等离子体发射光谱分析技术

123InfraRedRedIsaacNewton1666Wollaston1802Fraunhofer1814KirchoffandBunsen1861Kirchoff1859←WhiteLightVioletUltraViolet“”Foucault1848AtomicSpectroscopyHistory4TheoryofAtomicSpectroscopyExcitedstatesEnergyEnergyGroundstateAtom1Atom25TheoryofAtomicSpectroscopyhν=E2-E1=h(C/λ)BohrEE1E2E2hplanck6.626210-34J·S6TheoryofAtomicSpectroscopyev589.0nm7Wavelengthsofemittedlight•LargestenergydropresultsinemissionatshorterwavelengthsgroundstateenergyE2E1E3E48ElementsEmission9ElementWavelengths180nm800nm400nm--visible----uv--•Eachelementhasauniquesetofwavelengthsthatitcanemitλλλλλ1234510EffectofTemperatureonEmission2003004005006007008002000k3000k5000kCaNaLiKCaNaLiKKLiNaCaBaBaCuMgMgCuAsPbMn11Emissionsources/(DCP)(ICP)12Emissionsources1)2)3)4)5)6)7)13WhatisaPlasma?Plasma0.1%z106-108K105Kz114RF27.12MHz,2kw)ICP(~8000°C)105(ppb)~14L/min)Plasma15AdvantageofICPSource(ICP)152()0.x-x00ug/L3)4)5)30s616SampleTransportMXMM+M*+photon+photonM+*StateIStateIISolutionSolidGasAtomIon1718InstrumentDiagramSampleIntroductionSystemRFGeneratorPneumaticSystem(GasFlows)OpticalSystem(EchelleSpectrometer)DetectionandAcquisitionElectronicsIRIS/IntrepidCPUPlasmaControlElectronicsAutosamplerDataStation1920Detector‰‰‰21PMTDetectioneIncidentRadiationPhoto-CathodeVacuumEnclosureElectronMultiplierStages22STDDetector23CID&CCDCameraCID,“”−−−CCD24CID&CCDCamera253000XViewofOneCID38APixelCenterofpixelwhereRowcrossesoverColumnelectrodeFieldoxidethatisolateschargechannelbetweenpixelsEpitaxiallayerInter-leveloxideisolation(light)Columnelectrode(dark)PlanarizationoxideMetalstrap(lightareabetweendottedlines)PassivationlayerRowelectrodeContactholetostraprowpolywithmetalImaginaryboundarybetweenpixelsMosttransparentareaofpixel27umpixelpitchcentertocenter26CIDCameraPixelCCDintegrationDiagram27CIDCameraReadout28CCD-ChargeCoupledDevice---CCDCameraReadout29AdvantageofCIDchip••••30CIDFullFrame31CIDTDSTimeDomainSpectroscopy(TDS):TDSallowsfortheacquisitionofsignalintensityvs.timeforoptimizingICAPviewingzone,determiningsampleflushtimeandtheobservationoftransientevents(e.g.,couplingoftheeffluentofanionchromatographtotheICAP®).ConnectingtriggersignalcableisrequiredtolinkyourtransientsampledevicetotheIRIS.3233OpticalComponents•thelens•theslits•themirrors•theprism•thegrating3434NewNewIRISIntrepidIIOpticalSystem−−−−−−35OpticalConfigurations•Polychromator(simultaneous)•Monochromator(sequential)•Echelleoptics36TheMonochromator(Czerny-Turner)Ebert)37ThePaschen-RungePolychromator38TheEchelleSpectrometerIRIS/Intrepidopticallayout•two“active”opticalcomponents:anechellegratingandaprism•grating=wavelengthseparation(high,overlappingorders)•prism=opticalseparationoftheordersisachievedbycross-dispersion(“ordersorter”)•theresultingspectrumimageisrectangular•usesabi-dimensionaldetectortocapturethespectrum(CID)39OpticalComponents:ThePrism•thefirstuseddispersiondevices•dispersionisnon-linearwithwavelength(resolutionathighwavelengthsissignificantlylowerthanatthelowendofthespectrum).40TheDiffractionofLight•Lightpassingthroughasmallholeorslitnolongertravelsinastraightline–thisisthediffractionoflight•eachslitactsasthesourceofasphericalwave•thesphericalwavesinterferewitheachotherformingadiffractionpattern•theangleatwhichconstructiveinterferenceoccurs:nλ=dsinθwhereλ-wavelengthd-spacingbetweenslitsn-integer(order)Propagationofmonochromaticlightthroughadjacentslits41TheGratingEquationλdblazeangleλ1λ242DiffractionGrating•thediffractionanglerisafunctionofd,θandλ•dbetween1200and3600grooves/mm•ordersareoverlapping;resolutionincreaseswithorders•theblazeangleisselectedtomaximizefirst/secondorderfirstorderthirdordersecondorderfirstordersecondorder43TheEchelleGratingdgratingsubstrate•anechellegratingiscoarse(52.6grooves/mmonthehighresolutionIRIS/Intrepidat64.1degreesblazeangle)andisusedathighanglesinhighdiffractionorders•ordersusedarefrom30to200,heavilyoverlapped44OpticalResolution·α=β=ε··β)β45TheEchelleSpectrum200nm400nm800nm200nmorder20040000400nmorder100800nmorder503920040800Effectofthegrating(overlappinghighorders)Effectoftheprism(cross-dispersion)46TheEchelleSpectrumCa317.933{105}333822Cu324.754{103}33449Ba493.409{68}33551Na589.592{57}33606V292.402{115}33626K766.491{44}3372547TheEchelleSpectrumTheprismseparatestheorders–atthesamefirstorderwavelengthtwodifferentwavelengthsmustbeofdifferentorders!order105order103order115order68order57order4448TheEchelleSpectrumOrder4060801201001401040007800052000260000130000FirstOrderWavelength1040007800052000260000130000Effectofthegrating(overlappinghighorders):Effectoftheprism(cross-dispersion):49TheEchelleSpectrumwavelengthsaredispersedthisaxis(effectofthegrating)ordersaredispersedthisaxis(effectoftheprism)lowlowhighhigh5051SamplingSystem52ConcentricNebuliser53BurgenerNebuliserTeflonversionofaconcentricUsedforhighdissolvedsolidsorsamplescontainingHFHasalargercapilliary54Crossflownebuliser55UltrasonicNebuliser56SprayChamber57Torch58RFGeneratorRF----27.12MHz)(1500W)------LCf=1/2π(LC)1/240.68MHz---RF-----5------59PowerAMPDriveAMPRFSourceRFAGCIRISInt