(Polarography)

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?13? ??????? (Polarography) 13.1 ????????
???????????????? 13.2 ????????
??????????????????????? 13.3 ???????????
???????????????????? 13.4 ?????????
??????????????????? 13.5 ?????????
??????????????????????????
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?? ???????????,??????????
1922????????Jaroslav Heyrovsky ??????????????????,
???? Nobel ????,????????????,?????????????????????
???????????????????????,??????????????????????
50????60???,????????,??????????????
60????,???????????,???????????,??????????????,????
??????????????????????? HPLC ??????????
??,??????????????????????
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• ?????????
• 1)????????????????????????
• ??????
• 2)?????????????????
• ???????
• l ??????????????--??????????????
• ????????????
• ????????????--???????????(?SCE,?
• ?????-1.2V)?
• l ??????,??????,????????0.4V??????
• ?????????
• l ????,???,???????

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13.2 ???????? ?????? ?????
,??????????????????? ??Fick??????????????
??(?A) ????????????????,???????????????
????????????? ?????????(Ilkovic)??? ??
????????(?A)z?????
D????(cm2/s)m????(g/s)t???,??????(s)
c?????(mmol/L)?
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???????????? ?Ilkovic??,???????t1/6??,???????
???????????????????????????????,????,?????????,???
????????????????????,????????
0.5MCd2, 1MHCl
1MHCl
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??????????? ? Ilkovic ???,??????????? a) 
 ??????? ????,??????,??????D????????????????
???????? b) ???????? ???? m????? t
???????,???????????????m2/3t1/6????????????????h,?
mkh,tk/h, ????????m2/3t1/6kh1/2,?
?h1/2???? ??,????????????????????????????? c
) ???? ?z?,??????????,???????D????,?????1oC,??
?????1.3,????????0.5oC? ?????????????,?????????
????????
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?????????? ???????????,??????????????????
??????????????,?????! 1. ????(Residual
current) ????????,?????????????????????,??????(i
r)???????????????????????????????(?????)??????????
???????? ?????????????????????????????????
?????? ??????????,????????????????????????
??????????-?????-????--??????????10-7A, ???10-5
mol/mL???????????????????? ??ir
????????????????????
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2. ????(Migration current) ??????????????????????
??????,???? ?????????,????????????????
????? ??,???????????,??????? ????????
????(???????)??????? 3. ????(Maximum current)
?????????????????,???????????????
????????????,??????????????????
??,???????????????????????????
????????????????????????????
??????????????? ???????????????????,??????????
??? ??PVA?Triton X-100??
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4. ??(Oxygen waves) ????????
O22H2eH2O2 -0.2V (????)
(O2 H2O 2e
H2O2 2OH-) H2O22H2e2H2O -0.8V
(????) (H2O2
2e 2OH-) ??????????????????????(0-1.2V)
,??????????????????,??????? ??a) ???????H2?N2?CO2
(CO2???????) b) ???????????Na2SO3,??
O2 c) ?????????Na2CO3,???????????O2?
?? ??????,???????H2,???O2
d) ????????????????? e)
??????N2??(???????N2)?
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?????????
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13.3 ??????????? ????????????????????????
??,?????-???????????????????? if(?) ????
????????????????????????????????????????????,?????
?????? ??????? ???????????????????????
?????????????? ??????????????????????
? ???????? ??????????????????
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?????? 1. ????(???) 2. ????? ????? ir
?????????,?????????????????????????????????
?????HCl, H2SO4, NaAc-HAc, NH3-NH4Cl,
NaOH, KCl ????????,PVC, Triton X-100
??????????Na2SO3, ?????????? pH
????????? ??????????????????,??????
????????????????? ?????????????
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3. ??????????? 4. ???? a) ???? ??????????(14
hrs),?????????????,?????
??? ??????(?????????????)?80cm ? ?40cm?????(?
??? U ???,?????5HNO3?5Hg(NO3)2)????
?? ????23?? ???????,????????????
?,??????? ?????????? b) ?????
???????????????(???????????????,?????????????????
??????????)?
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???????? 1922???,?????????????????????????
????,????????????????????????? 1)???????????????
???????,???????????,?200mV/min??????????,?????????
??,?????????????????,???????????? 2)????????????
??,?????????200mV?????,???????????,?????? 3)????
???????????????10-5M???(??????)?????????,?????????
??????,???????????????? 4)iR????????,???????,???
iR????,???????????????? ??,???????,????????
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??????,??????????,????????,???????????,?????
??,??????????,??????? ??????,???????
??????,??????? ????? v ?????,tp
?????????,A???????? ???????????,????? v
??,?????,?????10-7M????????,???????,???????,??????
???????????????,??????????
????p???????????1/2?????? ?????????????,????????
?
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???????(Cyclic Voltammetry)
???????????????????????????????????????????,? Pt
????????????????? ?????,?????????????,????
??????,????????? ?????O 2e R ?????R O
2e
????(V)
??/s
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????????????????????????????????,??????????
? ??????????????? ipc ???? ?pc?????? ipa
?????pa???????,???????,????????????????????
??????????????????????
????,???????????????(?pa?pc)/2?
?????????????????
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2. ???????? ?????????????????,?????????,??????
?? Us?????C??????? ??,???????,?????????
???????,??,??????,?????????,???????? 3. ?? a)
???????????????(??????????) b) ?????(????,???????,
????????????????,??????????????,???????)??????????
?????
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???????????????????????
????????????if????????iN?????ic??????t-1/2?
t-n?e-t/RC??,??????????????????????
???????????????40-80ms,???????ms?????????????,????
??????iN?????ic??????0,??????????,??????????????