欢迎来到天天文库
浏览记录
ID:44076584
大小:258.34 KB
页数:15页
时间:2019-10-18
《EPA METHOD 7473 Mercury in Solids and Solutions by Thermal 》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、METHOD7473MERCURYINSOLIDSANDSOLUTIONSBYTHERMALDECOMPOSITION,AMALGAMATION,ANDATOMICABSORPTIONSPECTROPHOTOMETRY1.0SCOPEANDAPPLICATION1.1Method7473isdesignatedforthedeterminationofmercury(CASNo.7439-97-6)insolids,aqueoussamples,anddigestedsolutionsinboththelaboratoryandfieldenvironments.Integrationo
2、fthermaldecompositionsamplepreparationandatomicabsorptiondetectionreducesthetotalanalysistimeofmostsamplestolessthanfiveminutesineitherthelaboratoryorfieldsetting.Totalmercury(organicandinorganic)insoils,sediments,bottomdeposits,andsludge-typematerialsaswellasinaqueouswastesandgroundwaterscanbede
3、terminedwithoutsamplechemicalpretreatmentusingthismethod,exceptasnoted.Alternatively,thismethodcanbeusedforthedetectionoftotalmercuryfromtotaldecompositionsamplepreparationmethods,suchasMethod3052,orfordetectionofextractedorleachedmercurycompoundsorspeciesfrommethodssuchastheSW-8463000seriesmetho
4、ds(asdetailedinChapterThree).NOTE:Foruniquecircumstanceswhenmercurycouldbeboundinsilicatesorothermatricesthatmaynotthermallydecompose,validationofdirectanalysisofthesolidshouldbeconfirmedwithtotaldecompositionwithanEPAapprovedmethod(suchasMethod3052)andanalysiswiththismethod.2.0SUMMARYOFMETHOD2.1
5、Controlledheatinginanoxygenateddecompositionfurnaceisusedtoliberatemercuryfromsolidandaqueoussamplesintheinstrument.Thesampleisdriedandthenthermallyandchemicallydecomposedwithinthedecompositionfurnace.Thedecompositionproductsarecarriedbyflowingoxygentothecatalyticsectionofthefurnace.Hereoxidation
6、iscompletedandhalogensandnitrogen/sulfuroxidesaretrapped.Theremainingdecompositionproductsarethencarriedtoanamalgamatorthatselectivelytrapsmercury.Afterthesystemisflushedwithoxygentoremoveanyremaininggasesordecompositionproducts,theamalgamatorisrapidlyheated,releasingmercuryvapor.Flowingoxygencar
7、riesthemercuryvaporthroughabsorbancecellspositionedinthelightpathofasinglewavelengthatomicabsorptionspectrophotometer.Absorbance(peakheightorpeakarea)ismeasuredat253.7nmasafunctionofmercuryconcentration.2.2Thetypicalwo
此文档下载收益归作者所有