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1、METHOD6200FIELDPORTABLEX-RAYFLUORESCENCESPECTROMETRYFORTHEDETERMINATIONOFELEMENTALCONCENTRATIONSINSOILANDSEDIMENT1.0SCOPEANDAPPLICATION1.1Thismethodisapplicabletotheinsituandintrusiveanalysisofthe26analyteslistedinTable1forsoilandsedimentsamples.Somecommo
2、nelementsarenotlistedinTable1becausetheyareconsidered"light"elementsthatcannotbedetectedbyfieldportablex-rayfluorescence(FPXRF).Theyare:lithium,beryllium,sodium,magnesium,aluminum,silicon,andphosphorus.MostoftheanalyteslistedinTable1areofenvironmentalconc
3、ern,whileafewothershaveinterferenceeffectsorchangetheelementalcompositionofthematrix,affectingquantitationoftheanalytesofinterest.Generallyelementsofatomicnumber16orgreatercanbedetectedandquantitatedbyFPXRF.1.2Detectionlimitsdependonseveralfactors,theanal
4、yteofinterest,thetypeofdetectorused,thetypeofexcitationsource,thestrengthoftheexcitationsource,counttimesusedtoirradiatethesample,physicalmatrixeffects,chemicalmatrixeffects,andinterelementspectralinterferences.Generalinstrumentdetectionlimitsforanalyteso
5、finterestinenvironmentalapplicationsareshowninTable1.Thesedetectionlimitsapplytoacleanmatrixofquartzsand(silicondioxide)freeofinterelementspectralinterferencesusinglong(600-second)counttimes.Thesedetectionlimitsaregivenforguidanceonlyandwillvarydependingo
6、nthesamplematrix,whichinstrumentisused,andoperatingconditions.Adiscussionoffieldperformance-baseddetectionlimitsispresentedinSection13.4ofthismethod.Thecleanmatrixandfieldperformance-baseddetectionlimitsshouldbeusedforgeneralplanningpurposes,andathirddete
7、ctionlimitdiscussed,basedonthestandarddeviationaroundsinglemeasurements,shouldbeusedinassessingdataquality.ThisdetectionlimitisdiscussedinSections9.7and11.3.1.3UseofthismethodisrestrictedtopersonneleithertrainedandknowledgeableintheoperationofanXRFinstrum
8、entorunderthesupervisionofatrainedandknowledgeableindividual.ThismethodisascreeningmethodtobeusedwithconfirmatoryanalysisusingEPA-approvedmethods.Thismethod’smainstrengthisasarapidfieldscreeningprocedure.Themethodde
