil using nitric acid.This method is applicable for microwave-assisted nitric acid digestion of sludge, treated biowaste and
23、soils for the following elements:Aluminium (Al), antimony (Sb), arsenic (As), barium (Ba), beryllium (Be), bismuth (Bi), boron (B), cadmium (Cd), calcium (Ca), cerium (Ce), cesium (Cs), chromium (Cr), cobalt (Co), copper (Cu), dysprosium (Dy), erbium (Er), europium (Eu), gadolinium (Gd), gallium (Ga
24、), germanium (Ge), gold (Au), hafnium (Hf), holmium (Ho), indium (In), iridium (Ir), iron (Fe), lanthanum (La), lead (Pb), lithium (Li), lutetium (Lu), magnesium (Mg), manganese (Mn), mercury (Hg), molybdenum (Mo), neodymium (Nd), nickel (Ni), palladium (Pd), phosphorus (P), platinum (Pt), potassium
25、 (K), praseodymium (Pr), rubidium (Rb), rhenium (Re), rhodium (Rh), ruthenium (Ru), samarium (Sm), scandium (Sc), selenium (Se), silicon (Si), sodium (Na), strontium (Sr), sulfur (S), tellurium (Te), terbium (Tb), thallium (Tl), thorium (Th), thulium (Tm), tin (Sn), titanium (Ti), tungsten (W), uran
26、ium (U), vanadium (V), ytterbium (Yb), yttrium (Y), zinc (Zn) and zirconium (Zr).This International Standard may also be applicable for the digestion of other elements.Digestion with nitric acid will not necessarily accomplish total decomposition of the sample. The extracted analyte concentrations m
27、ay not necessarily reflect the total content in the sample.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the late
28、st edition of the referenced document (including any amendments) applies.ISO 3696, Water for analytical laboratory use Specification and test methodsISO 11464, Soil quality Pretreatment of samples for physico-chemical analysisINTERNATIONAL STANDARD ISO 16729:2013(E) ISO 2013 All rights reserved 1BS
29、ISO 16729:2013ISO 16729:2013(E)3 PrincipleA test portion is digested in concentrated nitric acid by means of microwave heating with a suitable laboratory microwave unit. The samples and acid(s) are placed in a fluorocarbon polymer or quartz microwave vessel or vessel liner. The vessel is sealed and
30、heated in the microwave unit. After cooling, the vessel contents are filtered, centrifuged or allowed to settle and the clear solution is separated and diluted to volume and analysed by the appropriate measurement method.4 Interferences and sources of errorsDue to the volatility of some compounds ca
31、re shall be taken that the sample is not heated before the digestion and that any volatile reaction products formed during the digestion do not escape.The container in which the sample is delivered and stored can be a source of errors. The material shall be chosen according to the elements to be det
32、ermined; e.g. elemental Hg can penetrate polyethylene walls very fast in both directions. Glass can contaminate samples containing e.g. B, Na, K, Al.A few refractory sample matrix compounds, such as quartz, silicates, titanium dioxide, alumina and other oxides may not be dissolved. These bound eleme
33、nts are considered non-mobile in the environment and are excluded from most aqueous pollution transport mechanisms.High acid and solute concentrations in the digest that cause interferences shall be properly addressed during determination.Ensure that the complete test portion is brought into contact
34、 with the acid mixture in the digestion vessel.There is a potential for vigorous reaction, especially with samples containing volatile or easily oxidized species. When digesting a matrix of this type, use no more than a 0,1 g sample to begin with. If a vigorous reaction occurs upon addition of reage
35、nt(s), allow the sample to pre-digest in the uncapped digestion vessel until the reaction ceases. Heat may be added during this step for safety considerations (for example, the rapid release of carbon dioxide from carbonates, easily oxidized organic matter). Once the initial reaction has ceased, the
36、 sample may continue through the digestion procedure.If the digested solution is filtrated, take care that the filtration procedure does not introduce contamination.5 ReagentsUse only acids and reagents of recognized analytical grade to avoid high blank values for subsequent analytical measurements.
37、 Use a test blank solution throughout the procedure applying all steps with the same amount of acids, but without a sample.5.1 Water, grade 2 as specified in ISO 3696 or better.The water for preparation of reagents shall meet the requirements of the subsequent analysis. Verify the purity by performi
38、ng a blank test.5.2 Nitric acid, c(HNO3) = 15 mol/l, = 1,4 kg/l.Another grade may be used, provided the reagent is of sufficient purity to permit its use without decreasing the accuracy of the subsequent analysis.5.3 Nitric acid, c(HNO3) = 0,5 mol/l; = 1,0 kg/l.2 ISO 2013 All rights reservedBS ISO 1
39、6729:2013ISO 16729:2013(E)6 ApparatusUsual laboratory apparatus. All glassware and plastics ware shall be adequately cleaned and stored in order to avoid any contamination.Depending on the concentration of the element of interest, a particular caution to the cleaning of the vessels shall be taken.6.
40、1 Microwave digestion system, corrosion resistant and well ventilated. All electronics shall be protected against corrosion for safe operation.Use a laboratory-grade microwave oven with temperature feedback control mechanisms.The microwave digestion system should be able to control the temperature w
41、ith an accuracy of 5 C and automatically adjust the microwave field output power within 2 s of sensing. Temperature sensors shall be accurate to 2 C, including the final reaction temperature of (175 5) C. Temperature feedback control provides the primary performance mechanism for the method. Due to
42、the variability in sample matrix types and microwave digestion equipment (i.e. different vessel types and microwave designs), control of the temperature during digestion is important for reproducible microwave heating and comparable data.The accuracy of the temperature measurement system should be p
43、eriodically controlled at an elevated temperature according to the manufactures instructions. If the temperature deviates by more than 2 C from the temperature measured by an external, calibrated temperature measurement system, the microwave temperature measurement system should be calibrated.6.2 Ro
44、tating turntable, with a minimum speed of 3 min1.6.3 Sample containers, plastics and glass containers are both suitable.All containers shall be adequately acid cleaned and stored in order to avoid any contamination.6.4 Digestion vessels of microwave transparent and reagent and temperature resistant
45、materials, such as fluorocarbon (e.g. perfluoroalkoxylalkane (PFA), modified polytetrafluoroethene (PTFE) or quartz.The vessels may contain layers of different microwave transparent materials for strength, durability and safety. The internal volume shall be at least 45 ml, and the vessel shall be ca
46、pable of withstanding pressures of at least 300 kPa and capable of controlled pressure relief.NOTE 1 These specifications provide an appropriate, safe, and durable reaction vessel.The inner wall of the vessel shall be inert and shall not release substances to the digest in excess of the purity requi
47、rements of the subsequent analysis. The vessel shall be suitable for the safe application in the temperature and pressure range applied.Energy regulation of the microwave digestion system shall be based on the temperature in the digestion solutions. Depending on the construction of the unit used tem
48、perature is measured indirectly in every vessel, outside the vessels with optical systems or only in one vessel.All digestion vessels shall be adequately acid cleaned and stored in order to avoid any contamination.NOTE 2 Digestion vessels may be cleaned in e.g. 10 % nitric acid.6.5 Filter paper, cel
49、lulose-based ashless type, hardened and resistant to nitric acid.6.6 Filter funnel, glass, polypropene (PP) or other appropriate material.6.7 Volumetric flask, usually of a nominal capacity of 50 ml or 100 ml. ISO 2013 All rights reserved 3BS ISO 16729:2013ISO 16729:2013(E)6.8 Graduated pipettes or dispensers.6.9 Analytical balance, with an accuracy of 0,1 mg or better.7 Digestion procedurePretreat the test sample according to ISO 11464, if not otherwise specified.Carry out a reagent blank test digestion in parallel with the
