15-16-Stable-Isotope-Techniques-for-Gas-Source-Mass-Spectrometry_2014_Reference-Module-in-Earth-Systems-and-Environmental-Sciences-from-Treatise-on-Ge

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1、15.16StableIsotopeTechniquesforGasSourceMassSpectrometryZDSharp,UniversityofNewMexico,Albuquerque,NM,USAã2014ElsevierLtd.Allrightsreserved.15.16.1Introduction29115.16.2MassSpectrometers29115.16.2.1InletSystem29215.16.2.1.1Dualinlet29215.16.2.1.2Continuousflowinlet29315.

2、16.2.2IonSource29515.16.2.3Analyzer29615.16.2.4CollectorAssembly29715.16.3Standardization29815.16.4MethodsofAnalysis29915.16.4.1Hydrogen29915.16.4.1.1Reductionmethods30015.16.4.1.2Equilibrationmethods30015.16.4.2Carbon30015.16.4.3Nitrogen30115.16.4.4Oxygen30115.16.4.5Su

3、lfur30215.16.4.6Chlorine30315.16.5LaserAbsorptionSpectrometry303References30515.16.1Introductionandotherearlyresearchersfacedabewilderingarrayofprob-lemsnotsharedwithmodernchemistsandphysicists,includingThegassourcemassspectrometerisoneofthemostpreciseunstableelectrical

4、sourcesandrudimentaryvacuumsystems.analyticalinstrumentsinexistence.ThesesophisticatedOneofthefirstmassspectrometers(spectrograph)wassetupmachineshaveevolvedfromcomplexandfinickyhomemadeintheCavendishLaboratoryatOxfordin1919,andwithinonlybeaststorobust,commerciallyavail

5、ableunits.Althoughsta-2years,theCavendishLaboratorygroupbeganconstructiononbilityandmaintenancehavebeendramaticallyimproved,asecond-generationinstrument,ledbyFrancisAston(1927).surprisingly,thesensitivityandprecisionattainablewithaTheseearlymassspectrographsrequiredboth

6、anelectrostaticconventionalgassourcemassspectrometerhavenotchangedandmagneticfieldtocompensateforthepolyenergeticionappreciablyoverthelasthalfcentury.Theadvantagesthathavesource.ShowninFigure1,nearlyallearlymassspectrometersbeenmadecentermoreoneaseofuse,allowingthegeoch

7、em-hada180flightpathtoenhancemassresolution.ThiscostlyisttospendmoretimeaddressingscientificquestionsandlessandcumbersomegeometrywasabandonedwhenAlfredNiertimeworkingtocollectdata.developedthenownearlyubiquitoussectormassspectrometer,Inthischapter,theauthorreviewsthefu

8、ndamentalsofusinga60wedgeinplaceofthecostly180earlierdesignsmassspectrometryandthebasicmethodsofapplicationt