Poly(N-methylaniline)/nickel modified carbon paste electrode as an efficient and cheep electrode for electrocatalytic oxidation of formaldehyde in alkaline medium

This research in finding a cheap and efficient catalyst for electrooxidation of formaldehyde give us an attempt to make and examine the behavior of poly(N-methylaniline)/nickel modified carbon paste electrode (Ni/P(NMA)/MCPE) in absence and presence of formaldehyde. This involves in situ electropolymerization of N-methylaniline at carbon paste electrode, which is following to the incorporation of Ni(II) to polymeric layer by immersion of modified electrode in 1.0 M nickel sulphate solution. The electrocatalytic oxidation of formaldehyde was studied by cyclic voltammetry and chronoamperometry methods. The effects of scan rate and formaldehyde concentration on the electrocatalytic oxidation of formaldehyde were also investigated at the surface of Ni/P(NMA)/MCPE. The diffusion coefficient (D = 14.1 × 10⁻⁵ cm² s⁻¹), and some kinetic parameters such as the transfer coefficient (α = 0.45) and also second-order rate constant (k = 8.96 × 10⁻⁴ cm³ mol⁻¹ s⁻¹) of formaldehyde were calculated.     

Electrodeposited indigotetrasulfonate film onto glutaraldehyde-cross-linked poly-l-lysine modified glassy carbon electrode for detection of dissolved oxygen

The nano composited film of indigotetrasulfonate (ITS) electrodeposited onto poly-l-lysine (PLL)–glutaraldehyde (GA) (ITS/PLL–GA) was modified on glassy carbon electrode (GCE) by multiple scan cyclic voltammetry. Composited of the proposed film was characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), electrochemical quartz crystal microbalance (EQCM), electrochemical impedance spectroscopy (EIS), and UV–vis spectrum for the absorption at λ_max at 566 nm. For the electrocatalytic reduction of dissolved oxygen, ITS/PLL–GA film modified electrodes was determined in 0.1 M acetate buffer solution (pH 5.6) by cyclic voltammetry and rotating disk electrode voltammetry. This dissolved oxygen electrochemical sensor exhibited a linear response range (from 0 to 178.4 μM, R² = 0.9949), lowest detection limit (2.2 μM), lowest overpotential at −0.09 V, high sensitivity (906 μA mM⁻¹) and relative standard deviation (RSD) for determining dissolved oxygen (n = 3) was 4.2%. In addition, the ITS/PLL–GA/GCE was advantageous in terms of its simple preparation, specificity, stability and the ability of regeneration.     

Fabrication of functionalized carbon nanotube modified glassy carbon electrode and its application for selective oxidation and voltammetric determination of cysteamine

The functionalized carbon nanotube electrode was fabricated by electrodeposition of 1,2-naphthoquinone-4-sulfonic acid sodium (Nq) on single-wall carbon nanotube (SWNT) modified glassy carbon electrode (GCE). This electrode was characterized by scanning electron microscopy (SEM) and the results showed that Nq can rapidly and effectively be deposited on the surface of SWNT film with high stability. The electrochemical properties of functionalized SWNT/GCE with Nq (SWNT–Nq/GCE) were studied using cyclic voltammetry, double step potential chronoamperometry and differential pulse voltammetry methods. The results indicated that SWNT could improve the electrochemical behavior of Nq and greatly enhances its redox peak currents. The SWNT–Nq/GCE exhibited a pair of well-defined redox peaks. The experimental results also demonstrated that the Nq deposited species on SWNT could catalyze cysteamine oxidation and SWNT–Nq exhibited a high performance with lowering the overpotential by more than 710 mV. The effect of pH value, number of scans and Nq concentration were investigated on the electrochemical behavior of cysteamine. The selectivity of the reaction has been assessed with no interference from tyrosine, lysine, methionine, tryptophan, alanine and glutathione. The presented method has highly selectivity for voltammetric detection of cysteamine in the dynamic range from 5.0 × 10⁻⁶ M to 2.7 × 10⁻⁴ M and with a detection of limit (3σ) 3.0 × 10⁻⁶ M.     

Simultaneous determination of adenine and guanine utilizing PbO2-carbon nanotubes-ionic liquid composite film modified glassy carbon electrode

A novel and reliable electrochemical sensor based on PbO₂-carbon nanotubes-room temperature ionic liquid (i.e., 1-butyl-3-methylimidazolium hexafluorophosphate, BMIMPF6) composite film modified glassy carbon electrode (GCE) (PbO₂–MWNT–RTIL/GCE) was proposed for simultaneous and individual determination of guanine and adenine. The guanine and adenine oxidation responses were monitored by differential pulse voltammetric (DPV) measurement. Compared with the bare electrode, the PbO₂–MWNT–RTIL/GCE not only significantly enhanced the oxidation peak currents of guanine and adenine, but also lowered their oxidation overpotentials, suggesting that the synergistic effect of PbO₂, MWNT and RTIL could dramatically improve the determining sensitivity of guanine and adenine. The PbO₂–MWNT–RTIL/GCE showed good stability, high accumulation efficiency and enhanced electrocatalytic ability for the detection of guanine and adenine. Besides, the modified electrode also exhibited good behaviors in the simultaneous detection of adenine and guanine with the peak separation of 0.29 V in 0.1 M pH 7.0 phosphate buffer solution (PBS). Under the optimal conditions, the detection limit for individual determination of guanine and adenine was 6.0 × 10⁻⁹ M and 3.0 × 10⁻⁸ M (S/N = 3), respectively. The proposed method for the measurements of guanine and adenine in herring sperm DNA was successfully applied with satisfactory results.     

Selective determination of dopamine in the presence of ascorbic acid at a multi-wall carbon nanotube-poly(3,5-dihydroxy benzoic acid) film modified electrode

A sensitive and selective method for determination of dopamine (DA) using multi-wall carbon nanotube (MWCNT)-poly(3,5-dihydroxy benzoic acid) [poly(DBA)] modified electrode is developed. The modified electrode shows excellent electrocatalytic activity toward the oxidation of dopamine in phosphate buffer solutions at pH 7.4. Using cyclic voltammetry, the linear range of 1 × 10⁻⁷–7.0 × 10⁻⁵ M in the interference of 500 μM ascorbic acid (AA) and the detection limit of 1.0 × 10⁻⁸ M were estimated for the measurement of DA in pH 7.4 phosphate buffer solutions. The value of DA current retained 98.36% of the initial response current after the modified electrode exposed to the air for one week. The interference studies showed that the modified electrode excludes effectively large excess of AA. The kinetic characteristics of the transfer of DA demonstrated that the electron propagation between DA and electrode was accelerated at MWCNT-poly(DBA) modified electrode. The work provided a valid and simple approach to selectively detect dopamine in the presence of AA in physiological environment.     

MWNT/Nafion composite modified glassy carbon electrode as the voltammetric sensor for sensitive determination of 8-hydroxyquinoline in cosmetic

In this paper, a multiwall carbon nanotube/Nafion composite modified glassy carbon electrode (MWNT/Nafion/GCE) was used as a voltammetric sensor to determine 8-hydroxyquinoline (8-HQ) in cosmetic. This voltammetric sensor exhibited strong catalytic effect toward the oxidation of 8-HQ and caused an anodic peak at 0.97 V in HAc-NaAc buffer solution (0.2 M, pH 3.6). Under the optimized condition, the anodic peak current was linear with the concentration of 8-HQ in the range of 2 × 10⁻⁸ M–1.0 × 10⁻⁵ M. The detection limit was 9 × 10⁻⁹ M. The practical application of MWNT/Nafion/GCE was carried out for determining 8-HQ in cosmetic sample with satisfactory results. The electrode reaction mechanism was studied by cyclic voltammetry and UV–vis spectra.     

A differential pulse voltammetric method for simultaneous determination of ascorbic acid,dopamine, and uric acid using poly (3-(5-chloro-2-hydroxyphenylazo)-4,5-dihydroxynaphthalene-2,7-disulfonic acid) film modified glassy carbon electrode

A stable modified glassy carbon electrode based on the poly 3-(5-chloro-2-hydroxyphenylazo)-4,5-dihydroxynaphthalene-2,7-disulfonic acid (CDDA) film was prepared by electrochemical polymerization technique to investigate its electrochemical behavior by cyclic voltammetry. The properties of the electrodeposited films, during preparation under different conditions, and their stability were examined. The homogeneous rate constant, k_s, for the electron transfer between CDDA and glassy carbon electrode was calculated as 5.25(±0.20) × 10² cm s⁻¹. The modified electrode showed electrocatalytic activity toward ascorbic acid (AA), dopamine (DA), and uric acid (UA) oxidation in a buffer solution (pH 4.0) with a diminution of their overpotential of about 0.12, 0.35, and 0.50 V for AA, DA, and UA, respectively. An increase could also be observed in their peak currents. The modified glassy carbon electrode was applied to the electrocatalytic oxidation of DA, AA, and UA, which resolved the overlapping of the anodic peaks of DA, AA, and UA into three well-defined voltammetric peaks in differential pulse voltammetry (DPV). This modified electrode was quite effective not only for detecting DA, AA, and UA, but also for simultaneous determination of these species in a mixture. The separation of the oxidation peak potentials for ascorbic acid–dopamine and dopamine–uric acid were about 0.16 V and 0.17 V, respectively. The final DPV peaks potential of AA, DA and UA were 0.28, 0.44, and 0.61 V, respectively. The calibration curves for DA, AA, and UA were linear for a wide range of concentrations of each species including 5.0–240 μmol L⁻¹ AA, 5.0–280 μmol L⁻¹ DA, and 0.1–18.0 μmol L⁻¹ UA. Detection limits of 1.43 μmol L⁻¹ AA, 0.29 μmol L⁻¹ DA and 0.016 μmol L⁻¹ UA were observed at pH 4. Interference studies showed that the modified electrode exhibits excellent selectivity toward AA, DA, and UA.     

Simultaneous determination of epinephrine and uric acid at a gold electrode modified by a 2-(2,3-dihydroxy phenyl)-1, 3-dithiane self-assembled monolayer

In the present paper, the use of a gold electrode modified by 2-(2,3-dihydroxy phenyl)-1,3-dithiane self-assembled monolayer (DPDSAM) for the determination of epinephrine (EP) and uric acid (UA) was described. Initially, cyclic voltammetry was used to investigate the redox properties of this modified electrode at various scan rates. The apparent charge transfer rate constant, k_s, and transfer coefficient, α, were calculated. Next, the mediated oxidation of EP at the modified electrode was described. At the optimum pH of 8.0, the oxidation of EP occurs at a potential about 155 mV less positive than that of an unmodified gold electrode. The values of electron transfer coefficients (α = 0.356), catalytic rate constant (k = 1.624 × 10⁴ M⁻¹ s⁻¹) and diffusion coefficient (D = 1.04 × 10⁻⁶ cm² s⁻¹) were calculated for EP, using electrochemical approaches. Based on differential pulse voltammetry, the oxidation of EP exhibited a dynamic range between 0.7 and 500.0 μM and a detection limit (3σ) of 0.51 μM. Furthermore, simultaneous determination of EP and UA at the modified electrode was described. Finally, this method was used for the determination of EP in EP ampoule.     

Silver nanoparticles modified carbon nanotube paste electrode for simultaneous determination of dopamine and ascorbic acid

A novel modified carbon-paste electrode was employed for the simultaneous determination of dopamine (DA) and ascorbic acid (AA) with good selectivity and high sensitivity. Silver nanoparticle and carbon nanotube modified carbon-paste electrode (Ag/CNT–CPE) displayed excellent electrochemical catalytic activities towards dopamine (DA) and ascorbic acid (AA). The oxidation overpotentials of DA and AA were decreased significantly compared with those obtained at the bare CPE. Differential pulse voltammetry was used for the simultaneous determination of DA and AA. The peak separation between DA and AA was 67 mV. The calibration curves for DA and AA were obtained in the range of 8.0 × 10⁻⁷–6.4 × 10⁻⁵ M and 3.0 × 10⁻⁵–2.0 × 10⁻³ M, respectively. The lowest detection limits (S/N = 3) were 3.0 × 10⁻⁷ M and 1.2 × 10⁻⁵ M for DA and AA, respectively. Method was applied to the determination of DA and AA in real samples.     

Electrocatalytic oxidation of hydrazine using glassy carbon electrode modified with carbon nanotube and terpyridine manganese(II) complex

Here, we report a simple and extremely effective method to modify a glassy carbon (GC) electrode with carbon nanotubes (CNTs) and [Mn(CH₃COO)(CH₃OH)₂(pyterpy)]ClO₄, (pyterpy = 4′-(4-pyridyl)-2,2′:6′,2′′-terpyridine) complex. The kinetics of the reaction between, the terpyridine manganese(II) complex, mediator and hydrazine has been characterized using cyclic voltammetry and rotating disk electrode voltammetry. The catalytic currents were proportional to the concentration of hydrazine giving rise to calibration curves characterized by two linear segments. The linear segment over the concentration range of 1.00 × 10⁻³–1.05 mM could be used with analytical purposes to determination of hydrazine with a detection limit of 0.50 μM and a sensitivity of 0.038 μA/μM. The heterogeneous rate constant, k′ for the oxidation of hydrazine at the surface of the modified electrode was determined by rotating disk electrode voltammetry using the Koutecky–Levich plot. The transfer coefficient (α) for electrocatalytic oxidation of hydrazine and the diffusion coefficient of this substance under the experimental conditions were also investigated. The resulting modified electrode retains its initial response for at least one month if stored dry in air.     

Application of surfactant modified zeolite membrane electrode towards potentiometric determination of perchlorate

Potentiometric electrodes based on the incorporation of surfactant-modified zeolite Y (SMZ) particles into poly vinyl chloride (PVC) membranes were described. The electrode characteristics were evaluated regarding the response towards perchlorate ions. PVC membranes plasticized with dioctyl phthalate and without lipophilic additives (co-exchanger) are used throughout this study. The influence of membrane composition on the electrode response was studied. The electrode exhibited a Nernstian response towards perchlorate in the concentration range of 7.9 × 10⁻⁶–8.0 × 10⁻² M with a slope of 59.7 ± 0.9 mV per decade of perchlorate concentration with a working pH range of 1.7–9.5 with a fast response time of ≤10 s. The lower and upper detection limits were 4.07 × 10⁻⁷ and 0.13 M, respectively. The electrode response to perchlorate remains constant in the temperature range of 20–40 °C and in the presence of 2.5 × 10⁻⁶–1 × 10⁻² M NaNO₃. The selectivity coefficients for perchlorate anion as test species with respect to other anions were determined. The proposed modified zeolite-PVC electrode can be used for at least 30 days without any considerable divergence in potential. It was applied as indicator electrode in water samples with satisfactory results. The results of this study and our previous work show HDTMA plays different roles according to the zeolite type and matrix, as HDTMA-zeolite Y in a carbon paste matrix showed a good Nernstian behavior towards phosphate anion.     

Determination of trace vanadium(V) by adsorptive anodic stripping voltammetry on an acetylene black paste electrode in the presence of alizarin violet

A sensitive and simplified voltammetric method is developed for the determination of trace amounts of vanadium(V) by adsorptive anodic stripping voltammetry using an acetylene black (AB) paste electrode. The method is based on the preconcentration of the V(V)–alizarin violet (AV) complex at open circuit while stirring the solution for 90 s in 0.15 mol dm⁻³ hexamethylenetetraamine–hydrochloric acid buffer (pH 4.4), the adsorbed complex is then oxidized, producing a response with a peak potential of 564 mV when scanning linearly from 0 to 1000 mV. For voltammetric determination of V(V), the parameters influencing the peak current have been optimized. Under the selected conditions, the peak current and concentration of V(V) accorded with linear relationship in the range of 8.0 × 10⁻¹⁰ mol dm⁻³–1.0 × 10⁻⁷ mol dm⁻³ (c_AV = 2.0 × 10⁻⁶ mol dm⁻³) and 1.0 × 10⁻⁷ mol dm⁻³–8.0 × 10⁻⁶ mol dm⁻³ (c_AV = 2.0 × 10⁻⁵ mol dm⁻³), the detection limit (three times signal to noise) was estimated to be 6.0 × 10⁻¹⁰ mol dm⁻³ for 90 s accumulation. The relative standard deviation (RSD) is 1.9% and 2.3% for V(V) concentrations of 1.0 × 10⁻⁷ mol dm⁻³ and 1.0 × 10⁻⁸ mol dm⁻³ respectively. Finally, this proposed method was successfully applied to the determination of V(V) in natural water samples.     

Electrochemistry of magnolol and interaction with DNA

The electrochemical behaviors of magnolol have been studied at glassy carbon electrode using cyclic voltammetry, linear sweep voltammetry and chronocoulometry. Moreover, its interaction with DNA was investigated in solution by electrochemical methods and ultraviolet–visible spectroscopy. The experiment results indicated that the electrochemical oxidation of magnolol was an irreversible process with one proton and one electron transfer. The electron transfer coefficient (α) was calculated to be 0.441 ± 0.001. At the scan rate from 100 mV/s to 450 mV/s, the electrode process was controlled by the adsorption step and at the range of 600–950 mV/s the electrochemical oxidation was diffusion controlled process. The corresponding electrochemical rate constant (k_s) was 0.0760 ± 0.0001 s⁻¹. Through chronocoulometry experiment, the diffusion coefficient (D) and the surface concentration (Γ) were obtained as (3.76 ± 0.01) × 10⁻⁷ cm²/s and (2.98 ± 0.01) × 10⁻¹⁰ mol/cm². In addition, the interaction of magnolol and DNA was ascribed to be electrostatic interaction and the calculated association constant (β) and Hill coefficient (m) were 1.14 × 10⁵ M⁻¹ and 0.973. At last a sensitive and convenient electrochemical method was proposed for the determination of magnolol.     

Voltammetric sensor based on ordered mesoporous carbon for folic acid determination

With ordered mesoporous carbon (OMC) as the modifier, a voltammetric sensor for folic acid (FA) was constructed on a glassy carbon electrode (GCE). Due to the good characteristics of OMC, FA exhibited an enhanced electrochemical response and lower reduction potential in the neutral solution. In addition, the experimental parameters such as pH values, accumulation time and potential were optimized. Using the differential pulse voltammetry (DPV) measurement, the peak current was found to be linear with FA concentration in the range from 5.0 × 10⁻¹⁰ to 1.0 × 10⁻⁷ M with a lower detection limit of 6.0 × 10⁻¹¹ M (S/N = 3). Also, in real samples analysis, the as-prepared sensor successfully gives satisfying results.     

Electrochemical layer-by-layer modified imprinted sensor based on multi-walled carbon nanotubes and sol–gel materials for sensitive determination of thymidine

A novel electrochemical sol–gel imprinted sensor for sensitive and convenient determination of thymidine was developed. Thin film of molecularly imprinted sol–gel polymers with specific binding sites for thymidine was cast on carbon electrode by electrochemical deposition. Multi-walled carbon nanotubes (MWCNTs) were introduced for the enhancement of electronic transmission and sensitivity. The morphology and performance of the imprinted film was characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV) and amperometric measurements (i–t) in detail. The results showed that the imprinted film exhibited high selectivity toward thymidine. The linear range is over the range from 2 to 22 μmol L⁻¹, and the linear regression equation for thymidine is I = 0.867C + 0.232 with the detection limit of 1.6 × 10⁻⁹ mol L⁻¹(S/N = 3). The imprinted sensor was successfully employed to detect thymidine in some zidovudine-tablet samples.     

Electrocatalytic activity of thianthrene toward one-electron oxidation of guanosine and DNA in a non-aqueous medium

In this study, the electrochemical behavior of thianthrene (TH) and its application toward the electrocatalytic oxidation of guanosine (Gs) and DNA in a non-aqueous solution are investigated using different voltammetric techniques. Guanosine and DNA are adsorbed on the glassy carbon electrode (GCE) by applying a positive potential to the GCE. The rate constant of catalytic reaction between DNA and TH and also between Gs and TH were evaluated using chronoamperometry which gave rate constants of 2.41 × 10⁶ cm³ mol⁻¹ s⁻¹ and 2.68 (±0.19) × 10⁶ cm³ mol⁻¹ s⁻¹, respectively. Also the diffusion coefficient of TH was obtained using hydrodynamic voltammetry (3.17 × 10⁻⁵ cm² s⁻¹). Furthermore, using hydrodynamic voltammetry, a one-electron mechanism for oxidation of Gs is suggested.     

Electron transfer kinetics and morphology of cytochrome c at the biomimetic phospholipid layers

Electrochemistry of cytochrome c (cyt c) at biomimetic phospholipid layers was studied in a phosphate buffer solution, which were formed with dilauroyl phosphatidic acid (DLPA, C12:0), dipalmitoyl phosphatidic acid (DPPA, C16:0), distearoyl phosphatidic acid (DSPA, C18:0), and palmitoyl–oleoyl phosphatidic acid (POPA, C16:0–18:1). The lipid-layers formed firstly at the air/water interface were immediately transferred onto the electrode surface using the Langmuir–Blodgett (LB) technique. The electrochemical properties of cyt c at the lipid covered electrodes depended on the orientation, number of layers of phospholipids, tail (or head) group down, and vice versa. Atomic force microscopy (AFM) images of cyt c adsorbed on the POPA monolayer (showing the head group diameter of POPA to be ca. 0.7 nm) formed on highly oriented pyrolytic graphite (HOPG) displayed uniform surface morphology of lipid layer and clumps of aggregated cyt c molecules with a minimum size corresponding to four cyt c molecules. The heterogeneous electron transfer rate constants, k⁰ values, of cyt c were determined to be 1.02 × 10⁻³, 0.98 × 10⁻³, and 0.67 × 10⁻³ cm/s for the lipid monolayer in the tail down orientation (X-type) of POPA, DLPA, and DPPA, and 0.67 × 10⁻³ and 0.50 × 10⁻³ cm/s for the head down orientation (Z-type) of POPA and DLPA monolayers, respectively.     

Development of a carbon nanotubes paste electrode modified with crosslinked chitosan for cadmium(II) and mercury(II) determination

A functionalized carbon nanotubes paste electrode modified with cross-linked chitosan for the determination of trace amounts of cadmium(II) and mercury(II) by linear anodic stripping voltammetry is described. Under optimal experimental conditions, the peak current was linear in the Cd(II) concentration range from 5.9 × 10⁻⁸ to 1.5 × 10⁻⁶ mol L⁻¹ with a detection limit of 9.8 × 10⁻⁹ mol L⁻¹ and, for Hg(II) from 6.7 × 10⁻⁹ to 8.3 × 10⁻⁸ mol L⁻¹with a detection limit of 2.4 × 10⁻⁹ mol L⁻¹. The proposed method was successfully applied for the determination of Hg(II) in natural and industrial wastewater samples, and Cd(II) in sediments, human urine, natural, and industrial wastewater samples.     

Crown ether-dendrimer based potentiometric Na sensor electrode

Poly(vinyl chloride) (PVC)-based membranes of silacrown end grafted carbosilane dendrimer (I) with sodium tetraphenylborate (NaTPB) as an anion inhibitor and dibutylphthalate (DBP), dioctylphthalate (DOP), dibutyl (butyl) phosphonate (DBBP) and 1-chloronaphthalene (CN) as plasticizing solvent mediators were prepared and used as Na⁺-selective electrodes. Optimum performance was observed with the membrane having I–PVC–NaTPB–DOP in the ratio 1:33:1:65 (w/w). The electrode works well over a wide concentration range 1.5 × 10⁻⁶–1.0 × 10⁻¹ M with Nernstian compliance 56.0 mV/decade between pH 5.8 and 9.2 with a fast response time of about 15 s. The selectivity relative to alkali, alkaline earth and transition heavy metal ions is good. The selectivity coefficient values towards potassium ions have been calculated to be 2.3 × 10⁻⁴ by utilizing Fixed Interference Method. The proposed electrode could be used for at least 2 months without considerable alteration in its potential. The effect of nonionic surfactants Tween 20, Tween 80, Triton X 100, Span 20 and Span 60 on the potentiometric properties of the sodium selective membrane was also studied.     

Sensitive electrochemical detection of hydroquinone with carbon ionogel electrode based on BMIMPF6

An ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF₆) based carbon ionogel electrode (CIE) was fabricated for the sensitive voltammetric sensing of hydroquinone (HQ) in this paper. Due to the specific characteristics of the prepared working electrode, HQ exhibited an enhanced electrochemical response on CIE with a pair of well-defined redox peaks appeared in pH 2.5 phosphate buffer solution. The electrochemical behaviors of HQ on CIE were investigated by different electrochemical methods such as cyclic voltammetry and differential pulse voltammetry with the electrochemical parameters calculated. Under the optimal conditions the oxidation peak currents exhibited good linear relationship with the HQ concentration in the range from 0.13 to 100.0 μmol L⁻¹ with the detection limit of 0.07 μmol L⁻¹ (3σ). The CIE showed separated electrochemical response to HQ and catechol in the mixture solution. The proposed method was successfully applied to HQ detection in artificial wastewater with the recovery in the range from 98.9% to 102.0%.