BS EN ISO 14254-2011 Soil quality Determination of exchangeable acidity in barium chloride extracts《土壤质量 氯化钡萃取液中互换酸性的测定》.pdf

1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN ISO 14254:2011Soil quality Determinationof exchangeable acidity inbarium chloride extracts (ISO14254:2001)BS EN ISO 14254:2011 BRITISH STANDARDNational forewordThis British

2、 Standard is the UK implementation of EN ISO 14254:2011. It is identical to ISO 14254:2001.The UK participation in its preparation was entrusted to Technical Committee EH/4, Soil quality.A list of organizations represented on this committee can be obtained on request to its secretary.This publicatio

3、n does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. BSI 2011 ISBN 978 0 580 73150 1 ICS 13.080.10 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the au

4、thority of the Standards Policy and Strategy Committee on 31 July 2011.Amendments issued since publicationDate T e x t a f f e c t e dEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 14254 June 2011 ICS 13.080.10 English Version Soil quality - Determination of exchangeable acidity in barium

5、chloride extracts (ISO 14254:2001) Qualit du sol - Dtermination de lacidit changeable dans un extrait au chlorure de baryum (ISO 14254:2001) Bodenbeschaffenheit - Bestimmung der Austauschaciditt in Bariumchloridextrakten (ISO 14254:2001) This European Standard was approved by CEN on 3 June 2011. CEN

6、 members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on appl

7、ication to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Ma

8、nagement Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Neth

9、erlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitation

10、 in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 14254:2011: EBS EN ISO 14254:2011EN ISO 14254:2011 (E) 3 Foreword The text of ISO 14254:2001 has been prepared by Technical Committee ISO/TC 190 “Soil quality” of the International Organization for Standardiza

11、tion (ISO) and has been taken over as EN ISO 14254:2011 by Technical Committee CEN/TC 345 “Characterization of soils” the secretariat of which is held by NEN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the

12、 latest by December 2011, and conflicting national standards shall be withdrawn at the latest by December 2011. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any o

13、r all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece,

14、 Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 14254:2001 has been approved by CEN as a EN ISO 14254:2011 without any mo

15、dification. BS EN ISO 14254:2011 ISO 14254:2001(E) ISO 2001 All rights reserved iiiForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISOmember bodies). The work of preparing International Standards is normally carried out through

16、 ISO technicalcommittees. Each member body interested in a subject for which a technical committee has been established hasthe right to be represented on that committee. International organizations, governmental and non-governmental, inliaison with ISO, also take part in the work. ISO collaborates c

17、losely with the International ElectrotechnicalCommission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.Draft International Standards adopted by the technical committees are circulated

18、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 International Standard may be the subject ofpatent rights. ISO shall not be held res

19、ponsible for identifying any or all such patent rights.International Standard ISO 14254 was prepared by Technical Committee ISO/TC 190, Soil quality, SubcommitteeSC 3, Chemical methods and soil characteristics.BS EN ISO 14254:2011BS EN ISO 14254:2011INTERNATIONAL STANDARD ISO 14254:2001(E) ISO 2001

20、All rights reserved 1Soil quality Determination of exchangeable acidity in bariumchloride extracts1 ScopeThis International Standard specifies a method for the determination of exchangeable acidity in barium chlorideextracts of soil samples obtained according to ISO 11260.The procedure described her

21、ein mainly concerns the determination of total exchangeable acidity by means of afixed-pH end-point titration (see note). Two optional procedures are also given, describing respectively,determinations of free H+acidity and of aluminium in the extracts.This International Standard is applicable to all

22、 types of air-dry soil samples which have been pretreated inaccordance with ISO 11464.NOTE Titration of exchangeable acidity by means of a fixed-pH end-point may not be specific to a given acid species. The end-point pH value retained is 7,8, corresponding to complete precipitation of Al+3ions in sy

23、nthetic solutions. Titration of soil extractsto this pH may also include some more weakly ionized species or weak acid organic compounds.2 Normative referencesThe following normative documents contain provisions which, through reference in this text, constitute provisions ofthis International Standa

24、rd. For dated references, subsequent amendments to, or revisions of, any of thesepublications do not apply. However, parties to agreements based on this International Standard are encouraged toinvestigate the possibility of applying the most recent editions of the normative documents indicated below

25、. Forundated references, the latest edition of the normative document referred to applies. Members of ISO and IECmaintain registers of currently valid International Standards.ISO 3696, Water for analytical laboratory use Specification and test methodsISO 11260, Soil quality Determination of effectiv

26、e cation exchange capacity and base saturation level usingbarium chloride solutionISO 11464, Soil quality Pretreatment of samples for physico-chemical analysesISO 11465, Soil quality Determination of dry matter and water content on a mass basis Gravimetric method3 PrincipleThe soil sample is extract

27、ed in accordance with ISO 11260. The extract is titrated with aNaOH solution up to . The use of phenolphthalein as indicator is allowed, but shall be specified in the testreport.An alternative method for determination of the free H+acidity is proposed, in which sodium fluoride is added to thesoil ex

28、tract before the titration (BaF2precipitates but an excess of NaF is not necessary). Aluminium ions arecomplexed and only the H+acidity is detected during the titration process.Two other optional methods for the determination of aluminium are proposed, using respectively flame atomicabsorption spect

29、rometry and inductively coupled plasma emission spectrometry.0,1 mol l10,05 mol l1pH = 7,8BS EN ISO 14254:2011ISO 14254:2001(E)2 ISO 2001 All rights reserved4 ReagentsUse only reagents of recognized analytical grade and distilled or deionized water for all solutions which shall bestoved in suitable

30、plastics bottles.4.1 Water having an electrical conductivity not higher than at (grade 2 water in accordancewith ISO 3696).4.2 Disodium tetraborate decahydrate (borax),Na2B4O710H2O (molecular mass = 381,5) of a purity ,which should be stored in a tightly closed bottle.4.3 Buffer solutions for pH-met

31、er calibration.4.3.1 Buffer solution ( ): Dissolve of potassium hydrogen phthalate, C8H5KO4,in water (4.1) and dilute to .4.3.2 Buffer solution ( ): Dissolve of potassium dihydrogen phosphate,KH2PO4, and of disodium hydrogen phosphate, Na2HPO4, in water (4.1) and dilute to .4.3.3 Buffer solution ( )

32、: Dissolve of disodium tetraborate decahydrate,Na2B4O710H2O, in water (4.1) and dilute to .Commercial buffer solutions can be used in accordance with the manufacturers instructions.4.4 Indicators (optional)4.4.1 Methyl orange (colour change between and ): in of water.4.4.2 Methyl red (colour change

33、between and ): in of ethanol.4.4.3 Phenolphthalein (colour change between and ): in of ethanol.4.5 Hydrochloric acid,Dilute of concentrated hydrochloric acid ( ) with water to . Thissolution shall be standardized by means of borax (4.2) following the reaction:5H2O+B4O72+2H+Gae 4H3BO3A mass of borax

34、of about dissolved in about of water (4.1) (heat slightly to accelerate dissolution) willneed of a solution of hydrochloric acid containing exactly to be neutralized.An end-point at shall be considered, or methyl red used as indicator. The concentration of this solution shallbe tested at least every

35、 month.A commercial standard solution can be used in accordance with the manufacturers instructions.4.6 Sodium hydroxide solution,Dissolve of carbonate-free sodium hydroxide in water (4.1) and dilute to . This solution shallbe standardized by titration with the hydrochloric acid solution (4.5) (end

36、point: or methyl orange asindicator).Its concentration shall be tested at least every week and shall be within the range to .With time, this solution can absorb carbon dioxide from the atmosphere. The presence of carbonate can be detectedby carrying out another titration as described above but down

37、to instead of (or phenolphthaleinas indicator instead of methyl orange). When a difference of volume is observed between the two end-points, then anew solution (4.6) shall be prepared.0,2 mS m125C 99,5 %pH = 4,00 20C 10,21 g 0,01 g1 000 mlpH = 7,00 20C 3,800 g 0,005 g3,415 g 0,005 g 1 000 mlpH = 9,2

38、2 20C 3,800 g 0,005 g 1 000 mlpH = 3,0 pH = 4,4 0,100 g 0,005 g 100 mlpH = 4,2 pH = 6,2 0,200 g 0,005 g 100 mlpH = 8,2 pH = 10,00 1,00 g 0,01 g 100 mlc(HCl)=1 mol l183 ml d = 1,19 g ml112 mol l11 000 ml1,928 g 100 ml10 ml 1 mol l1pH = 5c(NaOH)=(1,000 0,025) mol l140,0 g 0,5 g 1 000 ml pH = 3,50,975

39、mol l11,025 mol l1pH = 8,5 pH = 3,5BS EN ISO 14254:2011 ISO 14254:2001(E) ISO 2001 All rights reserved 3A commercial standard solution can be used in accordance with the manufacturers instructions.4.7 Sodium hydroxide solution,Pipette of the solution (4.6) in a volumetric flask and make up to volume

40、 with water (4.1). Store in abottle with a container on top filled with soda lime, regularly renewed, as CO2trap. This solution shall be preparedevery day.4.8 Sodium fluoride solution,Dissolve of sodium fluoride in water (4.1) and dilute to approximately . Adjust the pH to 7,0 withhydrochloric acid

41、(4.5) and the volume to with water (4.1).4.9 Barium chloride dihydrate,4.10 Stock solution of aluminium,Dissolve of aluminium metal (purity ) in of concentrated hydrochloric acid( ) and dilute to with water (4.1). A commercial standard solution can be used inaccordance with the manufacturers instruc

42、tions.4.11 Working solution of aluminium,Transfer of the aluminium stock solution (4.10) into a volumetric flask of and adjust to the mark withwater (4.1).4.12 Barium chloride solution,Dissolve of barium chloride (4.9) in approximately of water (4.1). Transfer the solution into avolumetric flask and

43、 adjust to the mark with water (4.1).4.13 Calibrations solutionsTransfer respectively , and aliquots of the working solution (4.11) in volumetric flasks, dilutewith approximately of water (4.1) and add of barium chloride solution (4.12). Finally adjust the volumewith water (4.1). A fourth solution i

44、s prepared in the same way but without aluminium so as to constitute thecalibration blank.5 Apparatus5.1 Usual laboratory glassware, including a burette graduated in intervals of or smaller.5.2 pH-meterSet up following the manufacturers instructions and calibrate with buffer solutions (4.3).5.3 Magn

45、etic stirrer5.4 Automatic titrimeter (optional)Set up following the manufacturers instructions and calibrate with buffer solutions (4.3). Results shall be expressedrelatively to an end-point of .5.5 Flame atomic absorption spectrometerEquip with a nitrous oxide/acetylene burner and set up following

46、the manufacturers instructions. Determination ofaluminium is commonly carried out at a wavelength of .c(NaOH)=50 103mol l11,25 103mol l150 ml 1 000 mlc(NaF)=1 mol l142,0 g 0,2 g 900 ml1 000 ml BaCl22H2O1,000 g l11,000 g 0,001 g 99,9 % 20 mld = 1,19 g ml11 000 ml0,100 g l110 ml 100 mlc(BaCl2)=0,5 mol

47、 l112,21 g 0,01 g 60 ml100 ml5 ml 10 ml 20 ml 100 ml20 ml 20 ml0,05 mlpH = 7,8396,2 nmBS EN ISO 14254:2011 ISO 14254:2001(E)4 ISO 2001 All rights reserved5.6 Inductively coupled plasma spectrometerSet up following the manufacturers instructions. Determination of aluminium is commonly carried out wit

48、hbackground correction at various wavelengths such as or .6 Sample6.1 Barium chloride extract, obtained in accordance with ISO 11260.6.2 Blank extract, obtained in the same way.7 Procedure7.1 Total exchangeable acidityPipette of the extract (6.1) into a container of sufficient capacity to also recei

49、ve the electrodes of the pH-meter(5.2). Introduce a bar magnet and set up the speed of the magnetic stirrer (5.3). Insert the electrodes and titrate withthe sodium hydroxide solution (4.7) until a pH value of 7,8 is reached and remains stable for .When phenolphthalein is used, titrate until the colour just turns permanently pink (in practice wait about ). Titrateof the blank solution (6.2) in the same way in order to obtain a blank value.7.2 Free H+acidity (optional)Pipette of the extract (6.1). Add of the sodium fl