Dispersion of multi-wall carbon nanotubes in polyethylenimine_A new alternative for preparing electrochemical sensors

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1、ARTICLEINPRESSElectrochemistryCommunications9(2007)480–484www.elsevier.com/locate/elecomDispersionofmulti-wallcarbonnanotubesinpolyethylenimine:AnewalternativeforpreparingelectrochemicalsensorsMarı´aD.Rubianes,GustavoA.Rivas*INFIQC,DepartamentodeFı´sicoQuı´mica,FacultaddeCienciasQu

2、ı´micas,UniversidadNacionaldeCo´rdoba,CiudadUniversitaria,5000Co´rdoba,ArgentinaReceived2August2006;receivedinrevisedform25August2006;accepted30August2006AbstractInthisworkwereportontheanalyticalperformanceofglassycarbonelectrodesmodifiedwithadispersionofmulti-wallcarbonnanotubesinp

3、olyethylenimine(GCE/(PEI/CNT)).Theresultingelectrodesshowanexcellentelectrocatalyticactivitytowarddifferentbioanalyteslikeascorbicacid,dopamine,3,4-dihydroxyphenylaceticacid(dopac)andhydrogenperoxide.Animportantdecreaseintheovervoltagesfortheoxidationofascorbicacid(505mV)andhydrogen

4、peroxide(350mV)andforthereductionofhydrogenper-oxide(450mV),aswellasadramaticimprovementinthereversibilityoftheelectrochemicalbehaviorofdopamineanddopacisobtained.ThecurrentsarehigherthanthoseobtainedwithotherdispersantagentslikeNafion,concentratedacidsorchitosan,evidenc-ingthehighe

5、fficiencyofthedispersioninPEI.TheGCE/(PEI/CNT)demonstratedtobehighlyreproducible,with3.0%RSDforthesensitivityofhydrogenperoxidefor10electrodespreparedwithfivedifferentdispersions.Differencesinsensitivityof10.0%wereobtainedforhydrogenperoxidewithelectrodespreparedusingthesamedispersionev

6、enafter14dayspreparation.TheCNT/PEIlayerimmobilizedonglassycarbonelectrodeshasbeenalsousedasaplatformforbuildingsupramoleculararchitecturesbasedontheself-assemblingofpolyelectrolyteswithoutanypretreatmentoftheelectrodesurface,oxidationorderivatizationofthecarbonnanotubes,justtaking

7、advantagesofthepolycationicnatureofthepolymerusedfordispersingthenanotubes.Theself-assemblingofglucoseoxi-dasehasallowedustoobtainasupramolecularmultistructureforglucosebiosensing,withdetectionlimitsof11lM(0.02g/L).SuchanexcellentperformanceofGCE/(PEI/CNT)towardhydrogenperoxideandt

8、heeffectivenessoftheuseofCN