DynamicElectrochemistry-UniversityofSulaymaniyah：动态电化学-大学苏莱曼尼亚

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1、ElectroanalyticalchemistryPotentiometry,VoltammetryandPolarographyElectroanalysismeasurethevariationofanelectricalparameter(potential,current,charge,conductivity)andrelatethistoachemicalparameter(theanalyteconcentration)Conductimetry,potentiometry(pH,ISE)

2、,coulometry,voltammetryPotentiometrythemeasureofthecellpotentialtoyieldchemicalinformation(conc.,activity,charge)Measuredifferenceinpotentialbetweentwoelectrodes:referenceelectrode(Econstant)indicatorelectrode(signalαanalyte)ReferenceelectrodesAg/AgCl:Ag(

3、s)

4、AgCl(s)

5、Cl-(aq)

6、

7、.....ReferenceElectrodesSCE:Pt(s)

8、Hg(l)

9、Hg2Cl2(l)

10、KCl(aq.,sat.)

11、

12、.....IndicatorElectrodesInert:Pt,Au,Carbon.Don’tparticipateinthereaction.example:SCE

13、

14、Fe3+,Fe2+(aq)

15、Pt(s)Certainmetallicelectrodes:detecttheirions(Hg,Cu,Zn,Cd,Ag)exampleS

16、CE

17、

18、Ag+(aq)

19、Ag(s)Ag++e-Ag(s)E0+=0.799VHg2Cl2+2e2Hg(l)+2Cl-E-=0.241VE=0.799+0.05916log[Ag+]-0.241VIonselectiveelectrodes(ISEs)Adifferenceintheactivityofaniononeithersideofaselectivemembraneresultsinathermodynamicpotentialdifferencebeingcreatedacrossthatm

20、embraneMembraneStructure(Examples)GlassMembraneLi2O,Cs2O,La2O3,SiO2,CaO,BaO.KM-IpotorKH-Na=10-13pHglasselectrodeNa2O(10.6%),Al2O3(10%),SiO2=(NAS10.6–10)KNa-K=10-3NaglasselectrodeSingleCrystalLanthanumFluorideLaF3dopedwithEu,SelectivetoF-MembraneMixedSalts

21、(Ag2S+AgX)ForAnionX,,and(Ag2S+MS)ForCationsExamplesonmixedsaltsForAnionsAg2S+AgBrforBr-Ag2S+AgClforCl-Ag2S+AgIforIAg2S+AgCNforCN-ExamplesonmixedsaltsForCationsAg2S+PbSforPb2+Ag2S+CuSforCu2+Ag2S+CdSforCd2+Ag2S+NiSforNi2+LiquidIonExchangerCalciumdidecylphos

22、phoricacidForCa2+TypesofIon-SelectiveElectrodesISEsCombinationglasspHElectrodeProperpHCalibrationE=constant–constant.0.0591pHMetermeasuresEvspH–mustcalibratebothslope&interceptonmeterwithbuffersMeterhastwocontrols–calibrate&slope1stusepH7.00buffertoadjust

23、calibrateknob2ndstepistouseanyotherpHbufferAdjustslope/tempcontroltocorrectpHvalueThiswillpivotthecalibrationlinearoundtheisopotentialwhichissetto7.00inallmetersmVpH47Calibrateknobraisesandlowersthelinewithoutchangi