教案分析化学chapt

1、BasicprincipleofAbsorptionColorSelectionBasicprincipleofAbsorptionColorSelectionofdetermination9F.Controlofdetermination9G.Colorimetryandsomespectrophotometric9H.Applicationof2Spectroscopyhasplayedavitaldevelopment of modern atomic theory. SpectrochemicalmethodshaveprovidedSpectroscopyhasplayedavita

2、ldevelopment of modern atomic theory. Spectrochemicalmethodshaveprovidedperhaps the most widely used tools for the elucidation ofthestructureofmolecularspeciesaswellasiveandanicivedeterminationanicboth39A. Basicprincipleof49A. Basicprincipleof4检测限大多可达10-3 10-4 gL检测限大多可达10-3 10-4 gLgmL58476459A-1.Gen

3、eralpropertiesofwave-particleE69A-1.Generalpropertiesofwave-particleE6monochromatic polychromatic color radiation绿黄黄蓝 绿 蓝紫紫7monochromatic polychromatic color radiation绿黄黄蓝 绿 蓝紫紫7selectedSubstance 色，与被该物质吸收的光呈互补色光selectedSubstance 色，与被该物质吸收的光呈互补色光光照射到固体物质白色对各种波长的光完全反灰色对各种波长的光吸收程度相有色选择性吸收某些波长的无色透明溶液各种

4、颜色的光透过的程度相有色溶液吸收部分波长的光，另外的89Selected wavelength range 9Selected wavelength range turquoise 9A-3.LambertAbsorbanceandI0 9A-3.LambertAbsorbanceandI0 Ia ItIrI0 Ia I:IncidentT 取值为0.0 % 100.0IT T = 0.0 T= 100.0 IncidentT 取值为0.0 % 100.0IT T = 0.0 T= 100.0 IThetransmittanceTofasolutionisthefractionoftheinc

5、ident electromagnetic radiationt is transmitted by a sTherelationshipnTandA：T = 0.0 A= T ：IT TherelationshipnTandA：T = 0.0 A= T ：IT IA lg I lg T=100.0% A = 0.0T = 36.8A= lgITT 10TheabsorbanceA ist the absorbance increases wiLambert-ALambertBeer Law适用于任何均匀、Lambert-ALambertBeer Law适用于任何均匀、bpathlengtho

6、fradiation molL-1或gL-A ：吸光液层的厚度，光程， c：吸光物质的浓度，g / bmol/A ：吸光液层的厚度，光程， c：吸光物质的浓度，g / bmol/取值与浓度相K a1cm- K Lmol1cm- Molara Mc：mol / c：g/ 截面积光程（path lengthg cm-2Sandell与截面积光程（path lengthg cm-2Sandell与 MS SandellMolarabsorptivity, Asolutioncontaining3.75mg/100mLofA(220g/mol)Asolutioncontaining3.75mg/100

7、mLofA(220g/mol)hastransmittanceof39.6%in a1.50-cm cell atCalculatetheabsorptivityaandthemolarofA,9B. AExitIncidentI A 9B. AExitIncidentI A lgIH2 andD2Tungsten:160380:350H2 andD2Tungsten:160380:3502200Tungsten/halogen:2402500glass， Instrumentglass，opticsglassglass，opticsglassTheabsorbingcharacteristi

8、csofaspeciesareconveniently described by means of an absorption spectrum, which is a plot of some function of the attenuation of a beam of radiation versus wavelength, frequency, or wavenumber.Twotermsarecommonlyemployediveofbeamattenuation: transmittanceTheabsorbingcharacteristicsofaspeciesareconve

9、niently described by means of an absorption spectrum, which is a plot of some function of the attenuation of a beam of radiation versus wavelength, frequency, or wavenumber.Twotermsarecommonlyemployediveofbeamattenuation: transmittanceand A光的吸收程度，以波长度（A）即为吸收光谱umWaelenma9C.AbsorptionAACA CAACA CysisB

10、AASelectedAA=b CysisBAASelectedAA=b CSelectionofA（样）= A（待测吸光物质）+ A （干扰）+ A（池A（参比）= ASelectionofA（样）= A（待测吸光物质）+ A （干扰）+ A（池A（参比）= A（干扰）+ A （池M-M+R=试显色溶剂 吸光物参比液组吸溶不加显色剂的试液基质吸吸吸显色剂+试液+ 测组分的掩蔽)A1、Thewavelengthrangeofvisible)A1、ThewavelengthrangeofvisiblelightisA.C.B.D.2、AccordingtotheLambert-BeersLaw)2

11、、AccordingtotheLambert-BeersLaw)andabsorbancevalueandmax willrespectively,whenonlytheAincrease,haveondecrease,havenohavenochange,havenochange,3、Whichoneaffectsthemolar(B)the3、Whichoneaffectsthemolar(B)thethicknessoftheabsorptionthewavelenghoftheincidenttheD.theeroftheincident4Thetransmittanceisdeter

12、minedasTin4ThetransmittanceisdeterminedasTin1.00cmcellwhentheconcentrationofthesolution is c. Based on the Lambert-Beers Law, calculatethetransmittancewhentheconcentrationchangedto0.50CB.D.T/ A.TC.TheUV-visspectrophotometer,thesourceis)hevisibleheUV-visspectrophotometer,thesourceis)hevisibleBH2 tung

13、stenhollowinfrared6、TherelationshipAlg6、TherelationshipAlgTnTandA 9D.Color定，此反应称为显色反应(colorreaction)，所用的试剂称为显色剂（color reagent）。定，以提高灵敏度Fe 9D.Color定，此反应称为显色反应(colorreaction)，所用的试剂称为显色剂（color reagent）。定，以提高灵敏度Fe 邻二氮桔红色9D-1.selectionofcolorHighsensitivityGood9D-1.selectionofcolorHighsensitivityGoodCons

14、tantStablechemicalpropertyColorsnoobviousabsorptionatselectedwavelength.(609D-2.coloraniccolor测定Fe3+、Mo()、9D-2.coloraniccolor测定Fe3+、Mo()、W()、Nb5+等硫aniccoloraniccolor chromophoricgroupauxochromegroup如-OHRH,chromophoricgroupauxochromegroup如-OHRH,NH2NHRSH,-BrI如-N=N-,C=C,-N=O, C=S、醌基等9D-4selectionofpara

15、metersincolor9D-4selectionofparametersincolorVolumeofcolorM+nR =+ pH=2 M+nR =+ pH=2 pH=4 pH=8A0A0+R=MAAA000ccc123 +R=MAAA000ccc123 入入Selectionofdetermination9E-1selectionof AAumSelectionofdetermination9E-1selectionof AAumum例波长为470 nm，但试样中的铁用酒石酸钠掩蔽后，在470 nm处也有一定吸收，干扰镍的测定。为避免铁的干扰，可以选择波长nm定，虽然例波长为470 n

16、m，但试样中的铁用酒石酸钠掩蔽后，在470 nm处也有一定吸收，干扰镍的测定。为避免铁的干扰，可以选择波长nm定，虽然9E-2calibrationcurve(standardA 9E-2calibrationcurve(standardA bc9E-3Bias oftheLarmbert-Beers9E-3Bias oftheLarmbert-BeersExitI A lgIExitI A lgI1. 12I1010 111I1I I 12I1010 111I1I I 2I22I1 + II I I02 10A 10II 1bc 122AAAA或22或对吸收光谱而言，bc AA 反映了对吸收

17、光谱而言，bc AA 反映了21 1 2 2.1Adilute 2.1Adilute2.2 2.3 2.3 2.4显色反应的干2.4显色反应的干EliminatecontroltheacidityoftheEliminatecontroltheacidityoftheaddthemaskingchangetheioneselectproperincreasethevolumeofthecolor9F.Controlofdetermination9F.Controlofdetermination?A(or T) dA A Ac 0 nAlgln ?A(or T) dA A Ac 0 nAlgln

18、 dA 又得relativeconcentration1E 100% %rTlnTln得T= 0.368= 36.8 A = A=得T= 0.368= 36.8 A = A= 0.2 bT 65 % Therelativeconcentrationerror is minimum.9G.Colorimetryandsomespectrophotometric 准确度低（半定量9G.Colorimetryandsomespectrophotometric 准确度低（半定量x8642x8642 Differential bcAxA A c) Differential bcAxA A c)xsxxsbcxAcx cx 液浓度稍低的标准溶液作参比，调节 T %至 液浓度稍低的标准溶液作参比，调节 T %至 比试液高的标液调节T %到0%，再用比试液低的标液调T 比试液高的标液调节T %到0%，再用比试液低的标液调T %至100%，然后测定样品溶液。最好能dT0.01,样品Tx 2.00Ts 10.02.00 Ir0.010.02lgIdT0.01,样品Tx 2.00Ts 10.02.00 Ir0.010.02lg