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首页 鸡蛋壳(Egg shell)

鸡蛋壳(Egg shell).doc

鸡蛋壳(Egg shell)

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2018-09-12 0人阅读 举报 0 0 0 暂无简介

简介:本文档为《鸡蛋壳(Egg shell)doc》,可适用于社会民生领域

鸡蛋壳(Eggshell)鸡蛋壳(Eggshell)FourExperimentalprincipleandexperimentalproceduresThemaincomponentofeggshellisCaCO,followedbyMgCO,protein,pigmentandasmallamountofFe,Alpretreatment:firsttheeggshellandeggshell,boilfor~min,theremovalofproteinfilminsidetheeggshellsurface,andthenplacedinabeakerwitheggshelldryingovenatDEGC,grindedintopowderstorageweighingbottle,putthesparedryertodeterminetheweighingeggshellquantity:testschemewithconstantweighingrange(eggshelltodeterminetheconcentrationofstandardsolution,about~ml,accordingtothecalculationoftheamountofeggshell,whilealsotakingintoaccounttheweighingerror(called>g)Iftheamountistoosmallorthesamplecanbecalledlarge(consideringuniformwithmlshellsolution,mlshiftexperiment)Casemol*LEDTAxmlxx=gWeighaccuratelygshell,equippedwithamlsolution,andthenshiftthemlexperiment)determinationofcalciumandmagnesiumcontentineggshell(designexperiment)ThedeterminationoftheeggshellCaEDTAtitrationmethod,totalMgInpH=,withchromeblackTasindicator(orKBindicator),EDTAisadirectmeasureofCa,totalMg,inordertoimprovethecoordinationselectivityinpH=,addingmaskingagenttriethanolamineandmaketheFe,Alplasmageneratedmorestablecomplexes,toexcludethemonCa,MgioninterferencemeasurementDoesnotaffectthepigmentDeterminationofCa,Mgtotalquantity:accuratelydetermineacertainamountofeggshellpowder(accurategeggshell,mlaccuratesolution,andthenmovemlexperiment)inthebeaker,coverthesurfacedish,CarefullyaddmolLHCl~mL,dissolvedfromthecupmouth,addmlofwater,lowheatremoval(CO=CaCO,thedecreaseinantilowacidityAsmallamountofproteinfilminsoluble),cooling,quantitativetransfertomLcapacitybottle,dilutetoclosetothecalibrationline,ifthereisfoam,drop~dropsofethanol(defoamingagent),afterthefoamiseliminated,dropwatertothescalelineshakeAccuratedrawtestsolutionmL,amLconicalflask,adddropsofmethylredsolution,usingmolLNHHOandtothered,yellow,anddeionizedwatermL,triethanolaminemL,MgEDTAmlAddNHClNHHObuffermL,shakeitwellDropdropsofchromiumblackTindicator,withEDTAstandardsolution(underthesameconditionscalibration,referencesubstanceCaCO)titrationtothesolution,frompurpletopureblue,thatisreachedtheendpoint,parallelthreecopiesThetotalamountofCaandMgwascalculatedaccordingtothevolumeofEDTAconsumed,representedbythecontentofCaOThedeterminationofCaintheeggshellofacidbasetitration,totalMgThecarbonateineggshellcanreactwithHCl,andtheexcessacidcanbedrippedbackbystandardNaOHThetotalamountofCaandMgineggshellisdeterminedaccordingtothestandardhydrochloricacidvolumeofreactionwithcarbonate,andtheresultisexpressedbyCaOmassfraction)molLNaOHpreparation:gNaOHsolidinsmallbeaker,dissolvedinHO,thenmovedtoplasticreagentbottle,dilutedwithdistilledwatertomL,withrubberstopper,shakewell)molLHClpreparation:theamountofconcentratedhydrochloricacidmLinmLreagentbottle,dilutedwithdistilledwatertomL,stamped,shake)pHcalibration:weighaccuratelyreferencematerialNaCO(DEGHdryerdrying,cooling)ingErlenmeyerflask,deionizedwater,addmLtoCOandtheboilingcoolingshake,dissolving,adding~dropsofmethylorangeindicator,usingtheabovepreparedHClsolutiontoorangeendpointCalculatetheexactconcentrationofHClsolutionThentheHClstandardsolutionwasusedtocalibratetheconcentrationofNaOHsolution(ortocalibrateNaOHwithKHCHO))Ca,totalamountofMg:accuratepretreatmentofeggshellpowder~g(accuratetomg)Payattentiontotheeggshell,thebetteritis,themoreinsolubleitisAboutthreeparts(org,mlaccuratesolution,andthenmlexperiment)Duetoeggshellinsoluble,butalsoconsider:withmolLHcl,accuratedilutionoftimes,calibration,respectivelycalculatemolLandmolLHclconcentrationgmlmolLshellwithHcldissolved,completelydissolvedaftersizing,withoutheating),wereplacedinErlenmeyerflaskwithacidburettebyHclstandardsolutionisaddedtothecalibratedmLdropsmolaroundL(tobeprecisereadings),waterbathheating(<(c)dissolvednormallynotbeheated,HCLdecrease,buttheHisstillnotdissolved,eggshellfloatontheliquid),cooling,addingmethylorange(CO)indicator~drops,withNaOHstandardsolutiondroppingbacktoorangeRecordandcalculationMattersneedingattention:becausetheacidisthinner,itneedstobeheatedforacertaintimewhendissolvingThereareinsolublesubstancesinthesample,suchasproteinandsoonButithaslittleeffectonthedeterminationPH,Fe,Alinterference,doesnotaffectthepigmentThedeterminationofCa,MgcontentineggshellbyPotassiumPermanganateTheuseofCa,Mgandoxalateineggshellformationofinsolublecalciumoxalateprecipitation(Ksp=*)andmagnesiumoxalateprecipitation(Ksp=*),thefilteringandwashingtheprecipitatedissolvedafterseparation,determinationofoxalatecontentbyPotassiumPermanganatemethod,calculatethecontentofCa,CaOReactionisasfollows:CaCO=CaCO:CaCOH=CaHCOHCOMnOHCO===MnHOSomemetalions(Ba,Sr,Pb,Cd,etc)canprecipitatewithCOandinterferewiththedeterminationofCaandMgWeighaccuratelyeggshellpowderthree,~geach,wereplacedinamLbeakerwith:HClmlandHOmL,dissolving,heating,uptoCO(antiCaCOcase),ifthereisnodissolvedprotein,canfilterThefiltrateplacedinabeaker,thenaddammoniumoxalatesolution(mlCa,Mgprecipitationexcess,completely,iftheprecipitation(may)CaCO,CaCO),addingHCltodissolvedconcentration(Ca),andthenheatedtotoDEGC(solubility,hightemperaturedecomposition,addingoxalicacid)~dropsofmethylorangesolutionwasaddeddropwisered,ammonia(slow,slowincreaseofpH,theconcentrationofCOincreasedslowly,stirringconstantly,untiltheprecipitation)andyellow(PH=,CaCOandsolubilityminimum)ammoniaescapefarThesolutionisplacedoveraging(orheatinginawaterbath(lessthanorequaltoDEGC)minChenHua),theordinarystandardfunnelmethodpouringfiltration,precipitationafterwashing,untilnoClion(KMnOoxidationofClions)Then,theverticalprecipitationwiththefilterpaperpostedonthepreviouslyusedwallonthesedimentationbeaker,withmolLsulfuricacidprecipitationbymLfilterwashedintothebeaker,thenwashthebottleblowing~times,thisfilterpaper,oncleansurfaceThen,adilutesolutiontovolumeisaboutmL,isheatedtotoDEGC,whileKMnOstandardsolution(NaCOthermalcalibrationbenchmark(note)titrationtitrationbeakeroperation)untilthesolutionispalered,thenputintothesolutioninthefilter(filterpaperconsumptionKMnOstandardsolution,theinputendpointnearbreak)andfade,addingtothelightreddoesnotdisappearinssofarCalculatethemassfractionrepresentedbyCaO

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