仪器分析仪器分析英文

1、Polarography Voltammetry (极谱和伏安分析法agroup of ytical methods in which information about yteisPolarography Voltammetry (极谱和伏安分析法agroup of ytical methods in which information about yteisderivedfromthemeasurementofcurrentasafunctiond potential obtained under t polarization of occursaroundaworkingelectrod

2、ewithsmall（以小面积工作电极在特殊条件下电解，通过测定电流-电IUPAC Polarography极谱法)amercuryelectrode（电极）isusedastheworking Voltammetry (伏安法) a electrode or a liquid 的液体电极）is used as with ic surface （ 表面working10.1Generalprinciplesofvoltammetric1922J.HeyrovskyCzechoslovakian捷克1.10.1Generalprinciplesofvoltammetric1922J.Heyrov

3、skyCzechoslovakian捷克1.Devicetoprovideapp Measurement deviceElectrolytecell电解池dpotential：B、R、Working electrode: Reference electrode：SCE; Electrolyte solutionMercury Electrode 电yte待测物质Supportingelectrolyte解质asuppressor极大抑制剂2v2-2极化电2v2-2极化电极（DME）：电位随外加电压的变化而变化，面积较去极化电极：电位稳定，不随外加电压而变化010.1Generalprincip

4、lesofvoltammetric1922J.HeyrovskyCzechoslovakian捷克1.10.1Generalprinciplesofvoltammetric1922J.HeyrovskyCzechoslovakian捷克1.Devicetoprovideapp Measurement deviceElectrolytecell电解池dpotential：B、R、Working electrode: Reference electrode：SCE; Electrolyte solutionMercury Electrode 电yte待测物质Supportingelectrolyt

5、e解质asuppressor极大抑制剂iRisEDME=ESCE EappiRisEDME=ESCE Eapp=iRisnotnegligible,=ESCE-A three-electrode cell is y to be in general voltammetry （三电极体系Workingelectrode工作microelectrode): placewhereoccurs(surfaceareafewmm2 tolimitcurrentCounterelectrode对电极playsnopartinredoxbutonlythecurrent（与工作电电池回路，反应的电流通过此回

6、路Reference electrode（参比电极）: only senses a potential doesnotdrawcurrent（与工作电电流通过电位监测回路，回路Why3potentialdropswhencurrentistakenfromelectrode(IRwithdrawn surface 消除IRWhy3potentialdropswhencurrentistakenfromelectrode(IRwithdrawn surface 消除IR(voltage source) drives nnworking and reference electrode 稳定工作电

7、Almostallcurrentcarriednworkingandcounter Voltagemeasurednworkingandreference2.GenerationofPolarographic(orPolarogram极谱波102.GenerationofPolarographic(orPolarogram极谱波10-3mol/LCdCl2+1mol/L2-edcba2.GenerationofPolarographicedcResidual current (bEDMEE析aE外分ir2.GenerationofPolarographicedcResidual current

8、 (bEDMEE析aE外分ir=Charging current（充电电流）+ faradaic redoxreactionsofimpuritiesinsolution(faradaicchargingofHgdrop(non-faradaicCdHg2e CddeLimitingcurrent极限电Arisesfromaherateatwhichthereactantcanbroughttothesurfaceoftheelectrodebymass-transportHalf-wavepotential半波电位) E1/2CiCix电极表面附近浓度的CS 0i(HgCiCix电极表面附近

9、浓度的CS 0i(Hgi K(co cs) Kc iiii2.GenerationofPolarographicedcResidual current (bEDMEE析aE外分ir=Charging current（充电电流）+ faradaic 2.GenerationofPolarographicedcResidual current (bEDMEE析aE外分ir=Charging current（充电电流）+ faradaic CdHg2e CddeLimitingcurrent极限Arisesfromaherateatwhichthereactantcanbroughttothesur

10、faceoftheelectrodebymass-transportHalf-wavepotential半波电位) E1/2CCCSi iiicomplete concentration polarization （完全浓差极化）of a working electrodepolarization浓差极化建立的条件complete concentration polarization （完全浓差极化）of a working electrodepolarization浓差极化建立的条件SurfaceareaofthepolarizationelectrodeisLowconcentration

11、ofUnstirred（不搅拌）favorablefortheformationofdiffu layer near electrode surfaceiErelationship foraComparisonofPolarographyandAComparisonofPolarographyandARef/AWork=ARef/AWork =transport pro(扩散migration (迁移)+ Current电流vs（电压电量(number of yteAminimalconsumptionof yte (很小，可忽略)All of theyte is converted to a

12、nother sGeneration of Polarographic it=708nDGeneration of Polarographic it=708nD1/2m2/3t1/6（C0-i 607nD1/2m2/31/6(CO -CSCEDME C(HgAdvantagesofnew surface is generated continuously 分析结果重现High overvoltage ted with the Advantagesofnew surface is generated continuously 分析结果重现High overvoltage ted with the

13、 reduction of H+, meansevenmetalswithhigh-veE0canbemeasuredH2formation (H2上析出的过电位高，减少H+析出的干扰achievementofconstantcurrentduringdropManymetalsercuryandformamalgam齐许多金属生齐，使其析出电位正移电极面积小，电解的物质少，溶液可多次重复分析Disadvantages of Hgeasilyoxidized,limiteduseasanode(E10-5 cumbersometouse(toxic3.(IlkovicEquation尤考维奇方

14、程式(Ilkovic 607nD1/2m2/33.(IlkovicEquation尤考维奇方程式(Ilkovic 607nD1/2m2/3idCurrentnnumberofcoefficientofytec-mflowrateofHgthroughthecapillarydroptimeofHgedyte concentration cba例：某M2+离子在滴 电极上还原为金属并形成逆极谱波。已知滴 流速为1.54mg/s，滴落时间为M例：某M2+离子在滴 电极上还原为金属并形成逆极谱波。已知滴 流速为1.54mg/s，滴落时间为M2+D810-6 cm2/s，其浓度为4.010-id607

15、2(8106)1/21.542/33.871/64.0 607nD1/2m2/3idFactorswhichinfluenceCapillary constant (毛细管特性常数 607nD1/2m2/3idFactorswhichinfluenceCapillary constant (毛细管特性常数 =0-PotentialofDisdependentonT:温度变化控制在范围内，温度引起的误差小于Theconstituentsofthe粘度0E-erferencingcurrentinResidualcurrent残余电流)当E外E分解时，redoxerferencingcurrent

16、inResidualcurrent残余电流)当E外E E 99%noxidationB. ive(noinformationonidentityC.Absolutemethod (nocalibration is(a)Conly. (b)AandC. (c) Band C. (d) Aonly. (e) A, B,and 3. Duringan anodicvoltammetryexperiment,thepotentialofworking electrode is held more ntheformalpotentialofhalf-hepreconcentrationstepandth

17、e directionduringthe(a)negative,(b)itive,4. Whyaremethodsmorenothervoltammetric5. Describe 4. Whyaremethodsmorenothervoltammetric5. Describe the relative magnitudes of the current in potentiometry, and coulometric titrations? What determines the current in each of methods, and in which of these meth

18、ods is the Explainyourle solution 6. A 1.000 g le of zinc (Zn) metal is dissolved in 50 ml of HCl and diluted 250 ml. A 25.00-ml aliquot is transferred to a polarographic cell, a few drops of um suppressor added, and O2 is flushed out. A polarogram is he range of 0 to 1 V against a mercury pool electrode. A wave with E1/2= -0.65 V, with id = 7.6 cm. A 5.00 ml portion of 510-4 M CdCl2 added directly to the polar