Determination Of Catechol Research Articles

L-Cysteine/glycine composite film modified glassy carbon electrode as an enhanced sensing platform for catechol determination

Voltammetric sensor based on a glassy carbon electrode modified with l-cysteine/glycine composite film for the quantitative detection of catechol.

Highly stable pyridinic nitrogen doped graphene modified electrode in simultaneous determination of hydroquinone and catechol

A highly stable pyridinic nitrogen doped graphene (pyridine-NG) was used as an excellent electrocatalyst for the construction of electrochemical sensor for simultaneous determination of hydroquinone (HQ) and catechol (CC) in 0.20M pH 5.5 acetate buffer solution. At the pyridine-NG modified electrode, both HQ and CC can cause a pair of quasi-reversible redox peaks and the potential difference of oxidation peaks between HQ and CC was 103mV. Under the optimized condition, the oxidation peak current of HQ was linear over the range from 5 to 200μM in the presence of 100μM CC, and the oxidation peak current of CC was linear over the range from 5 to 200μM in the presence of 100μM HQ. The detection limit is 0.38μM for HQ and 1μM for CC (S/N=3). This proposed sensor was successfully applied to the simultaneous determination of HQ and CC in artificial sample, and the results were good stability and high reproducibility. The excellent electrocatalysis of pyridine-NG can be due to the π–π interactions between the benzene ring of CC and graphene layer, the hydrogen bonds formed between hydroxyl in HQ molecule and pyridinic nitrogen atoms within graphene layers, especially the less density distribution of π electron cloud in pyridinic-NG in acidic condition.

Simultaneous determination of dihydroxybenzene isomers based on graphene-graphene oxide nanocomposite modified glassy carbon electrode

In this paper, a novel graphene-graphene oxide (GR-GO) nanocomposite which could be dispersed well in water was fabricated by mixing GR and GO together with the help of ultrasonication. The significant advantage of the method developed here is the omission of any stabilizing compound or organic solvent. The prepared material was characterized by the scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and electrochemical impedance spectra. The application of GR-GO nanocomposite in simultaneous determination of hydroquinone (HQ) and catechol (CC) was investigated by cyclic voltammetry and differential pulse voltammetry. The oxidation peak potential difference between HQ and catechol CC was about 102mV, which was wide enough to clearly discriminate the dihydroxybenzene isomers. In the presence of 50μM isomer, the oxidation peak currents of HQ and CC were linear over the range of 0.5–300μM with the detection limits of 0.16μM (S/N=3) for HQ and 0.2μM (S/N=3) for CC, respectively.

Amperometric determination of hydroquinone and catechol on gold electrode modified by direct electrodeposition of poly(3,4-ethylenedioxythiophene)

Poly(3,4-ethylenedioxythiophene) (PEDOT) was directly deposited onto a gold electrode through potentiostatic technology, and the PEDOT modified electrode was developed for the amperometric determination of hydroquinone and catechol in 0.1M phosphate buffer solution (pH 7.0). Compared with the bare electrode, both hydroquinone and catechol exhibited well-defined redox peaks and much larger peak currents at PEDOT modified gold electrode, which suggested the higher specific surface area and conductivity of the PEDOT film. Under the optimized condition, the amperometric current response on PEDOT modified electrode were linear over ranges from 1.0×10−7M to 4.9×10−5M for hydroquinone, and from 9.1×10−8M to 9.8×10−4M for catechol, with the detection limits of 1.2×10−8M and 0.9×10−8M, respectively. The proposed method was applied on the determination of the mixture of hydroquinone and catechol with satisfactory results.

Fe3O4 Microspheres and Graphene Oxide Encapsulated with Chitosan: A New Platform for Sensitive Determination of Hydroquinone and Catechol

AbstractA novel sensor for sensitive determination of hydroquinone (HQ) and catechol (CC) was proposed using a Fe3O4 microspheres‐graphene oxide (Fe3O4‐GO) composites modified glassy carbon electrode (GCE) which was further encapsulated with chitosan (Chit‐Fe3O4‐GO/GCE). The excellent electrocatalytic performance is probably related to the strong synergistic effect of the composites. The proposed sensor shows a linear response for HQ and CC in wide concentration ranges from 1.5 to 150 µM and 1 to 410 µM, with detection limits (S/N=3) of 20 and 250 nM, respectively. Additionally, the sensor exhibits good selectivity and stability in tap water samples.

Simultaneous electrochemical determination of hydroquinone and catechol based on three-dimensional graphene/MWCNTs/BMIMPF6 nanocomposite modified electrode

A three-dimensional glassy carbon electrode (GCE) was fabricated from one-dimensional multiwalled carbon nanotubes (MWCNTs) and two-dimensional graphene (GR), using 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) ionic liquid to improve its dispersibility and stability. This GR/MWCNTs/BMIMPF6 modified GCE was found to be a highly sensitive electrochemical sensor for the simultaneous determination of hydroquinone (1,4-dihydroxybenzene, HQ) and catechol (1,2-dihydroxybenzene, CT). The GR was characterized using a transmission electron microscope. The electrochemical behaviours of HQ and CT at the GR/MWCNTs/BMIMPF6/GCE were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The chemically modified electrode exhibited excellent electrochemical catalytic activities towards HQ and CT. Linear relationships between the oxidation peak current and concentration of HQ/CT were obtained in the ranges 0.5μM to 2.9mM and 0.2μM to 0.66mM with detection limits (S/N=3) of 0.1μM and 0.06μM, respectively. This GR/MWCNTs/BMIMPF6/GCE showed many advantages in terms of dispersibility, stability, sensitivity, facility and economy.

Discrimination and simultaneous determination of hydroquinone and catechol by tunable polymerization of imidazolium-based ionic liquid on multi-walled carbon nanotube surfaces

Tunable polymerization of ionic liquid on the surfaces of multi-walled carbon nanotubes (MWCNTs) was achieved by a mild thermal-initiation-free radical reaction of 3-ethy-1-vinylimidazolium tetrafluoroborate in the presence of MWCNTs. Successful modification of polymeric ionic liquid (PIL) on MWCNTs surfaces (PIL-MWCNTs) was demonstrated by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and X-ray photoelectron spectroscopy. The resulting PIL-MWCNTs possessed unique features of high dispersity in aqueous solution and tunable thickness of PIL layer, due to positive imidazole groups along PIL chains and controllable ionic liquid polymerization by tuning the ratio of precursor. Based on cation-π interaction between the positive imidazole groups on PIL-MWCNTs surface and hydroquinone (HQ) or catechol (CC), excellent discrimination ability toward HQ and CC and improved simultaneous detection performance were achieved. The linear range for HQ and CC were 1.0×10−6 to 5.0×10−4M and 1.0×10−6 to 4.0×10−4M, respectively. The detection limit for HQ was 4.0×10−7M and for CC 1.7×10−7M (S/N=3), correspondingly.

An electrochemical sensor based on titanium oxide–carbon nanotubes nanocomposite for simultaneous determination of hydroquinone and catechol

A novel TiO2/multi-walled carbon nanotubes (MWCNTs) composite film-modified electrode was fabricated to devolop an electrochemical sensor for the simultaneous determination of hydroquinone (HQ) and catechol (CC). The prepared electrode not only separated the peaks of HQ and CC on the cyclic voltammogram with oxidation potential difference of 116 mV but also lowered the overpotential significantly and increased the reversible process and the peak currents of HQ and CC. In 0.1 M PBS (pH = 7.0). The oxidation peak current was linearly proportional to the concentration of CC and HQ in two broad linear ranges with the detection limit of 0.8 μM. The present electrochemical sensor for the simultaneous determination of CC and HQ showed high sensitivity and low detection limit.

Direct Synthesis of Ag Nanoparticles Incorporated on a Mesoporous Hybrid Material as a Sensitive Sensor for the Simultaneous Determination of Dihydroxybenzenes Isomers

AbstractThis paper describes the synthesis, characterization, and applications of a mesoporous silica/ multiwalled carbon nanotube (SiO2/MWCNT) hybrid material, which was obtained by a sol–gel process and decorated with silver nanoparticles (AgNPs) ranging in size from 5 to 8 nm. The AgNPs were prepared directly on the surface of the SiO2/MWCNTs material by using N,N‐dimethylformamide (DMF) as the reducing agent, and the resulting material was designated Ag/SiO2/MWCNT. The Ag/SiO2/MWCNT material was characterized by scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDS), high‐resolution transmission electron microscopy (HR‐TEM), and X‐ray photoelectron spectroscopy (XPS). A glassy carbon electrode, modified with the Ag/SiO2/MWCNT material, was used in the development of a sensitive electrochemical sensor for the determination of hydroquinone and catechol in the presence of resorcinol by squarewave voltammetry. Well‐defined and separate oxidation peaks were observed in phosphate buffer solution (PBS) at pH 7. The Ag/SiO2/MWCNT‐modified electrode exhibited high sensitivity for the simultaneous determination of hydroquinone and catechol in the presence of resorcinol, and the limits of detection for hydroquinone and catechol are 0.0117 and 0.0121 μM, respectively. No significant interference was seen for 2,6‐dichloroindophenol, phenol, 4‐nitrophenol, and nitrite ions in the detection of dihydroxybenzenes. Our study demonstrates that the resultant Ag/SiO2/MWCNT‐modified electrode can be used for hydroquinone and catechol detection in the presence of resorcinol and other potentially interfering materials in river water samples.

Simultaneous Determination of Catechol and Hydroquinone Using a Self-Assembled Laccase Biosensor Based on Nanofilm

Simultaneous Determination of Catechol and Hydroquinone Using a Self-Assembled Laccase Biosensor Based on Nanofilm

A sensor based on graphitic mesoporous carbon/ionic liquids composite film for simultaneous determination of hydroquinone and catechol

The graphitic mesoporous carbon (GMC) was synthesized by using SBA-15 as template and ionic liquid as a novel carbon source with the assistance of ferric nitrate. A homogeneous and stable conducting film could be formed with graphitic mesoporous carbon/1-butyl-3-methylimidazolium hexafluorophosphate (GMC/BMIMPF6) composite on the electrode surface, which was particularly useful for preparing modified electrode to determinate the hydroquinone (HQ) and catechol (CC). The cyclic voltammetry (CV) of GMC/BMIMPF6/GC electrode showed two couples of independent well-defined quasi-reversible redox peaks for HQ and CC. The peak current value of cathode was linear with the concentration of HQ in the range of 1×10−7 to 5.0×10−5molL−1 in the presence of 5×10−5molL−1 CC and with the concentration of CC in the range of 1×10−7 to 5.0×10−5molL−1 in the presence of 5×10−5molL−1 HQ with detection limits (S/N=3) of 5×10−8molL−1 (HQ) and 6×10−8molL−1 (CC), respectively.

Tyrosinase biosensor based on a glassy carbon electrode modified with multi-walled carbon nanotubes and 1-butyl-3-methylimidazolium chloride within a dihexadecylphosphate film

A glassy carbon electrode modified with functionalized multi-walled carbon nanotubes (MWCNT), 1-butyl-3-methylimidazolium chloride (ionic liquid=IL) and tyrosinase (Tyr) within a dihexadecylphosphate (DHP) film for the development of a biosensor is proposed. MWCNT, IL and Tyr were efficiently immobilized in the film using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) as crosslinking agents, and which was characterized by cyclic voltammetry (CV) in the presence of catechol. The IL-MWCNT nanocomposite showed good conductivity and biocompatibility with Tyr enzyme, since the biosensor presented biocatalytic activity toward the oxidation of catechol to o-quinone which was electrochemically reduced to catechol at a potential of 0.04V. The analytical curve ranged from 4.9×10−6 to 1.1×10−3molL−1 with a detection limit of 5.8×10−7molL−1. The developed Tyr-IL-MWCNT-DHP/GCE biosensor showed a wide linear range, good reproducibility, sensitivity and stability and the biosensor was successfully applied to the determination of catechol in natural water samples, with satisfactory results compared with a spectrophotometric method, at the 95% confidence level.

Carbon nanotubes/carbon paper composite electrode for sensitive detection of catechol in the presence of hydroquinone

The fabrication and application of carbon nanotubes/carbon paper (CNTs/CP) composite electrochemical sensors are reported. This sensing platform allows the sensitive determination of catechol in the range of 1μM to 100μM with a detection limit of 0.29μM. The catechol detection in tea samples demonstrates the applicability of this method. The present study explores an interesting and significant application of CNTs/CP composite in electroanalysis.

Facile preparation of polyaniline/MnO2 nanofibers and its electrochemical application in the simultaneous determination of catechol, hydroquinone, and resorcinol

In this study, polyaniline/MnO2 nanofibers were synthesized by the simple mixing of aqueous dispersed solution of polyaniline (PANI) nanofibers and KMnO4 aqueous solution. Materials were characterized by X-ray diffraction, nitrogen sorption, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and FT-IR. The electrochemical oxidation of hydroquinone, catechol, and resorcinol was investigated using cyclic and differential pulse voltammetries at PANI/MnO2 modified electrode. PANI/MnO2 exhibited high current sensitivity for these analytes compared to MnO2 and PANI modified electrodes, which is due to the presence of highly dispersed MnO2 in PANI matrix. The performance of this material was demonstrated in the detection of hydroquinone, catechol, and resorcinol in water samples. The reliability and stability of the modified electrode provides a good possibility for applying the technique in routine analysis for a selected class of electroactive organic/bio-molecules.

Gold Nanoparticles-Enhanced Amperometric Tyrosinase Biosensor Based on Three-Dimensional Sol-Gel Film-Modified Gold Electrodes

An amperometric biosensor for the determination of catechol was developed by immobilizing tyrosinase (tyr) on gold nanoparticles (AuNPs) and a (3-mercaptopropyl)-trimethoxysilane (MPTS) sol-gel three-dimensional network film-modified gold electrode. The AuNPs self-assembled in a sol-gel network provided an excellent microenvironment for an enzymatic reaction between tyrosinase and the substrate. It was found that the AuNPs could significantly affect the electron-transfer kinetics of the enzyme reaction, and remarkably enhance the electrochemical reduction of the corresponding o-quinones at the electrode surface. The nanostructured electrode showed high sensitivity (306.7 mA M(-1) cm(-2)) toward catechol, with an amperometric detection limit of 0.56 μM. The catalytic current of the biosensor was linear with the catechol concentration ranging from 1.7 to 96 μM with a correlation coefficient of 0.9992. The proposed biosensor exhibited a short response time, good anti-interferent ability, and excellent operational and storage stability.

Optical fiber spectroelectrochemical device for detection of catechol at press-transferred single-walled carbon nanotubes electrodes

A new long-optical-pathway spectroelectrochemical cell for absorptometric measurements in the UV-Vis region was developed. This cell consists of two optical fibers brought face to face and fixed on the working electrode support. As a proof of concept, the spectroelectrochemical cell was applied to the determination of catechol using a press-transferred single-walled carbon nanotube film as the working electrode. Voltabsorptometry was demonstrated to be very helpful in understanding the mechanism of catechol oxidation. The experiments showed that the main oxidation product is o-benzoquinone, but other soluble side products are also observed. Multivariate calibration explains the selection of 390 nm as the best wavelength for the univariate absorptometric determination of catechol, avoiding the interference of oxidation side products. Catechol was quantified using both the electrochemical and the spectroscopic signal, demonstrating that this hybrid technique is an autovalidated analytical method. Dual detection of catechol was also carried out using amperometric spectroelectrochemistry. Finally, spectroelectrochemistry was used to quantify catechol in the presence of hydroquinone.

Simultaneous determination of hydroquinone and catechol based on glassy carbon electrode modified with gold-graphene nanocomposite

We have synthesized a virtually monodisperse gold-graphene (Au-G) nanocomposite by a single-step chemical reduction method in aqueous dimethylformamide solution. The nanoparticles are homogenously distributed over graphene nanosheets. A glassy carbon electrode was modified with this nanocomposite and displayed high electrocatalytic activity and extraordinary electronic transport properties due to its large surface area. It enabled the simultaneous determination of hydroquinone (HQ) and catechol (CC) in acetate buffer solution of pH 4.5. Two pairs of well-defined, quasi-reversible redox peaks are obtained, one for HQ and its oxidized form, with a 43 mV separation of peak potentials (ΔEp), the other for CC and its oxidized form, with a ΔEp of 39 mV. Due to the large separation of oxidation peak potentials (102 mV), the concentrations of HQ and CC can be easily determined simultaneously. The oxidation peak currents for both HQ and CC increase linearly with the respective concentrations in the 1.0 μM to 0.1 mM concentration range, with the detection limits of 0.2 and 0.15 μM (S/N = 3), respectively. The modified electrode was successfully applied to the simultaneous determination of HQ and CC in spiked tap water, demonstrating that the Au-G nanocomposite may act as a high-performance sensing material in the selective detection of some environmental pollutants.

Poly(brilliant Cresyl Blue)-Modified Electrode for Highly Sensitive and Simultaneous Determination of Hydroquinone and Catechol

A selective and highly sensitive electrochemical method, based on a poly(brilliant cresyl blue)-modified activated glassy carbon electrode, was developed for the simultaneous determination of hydroquinone (HQ) and catechol (CT). The modified electrode was characterized by cyclic voltammetry (CV). It was found that the modified electrode showed an excellent catalytic activity and enhanced reversibility toward the oxidation of both HQ and CT in 0.1 M phosphate buffer solution (PBS, pH 7.0). The peak-to-peak separations (ΔEp) between oxidation and reduction waves in CV were decreased significantly from 360 and 285 mV at the bare electrode, to 59 and 56 mV at the poly(brilliant cresyl blue) modified electrode for HQ and CT respectively. Furthermore, the redox responses from the mixture of HQ and CT were easily resolved in both CV and differential pulse voltammetry (DPV). The oxidation peak currents of HQ and CT were linear up to 250 μM with the detection limits (S/N = 3) of 60 and 56 nM for HQ and CT, respectively. The developed sensor was successfully examined for real sample analysis with tap water and it showed a stable and reliable recovery data with high reproducibility.

Simultaneous electroanalytical determination of hydroquinone and catechol in the presence of resorcinol at an SiO2/C electrode spin-coated with a thin film of Nb2O5

This paper describes the development, characterization and application of an Nb(2)O(5) film formed on the surface of a carbon ceramic material, SiO(2)/C, obtained by a sol-gel method, using the spin-coating technique. The working electrode using this material will be designated as SiCNb. Hydroquinone and catechol can be oxidized at this electrode in the presence of resorcinol, allowing their simultaneous detection. The electrochemical properties of the resulting electrode were investigated using cyclic and differential pulse voltammetry techniques. Well-defined and separated oxidation peaks were observed by differential pulse voltammetry in Tris-HCl buffer solution at pH 7 containing 1 mol L(-1) KCl in the supporting electrolyte solution. The SiCNb electrode exhibited high sensitivity in the simultaneous determination of hydroquinone and catechol in the presence of resorcinol, with the limits of detection for hydroquinone and catechol being 1.6 μmol L(-1) and 0.8 μmol L(-1), respectively. Theoretical calculations were performed to determine the ionization energies of hydroquinone, catechol and resorcinol; the results were used to explain the simultaneous determination of species by differential pulse voltammetry. The presence of resorcinol did not produce any interference in the simultaneous detection of hydroquinone and catechol on the surface of the modified electrode.

Electrocatalytic oxidation and simultaneous determination of catechol and hydroquinone at a novel carbon nano-fragment modified glassy carbon electrode

In this paper, the electrochemical oxidation and differential pulse voltammetry (DPV) determination of catechol (CC) and hydroquinone (HQ) are studied at a novel carbon nano-fragment (CNF) modified glassy carbon electrode (CNF/GCE). The CNF modifier is prepared using the graphite cycled in lithium-ion batteries as the raw material through a ball mill process. The redox reactions of CC and HQ at the CNF/GCE are a two proton and electron process and controlled by the diffusion step. Compared to the GCE, the as-prepared CNF/GCE shows enhanced electrocatalytic activity and a peak potential difference of about 104 mV towards the oxidation of CC and HQ in a 0.1 mol L−1 acetate buffer solution (ABS, pH = 5.9), which makes it suitable for simultaneous determination of CC and HQ by DPV. Under the optimized conditions, the oxidation peak current of CC is linear over a range from 2.0 × 10−6 mol L−1 to 2.0 × 10−4 mol L−1 in the presence of 5.0 × 10−5 mol L−1 HQ with a detection limit of 1.0 × 10−7 mol L−1 (S/N = 3). Correspondingly, the oxidation peak current of HQ is linear over a range from 6.0 × 10−6 mol L−1 to 2.0 × 10−4 mol L−1 in the presence of 5.0 × 10−5 mol L−1 CC with a detection limit of 2.5 × 10−7 mol L−1 (S/N = 3). In addition, this CNF/GCE exhibits high selectivity, reproducibility and stability, showing its promising application prospect.