Catechol In Real Samples Research Articles

Dual-Amplifying Electrochemiluminescence Sensor Based on CdS QDs@HKUST-1/MWCNTs Composite for Sensitive Catechol Assay

Herein, a novel electrochemiluminescence (ECL) sensor was developed using a dual signal amplification mechanism based on a typical HKUST-1 metal-organic framework, [Cu3(BTC)2(H2O)3, BTC=1,3,5-benzene tricarboxylate], CdS quantum dots (QDs) and multi-walled carbon nanotubes (MWCNTs) for ultrasensitive determination of catechol. HKUST-1 not only has a dispersion effect to carry more CdS QDs for enhancing stability, but also acts as effective catalyzer to accelerate the transformation of persulfate ion (S2O8 2−) for generating more sulfate radical anions (SO4 •−), therefore amplifying the signal of the ECL sensor. Meanwhile, the introduction of MWCNTs to the ECL process could promote the electron transfer rate and accelerate the kinetics of the electro-catalytic reaction attributing to its stronger conductivity, achieving dual-amplifying effect, which could obviously increase the sensitivity of the ECL sensor. The proposed sensor displayed a wide linear range of 1 × 10−7 − 1 × 10−3 M and a low detection limit of 3.8 × 10−8 M with excellent stability, high repeatability and outstanding anti-interference ability under the optimal conditions. Impressively, the sensor possessed commendable feedback when detecting catechol in real samples. Therefore, this research provided a new strategy combining the advantages of MOFs, QDs and MWCNTs materials for phenolic pollutants detection.

Poly(safranine T)-deep eutectic solvent/copper oxide nanoparticle-carbon nanotube nanocomposite modified electrode and its application to the simultaneous determination of hydroquinone and catechol

This work presents the combined use of safranine (SF) as a redox polymer and multiwalled carbon nanotubes (MWCNT)-copper oxide nanoparticles (CuO) in the development of a novel sensor for the simultaneous analysis of hydroquinone (HQ) and catechol (CAT). Electropolymerisation of SF was carried out in acid-doped ethaline deep eutectic solvent to prepare poly(safranine) (PSFEthaline) film electrodes with three different nanostructured architectures on pencil graphite electrodes (PGE) as electrode substrate. The polymerisation was done after nanomaterial surface modification to obtain PSFEthaline-HCl/MWCNT/PGE, PSFEthaline-HCl/CuO/PGE, and PSFEthaline-HCl/MWCNT-CuO/PGE. The synthesis, preparation, and characterisation of PSF film-coated electrodes were studied using cyclic voltammetry and electrochemical impedance spectroscopy to investigate the contribution of each nanomaterial on sensor performance. The best result for polymer film growth was obtained with PSF electrodeposited on MWCNT-CuO/PGE in HCl doped-ethaline. The analytical performance of the modified electrode was evaluated for electrochemical sensing of HQ and CAT by differential pulse voltammetry in aqueous Britton-Robinson buffer solution. Due to the combined effect of MWCNT-CuO nanocomposite film and PSF, the modified electrode sensor provided sensitive and selective detection of HQ and CAT with good peak separation. The simultaneousdetermination of HQ and CAT in both tap water and milk samples was successfully carried out to demonstrate the analytical applicability of the sensor. The sensor could be a promising analytical approach for monitoring the amount of HQ and CAT in real samples.

Simultaneous electrochemical detection of hydroquinone and catechol using MWCNT-COOH/CTF-1 composite modified electrode

In this present work, a carboxylated multi-walled carbon nanotubes (MWCNT-COOH) and covalent triazine framework (CTF-1) co-modified glassy carbon electrode (GCE) is prepared and used for simultaneous electrochemical detection of hydroquinone (HQ) and catechol (CC). Due to the synergistic effect between the high electrocatalytic activity and good conductivity of MWCNT-COOH and large surface area of CTF-1, the prepared modified electrode exhibits good selectivity and high sensitivity for the simultaneous determination of HQ and CC. In the neutral phosphate buffer, HQ and CC produce a pair of well-defined redox peaks on the MWCNT-COOH/CTF-1/GCE. The concentrations of CC and HQ show good linearity in the range of 2–280 μM and the detection limits of HQ and CC are 0.12 μM and 0.17 μM, respectively. The prepared electrochemical sensor can be employed to determine contents of HQ and CC in real samples. • The MWCNT-COOH/CTF-1 composite exhibits superior electrocatalytic performance towards hydroquinone and catechol detection. • The research paves a feasible way to unlock high performance CTF electrode materials. • The sensor showed excellent specificity, good stability, and desirable reproducibility.

Synthesis and characterization of nanocomposite based on reduced graphene oxide-gold nanoparticles-carbon dots: electroanalytical determination of dihydroxybenzene isomers simultaneously

This work describes the synthesis, characterization, and application of a new ternary rGO-AuNPs-Cdots nanocomposite, which was extensively characterized by high-resolution electron microscopy (HR-TEM), UV-Vis spectroscopy, Raman spectroscopy, atomic force microscopy (AFM), X-ray diffraction (XRD), and electrochemical techniques. The nanocomposite was used to modify the surface of the glassy carbon electrode aiming to develop an electrochemical sensor for simultaneous determination of phenolic isomers. Electrochemical studies were performed in acetate buffer, pH 5.5. The modified rGO-AuNPs-Cdots electrode showed good electrocatalytic response for simultaneous determination of hydroquinone and catechol in the presence of resorcinol with detection limit of 1.2 × 10−8 mol L−1 and 9.6 × 10−8 mol L−1, respectively. This electrode also showed good electrocatalytic response for simultaneous determination of hydroquinone and catechol in real samples in the presence of other interferents.

Fabrication of Efficient and Selective Modified Graphene Paste Sensor for the Determination of Catechol and Hydroquinone

An electrochemical sensor, based on a graphene paste electrode (GPE), was modified with a polymerization method, and the electrochemical behavior of catechol (CC) and hydroquinone (HQ) was investigated using electroanalytical methods like cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The effect of CC at the modified electrode was evidenced by the positive shift of the oxidation peak potential of CC at the poly (rosaniline)-modified graphene paste electrode (PRAMGPE) and the nine-fold enhancement of the peak current, as compared to a bare graphene paste electrode (BGPE). The sensitivity of CC investigated by DPV was more sensitive than CV for the analysis of CC. The DPV method showed the two linear ranges of 2.0 × 10−6–1.0 × 10−5 M and 1.5 × 10−5–5 × 10−5 M. The detection limit and limit of quantification were determined to be 8.2 × 10−7 and 27.6 × 10−7 M, respectively. The obtained results were compared successfully with respect to those obtained using the official method. Moreover, this sensor is applied for the selective determination of CC in the presence of HQ. The high sensitivity, good reproducibility, and wide linear range make the modified electrode suitable for the determination of CC in real samples. The practical application of the sensor was demonstrated by determining the concentration of CC in water samples with acceptable recoveries (97.5–98%).

An asymmetric flow injection determination of hydroquinone and catechol: An analytic hierarchy and artificial neural network approach

A new reaction rate system was introduced for differential kinetic simultaneous determination of hydroquinone (HQ) and Catechol (CC). The method is based on the different kinetic behavior of HQ and CC in their reaction with iron (III) in the presence of 1, 10-phenanthroline (Phen) as a chromogenic reagent. An asymmetric double line flow injection manifold coupled with a spectrophotometric detector was designed and optimized using TOPSIS (Technique of ranking Preferences by Similarity to the Ideal Solution) methods based upon AHP (Analytic Hierarchy Process). Under optimal conditions, Bayesian Regularized Artificial Neural Network (BR-ANN) trained by back-propagation of errors was utilized as a non-linear model calibration of flow injection manifold. Detection limits of 0.05 and 0.07 mg L−1 were obtained for HQ and CC, respectively. The linear dynamic range was 0.5–3.0 mg L−1 for both analytes. The suggested method was applied for simultaneous determination of HQ and CC in real samples.

In situ immobilization of CuO on SiO2/graphite matrix, modified with benzimidazolium-1-acatate ionic liquid: Application as catechol sensor

Carbon ceramic material (SiO2/C) was prepared using the sol-gel technique. Copper oxide was in situ synthesized on the pores of the matrix, to ensure homogenous distribution of the electroactive species in the matrix pores. To enhance the conductivity of material, the SiO2/C/CuO was modified with benzimidazolium-1-acetate ionic liquid. The surface area (SBET 432.56m2/g) and pore volume (0.90cm3/g) of the material were calculated from BET analysis. SEM images showed compactness of materials, having no phase segregation within the magnification used. The structure of ionic liquid was confirmed using NMR and FTIR analysis. The electrodes as a pressed disk fabricated from SiO2/C, SiO2/C/CuO, and SiO2/C/CuO/IL materials were tested as an electrochemical sensor for catechol determination. Electrochemical impedance spectroscopy has revealed that the SiO2/C/CuO/IL-based sensor assists the charge transfer owing to electron rich density, resonance, and conductance of ionic liquid structural moiety. SiO2/C/CuO/IL electrode exhibits excellent sensitivity, linear response range and low limit of detection (LOD) of 712μAμmol−1dm3cm−2, 0.2mM–10mM and 0.7×10−8molL−1, respectively. The sensor was also tested for the determination of catechol in real samples and gives very good results for its determination.

One pot electrochemical synthesis of poly(melamine) entrapped gold nanoparticles composite for sensitive and low level detection of catechol

A simple and cost effective synthesis of nanomaterials with advanced physical and chemical properties have received much attention to the researchers, and is of interest to the researchers from different disciplines. In the present work, we report a simple and one pot electrochemical synthesis of poly(melamine) entrapped gold nanoparticles (PM-AuNPs) composite. The PM-AuNPs composite was prepared by a single step electrochemical method, wherein the AuNPs and PM were simultaneously fabricated on the electrode surface. The as-prepared materials were characterized by various physicochemical methods. The PM-AuNPs composite modified electrode was used as an electrocatalyst for oxidation of catechol (CC) due to its well-defined redox behavior and enhanced electro-oxidation ability towards CC than other modified electrodes. Under optimized conditions, the differential pulse voltammetry (DPV) was used for the determination of CC. The DPV response of CC was linear over the concentration ranging from 0.5 to 175.5μM with a detection limit of 0.011μM. The PM-AuNPs composite modified electrode exhibits the high selectivity in the presence of range of potentially interfering compounds including dihydroxybenzene isomers. The sensor shows excellent practicality in CC containing water samples, which reveals the potential ability of PM-AuNPs composite modified electrode towards the determination of CC in real samples.