仪器分析英文原版教案(14)

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1、LiquidChromatography(Chapter28):Fourtypesofhighperformanceliquidchromatography(HPLC):¥partition¥adsorption(liquid-solid)¥ionexchange¥sizeexclusionorgelFig28-1:CEM333page16.1InstrumentationforHPLC:¥Forreasonableanalysistimes,moderateflowraterequiredbutsmallparticles(1-10mm)¥Solventforcedthroughcol

2、umn1000-5000psi-moreelaborateinstrumentthanGC¥Solventsdegassed-"sparging"¥HighpuritysolventsSinglemobilephasecomposition-isocraticelutionProgrammedmobilephasecomposition-gradientelutionFig28-4CEM333page16.2ReciprocatingPump(Fig28-6):¥Upto10,000psi,smallinternalvolumes¥ProducespulsationSampleinjec

3、tion(Fig28-7):¥SimilartoFIA,GC¥Introducesmallsample(0.1-100mL)withoutdepressurization¥Microsyringe/septumsystem(only<1500psi)CEM333page16.3HPLCColumns:¥Stainlesssteel¥10-30cmlong¥4-10mminternaldiameter¥1-10mmparticlesize-40,000-60,000plates/mHighSpeedIsocraticSeparation(Fig28-8):¥100,000plates/mC

4、EM333page16.4GradientElution:¥Solventpolarity(composition)continuouslyvariedorsteppedFig28-5CEM333page16.5Figure28-18:CEM333page16.6Detectors:Allpropertiespreviouslydiscussedand¥smallinternalvolumetoreducezonebroadeningBulkpropertydetectors-measurepropertyofmobilephase(refractiveindex,dielectricc

5、onstant,density)Solutepropertydetectors-measurepropertyofsolutenotpresentinmobilephase(UVabsorbance,fluorescence,IRabsorbance)CEM333page16.7UV-VisDetectionforHPLC(Fig28-9):sources:¥singleline(arcorhollowcathodelamp,laser)¥continuum(Xe,D2lamp)detector:¥photodiode/photomultipliertube¥photodiodearra

6、yCombinationofseparationandanalysis(GC-MS,HPLC-UV-Vis)-verypowerful(Fig28-10)CEM333page16.8PartitionChromatography:¥Mostpopularmethod¥Lowmolecularweight(mw<3000)analytes¥Polarornon-polar¥Bondedstationaryphasecolumn(liquidchemicallybondedtosupportparticles)3,5or10mmhydrolyzedsilicaparticlescoatedw

7、ithsiloxanesR1SiO*nR2NormalphaseHPLCnonpolarsolvent/polarcolumnReversedphaseHPLCpolarsolvent/nonpolarcolumnCEM333page16.9Normal-(polarcolumn)versusReversedPhase(nonpolar)elution:Fig28-14Reversed-phaseHPLCmostcommon(hig