Electrocatalytic oxidation of ascorbic acid by [Fe(CN)6] redox couple electrostatically trapped in cationic N,N-dimethylaniline polymer film electropolymerized on diamond electrode

Multinegatively charged metal complex, hexacyanoferrate ([Fe(CN)₆]⁴⁻), was electrostatically trapped in the cationic polymer film of N,N-dimethylaniline (PDMA) which was electrochemically deposited on the boron-doped diamond (BDD) electrode by controlled-potential electro-oxidation of the monomer. This ferrocyanide-trapped PDMA film was used to catalyze the oxidation of ascorbic acid (AA). Increase in the oxidation current response with a negative shift of the anodic peak potential was observed at the cationic PDMA film-coated BDD (PDMA|BDD) electrode, compared with that at the bare BDD electrode. A more drastic enhancement in the oxidation peak current as well as more negative shift of oxidation potential was found at the ferrocyanide-trapped PDMA film-coated BDD ([Fe(CN)₆]^3−/4−|PDMA|BDD) electrode. This [Fe(CN)₆]^3−/4−|PDMA|BDD electrode can be used as an amperometric sensor of AA. Ferrocyanide, electrostatically trapped in the polymer film shows more electrocatalytic activity than that coordinatively attached to the polymer film or dissolved in the solution phase. The electrocatalytic current depends on the surface coverage of ferricyanide, Γ_Fe, within the polymer film. Diffusion coefficient (D) of AA in the solution was estimated by rotating disk electrode voltammetry: D = (5.8 ± 0.3) × 10⁻⁶ cm² s⁻¹. The second-order rate constant for the catalytic oxidation of AA by ferricyanide was also estimated to be 9.0 × 10⁴ M⁻¹ s⁻¹. In the hydrodynamic amperometry using the [Fe(CN)₆]^3−/4−|PDMA|BDD electrode, a successive addition of 1 μM AA caused the successive increase in current response with equal amplitude and the sensitivity was calculated as 0.233 μA cm⁻² μM⁻¹.     

Reduction process of uranium(IV) and uranium(III) in molten fluorides

This study focused on the electroreduction process of uranium cations in molten fluorides. It involved cyclic voltammetry, chronopotentiometry with and without current reversal, and square wave voltammetry.The results indicate a two-step reduction process for uranium(IV). The first step U(IV)/U(III) exchanging one electron corresponds to a soluble/soluble system and is limited by U(IV) diffusion with D_U(IV) = 1.25 ± 0.35 × 10⁻⁵ cm² s⁻¹ in LiF-NaF at 720 °C.In order to perform a thorough study of the second step U(III)/U(0) in the reduction process, the melt was chemically reduced in U(III) with U metal as reducing agent. Alternatively to the use of LiF-NaF where U metal is unstable at 720 °C, the chemical reduction of U(IV) in U(III) was performed in a LiF-CaF₂-UF₄ solution containing U metal at 810 °C. It has been confirmed that the reduction of U(III) proceeds in one step exchanging three electrons and by a diffusion controlled process with D_U(III) = 2.2 ± 0.7 × 10⁻⁵ cm² s⁻¹ in LiF-CaF₂ at 810 °C.     

Electrochemistry of TiCl4 in 1-butyl-2,3-dimethyl imidazolium azide

Electrochemical behaviour of titanium tetrachloride solutions in 1-butyl-2,3-dimethyl imidazolium azide (BMMImN₃) at 65 °C has been examined. Ti(IV) reduction was studied with chronopotentiometry and cyclic voltammetry methods in melts with different concentrations of TiCl₄. According to IR spectra, Ti(IV) exists in form of a hexaazidotitanate complex. The electrochemical reduction of this complex was found to proceed irreversibly to Ti(III) species only. Diffusion coefficients of Ti(IV) in this ionic liquid at temperature 65 °C were calculated based on the chronopotentiometry measurements at different TiCl₄ concentrations (D_Ti(IV) = 1.3 ± 0.6 × 10⁻⁶ cm² s⁻¹).     

Electrochemical study on the selective formation of [Pb(cyclodextrin)]surface inclusion complexes at the carbon paste electrode/ClO4 1 M interphase

The formation constants of surface inclusion complexes were determined using a carbon paste electrode, CPE, and cyclic voltammetry for aqueous-based media containing Pb(II) and α, β and γ cyclodextrins. In order to promote the occupation of the molecular cavities in the cyclodextrins, the medium with the support electrolyte contained ClO₄⁻ ions, which have the capacity to modify the hydrophobic properties of such cavities. The results obtained were: Pb(II)-α_CDK = 883.7 ± 13.6 M⁻¹, Pb(II)-β_CDK = 727.5 ± 20.2 M⁻¹, Pb(II)-γ_CDK = 782 ± 10.7 M⁻¹.     

Termination rate coefficients for acrylamide in the aqueous phase at low conversion

The kinetics of acrylamide (AAm) free radical polymerization at low conversion of monomer to polymer in the aqueous phase was investigated at 50 °C using γ-radiolysis relaxation, which is sensitive to radical-loss processes. The values of the termination rate coefficients for AAm ranged from 8×10⁶ to 3×10⁷ M⁻¹ s⁻¹ as the weight fraction of polymer ranged from 0.002 to 0.0035, which is significantly lower than the low-conversion values for monomers such as styrene (2×10⁸ M⁻¹ s⁻¹) and methyl methacrylate (4×10⁷ M⁻¹ s⁻¹) in organic media. These can be quantitatively explained by applying a chain-length-dependent model of free-radical polymerization kinetics [Russell GT, Gilbert RG, Napper DH. Macromolecules 1992;25:2459. [19]] in which termination kinetics are expressed in terms of a diffusion-controlled encounter of radicals which ultimately yields an expression for the chain-length-averaged termination rate coefficient, 〈k_t〉. The lower 〈k_t〉 for AAm arises due to a combination of the high k_p value, promoting rapid formation of slower terminating long chains, and the slow diffusion of short propagating chains, relative to other common monomers. The chain transfer to monomer constant for AAm in water at 50 °C, C_M, was estimated using the chain-length-distribution method with correction for band-broadening [Castro JV, van Berkel KY, Russell GT, Gilbert RG. Aust J Chem 2005;58:178. [21]] and found to be 1.2×10⁻⁴ (±10%). The diffusion characteristics for AAm were adapted from those obtained for a similar aqueous system (hydroxyethyl methacrylate) together with a 0.5 exponent for the power law dependence on penetrant degree of polymerization at zero weight fraction polymer. This provides an adequate fit to the 〈k_t〉 data. This is the first application of the chain-length-dependent model to describe experimental termination rate coefficients for an aqueous system at low conversion to polymer. The result that the experimental termination rate coefficients can be reproduced with an a priori model with physically reasonable parameters supports the physical assumptions underlying that model.     

Subaquatic oxidation of coal by water-dissolved oxygen

Subaquatic oxidation of two bituminous coals by water-dissolved oxygen was investigated using batch reactor equipped with membrane oxygen sensor. Effects of time, temperature and coal grain size were studied as basic parameters influencing the oxidation process. Obtained results showed the subaquatic coal oxidation can be considered as interaction of the first reaction order with respect to oxygen. From temperature dependence of oxidation rate, activation energies E = 72 ± 4 kJ mol⁻¹ and/or 50 ± 4 kJ mol⁻¹ were calculated. For the samples, oxygen consumption R_O2 was found to be in the range of 2 × 10⁻⁷ mol O₂ kg⁻¹ s⁻¹ to 6 × 10⁻⁷ mol O₂ kg⁻¹ s⁻¹, such values being quite comparable with R_O2 for aerial oxidation of bituminous coals.     

Electrochemical study of the interaction between Eu and ciliate Euplotes octocarinatus centrin

A new species was formed when protein P₂₃ (one segment of ciliate Euplotes octocarinatus centrin) was added to a solution of Eu³⁺. The interaction between P₂₃ and Eu³⁺ was investigated by cyclic voltammetry, pulse voltammetry and electrochemical impedance spectroscopy in 10 mM N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid (HEPES) buffer (pH 7.4) using a pyrolytic graphite electrode. The formal potential (E^o′) of Eu³⁺ shifted from −0.61 to −0.84 V (versus saturated calomel electrode) after P₂₃ was added to the Eu³⁺ solution. The diffusion coefficient (D), the charge-transfer coefficient (α) and the electron transfer standard rate constant (k_s) were obtained in the absence and the presence of P₂₃. The affinity constant of Eu³⁺ and P₂₃ was determined to be (1.89 ± 0.51) × 10⁴ M⁻¹. The electrochemical investigation of europium bound to the protein provided useful data for the studies of calcium-binding proteins.     

Free-radical propagation and termination kinetics of the butyl acrylate dimer studied by pulsed laser polymerization techniques

The propagation and termination rate coefficients for bulk polymerization of the butyl acrylate dimer (BA dimer) are determined by pulsed laser techniques. The rate coefficient for propagation, k_p, is deduced for temperatures from 20 to 90 °C via the pulsed laser polymerization-size exclusion chromatography (PLP-SEC) method at pulse repetition rates between 1 and 10 Hz. The Arrhenius parameters were found to be: E_A(k_p) = (34.2 ± 1.0) kJ mol⁻¹ and A(k_p)/L mol⁻¹ s⁻¹ = (1.08 ± 0.49) × 10⁷ L mol⁻¹ s⁻¹. The termination rate coefficient, k_t, has been measured via SP-PLP-ESR, single pulse-pulsed laser polymerization in conjunction with time-resolved electron spin resonance detection of radical concentration. The resulting Arrhenius parameters as deduced from the temperature range −15 to +30 °C are: E_A(〈k_t〉) = (22.8 ± 3.7) kJ mol⁻¹ and log(A/L mol⁻¹ s⁻¹) = 10.6 ± 1. The chain-length dependence of k_t was studied at 30 °C. For short chains a significant dependence was found which may be represented by an exponent α = 0.79 in the power-law expression k_t(i) = k_t⁰i^−α.     

2,2,6,6-Tetramethyl piperidine-1-oxyl (TEMPO)-mediated catalytic oxidation of benzyl alcohol in acetonitrile and ionic liquid 1-butyl-3-methyl-imidazolium hexafluorophosphate [BMIm][PF6]: Kinetic analysis

TEMPO (2,2,6,6-tetramethyl piperidine-1-oxyl) is electrochemically oxidized to a stable form of the cation (TEMPO⁺) in acetonitrile (CH₃CN) or 1-butyl-3-methyl-imidazolium hexafluorophosphate ([BMIm][PF₆]) media. Cyclic voltammograms were characterized by a well-defined one-electron reversible redox couple in both media at low scan rates. The reduced form of TEMPO⁺ is catalytically regenerated in a follow-up chemical reaction with benzyl alcohol (BA) in the presence of 2,6-lutidine. It was observed that in [BMIm][PF₆], the redox currents are largely suppressed compared to that in CH₃CN. The apparent heterogeneous electron-transfer rate constant () of the quasi-reversible redox reaction of TEMPO was determined at a Pt electrode and found to be 1.9 × 10⁻³ cm s⁻¹ and 4.5 × 10⁻² cm s⁻¹ in [BMIm][PF₆] and CH₃CN, respectively. With the aid of chronoamperometry (CA), the homogeneous rate constant for the catalytic oxidation of benzyl alcohol by TEMPO, in the presence of 2,6-lutidine in CH₃CN was estimated to be 5.53 × 10¹ M⁻¹ s⁻¹ which is approximately double, relative to the value of 2.91 × 10¹ M⁻¹ s⁻¹ determined in [BMIm][PF₆].     

Studies on the electrochemical behavior of 3-nitrobenzaldehyde thiosemicarbazone at glass carbon electrode modified with nano-γ-Al2O3

Nano-γ-Al₂O₃ is dispersed onto the glass carbon electrode (GCE) by polishing. This nanostructured modified GCE exhibits a great enhancement to the redox responses of 3-nitrobenzaldehyde thiosemicarbazone (3-NBT). In comparison with bare GCE, 3-NBT gives a more sensitive voltammetric response because of the nanoparticle’s unique properties. The lowest detectable concentration (3σ) of 3-NBT is estimated to be 1.18 × 10⁻⁶ M (accumulation for 4 min). The linear relationship between peak current and concentration of 3-NBT holds in the range 1.0 × 10⁻⁵ M to 1.0 × 10⁻⁴ M (r = 0.9981). The electrochemical properties of 3-NBT on this modified electrode have been investigated with various electrochemical methods. The results indicate that the transference of one electron and one proton involves electrode radical reaction processes I and II, respectively. The coverage value (Γ) of 1.62 × 10⁻⁹ mol cm⁻² was calculated and the electrochemical parameters, diffusion coefficient D (2.54 × 10⁻³ cm² s⁻¹, 2.03 × 10⁻³ cm² s⁻¹) and reaction rate constant k_s (5.9573 s⁻¹, 7.15 × 10⁻² cm s⁻¹) were obtained for quasi-reversible system I and irreversible system II, respectively.     

A new fast methodology to measure total diene content in gasoline

The rate constants for the quenching of biacetyl phosphorescence by a series of conjugated dienes were measured. 1,3-cyclohexadiene (k_qP = 2.94 × 10⁹ s⁻¹ mol⁻¹ L), 2,5-dimethyl-2,4-hexadiene (k_qP = 1.91 × 10⁹ s⁻¹ mol⁻¹ L), 2,4-dimethyl-1,3-pentadiene (k_qP = 1.78 × 10⁸ s⁻¹ mol⁻¹ L), 3-methyl-1,3-pentadiene (k_qP = 1.22 × 10⁸ s⁻¹ mol⁻¹ L), 2,4-hexadiene (k_qP = 1.35 × 10⁸ s⁻¹ mol⁻¹ L) and trans-2-methyl-1,3-pentadiene (k_qP = 3.84 × 10⁸ s⁻¹ mol⁻¹ L). Cyclooctene also quenched biacetyl phosphorescence but with a lower rate (k_qP = 1.97 × 10⁷ s⁻¹ mol⁻¹ L). Quenching was not observed with 1-methylnaphthalene. Since conjugated dienes quench biacetyl phosphorescence preferentially, this method was studied using gasoline samples with known diene composition. A good correlation was found between the rate of quenching of biacetyl by the gasoline samples and the quantity of conjugated dienes present.     

Sticking probability of CN radicals

The sticking probability, s, of CN(X²Σ⁺) radicals which were the precursor of the formation of amorphous carbon nitride films with high [N]/([N]+[C]) ratios (≤ 0.5) was re-evaluated. CN(X²Σ⁺) radicals were generated from the decomposition of BrCN with the microwave discharge flow of Ar of the pressure of 0.2-0.4 Torr. The number density of CN(X²Σ⁺), n_CN(X), was evaluated from the intensity of the CN(A²Π_i-X²Σ⁺) laser-induced fluorescence spectrum calibrated against Rayleigh scattering intensity of Ar. The weight of the C and N components of films, w, was evaluated from the compositional analysis for the deposited films using Rutherford back scattering and elastic recoil detection analysis. The [N]/([N]+[C]) ratios of films were 0.4-0.5. Based on n_CN(X), w, and the flow speed measured by a time-resolved emission, s was evaluated both under the desiccated and H₂O-added conditions as (8.5 ± 2.1) × 10^− 2 − (6.1 ± 1.2) × 10^− 2 and (11.4 ± 1.3) × 10^− 2 − (7.4 ± 1.8) × 10^− 2, respectively. The variation of s under various experimental conditions was discussed based on the electron densities in the reaction region.     

Probing the electrochemical behaviour of SWCNT-cobalt nanoparticles and their electrocatalytic activities towards the detection of nitrite at acidic and physiological pH conditions

The electrochemical decoration of edge plane pyrolytic graphite electrode (EPPGE) with cobalt and cobalt oxide nanoparticles integrated with and without single-walled carbon nanotubes (SWCNTs) is described. Successful modification of the electrodes was confirmed by field emission scanning electron microscopy (FESEM), AFM and EDX techniques. The electron transfer behaviour of the modified electrodes was investigated in [Fe(CN)6]^3−/4− redox probe using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) and discussed. The study showed that cobalt nanoparticles modified electrodes exhibit faster electron transfer behaviour than their oxides. The catalytic rate constant (K) obtained at the EPPGE-SWCNT-Co for nitrite at pH 7.4 and 3.0 are approximately the same (∼3 × 10⁴ cm³ mol⁻¹ s⁻¹) while the limits of detection (LoD = 3.3δ/m) are in the μM order. From the adsorption stripping voltammetry, the electrochemical adsorption equilibrium constant β was estimated as (13.0 ± 0.1) × 10³ M⁻¹ at pH 7.4 and (56.7 ± 0.1) × 10³ M⁻¹ at pH 3.0 while the free energy change (ΔG°) due to the adsorption was estimated as −6.36 and −10.00 kJ mol⁻¹ for nitrite at pH 7.4 and 3.0, respectively.     

Diffusional mass transfer model for the adsorption of food dyes on chitosan films

The adsorption kinetics of erythrosine B and indigo carmine on chitosan films was studied by a diffusional mass transfer model. The experimental curves were obtained in batch system under different conditions of stirring rate (80–200 rpm) and initial dye concentration (20–100 mg L⁻¹). For the model development, external mass transfer and intraparticle diffusion steps were considered and the specific simplifications were based on the system characteristics. The proposed diffusional mass transfer model agreed very well with the experimental curves, indicating that the surface diffusion was the rate limiting step. The external mass transfer coefficient (k_f) was dependent of the operating conditions and ranged from 1.32 × 10⁻⁴ to 2.17 × 10⁻⁴ m s⁻¹. The values of surface diffusion coefficient (D_s) increased with the initial dye concentration and were in the range from 0.41 × 10⁻¹⁴ to 22.90 × 10⁻¹⁴ m² s⁻¹. The Biot number ranged from 17.0 to 478.5, confirming that the intraparticle diffusion due to surface diffusion was the rate limiting step in the adsorption of erythrosine B and indigo carmine on chitosan films.     

Cyclic voltammetry and scanning electrochemical microscopy studies of methylene blue immobilized on the self-assembled monolayer of n-dodecanethiol

Electron transfer (ET) kinetics through n-dodecanethiol (C₁₂SH) self-assembled monolayer on gold electrode was studied using cyclic voltammetry (CV), scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS). An SECM model for compensating pinhole contribution, was used to measure the ET kinetics of solution-phase probes of ferrocyanide/ferricyanide (Fe(CN)₆^4−/3−) and ferrocenemethanol/ferrociniummethanol (FMC^0/+) through the C₁₂SH monolayer yielding standard tunneling rate constant () of (4 ± 1) × 10⁻¹¹ and (3 ± 1) × 10⁻¹⁰ cm s⁻¹ for Fe(CN)₆^4−/3− and FMC^0/+ respectively. Decay tunneling constants (β) of 0.97 and 0.96 Å⁻¹ for saturated alkane thiol chains were obtained using Fe(CN)₆⁴⁻ and FMC respectively. Also, it was found that methylene blue (MB) molecules are effectively immobilized on the C₁₂SH monolayer and can mediate the ET between the solution-phase probes and underlying gold substrate. SECM-mediated model was used to simultaneously measure the bimolecular ET between the solution-phase probes and the monolayer-immobilized MB molecules, as well as tunneling ET between the monolayer-immobilized MB molecules and the underlying gold electrode, allowing the measurement of k_BI = (5 ± 1) × 10⁶ and (4 ± 2) × 10⁷ cm³ mol⁻¹ s⁻¹ for the bimolecular ET and and (7 ± 3) × 10⁻² s⁻¹ for the standard tunneling rate constant of ET using Fe(CN)₆^4−/3− and FMC^0/+ probes respectively.     

Adsorption dynamics and interfacial properties of thiol-based cobalt terpyridine monolayers

Spontaneously adsorbed monolayers of [Co(ttp-CH₂-SH)₂](PF₆)₂ have been formed on platinum microelectrodes by exposure to micromolar solutions of the complex in 0.1 M TBABF₄ in acetonitrile, ttp-CH₂-SH is 4′-(p-(thiolmethyl)-phenyl)-2,2′:6′,2″-terpyridine. Resonance Raman spectroscopy on roughened polycrystalline platinum macro electrodes show that the molecule undergoes adsorption through the sulphur atom onto the platinum surface. The monolayers show reversible and well defined cyclic voltammetry when switched between Co²⁺ and Co³⁺ forms, with a peak to peak splitting of 0.040 ± 0.005 V up to 200 V s⁻¹ and an FWHM of 0.138 ± 0.010 V. Adsorption is irreversible leading to the maximum surface coverage, 6.3 ± 0.3 × 10⁻¹¹ mol cm⁻² for 2.5 ≤ [Co(ttp-CH₂-SH)₂] ≤ 10 μM. The rate of monolayer formation appears to be controlled not by mass transport or interfacial binding but by surface diffusion of the complex. The surface diffusion coefficient is 5.5 ± 1.1 × 10⁻⁷ cm² s⁻¹ indicating that prior to formation of an equilibrated monolayer, the adsorbates have significant mobility on the surface. The electron transfer process across the monolayer-electrode interface has been probed by high speed chronoamperometry and the standard heterogeneous electron transfer rate constant, k°, is approximately 3.06 ± 0.03 × 10⁴ s⁻¹. The reorganization energy is at least 18.5 kJ mol⁻¹.     

Hydrodynamic and mass transfer characterization of a flat-panel airlift photobioreactor with high light path

This work evaluates the volumetric mass transfer coefficient (k_La), the gas hold-up (?) and the mixing time (t_m) as a function of superficial gas velocity (U_G) in a flat-panel photobioreactor (PBR) with high light path. CO₂ utilization efficiency and volumetric power consumption (P/V) were also evaluated. A 50 L working volume photobioreactor was developed, 0.67 m in length, 0.57 m in height and 0.15 m in width (light path). The height-width ratio was 3.8, which is lower than reported in most PBRs. Initially, experiments were performed with air and tap water (biphasic system) and, subsequently, using a Spirulina sp. culture (triphasic system: air, culture medium, cells). Minimum and maximum superficial gas velocity values were 5 × 10⁻⁵ and 8.4 × 10⁻³ m s⁻¹, respectively. Maximum values for k_La and ? were 20.34 h⁻¹ (0.0057 s⁻¹) and 0.033 in the biphasic system, and 31.27 h⁻¹ (0.0087 s⁻¹) and 0.065 in the triphasic system. CO₂ utilization efficiency was 30.57%. Results indicate that the hydrodynamic and mass transfer characteristics of this photobioreactor are more efficient than those reported elsewhere for tubular and other flat-plate PBRs, which opens the possibility of using PBRs with higher light paths than yet proposed.     

Flow injection amperometric determination of pyridoxine at a Prussian blue nanoparticle-modified carbon ceramic electrode

This work describes the electrocatalytic properties of a carbon composite electrode (CCE) modified with Prussian blue (PB) nanoparticles (NPs) for the electrocatalytic oxidation of pyridoxine (PN). The morphology of the PBNP-modified CCE was characterized by scanning electron microscopy (SEM). The mechanism and kinetics of the catalytic oxidation reaction of PN were monitored by cyclic voltammetry and chronoamperometry. The rate-limiting step of the charge transfer reaction was found to be a one-electron abstraction. The value of α, k, and D were calculated as 0.66, 6.7 × 10⁴ M⁻¹ s⁻¹, and 1.88 × 10⁻⁵ cm² s⁻¹, respectively. The modified electrode showed electrocatalytic activity toward the oxidation of PN and was used as an amperometric sensor. The sensor exhibited good linear response for PN over the concentration ranges 5-69 and 1-80 μM with detection limits of 0.51 and 0.87 μM, and sensitivities of 0.97 and 0.673 A M⁻¹ cm⁻² in batch and flow conditions, respectively. Some important advantages such as simple preparation, fast response, good stability, and reproducibility of the sensor for the amperometric determination of PN were achieved.     

The ultrasonic electropolymerization of an 5-[o-(4-bromine amyloxy)phenyl]-10,15,20-triphenylporphrin (o-BrPETPP) film electrode and its electrocatalytic properties to dopamine oxidation in aqueous solution

5-[o-(4-Bromine amyloxy)phenyl]-10,15,20-triphenylporphrin (o-BrPETPP) was electropolymerized on a glassy carbon electrode (GCE), and the electrocatalytic properties of the prepared film electrode response to dopamine (DA) oxidation were investigated. A stable o-BrPETPP film was formed on the GCE under ultrasonic irradiation through a potentiodynamic process in 0.1 M H₂SO₄ between −1.1 V and 2.2 V versus a saturated calomel electrode (SCE) at a scan rate of 0.1 V s⁻¹. The film electrode showed high selectivity for DA in the presence of ascorbic acid (AA) and uric acid (UA), and a 6-fold greater sensitivity to DA than that of the bare GCE. In the 0.05 mol L⁻¹ phosphate buffer (pH 6.0), there was a linear relationship between the oxidation current and the concentration of DA solution in the range of 5 × 10⁻⁷ mol L⁻¹ to 3 × 10⁻⁵ mol L⁻¹. The electrode had a detection limit of 6.0 × 10⁻⁸ mol L⁻¹(S/N = 3) when the differential pulse voltammetric (DPV) method was used. In addition, the charge transfer rate constant k = 0.0703 cm s⁻¹, the transfer coefficient α = 0.709, the electron number involved in the rate determining step n_α = 0.952, and the diffusion coefficient D_o = 3.54  10⁻⁵ cm² s⁻¹ were determined. The o-BrPETPP film electrode provides high stability, sensitivity, and selectivity for DA oxidation.