八级杆工作原理(ICP-MS).ppt

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1、HowDoestheReactionCellWork?FeaturingtheAgilentOctopoleReactionSystem1WhatisaCollision/ReactionCell?TheOctopoleReactionSystem(ORS)isanoctopoleionguidecontainedwithinastainlesssteelvesselandpressurizedwithagas,mostoftenH2orHe.TheORSispositionedbetweenth

2、eionlensassemblyandthequadrupolemassfilter.Asionsfromthesampleenterthiscell,theyinteractwiththegas,resultinginthereductionofthemolecularinterferencenormallybelowtheleveloftheblanksolution.Eliminateskeyinterferencesarisingfromthesamplematrixthatarenota

3、rgonbasedandcannotbeeliminatedusing“traditional”approaches.2WhyuseanOctopole?(1)=analyteionOctopoleReactionSystemInitialIonEnergyEnergyAfterCollisionSmalldiameterIonsenteringthereactioncellhaveanionenergyintheradialdirectioncorrespondingtothedottedlin

4、elabelledInitialIonEnergy.Asionsenterthecellandinteractwiththereactiongas,energytransfertakesplaceandtheanalyteionsloseenergy.Whenionsloseenergy(EnergyAfterCollision),thevoltagesplacedonthereactioncellforcetheionstomovealongthepotentialenergydistribut

5、ion(drawninblack)andtheionsaresubsequentlyconfinedwithintheshadedregion.NotethattheconfinementareaintheOctopoledesignisrelativelydiffuse.AsmalldiameterOctopolecanbeusedtophysicallyconfinetheionsintoatightlyfocusedionbeam.3WhyuseanOctopole?(2)=analytei

6、onQuadrupoleBasedReactionCellsInitialIonEnergyEnergyAfterCollisionCollisionalFocusingIncontrasttotheOctopoledesign,ionswhichloseenergyinaquadrupolereactioncellareconfinedtoanarrowpotentialfield.Thiseffectisknownascollisionalfocusingandisrequiredinsyst

7、emshavinginherentlylowsensitivityorinwhichthereactioncellandthemassanalyzerareofthesamephysicaldiameter.Collisionalfocusingrequiresalargenumberofionmoleculeinteractionswithinthecelltoensureionenergyloss.Therefore,highlyreactive,heavymoleculargasesareo

8、ftenrequiredwiththesedesignstopreventdramaticlossofsensitivity.Complexionfilteringtechniquesareoftenutilizedwiththisconfigurationtoremovereactionby-productscausedbyhighlyreactivegasesusedinthecell–increasescomplexityandreducessensitivity.4Proc