Transition metal ion-substituted polyoxometalates entrapped in polypyrrole as an electrochemical sensor for hydrogen peroxide (original) (raw)
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Sensors, 2008
A modified electrode for hydrogen peroxide (H 2 O 2) sensing was prepared via thiophene (Th) with epoxy group. Thiophene (EpoxyTh) with epoxy group was synthesized by reaction of 3-bromothiophene and glycidyl methacrylate (GMA) in acetonitrile according to Heck Reaction. The electrocopolymerization of Th and EpoxyTh was performed on the surface of indium tin oxide (ITO) electrode by cycling the potential between-1.0 and +2.5 V in mixture of thiophene (Th) and EpoxyTh. Poly(Th-co-EpoxyTh) grown onto the ITO electrode was successfully confirmed by SEM, AFM, and water contact angle analysis, respectively. Finally, the HRP was immobilized on the surface of poly(Th-co-EpoxyTh) electrode by covalent binding. The amperometric response of the HRP-immobilized poly(Th-co-EpoxyTh) electrode for H 2 O 2 was examined by cyclic voltammetry (CV). The HRP-immobilized poly(Th-co-EpoxyTh) electrode showed linearity from 0.1 to 30 mM H 2 O 2 , good reproducibility, and long life time.
SENSORS AND ACTUATORS B-CHEMICAL, 2001
An amperometric hydrogen peroxide biosensor was designed based on horseradish and tobacco peroxidase entrapped into a conducting redox-polymer immobilised on either glassy-carbon or platinum electrodes. A versatile one-step immobilisation method was carried out based on the electrochemical polymerisation of a pyrrole monomer functionalised with an Os-complex. Cyclic voltammetry and constant potential amperometry performed with the different peroxidases in solution or entrapped within the conducting redox-polymer ®lm suggests that the redox centre within the active site of horseradish peroxidase exhibits a better accessibility for the either free-diffusing or polymerbound Os-complexes than that of tobacco peroxidase. Therefore, the obtained sensitivities for the reduction of H 2 O 2 are signi®cantly higher for the HRP-based sensors as compared with the tobacco peroxidase-based ones. The direct reduction of H 2 O 2 on the polymer backbone was identi®ed as a side reaction even though the bioelectroreduction through horseradish peroxidase is a much more ef®cient reaction pathway. #
Materials Chemistry and Physics, 2013
This study focuses on the synthesis and application of polypyrrole coated manganese nanowires (Mn/PPy NWs) as an enzyme-less sensor for the detection of hydrogen peroxide (H 2 O 2 ). The X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) results confirm a coreeshell structure with the Mn nanowires encapsulated by the PPy. An electrochemical sensor based on the Mn/PPy NWs for amperometric determination of H 2 O 2 is prepared. The electrochemical behaviour of H 2 O 2 is investigated by cyclic voltammetry with the use of modified glassy carbon electrode (GCE) with Mn/PPy NWs film. The modified glassy carbon electrode (GCE) with Mn/PPy NWs shows enhanced amperometric response for the detection of H 2 O 2 . This is due to the high available surface area of Mn/PPy NWs which can provide a suitable area for the reaction of H 2 O 2 . The detection limit and limit of quantification (S/N ¼ 3) for two linear segments (low and high concentration of H 2 O 2 ) are estimated to be 2.12 mmol L À1 , 7.07 mmol L À1 and 22.3 mmol L À1 , 74.5 mmol L À1 , respectively. In addition, the sensitivity for these two linear segments is 0.4762 mA mM À1 and 0.0452 mA mM À1 respectively.
Electrochimica Acta, 2010
A robust and stable film comprising n-octylpyridinum hexafluorophosphate ([C 8 Py][PF 6 ]) and 1:12 phosphomolybdic acid (PMo 12) was prepared on glassy carbon electrodes modified with multiwall carbon nanotubes (GCE/MWCNTs) by dip-coating. The cyclic voltammograms of the GCE/MWCNTs/[C 8 Py][PF 6 ]-PMo 12 showed three well-defined pairs of redox peaks due to the PMo 12 system. The surface coverage for the immobilized PMo 12 and the average values of the electron transfer rate constant for three pairs of redox peaks were evaluated. The GCE/MWCNTs/[C 8 Py][PF 6 ]-PMo 12 showed great electrocatalytic activity towards the reduction of H 2 O 2 and iodate. The kinetic parameters of the catalytic reduction of hydrogen peroxide and iodate at the electrode surface and analytical features of the sensor for amperometric determination of hydrogen peroxide and iodate were evaluated.
Enzymeless Hydrogen Peroxide Sensor Based on Mn-containing Conducting Metallopolymer
Procedia Engineering, 2012
The [Mn 4 IV O 5 (terpy) 4 (H 2 O) 2 ] 6+ complex, show great potential for electrode modification by electropolymerization using cyclic voltammetry. The voltammetric behavior both in and after electropolymerization process were also discussed, where the best condition of electropolymerization was observed for low scan rate and 50 potential cycles. A study in glass electrode for better characterization of polymer was also performed. Electrocatalytic process by metal centers of the conducting polymer in H 2 O 2 presence with an increase of anodic current at 0.85 V vs. SCE can be observed. The sensor showed great response from 9.9 x 10 -5 to 6.4 x 10 -4 mol L -1 concentration range with a detection limit of 8.8 x 10 -5 mol L -1 , where the electrocatalytic mechanism was based on oxidation of H 2 O 2 to H 2 O with consequently reduction of Mn IV to Mn III . After, the Mn III ions are oxidized electrochemically to Mn IV ions.
Biomaterials, 2011
Polyamic acids (PAAs) containing benzothiazole (BT) and benzoxazole (BO) pendent groups (PAA-BT and PAA-BO, respectively) which possessed electroactivity were synthesized successfully. The addition of H 2 O 2 chemically oxidized the intrinsic carboxylic acid groups of PAA to form peroxy acid groups, and the peroxy acid further oxidized the electroactive sites of BT and BO to form N-oxides. The N-oxides could be reverted to their original form by electrochemical reduction, thus increasing the electrochemical reductive current. Based on this mechanism, enzyme-free hydrogen peroxide (H 2 O 2 ) biosensors were prepared by modifying gold electrodes with the PAA derivatives (PAA-BT/Au and PAA-BO/Au, respectively). These biosensors had rapid response times (3.9e5.2 s) and high selectivity and sensitivity (280.6 e311.2 mA/mM-cm 2 ). A comparison of the PAA-BT/Au and PAA-BO/Au electrodes with electrodes prepared using polyamide-BT or polyamide-BO (i.e., lacking the carboxylic acid groups) confirmed the mechanism by which PAA derivatives detect H 2 O 2 . Modifying the surface morphology of the electrode from a planar to a three-dimensional (3D) configuration enhanced the performance of the PAA-BO/Au electrode. The sensitivity of the 3D-PAA-BO/Au electrode was 1394.9 mA/mM-cm 2 , w4.5 times higher than that of the planar electrode. The detection limit was also enhanced from 5.0 to 1.43 mM. The biosensor was used analytically to detect and measure H 2 O 2 in urine samples collected from healthy individuals and patients suffering from noninvasive bladder cancer. The results were promising and comparable to that measured by a classical HPLC method, which verified the developed biosensor had a potential to provide a usefully analytical approach for bladder cancer.
A poly(o-aminophenol) modified electrode as an amperometric hydrogen peroxide biosensor
Electrochimica Acta, 1998
AbstractÐAn enzymatic biosensor for hydrogen peroxide based on a horseradish peroxidase (HRP)-ferrocene carbon paste modi®ed electrode and coated with a layer of electrochemically generated poly(o-aminophenol) is reported. A linear calibration curve is obtained over the range 1 Â 10 À8 M to 1 Â 10 À5 M. The biosensor responds to hydrogen peroxide in a few seconds and has a detection limit of 8.5 Â 10 À9 M. The response of the biosensor is diusion controlled at low substrate concentrations. Flow injection assays of hydrogen peroxide at a sampling rate of 150 injections per hour with a relative standard deviation of 0.8% (50 samples) are possible. Applicability of the sensor for measurement of hydrogen peroxide in real samples (milk) was demonstrated. #