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1、253J.Ekctroanal.Chem.,345(1993)253-271ElsevierSequoiaS.A.,LausanneJEC02384ElectrochemicaloxidationofH,O,onPtandPt+IrelectrodesinphysiologicalbufferanditsapplicabilitytoH,O,-basedbiosensorsYananZhangandGeorgeS.WilsonDepartmentofChemistry,UniversityofKansas,Lawrenc
2、e,KS66045(USA)(Received14March1991;inrevisedform10July1992)AbstractTheelectrochemicaloxidationofhydrogenperoxideonPtdiskandPt+IrwireelectrodeswasstudiedinphysiologicalbufferatpH7.40inordertoestablishapracticalprotocolforH,O,-basedbiosensors.Theelectrodereactionis
3、atwo-electronirreversibleprocess.TheoxidationofHzO,onPtandPt+IrelectrodesurfacesisacatalyticreactionwhichisH,OzconcentrationdependentbutOzpressureindependentatlowHzO,concentration.AmperometricdetectionofHzO,isstronglyaffectedbypH,temperatureandelectrodesurfacecon
4、ditioning.AnoxidizedsurfaceisrequiredtoobtainastableH,O,response,andreductivepretreatmentoftheelectrodealwaysyieldsprolongedstabilizationtimes.Theapplicationofacelluloseacetatemembranetothesurfacecanprotecttheoxidizedsurfaceandthereforesubstantiallyreducethestabi
5、lizationtimeforH,Ozmeasurements.INTRODUCTIONThecouplingofH,O,electrochemicaloxidationtoamperometricbiosensorsasthesignaltransducingdevicehasbeenoneofthemajorsuccessesinthecourseofsensordevelopment.Forexample,themostfrequentlyusedenzymesensortodatehasbeentheglucos
6、esensorwithglucoseoxidaseasthebiospecificreagent.Thereactionsinvolvedintheprocessareglucose+0,%gluconicacid+H,O,(1)H,O,electrode0,+2H++2e-(2)Asuccessfulglucosesensorisexpectedtogiveasignallinearlyproportionaltotheenvironmentalglucoseconcentration.Thereforetheover
7、allprocesshastobeglucosediffusioncontrolled,whichrequiresthattherateofreaction(1)shouldnot0022-0728/93/$06.0001993-ElsevierSequoiaS.A.Allrightsreserved254dependonoxygen.Reaction(2)shouldberelativelyfastsuchthattherate-de-terminingstepisreaction(1)toensurethatthes
8、ensoroutputisglucosedepen-dent.Theenzymaticreaction(1)isgovernedbytheenzymeturnovernumberanditsintrinsicrateisnotmanipulable.Thetotalenzymeloadingcanbeincrease
