282-paper-Determination of Trace Elements in Steel

DeterminationofTraceElementsinSteelbyhighsensitivityinductivelycoupledplasma-massspectrometrywithoutmatrixseparationNIELingqing1*,JIHongling1,CHENYingying1,LIUXiaoping1,WANGYangping2（1.BaosteelResearchInstitute,Shanghai201900,China;2EastChinaUniversityofScienceandTechnology,200237,China）Abstract:Inconnectionwithincreasingqualitydemandsinsteelandsteelproduction,decreasingchemicalanalysisofthesetraceelementsdowntotheｕg/grangeisincreasingimportant.Inourstudy,afast,preciseandaccuratemultielementsdeterminationmethodfortraceelementsB,Al,P,Pb,Sn,Sb,AsandBiintherangeofμgg-1subμgg-1insteelhasbeenestablishedbyhighsensitivityinductivelycoupledplasma-massspectrometry(HR-ICPMS)withoutanymatrixseparationoranyinternalstandard.IthasgoodprecisionandlowlimitofdetectionwithRSD5%andLOD0.01μgg-1formostelements.Themeasuredvaluetalliedwiththestandardvalve.Therecoveryissatisfied.Keywords:HR-ICPMS;steel;traceelements;withoutmatrixseparation0IntroductionThepropertiesandqualityofsteelareamongotherthingsaffectedbytrampandtraceelements,whichareeitheraddedduringthesteelmakingprocessorpresentasimpuritiesoriginatingfromtherawmaterials1.AndsomeelementssuchasPbareunwholesometous.Inconnectionwithincreasingqualitydemandsinsteelandsteelproduction,decreasingchemicalanalysisofthesetraceelementsdowntotheｕg/grangeisofincreasingimportant2.Inrecentyears,HR-ICPMShasbeenemployedtodeterminingtraceanalysisinvariousfields.Inironandsteelfield,somepaper3,4reporteddeterminingoftraceamountsofelementsinhigh-purityironandsteelafterseparatingtheironmatrixbyexchangechromatographyorbysolidphaseextraction,Insomeresearch5,traceelementswereanalyzedusingmatrixmatchedstandardsolutioncalibrationandinternalstandard.1EXPERIMENTAL1.1InstrumentationTheICP-MSusedinourstudywasElement2(FinniganMAT,Bremen,USA).TheconditionsforICP-MSweredailyoptimized.Sotheconditionsspecialtorchpositionandgasflowwerealittledifferentdaily.ThemicrowaveusedinthisstudywasMDS-2100(CEM,USA).Theconditionsformicrowavepressure120psiandTAP30min.1.2SampleandregentsWechoosecertifiedsteelreferencematerialsGBW01323,GBW01327,JSS001-4,JSS003-4,NIST2167,GSBH40036-93,90-1,GSBH40032-93,GSBH40031-93,NBS1265aandsteelsmadebysteelworkingfactoryasanalyticalsamples.CriterionsolutionscontaininginterestingelementswerepurchasedformSpexCertiprep,Inc.Hydrochloricacid(30%)andhydrofluoricacid(40%)waspurchasedformMerck,Germany.Nitricacidwaspreparedbyserialdilutionjustunderboilingpointofthestocksolution(electronicchemicalgrade).ThedeionizedwaterwasobtainedformaMill-QElementwaterpurifier(Millipore,Bedford,MA,USA).BottlesweremadewithPFAorPP.1.3Sampledissolutionandanalyticalprocedure0.5000gofsamplewasdissolvedinhighpressurevesselwith5mlnitricacid(acid:water3:1)and1.5mLofhydrochloricacidfordeterminingtotalBortotalAl.0.5000gofsamplewasdecomposedbyelectrothermalheatingwith8mlnitricacid(acid:water3:1)fordeterminingotherelements.1.0mlofhydrofluoricacidwasneededwhenconcentrationofsiliconishigh.Theobtainedsolutionwasevaporatednearlytodryness.Aftercoolingthesolutionwastransferredintoa50mLflaskandmadeuptovolumewithdeionizedwater.Thesolutionswereelutedandtheresultingsolutionwasequivalentto100μgmL-1ofsampleinsolution.Thesameprocedure,butwithoutanysample,wasusedfortherespectiveblanktest.ThesamplesweredeterminedbyICP-MSwithstandardaddingcalibrationmethod.2RESULTSANDDISCUSSION2.1SpectruminterferencesandSelectionofIsotopesMostofelementshavemorethantwoisotopesinnature.Manyisotopeswereinterferedbyisotopesorpolyatomicionswiththesamemass.Insomepaper3,4,6,theinterferenceswerecorrectedbycalculatingtheabundanceoftheisotopesorbyseparatingtheironmatrix.Butinourstudy,Element2ishigh-resolutioninstrument.Itprovidesthreefixedresolutionssettings(m/△m=300,4000,10000).Consideringthecompositionofsteels,samplegas,solutionandtheabundanceofisotopes,therewereappropriateresolutionsformostinterestingelementsinourstudy.Theisotopesandresolutionsselectedwereshownintable1.Table1IsotopeandresolutionselectedElementBPAlPbAsSnSbBiSelectedIsotope11B31P27Al208Pb75As120Sn123Sb209BiSelectedResolutionLRMRMRLRMRLRLRLR2.2MatrixeffectsandselectionofinternalstandardelementsGenerally,matrixeffectswerecoursedbyalargeamountofFeandcomplexcompositionofsteelwhereastheextentofinfluenceisdifferentfromdifferentinstrument.Inourstudy,onlyafewminuteswereneededinourexperimentalprocesscommonlyandmatrixeffectsareinconspicuousformostelements(2ngg-1)under100μgg-1matrixwhenusingshortinjectingtimeasshowninFig.1.Ontheotherhand,thehigherconcentrationofmatrixis,theeasiliertheconeorificeiscloggedbydepositofdissolvedmetaloxidesinsolutions.So,wechoose100μgg-1matrixwithoutanyinternalstandardastheanalyticalsolutioninourstudy.Fig.1signalvarietyforcontinueinjectingtimeInordertovalidateourconclusion,thefunctionofinternalstandardelementswasstudy.WedeterminedofBwithandwithoutinternalstandard.Asshownintable2,therewasn’tanyconspicuousdifferencebetweenthedatafrom“withoutinternalstandard”methodandthedatafrom“withinternalstandard”method.Table2themeasurevalueofBwithorwithoutinternalstandardelement2.3LimitofdetectionandR