1、BRITISH STANDARD BS EN 13654-1:2001 Soil improvers and growing media Determination of nitrogen Part 1: Modified Kjeldahl method The European Standard EN 13654-1:2001 has the status of a British Standard ICS 65.080 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBS EN 13654-1:20
2、01 This British Standard, having been prepared under the direction of the Consumer Products and Service Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 09 November 2001 BSI 09 November 2001 ISBN 0 580 38268 0 National foreword
3、 This British Standard is the official English language version of EN 13654-1:2001. The UK participation in its preparation was entrusted to Technical Committee AW/20, Top soil and other growing media, which has the responsibility to: A list of organizations represented on this committee can be obta
4、ined on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” f
5、acility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obl
6、igations. aid enquirers to understand the text; present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This
7、 document comprises a front cover, an inside front cover, the EN title page, pages 2 to 10, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEANSTANDARD
8、 NORMEEUROPENNE EUROPISCHENORM EN136541 September2001 ICS65.080 Englishversion SoilimproversandgrowingmediaDeterminationofnitrogen Part1:ModifiedKjeldahlmethod Amendementsdusoletsupportsdeculture DterminationdelazotePartie1:MthodedeKjeldahl modifie BodenverbessungsmittelundKultursubstrateBestimmung
9、vonStickstoffTeil1:ModifiziertesVerfahrennachKjeldahl ThisEuropeanStandardwasapprovedbyCENon11August2001. CENmembersareboundtocomplywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliogr
10、aphicalreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheManagementCentreortoanyCENmember. ThisEuropeanStandardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtoth
11、eManagementCentrehasthesamestatusasthe official versions. CENmembersarethenationalstandardsbodiesofAustria,Belgium,CzechRepublic,Denmark,Finland,France,Germany,Greece, Iceland,Ireland,Italy,Luxembourg,Netherlands,Norway,Portugal,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMMITTEEFORSTANDARDI
12、ZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2001CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.EN136541:2001EEN136541:2001(E) 2 Contents page Foreword .3 1 Scope4 2 Normativereferences
13、 4 3 Termsanddefinitions . 4 4 Principle .4 5 Reagents 4 6 Apparatus.5 7 Testsample. .5 8 Procedure.5 9 Calculation .7 10 Expressionofresults 7 11 Precision 7 12 TestReport .7 AnnexA (informative) Resultsofaninterlaboratorytrialtodeterminenitrogen(modified Kjeldahlmethod) . 8 AnnexB (informative) Me
14、thodsofanalysisusedintheinterlaboratorytrial.9 Bibliography10EN136541:2001(E) 3 Foreword ThisEuropeanStandardhasbeenpreparedbyTechnicalCommitteeCEN/TC223“Soilimproversand growingmedia“,thesecretariatofwhichisheldbyBSI. ThisEuropeanStandardshallbegiventhestatusofanationalstandard,eitherbypublicationo
15、fanidentical textorbyendorsement,atthelatestbyMarch2002,andconflictingnationalstandardsshallbewithdrawnat thelatestbyMarch2002. TheannexesAandBareinformative. AccordingtotheCEN/CENELECInternalRegulations,thenationalstandardsorganizationsofthefollowing countriesareboundtoimplementthisEuropeanStandard
16、Austria,Belgium,CzechRepublic,Denmark, Finland,France,Germany,Greece,Iceland,Ireland,Italy,Luxembourg,Netherlands,Norway,Portugal, Spain,Sweden,SwitzerlandandtheUnitedKingdom.EN136541:2001(E) 4 SAFETYPRECAUTIONSCareshouldbetakenwhenhandlingsamplesthatmaycontain sharpsorisofadustynature. 1Scope This
17、EuropeanStandardspecifiesamethodforthedeterminationofnitrogeninsoilimproversand growingmedia.TheKjeldahlmethoddeterminesammoniumN,nitrateN,nitriteNandorganicN contentofsoilimproversandgrowingmedia.NitrogeninNNlinkages,NOlinkagesandsome heterocyclics(especiallypyridine)isonlypartiallydetermined.6,7,8
18、 Themethodisnotapplicabletolimingmaterialsandpreformedmaterialssuchasmineralwoolslabs andfoamslabs. NOTE Therequirementsofthestandardmaydifferfromthenationallegalrequirementsforthedeclarationof theproductsconcerned. 2 Normativereferences ThisEuropeanStandardincorporatesbydatedorundatedreference,prov
19、isionsfromother publications.Thesenormativereferencesarecitedattheappropriateplacesinthetext,andthe publicationsarelistedhereafter.Fordatedreferences,subsequentamendmentstoorrevisionsofany ofthesepublicationsapplytothisEuropeanStandardonlywhenincorporatedinitbyamendmentor revision.Forundatedreferenc
20、esthelatesteditionofthepublicationreferredtoapplies(including amendments). ENISO3696, WaterforanalyticallaboratoryuseSpecificationandtestmethods(ISO3696:1987). EN13040:1999,SoilimproversandgrowingmediaSamplepreparationforchemicalandphysical test,determinationofdrymattercontent,moisturecontentandlabo
21、ratorycompactedbulkdensity. 3 Termsanddefinitions ForthepurposesofthisstandardthetermsanddefinitionsgiveninEN13040apply. 4Principle Thenitrogencontentofthesampleisdeterminedusingamethodbasedonasulfuricacid/potassium sulfatedigestion.Coppersulfateisusedasthecatalyst. 5Reagents 5.1General Allreagentss
22、hallbeofrecognizedanalyticalgrade.Usewaterofgrade2complyingwithENISO 3696. 5.2 Salicylicacid/sulfuricacid,dissolve25gofsalicylicacid(HO.C 6 H 4 COOH)in1000mlof concentratedsulfuricacid( =1,84g/ml). 5.3 Potassiumsulfatecatalystmixture, grindandthoroughlymix200gofpotassiumsulfate,6gof copper(II)sulfat
23、epentahydrate.(Thismixturemaybeavailablecommercially).EN136541:2001(E) 5 5.4 Sodiumthiosulfatepentahydrate, crushthecrystalstoformapowderthatpassesthrougha sievewithanapertureof0,25mm. 5.5 Calibrationsubstances,puresubstancesofknownnitrogencontent,forexampleacetanilide (C 8 H 9 NO),Lasparticacid(C 4
24、 H 7 NO 4 ),oraminoacidsofknowncomposition. NOTE Thetotalcontentofnitrogenofthecalibrationsubstanceshouldbeassimilartothesamplenitrogen contentaspossible. 6Apparatus Usuallaboratoryapparatus,andinparticularthefollowing: 6.1 Analyticalbalance, capableofweighingaccuratelyto1,0mg. 6.2 Kjeldahldigestion
25、flasks ortubes,ofnominalvalue50ml,suitableforthedigestionsystem (6.3) NOTE Largerflasks(300mlto500ml)mayberequiredforbulkymaterialsorwherealargersamplemass isused. 6.3 Digestionormineralisationsystem withvariableheatingcontrols. 6.4 Sieve, aperture5mm 6.5Stand,capableofholdingthedigestionflasksortub
26、es. 7 Testsample PreparethetestsampleinaccordancewithEN13040:1999,clause9. LossesofnitrogencanoccurwithsamplesofhighammoniumNcontentinalkalinesituationsand particularlywhenthesesamplesaredried.Ifthesamplecontains(orissuspectedtocontain)500 mg/lNH 4 Nfreshbasis,asdeterminedbyprEN13651:20014orprEN1365
27、2:20015,analyzethe freshmaterialassoonaspossible. 8 Procedure 8.1 WARNINGDigestionswithsulfuricacidarepotentiallyhazardousandlaboratorycoats, glovesandsafetyspectaclesorgogglesshallbeused. Thedigestionshallbecarriedoutinawellventilatedfumecupboardwiththerefluxdigestion onatemperaturecontrolledheatin
28、gapparatus.Antibumpinggranules(orroughenedglass beads)maybeaddedbothtotheblankandthesamplestopreventbumpingandlossof solution.Itisimportanttomaintaingentlereflux,bothoftheblankandthetestsamples,to avoidtemperaturefluctuations,whichcouldcauselocalsuperheating. Thetoxicityorcarcinogenicityofeachreagen
29、tusedinthismethodhasnotbeenprecisely defined;however,eachchemicalcompoundneedstobetreatedasapotentialhealthhazard. Fromthisviewpoint,reduceexposuretothesechemicalstothelowestpossiblelevelby whatevermeansavailable. Toxicfumesareevolvedbyboilingsulfuricacid.Alwaysusetheconcentratedacidinafume cupboard
30、EN136541:2001(E) 6 8.2 Driedsample Placeaportionofthedriedgroundsample( clause7 )ofbetween0,2g(expectednitrogencontent 0,5%)and1,0g(expectednitrogencontent 0,1%)inthedigestionflask(6.2).Add4mlof salicylic/sulfuricacid(5.2)andswirluntiltheacidisthoroughlymixedwiththesample.Allowthe mixturetostandfor
31、severalhours(overnight).Add0,5gofsodiumthiosulfate( 5.4)throughadry funnelwithalongstemthatreachesdownintothebulb,orjustabovetheacidifatubeisused.Heat themixturecautiouslyonthedigestionstand( 6.3)untilfrothinghasceased. Cooltheflask;add1,1gofthecrystallinemixture( 5.3)andheatuntilthedigestionmixture
32、becomes clear.Boilthemixturegentlyforupto5hsothatthesulfuricacidcondensesabout1/3ofthewayup theneckoftheflask.Ensurethatthetemperatureofthesolutiondoesnotexceed400 C. NOTE Inmanycasesaboilingtimeofabout2hissufficient. 8.3 Residualmoisture Themoistureintheanalyzedsample( 8.2)isdeterminedinaccordancew
33、ithEN13040:1999,clause 10,using10gofthedriedsampleobtainedfromEN13040:1999,clause9. 8.4 Freshsamples Freshsamplesshallbereducedinsizetopassa5mmsieveormilledinthepresenceofdryice (solidcarbondioxide).Weighupto20gsampleintoalargeKjeldahlflask.Addsufficient salicylic/sulfuricacid(5.2)untiltheacidisthor
34、oughlymixedwiththesample.Allowthemixtureto standforseveralhours(overnight).Addsodiumthiosulfate( 5.4)(0,5gforevery4mlofacidused) throughadryfunnelwithalongstemthatreachesdownintothebulb.Heatthemixturecautiouslyon thedigestionstand( 6.3)untilfrothinghasceased. Cooltheflask,addthecrystallinemixture( 5
35、3)(1,1gforevery4mlofacidused)andheatuntilthe digestionmixturebecomesclear.Boilthemixturegentlyforupto5hsothatthesulfuricacid condensesabout1/3ofthewayuptheneckoftheflask.Ensurethatthetemperatureofthesolution doesnotexceed400 C. 8.5 Determinationofammoniumnitrogeninthedigestion Thenitrogeninthediges
36、t,asammonium,maybedeterminedbydistillation,spectrophotometricallyor anyothersuitabletechnique(SeeannexB). 8.6 Moisturecontent DeterminethemoisturecontentofthefreshsampleinaccordancewithEN13040:1999,clause10. 8.7 Blankdetermination Thereagentblanktestshallbecarriedoutinparallelwiththedetermination,by
37、thesameprocedure, outlinedin( 8.2)and (8.4)aboveusingthesamequantitiesofallthereagentsasinthedetermination butomittingthetestportion. NOTE Themeasurementofablankisintroducedtodeterminethecontributionoftheextractingsolutionand glasswareused. 8.8 Calibration Weighoutaquantityofthecalibrationstandard(
38、5.5)equivalentinnitrogencontenttothesamples beinganalyzedandproceedasin( 8.2).Thenitrogendeterminedshouldexceed95%ofthe calculatedvalue.EN136541:2001(E) 7 8.9 Laboratorycompactedbulkdensity DeterminethelaboratorycompactedbulkdensityinaccordancewithEN13040:1999,annexA. 9 Calculation Thenitrogenconten
39、tinmilligramspergramdrymatterormilligramsperlitreasreceivedbasisis calculatedaccordingtothefinalmethodofdeterminationused. 10 Expressionofresults Subtractthevaluesdeterminedforreagentblankfromthoseobtainedforthesamples.Reportall resultsonamass/massbasiscalculatedtoadrymatterbasisormass/volumeonasrec
40、eivedbasis. 11 Precision Therepeatabilityandreproducibilityofthenitrogencontentinseparatelypreparedsamplesshouldbe inaccordancewithTableA.1. Asummaryoftheresultsofaninterlaboratorytrialtodeterminetheprecisionofthemethod,in accordancewithISO57251,isgiveninannexA. NOTE Thevaluesderivedfromthisinterlab
41、oratorytrialmaynotbeapplicabletoconcentrationsand matricesotherthanthosetested. 12 TestReport Thetestreportcanbepreparedseparatelyorinconjunctionwiththetestreportofthesubsequent analyticalmethod. Thetestreportshallincludethefollowinginformation: a)areferencetotheEuropeanStandard; b)acompleteidentifi
42、cationofthesample; c)alltheanalyticalmethodsused; d)astatementwhethergroundorungroundsamplehasbeenused; e)theresultsofthedeterminationexpressedasmass/massondrymatterbasisfordriedsamples;for freshsamplesonamass/massormass/volumebasisasreceivedorcalculatedtomass/massdry matterbasis; f)moisturecontent;
43、 g)thelaboratorycompactedbulkdensity; h)anydetailsnotspecifiedintheEuropeanStandard,orwhichareoptional,aswellasanyother factor,whichmayhaveaffectedtheresults.EN136541:2001(E) 8 AnnexA (informative) Resultsofaninterlaboratorytrialtodeterminenitrogen(modifiedKjeldahlmethod) Aninterlaboratorytrialwasorganisedin1997undertheauspicesoftheEuropeanCommitteeforStandardization,totestthepr oceduresspecifiedinthisEuropeanStandard. InthistrialthenumberoflaboratoriesgiveninTableA.1determinedthenitrogencontentusingthemodifiedKjeldahlmethod insixsample
