2021关于英语实验报告.docx

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1、关于英语实验报告关于英语实验报告　　关于英语实验报告　　Determinationofheavymetalsinsoilbyatomicabsorptionspectrometry(AAS)　　Name:XuFeiGroup:The3rdgroup　　Date:Sep.20th20xx　　Part1Theintroduction　　1.1Thepurposes　　(1)Learnhowtooperatetheatomicabsorptionspectrometry;　　(2)Learnhowtodothe

2、pretreatmentofsoilsamples;　　(3)Getfamiliarwiththeapplicationofatomicabsorptionspectrometry.　　1.2Theprinciples　　AtomicAbsorptionSpectrometry(AAS)isatechniqueformeasuringquantitiesofchemicalelementspresentinenvironmentalsamplesbymeasuringtheabsorbedradiatio

3、nbythechemicalelementofinterest.Thisisdonebyreadingthespectraproducedwhenthesampleisexcitedbyradiation.Theatomsabsorbultravioletorvisiblelightandmaketransitionstohigherenergylevels.　　Atomicabsorptionmethodsmeasuretheamountofenergyintheformofphotonsoflight

4、thatareabsorbedbythesample.Adetectormeasuresthewavelengthsoflighttransmittedbythesample,andcomparesthemtothewavelengthswhichoriginallypassedthroughthesample.Asignalprocessorthenintegratesthechangesinwavelengthabsorbed,whichappearinthereadoutaspeaksofenerg

5、yabsorptionatdiscretewavelengths.Theenergyrequiredforanelectrontoleaveanatomisknownasionizationenergyandisspecifictoeachchemicalelement.Whenanelectronmovesfromoneenergyleveltoanotherwithintheatom,aphotonisemittedwithenergyE.Atomsofanelementemitacharacteri

6、sticspectralline.Everyatomhasitsowndistinctpatternofwavelengthsatwhichitwillabsorbenergy,duetotheuniqueconfigurationofelectronsinitsoutershell.Thisenablesthequalitativeanalysisofasample.　　TheconcentrationiscalculatedbasedontheBeer-Lambertlaw.Absorbanceisd

7、irectlyproportionaltotheconcentrationoftheanalyteabsorbedfortheexistingsetofconditions.Theconcentrationisusuallydeterminedfromacalibrationcurve,obtainedusingstandardsofknownconcentration.CalibrationCurveMethod:Preparestandardsolutionsofatleastthreediffere

8、ntconcentrations,measuretheabsorbanceofthesestandardsolutions,andprepareacalibrationcurvefromthevaluesobtained.Thenmeasuretheabsorbanceofthetestsolutionadjustedinconcentrationtoameasurablerange,anddeterminetheconcen