Inductively coupled plasma | HiQ

An inductively coupled plasma can be generated by directing the energy of a radio frequency generator into a suitable gas, usually ICP argon. Other plasma gases ... SkiptoMainContent Analyticalmethods Gaschromatography Liquidchromatography Infraredspectroscopy Otherspectroscopy Othermethods Inductivelycoupledplasma Massspectrometry Nuclearmagneticresonance Analyticalmethods Inductivelycoupledplasma Inductivelycoupledplasma Themostcommonlyusedtechniquesforthedeterminationoftraceconcentrationsofelementsinsamplesarebasedonatomicemissionspectrometry(AES). Todissociatesamplemoleculesintofreeatoms,thermalsourcessuchasflames,furnacesandelectricaldischargesareused. Morerecently,othertypesofelectricaldischarges,namelyplasmashavebeenusedasatomization/excitationsourcesforAES.Thesetechniquesincludeinductivelycoupledplasma(ICP)anddirectcoupledplasma(DCP).Plasmasourcesoffersseveraladvantagescomparedwithflameandelectrothermalmethods.Theadvantagesarethatitisamulti-elementtechniqueandithaswiderange.Currentplasmasources(DCP)provideamucheasiermethodofhandlingliquidandgaseoussamples.Spectrafordozensofelementscanberecordedatthesametimewhichisimportantwhenthesampleisverysmall.Plasmasourcesalsopermitdeterminationofnon-metalssuchaschlorine,bromine,iodineandsulfur. InductivelyCoupledPlasma-Inductivelycoupledplasma Aninductivelycoupledplasmacanbegeneratedbydirectingtheenergyofaradiofrequencygeneratorintoasuitablegas,usuallyICPargon.OtherplasmagasesusedareHeliumandNitrogen.Itisimportantthattheplasmagasispuresincecontaminantsinthegasmightquenchthetorch. Couplingisachievedbygeneratingamagneticfieldbypassingahighfrequencyelectriccurrentthroughacooledinductioncoil.Thisinductorgeneratesarapidlyoscillatingmagneticfieldorientedintheverticalplaneofthecoil.IonizationoftheflowingargonisinitiatedbyasparkfromaTeslacoil.TheresultingionsandtheirassociatedelectronsfromtheTeslacoiltheninteractwiththefluctuatingmagneticfield.Thisgeneratesenoughenergytoionizemoreargonatomsbycollisionexcitation.Theelectronsgeneratedinthemagneticfieldareacceleratedperpendicularlytothetorch.Athighspeeds,cationsandelectrons,knownaseddycurrent,willcollidewithargonatomstoproducefurtherionizationwhichcausesasignificanttemperatureraise.Within2ms,asteadystateiscreatedwithahighelectrondensity.Aplasmaiscreatedinthetopofthetorch.Thetemperaturewithintheplasmarangesfrom6,000-10,000K.Along,well-definedtailemergesfromthetopofthehightemperatureplasmaonthetopofthetorch.Thistorchisthespectroscopicsource.Itcontainsalltheanalyteatomsandionsthathavebeenexcitedbytheheatoftheplasma.ThesuccessofICPleansonitscapabilitytoanalyzealargeamountofsamplesinashortperiodwithverygooddetectionlimitsformostelements.ICPsusedinthemarkettodayareoftenconnectedtodifferentdetectionsystems,suchasICPmassspectrometryandICPatomicemissionspectrometry. InductivelyCoupledPlasma-Directcoupledplasma Adirect-currentplasma(DCP)iscreatedbyanelectricaldischargebetweentwoelectrodes.Aplasmasupportgas,commonlyICPargon,isnecessary.Samplescanbedepositedononeoftheelectrodes,orifconductingcanmakeuponeelectrode.Insulatingsolidsamplesareplacednearthedischargesothationizedgasatomssputterthesampleintothegasphasewheretheanalyteatomsareexcited.Thissputteringprocessisoftenreferredtoasglow-dischargeexcitation.InstrumentationSamplerAnebulizerconvertsthesampletoanaerosolthatisintroducedintotheexcitationareaoftheplasma. SourceTheplasmajetsourceismadeofthreeelectrodesformedlikeatripod.Ineacharmthereisagraphiteanodeandattheinvertedbase,atungstencathodeislocated.Ahigh-velocityinertgas,usuallyICPargon,producesahightemperatureplasmaandseparatestheexcitationregionfromtheanalyticalobservationzone.Theexcitationareaissituatedinthecrookofthetripodandithasatemperatureof6,000K.Toincreasethecurrentdensityandthustheplasmatemperatureitisnecessarytosqueezetheplasmainordertodecreasethecurrentcrosssection.Thisisaccomplishedbycoolingtheedgesoftheplasmawithahigh-velocityinertgas.  Analyzer Theanalyzeriseitheramono-orpolychromator. DetectorAphotomultiplierconvertsradiantenergytomeasurablesignalsout. InductivelyCoupledPlasma-AtomicEmissionSpectroscopy Inductivelycoupledplasma-atomicemissionspectroscopyisatypeofemissionspectroscopythatusestheinductivelycoupledplasmatoproduceexcitedatomsandionstoemitelectromagneticradiationatwavelengthscharacteristicofaparticularelement.Theintensityofthisemissionisindicativeoftheconcentrationoftheelementwithinthesample.ExamplesofICP-AESapplicationsincludethedeterminationofsmallquantitiesofmetaliccompoundsinwine,arsenicinfood,traceelementsinsoilandtraceelementsboundtoproteins.Ithasalsobereferredtoasinductivelycoupledplasmaopticalemissionspectrometry(ICP-OES),whereitiswidelyusedinmineralsprocessingtoprovidethedataongradesofvariousorestreamsfortheconstructionofmassbalances.ThisanalyticalmethodisalsoreferredtoasInductivelyCoupledPlasmaAtomicEmissionSpectrophotometryandInductivelyCoupledPlasma-AtomicEmissionSpectrometer.InductivelyCoupledPlasma–AtomicEmissionSpectroscopy(ICP–AES) Detectionlimit Gasrecommendation Regulatorrecommendation Gasgeneratorrecommendation Purgegas ≤100ppb HiQArgon5.0 BASELINEC106series n/a ≤100ppb HiQNitrogen5.0 BASELINEC106series HiQMISTRALNitrogen Sheargas ≤100ppb HiQAir4.0 BASELINEC106series HiQZeroAir ≤100ppb HiQNitrogen4.6 BASELINEC106series HiQMISTRALNitrogen Torchgas ≤100ppb HiQArgon4.8 BASELINEC106series n/a     Anyquestions? Askourexperts! Contact Relateddownloads Argon(PDF 167.0KB) Amonia(PDF 181.0KB) SulfurOfftheMenu,2012(PDF 757.0KB) ThoughtForFood,2011(PDF 224.0KB)