u主量元素分析方法说明

♦主量元素分析方法说明Majorelementdataforwhole-rocksampleswereobtainedbyX-RayFluorescence(XRF)spectrometryonfusedglassdiscsusingaPANalyticalAXIOSMineralsinstrumentattheRock-MineralPreparationandAnalysisLab,theInstituteofGeologyandGeophysics(IGG;Beijing),ChineseAcademyofSciences(CAS).ThePANalyticalAXIOSMineralsequippedwithaRhanodeX-raytubeand4kWexcitationpowerisasequentialinstrumentwithasinglegoniometerbasedmeasuringchannelcoveringthecompleteelementalmeasurementrangefromFtoUintheconcentrationrangefrom1.0ppmto%level,determinedinvacuummedia[1].GlassdiscsforWD-XRFanalysiswerepreparedbyfusionof0.6gofthestandardsamplewith6.0goflithiumtetraborate:metaborate(2:1)(Lithiumborates67-33,Claisse,Canada),usingPt-Aucruciblesandmouldsemployingelectricfusionequipment(ClaisseFluxy,CorporationScientificClaisseInc.,Quebec,Canada)[2].Lossonignition(LOI)wasmeasuredastheweightlossofthesamples,whichwasobtainedindependentlybyigniting0.5gdrysamplealiquotinaporcelaincruciblefor1.5hat1000℃inamufflefurnace[1].Thespectrometerwascalibratedaftermeasuringintensitiesinthefollowingfiftyinternationalreferencematerials:GBW03102,GBW03102,GBW03113,GBW03116,GBW03134,GBW07101,GBW07102,GBW07103,GBW07104,GBW07105,GBW07106,GBW07107,GBW07108,GBW07109,GBW07110,GBW07111,GBW07112,GBW07113,GBW07114,GBW07212,GBW07309,GBW07310,GBW07311,GBW07312,GBW07401,GBW07402,GBW07403,GBW07404,GBW07405,GBW07406,GBW07407,GBW07408(IGGE,China);AGV-2,BCR-2,BIR-la,BHVO-2,DNC-la,DTS-2B(USGS,USA);JGB-2a,JP-1,JH-la,JG-2,JB-2(GSJ,Japan);AN-G,BE-N,PM-S,WS-E(GIT-IWG,GroupeInternationaldeTravail-InternationalWorkingGroup);DR-N,UB-N(ANRT,Paris);Mica-Fe(CRPG,CentredeRecherchesPetrographiquesetGeochimiques);Thecriteriatoselectthesesamplesweretherequiredintervalofconcentration[2].GSR-1,GSR-2,andGSR-3areusedtomonitorthepreparationprocessandinstrumentstatus.FerrousironwasdeterminedbyXue'stitrationmethod.About0.2gofsamplepowderwasweighedbydeterminingthedifferenceinthePTFEvessel,andthen,thevesselwassubjectedtoavacuumtoremovegasesandthenrefilledwithinertgasthreetimestoensureaninertatmosphere.Next,near-boiling50%H2so4(10mL)andHF(5mL)wereaddedtothedigestionvessel,thenheatedunder170℃for10min.Subsequently,saturatedboricacid(50mL)wasadded.Finally,theresultantmixturewastitratedwithstandardKMnCUsolution.Thetitrationspeedwasadjustedaccordingtotherateatwhichthepermanganatecolordisappeareduntilonedropproducedafaintpinkcolorthatpersistedfor30s.Thefinalsmalldropstoreachtheend-pointwereflushedfromthemicroburettetipwithawashbottleintothedigestionvessels.Themicroburetwasreadatthetoplevelofthemeniscus.Thewholeprocessduringsampledigestionandtitrationwascarriedoutunderinertatmospheretopreventoxidationofferrousmaterial.Blanksampleswerealsoprepared,followingthesameprocedureintheabsenceofthesample.[3](DingshuaiXue*,HongyueWang,YanhongLiu,LiewenXie,PingShen;2017,GeostandardsandGeoanalyticalResearch,DOI:2017,Volume41,Issue3,Pages411-425).TheSuperQsoftwarecanautomaticallyprovidethelimitofdetection(LOD)foreachelement.ThecalculationequationusedbytheSuperQsoftwareis[1]:LOD=乎盘(3)wherenisaconstant.Thedefaultis2,whichcorrespondstoasignificanceof2,withaconfidencelevelof95%.sisthesensitivityincps/ppm(cpsiscountspersecondandppmis|igg-1).Rbistheestimatedbackgroundintensityincpsatthepeakposition.Tbisthetotalmeasurementtimespentonthebackground.Thelimitofdetection(LOD)isthelowestconcentrationlevelthatcanbedeterminedtobestatisticallydifferentfromananalyteblank.Forquantitativemeasurements,thelimitofquantitation(LOQ)isgenerallyconsideredtobethatvaluecorrespondingto10standarddeviationsabovethebaseline,approximately3.3timestheLOD.Table.Datafortherangeofstandardsamplecompositions,limitsofdetection(LOD)andlimitsofquantitation(LOQ)ofthemethod.NumberElementsRangeofStandardSampleCompositionLOD(Pggi)LOQ(Pgg-1)Major(m/m%a)1SiO2147.90488.072TiO229.3496.823AI2O3161.83534.044TFezOsb16.2853.725MnO11.0936.606MgO85.41281.857CaO49.68163.948Na2O77.23254.869K2O20.3767.2210P2O516.6755.01SO3c28.7494.84Minor(Rgg-1)11Ba6.4-400052.67173.8112Co0.12-1208.6628.5813Cr1.6-1550011.1936.9314Cu0.82-12307.1323.5315Ni0.9-37805.5218.2216Rb0.8-36005.5118.1817Sr2.3-120004.0413.3318V0.0022-76813.1643.4319Zn3.5-13005.7418.9420Zr0.7-15402.157.10am/m%isthemasspercentage;bTFezChisthetotalironoxideasferriciron;cThisdataisforreferencepurposesonly.References:Xue,Ding-Shuai;Su,Ben-Xun;Zhang,Dan-Ping;Liu,Yan-Hong;Guo,Ju-Jie;Guo,Qian;Sun,Jie-FangandZhang,Shu-Ying.Quantitativeverificationof1:100dilutedfusedglassbeadsforX-rayfluorescenceanalysisofgeologicalspecimens.JournalofAnalyticalAtomicSpectrometry,2020,DOI:10.1039/D0JA00273A.Zhang,Dan-Ping;Xue,Ding-Shuai;Liu,Yan-Hong;Wan,Bo;Guo,Qian;Guo,Ju-Jie.ComparativeStudyofThreeMixingMethodsinFusionTechniqueforDeterminingMajorandMinorElementsUsingWavelengthDispersiveX-rayFluorescenceSpectroscopy.Sensors,2020,20,no.18:5325.Xue,