ISO 2447-1998 Fruit and vegetable products - Determination of tin content《水果和蔬菜制品 锡含量的测定》.pdf
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1、A Referencenumbe r ISO2447:1998 (E) INTERNATIONAL STANDARD ISO 2447 Secondedition 19980801 Fruitandvegetableproducts Determinationoftincontent ProduitsdrivsdesfruitsetlgumesDterminationdelateneur entainISO2447:1998(E) ISO1998 Allrightsreserved.Unlessotherwisespecified,nopartofthispublicationmayberep
2、roducedorutilizedinanyformorbyan ymeans,electronic ormechanical,includingphotocopyingandmicrofilm,withoutpermissioninwritingfromthepublisher. InternationalOrganizationforStandardization Casepostale56 CH1211Genve20 Switzerland Internet iso.ch PrintedinSwitzerland ii Foreword ISO(theInternationalOrgan
3、izationforStandardization)isaworldwidefederationofnationalstandardsbodies(ISO memberbodies).TheworkofpreparingInternationalStandardsisnormallycarriedoutthroughISOtechnical committees.Eachmemberbodyinterestedinasubjectforwhichatechnicalcommitteehasbeenestablishedhas therighttoberepresentedonthatcommi
4、ttee.Internationalorganizations,governmentalandnongovernmental,in liaisonwithISO,alsotakepartinthework.ISOcollaboratescloselywiththeInternationalElectrotechnical Commission(IEC)onallmattersofelectrotechnicalstandardization. DraftInternationalStandardsadoptedbythetechnicalcommitteesarecirculatedtothe
5、memberbodiesforvoting. PublicationasanInternationalStandardrequiresapprovalbyatleast75%ofthememberbodiescastingavote. InternationalStandardISO2447waspreparedbyTechnicalCommitteeISO/TC34, Agriculturalfoodproducts, SubcommitteeSC3, Fruitandvegetableproducts . Thissecondeditioncancelsandreplacesthefirs
6、tedition(ISO2447:1974),whichhasbeentechnicallyrevised.INTERNATIONALSTANDARD ISO ISO2447:1998(E) 1 FruitandvegetableproductsDeterminationoftincontent 1Scope ThisInternationalStandardspecifiesamethodforthedeterminationofthetincontentinfruitandvegetable products. Themethodisapplicabletoproductswhichmay
7、contain,perkilogram,upto: 1,25gofcopper; 0,6goflead; 6gofzinc; 40gofphosphorus. 2Normative reference Thefollowingstandardcontainsprovisionswhich,throughreferenceinthistext,constituteprovisionsofthis InternationalStandard.Atthetimeofpublication,theeditionindicatedwasvalid.Allstandardsaresubjectto rev
8、ision,andpartiestoagreementsbasedonthisInternationalStandardareencouragedtoinvestigatethe possibilityofapplyingthemostrecenteditionofthestandardindicatedbelow.MembersofIECandISOmaintain registersofcurrentlyvalidInternationalStandards. ISO5515:1979,Fruits,vegetablesandderivedproductsDecompositionofor
9、ganicmatterpriortoanalysis Wetmethod. 3Principle Afterdestructionoftheorganicmatterbymeansofsulfuricandnitricacids,andconversionofthetintothestannic form,acomplexisformedinabufferedsolutionofpH1,0topH1,2theiron( III)beingmasked,ifnecessary,by reductionwithascorbicacid.Thecomplexiscolouredorangewithp
10、henylfluoroneandthecolourcomparedwith thoseobtainedunderthesameconditionsbutstartingfromstandardsolutionsofpuretin. 4Reagents Useonlyreagentsofrecognizedanalyticalgrade,anddistilledordemineralizedwaterorwaterofequivalentpurity. 4.1 Sulfuricacid , r 20 =1,84g/ml. 4.2 Dilutesulfuricacid ,1,25mol/l. 4.
11、3 Ascorbicacid ,50g/lsolution. 4.4 Nitricacid , r 20 =1,42g/ml.ISO2447:1998(E) ISO 2 4.5 Hydrochloricacid , r 20 =1,19g/ml. 4.6 Methanol. 4.7 Ethanol,95%( V/V). 4.8 Poly(vinylalcohol) ,16g/lsolution. Dissolve1,6gofpoly(vinylalcohol)inalittlewaterwithgentlewarmingandagitation.Diluteto100mlaftercoolin
12、g. 4.9 Buffersolution ,containing450gofsodiumacetate(CH 3 COONa)and240mlofaceticacid(CH 3 COOH)per litre. 4.10 Tin,standardvolumetricsolution I,containing500 m g/mlinasulfuricacidmedium,approximately3mol/l. Dissolve,withheating,0,5gofpuretininamixtureof50mlofsulfuricacid(4.1),5mlofnitricacid(4.4)and
13、25ml ofwater.Aftercompletesolution,oxidizethetintothestannicformbyboilinguntilwhitefumesappear. Coolthesolutionandpouritintoa1000mlvolumetricflaskcontaining116mlofsulfuricacid(4.1)and100mlof water.Coolanddiluteto1000mlwithwater. NOTE Alternatively,thetinstandardsolutionI(4.10)maybepreparedbydilution
14、ofasuitableproprietarystandard solution. 4.11 Tin,standardvolumetricsolutionII,containing10m g/mlinasulfuricacidmedium,approximately 0,25mol/l. Transfer20mlofthetinstandardvolumetricsolution I(4.10)toa1000mlvolumetricflask.Add10mlofsulfuric acid(4.1)anddiluteto1000mlwithwater. 4.12 Phenylfluoronerea
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