atomic emission spectroscopy - webpage pace原子发射光谱-网页的速度

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1、CHE.331Chapter10AtomicEmissionSpectroscopy.HistoryandTheoryofAtomicAbsorptionSpectroscopyAsthenameimplies,atomicabsorptionistheabsorptionoflightbyfreeatoms.Anatomicabsorptionspectrophotometerisaninstrumentthatusesthisprincipletoanalyzetheconcentrationofme

2、talsinsolution.Theversatilityofatomicabsorptionananalyticaltechnique(Instrumentaltechnique)hasledtothedevelopmentofcommercialinstruments.Inall,atotalof68metalscanbeanalyzed.AdvantagesofAA·Determinationof68metals·Abilitytomakeppbdeterminationsonmajorcompon

3、entsofasample·Precisionofmeasurementsbyflamearebetterthan1%rsd.Therearefewotherinstrumentalmethodsthatofferthisprecisionsoeasily.·AAanalysisissubjecttolittleinterference.·Mostinterferencethatoccurshavebeenwellstudiedanddocumented.·Samplepreparationissimpl

4、e(ofteninvolvingonlydissolutioninanacid)·InstrumenteasytotuneandoperateKirchoffandBunsen'sExperimentBetween1859to1861,GustavKirchoff(Prussianphysicist),withhiscolleagueRobertTunsen,aGermanchemist,attheUniversityofHeidelbergdemonstratedthateveryelementgive

5、soffacharacteristiccolorwhenheatedinincandescence.Theapparatususedfortheirclassicexperimentisshownhere.Applyingthisnewresearchtool,theydiscoveredtheelementcesiumandrubidium.Kirchoff-Absorbance&EmissionLineKirchoffandBunsennotonlyidentifiedvariouscharacter

6、isticspectra,buttheyestablishedtherelationshipbetweentheemissionspectraandtheabsorptionspectrathusexplainingthepresenceofthedarklinesinthesolarspectra.GroundStateAtomWiththatbriefhistoryofthedevelopmentoftheatomicabsorptionprocedureandVarianatomicabsorpti

7、oninstruments,wewillnowexaminetheatomictheorythatexplainshowanatomicabsorptionsignalisgenerated.Inordertounderstandtheatomicabsorptionprocessonemustfirstunderstandthestructureoftheatomanditsorbitals.Theatomconsistsofthecentralcore,ornucleus,madeupofpositi

8、velychargedprotonsandneutralneutrons.Surroundingthenucleusinpreciselydefinedenergyorbitalsaretheelectrons.Allneutralatomshaveanequalnumberofprotonsinthenucleus.Thismeansthateachelementhasauniquenumberofelectronsandp