Determination Of Hydroquinone Research Articles

Sensitive determination of hydroquinone and catechol using an electrochemical sensor based on nitrogen-doped malic acid carbon quantum dots

This study introduces an advanced electrochemical sensor fabricated by immobilizing nitrogen-doped malic acid carbon quantum dots (N-MCQDs) onto a glassy carbon electrode (GCE) via microwave-assisted synthesis and electrodeposition. The N-MCQDs were comprehensively characterized using high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and atomic force microscopy (AFM), confirming their successful synthesis and uniform distribution on the GCE surface. The N-MCQDs-modified GCE electrode (N-MCQDs/GCE) sensor displayed a remarkable linear detection range of 1–500 μM for hydroquinone (HQ) and 1–200 μM for catechol (CC), with ultra-low detection limits of 0.18 μM for HQ and 0.13 μM for CC. It also exhibits commendable stability, interference resistance, and the capability to accurately measure in complex real sample. These superior characteristics were attributed to the enhanced electrical conductivity and increased active sites due to nitrogen doping. This study not only broadens the application spectrum of carbon quantum dots but also offers a novel perspective for the design of high-performance electrochemical sensors for environmental analysis.

Simultaneous Electrochemical Determination of Hydroquinone, Catechol and Bisphenol A using Nickel Oxide@Reduced Graphene Oxide Nanocomposites in Water Samples

Phenolic compounds, prevalent in both human life and the natural environment, pose a significant threat to human health due to their toxic effects. Therefore, accurate determination of these compounds are crucial. Herein, we developed a new electrochemical sensor based on a NiO/C@reduced graphene oxide nanocomposite (NiO/C@rGO) to simultaneously assess three phenolic compounds: hydroquinone (HYQ), catechol (CAT), and bisphenol A (BPA). The NiO/C@rGO nanocomposite was synthesized via Ni(gallate)@GO pyrolysis and extensively characterized using various techniques. Subsequently, a glassy carbon electrode (GCE) modified with the NiO/C@rGO nanocomposite was utilized as the electrochemical sensor to simultaneously detection. The developed nanosensor (NiO/C@rGO/GCE) exhibited exceptional selectivity and a broad linear ranges for HYQ, CAT, and BPA, spanning from 0.01 to 100 μM, with impressively low detection limits. Furthermore, the NiO/C@rGO nanocomposite demonstrated remarkable stability and high reproducibility. Moreover, we successfully applied the NiO/C@rGO-based sensor to evaluate the three phenolic compounds in tap water, drinking water, and mineral water samples. The results underscore the potential of the developed electrochemical sensor as a reliable tool for the sensitive and fast detection of phenolic compounds in various water sources, addressing the critical need for safeguarding human health and the environment from their adverse effects.

Development of novel electrochemical sensor based on Co-Fe layered double hydroxide for simultaneous determination of Hydroquinone, Catechol, and Resorcinol

In this work, a novel electrochemical sensor was developed using a glassy carbon electrode modified with Co-Fe-layered double hydroxides (Co/Fe-LDH/GCE) for the detection of dihydroxybenzene isomers (Hydroquinone (HQ), Catechol (CC), and Resorcinol (RS) due to the large active surface area, facile electronic transport, and high electrocatalytic activity features of LDH. X-ray diffraction (XRD), X-ray energy dispersive spectroscopy (EDX), and scanning electron microscopy (SEM) techniques were used to characterize the modifier. Under the optimized conditions, the differential pulse voltammetry (DPV) method was used as a sensitive and efficient method to measure dihydroxybenzene isomers. Well-separated oxidation peak potentials corresponding to HQ, CC, and RS were observed at 0.04 V, 0.150 V, and 0.560 V, respectively. The linear range was 2.5 × 10−9 to 1.2 × 10−5 M for hydroquinone and catechol and 7.5 × 10−9 to 4.2 × 10−6 M for resorcinol, with a detection limit of 0.001, 0.001, and 0.005 µM (S/N=3) for hydroquinone, catechol, and resorcinol, respectively. The Co/Fe-LDH sensor demonstrated a fast response, high sensitivity, excellent stability, and satisfactory repeatability. The modified electrode was successfully applied to the direct determination of DBIs in river water, providing reliable recovery data.

Determination of hydroquinone in beverages using colorimetric and electrochemical sensors on paper-based device.

Hydroquinone (HQ) is aphenolic compound used in industry processes. We aim to demonstrate a rapid and simple procedure forthe determination ofHQ. This work has developed two techniques, including colorimetric and electrochemical sensors on paper-based devices. Firstly, we havedevelopedthe colorimetric detection for the rapid screening test of HQ using 1.5% 4-(dimethylamino) benzaldehyde with alkaline condition (5M NaOH). Under suitable conditions, the calibration curve between the intensity and HQ concentration wasin the range of50-500mg L-1. Then, we developed a multi-walled carbon nanotube/graphene oxide/copper/palladium/platinum (MWCNT/GO/Cu/Pd/Pt) onto a screen-printed carbon electrode (SPCE). The optimalamount ofMWCNT/GO/Cu/Pd/Pt nanomaterial is 2mg for HQ detection.The linear concentration range was foundin the range 1 to 20mg L-1anda detection limit was foundto be 0.40mg L-1 (3.6µM) for HQ. Moreover, the proposed device can be applied to determine HQ inrealsamples and is inexpensivetechnique, portable, and low consumer time.

Montmorillonite‐supported Ru‐doped CuBi2O4 nanozyme with enhanced peroxidase‐like activity for sensitive determination of hydroquinone

Nanozymes constitute a category of nanomaterials presenting the potential to replace natural enzymes. Nonetheless, weak catalytic activity becomes the biggest barrier hindering their practical applications. In this study, we fabricated a montmorillonite (MMT)‐supported ruthenium (Ru)‐doped CuBi2O4 nanozyme (Ru/CuBi2O4‐MMT) with robust peroxidase (POD)‐like activity by hydrothermal method and studied its application in determination of hydroquinone (HQ). Specifically, the CuBi2O4 material is brought into nanozyme field for the first time. MMT‐supported CuBi2O4 material possesses smaller size and larger surface area than pure CuBi2O4. Ru‐doped exhibits significantly higher POD‐like activity in comparison to CuBi2O4 due to the increase of defect sites. Both of strategies synergistically enhance the POD‐like activity of CuBi2O4 material. The POD‐like activity of nanozyme originates from the photogenerated holes (h+) and superoxide radicals (•O2−) produced during the catalytic decomposition of H2O2. Ru/CuBi2O4‐MMT nanozyme can be successfully applied for HQ colorimetric detection by redox reaction. Our newly developed nanozyme exhibits exceptional POD‐like activity by introducing support and element doping strategies, holding great potential for detecting pollutants in practical applications.

A new sensing platform based on poly(valine)-modified carbon paste electrode for the determination of hydroquinone and resorcinol

A new sensing platform based on poly(valine)-modified carbon paste electrode for the determination of hydroquinone and resorcinol

Novel electrochemical ZnO/MnO2/rGO nanocomposite-based catalyst for simultaneous determination of hydroquinone and pyrocatechol.

An innovative electrochemical sensing method is introduced for dihydroxy benzene (DHB) isomers, specifically hydroquinone (HQ) and pyrocatechol (PCC), employing a zinc-oxide/manganese-oxide/reduced-graphene-oxide (ZnO/MnO2/rGO) nanocomposite (NC) as an electrode modifier material. Comprehensive characterization confirmed well-dispersed ZnO/MnO2 nanoparticles on rGO sheets. Electrochemical analysis revealed the ZnO/MnO2/rGO-NC-based modified electrode possesses low electrical resistance (126.2 Ω), high electrocatalytic activity, and rapid electron transport, attributed to the synergies between ZnO, MnO2 and rGO. The modified electrode demonstrated exceptional electrochemical performance in terms of selectivity for the simultaneous detection of HQ and PCC. Differential pulse voltammetry studies validated the proposed sensor's ability to detect HQ and PCC within linear response ranges of 0.01-115 μM and 0.03-60.53 μM, with detection limits of 0.0055 µM and 0.0053 µM, respectively. Practical validation using diverse water samples showcased excellent percent recovery of HQ and PCC using the ZnO/MnO2/rGO-based electrochemical sensor, underscoring the sensor's potential for real-world applications in environmental monitoring.

Electrochemical detection of hydroquinone as an environmental contaminant using Ga2O3 incorporated ZnO nanomaterial

The primary objective of this research endeavor is to develop a highly sensitive and selective electrochemical sensor for the accurate detection of hydroquinone (HQ), a prevalent environmental contaminant. To achieve this, we employed a novel nanocomposite consisting of Ga2O3-doped ZnO (Ga2O3.ZnO) as the active nanomaterial for fabricating a glassy carbon electrode (GCE). The structure and morphology of the Ga2O3.ZnO nanocomposite were rigorously analyzed using a diverse range of techniques to ensure its suitability as the sensing nanomaterial. This innovative sensor exhibits remarkable capabilities, enabling the detection of HQ across a broad concentration range, spanning from 1 to 11070 µM, in a neutral phosphate buffer solution. It boasts an exceptionally high sensitivity of 1.0229 µA µM−1 cm−2 and an impressive detection limit of 0.063 µM. Thanks to its exceptional sensitivity and specificity, this sensor can precisely quantify HQ levels in real-world samples. Moreover, its outstanding reproducibility, repeatability, and stability establish it as a dependable and resilient choice for HQ determination.

Cresyl violet electropolymerization on functionalized multiwalled carbon nanotubes in carboxylic acid based ternary deep eutectic solvents for hydroquinone sensing

The phenazine dye cresyl violet (CVio) has been evaluated as precursor for the preparation of a new electrochemical sensor based on poly(cresyl violet) deposited on multiwalled carbon nanotube (CNT) modified glassy carbon electrodes (GCE) in neutralized acid-doped ternary deep eutectic solvents (DES). DES with choline chloride as hydrogen bond acceptor and with different hydrogen bond donors (HBD), namely acetic acid, ethylene glycol and oxalic acid were evaluated for CVio electropolymerization by potential cycling. The best polymer films were obtained in ternary DES with the two HBD acetic acid plus ethylene glycol doped with H2SO4 and followed by NaOH neutralization. Electrochemical characterization (voltammetric and electrochemical impedance) showed the formation of anthraquinone groups during electropolymerization, which is initiated on the CNT by the formation of a cation radical. Anthraquinones in the polymer film led to an increased response at the modified electrode for the determination of hydroquinone (H2Q) with low LOD (0.25 µmol L−1) in a broad linear range (1–80 µmol L−1), with good reproducibility, repeatability, and stability. The sensor was successfully applied to the quantification of H2Q in dermatological creams with no matrix effect towards hydroquinone response.

One-step solvent thermal synthesis of 3D networked MOF composites for preparation of anultrasensitive chemosensor for hydroquinone and catechol.

Pharmaceuticals and personal care products (PPCPs) have a significant impact on the environment and human health, due to their sometimestoxic and carcinogenic characteristics. Therefore, an innovative chemosensor was constructed for ultrasensitive determinationof two typical PCCPs (hydroquinone (HQ) and catechol (CC)) in several minutes. The homemade chemosensor (UiO-67@GO/MWCNTs) consisted of MOF(UiO-67), graphene oxide (GO), and multi-walled carbon nanotubes (MWCNTs) composites; it was a networked, structurally sparse, porosity-rich, homogeneous octahedral composite, and had ultra-high electrical conductivity, which provided lots of active adsorption sites, promote charge transfer, and enrich lots of molecules to be measured in a few minutes. The prepared electrochemical sensor showed good long-term stability, applicability, reproducibility, and immunity to interference for the determination of HQ and CC, with a wide linear range of response of 5.0 ~ 940µM for both HQ and CC, and a low limit of detection with satisfactory recoveries. In addition, a new strategy of using MOF composites as the basis for electrochemical determination of organic small molecules was established, and a new platform was constructed for the quantitative determination of organic small molecules in various environmental samples.

Cu/Mn Synergy Catalysis-Based Colorimetric Sensor for Visual Detection of Hydroquinone

The reliable detection of environmental contaminants can correctly forecast the degree of environmental pollution that has occurred, which contributes to improving the environmental purification rate and maintaining the ecological balance. Herein, a novel hierarchical biomimetic catalysis MnO2@CuAl-CLDHs was designed and synthesized using a facile method, which exhibited significantly enhanced peroxidase-like activity due to the unique composition and hierarchical mesoporous structure. Under optimized operational conditions, a visible colorimetric array based on the superior nanozyme activity of MnO2@CuAl-CLDHs was developed for the quantitative determination of hydroquinone with a wide linear detection range (1–100 μM) and a low detection limit (0.183 μM). Simultaneously, our presented strategy could analyze hydroquinone in real water samples with high accuracy. Therefore, the bimetallic co-catalyzed nanozymes are expected to be the perfect replacement for natural enzymes to develop convenient and efficient sensors.

Porphyrin functionalized montmorillonite Loaded Cu2O-Fe3O4 as a sustainable peroxidase nanozyme for colorimetric determination of hydroquinone

Designing sustainable efficient peroxidase nanozymes and elucidating its peroxidase-like mechanism are very important for constructing colorimetric sensing platforms. Herein, a sustainable peroxidase nanozyme, porphyrin functionalized montmorillonite (PorMMT) loaded Cu2O-Fe3O4 nanocomposites, is prepared by the two-step hydrothermal method and can be recycled conveniently by virtue of magnetism of Fe3O4 from the composite (Cu2O-Fe3O4/PorMMT). Cu2O-Fe3O4/PorMMT peroxidase nanozyme can quickly catalyze the oxidation of the colourless substrate 3,3′,5,5′-tetramethylbiphenylamine (TMB) by H2O2 into a blue product (oxTMB) only in 3 min. Compared with pure MMT, Cu2O and Fe3O4 individual, Cu2O-Fe3O4/PorMMT exhibits the higher peroxidase-like activity. The catalytic activity of Cu2O-Fe3O4/PorMMT is reached the maximum at pH = 4 and T = 50 ℃. The catalytic behaviors of Cu2O-Fe3O4/PorMMT follow the Michaelis-Menten kinetic equation. The catalytic mechanism of Cu2O-Fe3O4/PorMMT is from the produced active species including superoxide free radicals (•O2−) and holes (h+). Based on the peroxidase-like activity of Cu2O-Fe3O4/PorMMT, a fast convenient colorimetric sensing platform has been designed to detect H2O2 and hydroquinone (HQ), respectively. H2O2 detection can be realized in the linear range of 510 mM with the limit of detection (LOD) of 2.68 mM, as well as hydroquinone (HQ) in the linear range of 550 μM with a much lower LOD of 4.37 μM. The convenient visual sensing platform has a potential application in monitoring HQ remains in lakes and rivers near dressing plants.

Electrochemical sensor based on PEDOT/CNTs-graphene oxide for simultaneous determination of hazardous hydroquinone, catechol, and nitrite in real water samples

Hydroquinone (HQ), catechol (CC) and nitrite (NT) are considered aquatic environmental pollutants. They are highly toxic, harm humans’ health, and damage the environment. Thus, in the present work we introduce a simple and efficient electrochemical sensor for determination of HQ, CC, and NT simultaneously in wastewater sample. The sensor is fabricated by modifying the surface of a glassy carbon electrode (GCE) by two successive thin films from poly(3,4-ethylenedioxythiophene) (PEDOT) and a mixture of carbon nanotubes-graphene oxide (CNT-GRO). Under optimized conditions the HQ, CC, and NT are successfully detected simultaneously in wastewater sample with changing their concentrations in the ranges (0.04 → 100 µM), (0.01 → 100 µM) and (0.05 → 120 µM), the detection limits are 8.5 nM, 3.8 nM and 6.1 nM, respectively. Good potential peak separations: 117 mV and 585 mV are obtained between the HQ-CC, and CC-NT. The sensor has an excellent catalytic capability toward the oxidation of HQ, CC, and NT due to good synergism between its composite components: PEDOT, GRO and CNTs. The features of the sensor are large active surface area, good electrical conductivity, perfect storage stability, good reproducibility, anti-interference capability and accepted recovery rate for HQ, CC, and NT determination in wastewater sample.

A stability indicating RP-HPLC-UV assay method for the simultaneous determination of hydroquinone, tretinoin, hydrocortisone, butylated hydroxytoluene and parabens in pharmaceutical creams

Multicomponent drugs are medications that combine two or more active pharmaceutical ingredients in a single dosage form. These dosage forms improve the patient compliance, reduce the risk of drug interactions, and simplify dosing regimens. However, quality control of these multicomponent dosage forms can be challenging, especially if the final product contains four or more ingredients that are active (comprise stabilizers, preservatives, excipients, and other components). This problem can be more pronounced if the excipients can interfere with the analysis. In this work, a stability indicating assay method was developed and validated (according to the ICH International Guidelines) for the simultaneous determination of hydroquinone (HQ), tretinoin (TRT), hydrocortisone (HCA), butylated hydroxytoluene (BHT), methyl paraben (MP) and propyl paraben (PP) in commercially available pharmaceutical creams. The proposed method is based on gradient elution using X-Bridge C18 (150 × 4.6 mm, 5 µm) column with a flow rate of 1 mL/min. The linear ranges (μg/mL) were 240–560 for HQ, 24–56 for MP, 132–308 for HCA, 6–14 for PP, 12–28 for BHT, 6.6–15 for TRT. During the validation process, the intra- and interday precision and trueness (evaluated as recovery) were found to be below 2.0% and between 100–102%, respectively. System suitability tests (SST) allow validating the herein proposed procedure specifically for pharmaceutical and industrial applications. SST test shows that the reported procedure fulfill with the Guidelines, allowing excellent separation of the analytes with very sensitive, accurate (precise and true) and reproducible quantitation of each analytes. The method was successfully applied in forced degradation studies of the six analytes. Specifically, acid degradation slightly affected HCA and BHT (91% recovery), while alkaline degradation drastically reduced HCA recovery (5.5%) and moderately affected BHT (85%). Photodegradation primarily influenced TRT quantity, and oxidative degradation intensified the BHT peak (130%).

Porphyrin-based covalent organic framework integrated with nitrogen doped carbon nanotube as electrode modifier for selective and simultaneous detection of hydroquinone and catechol with high sensitivity

A novel Co-porphyrin-based covalent organic framework (TT-COF(Co)) was synthesized and further integrated with nitrogen doped carbon nanotube (N-CNTs), which was used as electrode modifier material for the application in selective and simultaneous electrochemical detection of hydroquinone (HQ) and catechol (CA). The successful formation of TT-COF(Co)/N-CNTs nanocomposite was confirmed through a series of different characterization techniques, including scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Electrochemical results indicated that TT-COF(Co)/N-CNTs nanocomposite modified electrode had excellent sensing performance for HQ and CA in phosphate buffer, enabling selectively and simultaneously determination of these two dihydroxybenzene isomers. Under optimal testing conditions, linear calibration curves for the selective determination of HQ or CA in the presence of 30 µM of the corresponding isomers were obtained over the concentration range of 0.01–500 µM. The linear ranges for the simultaneous determination of HQ and CA were 0.003–300 µM, with detection limits of 0.81 nM for HQ and 0.74 nM for CA, respectively. The sensor also demonstrated satisfactory selectivity and stability, and was successfully used to analyse HQ and CA in real water samples. Our work made a useful contribution to strategical design of functionalized COFs materials for electrochemical sensing applications.

Ultrasensitive simultaneous determination of hydroquinone and catechol by Ni3ZnC0.7/Ni porous composites derived from Ni/Zn-MOF

Rational constructing metal–organic frameworks (MOFs) based composite materials with outstanding catalytic capability is vital to accomplish high-performance electrochemical sensors. In this paper, the precursor Ni/Zn-MOF was fabricated by a simple one-step solvothermal method, and then the Ni nanoparticle-supported porous microsphere composites (Ni3ZnC0.7/Ni) were obtained by pyrolysis in N2 atmosphere. The physicochemical characteristics of the as-prepared Ni3ZnC0.7/Ni were studied by XRD, SEM, EDS, TEM, FTIR and XPS, and their electrocatalytic activity were tested by Cyclic voltammetry (CV) and differential pulse voltammetry (DPV). On this basis, an electrochemical sensor strategy for the simultaneous determination of hydroquinone (HQ) and catechol (CC) with Ni3ZnC0.7/Ni modified glassy carbon electrode (GCE) was proposed. In addition, they were applied to the electrochemical simultaneous detection of HQ and CC for the first time. Compared with NiC and ZnC modified electrode, the Ni3ZnC0.7/Ni composites modified electrode can significantly enhance electrocatalytic activity and improve the selectivity and sensitivity of the detection of HQ and CC. The performance was due to increasing the active surface area of the modified electrode and the Ni atom has excellent electrocatalytic capability to dihydroxybenzene. The experimental results exhibits that the composite was used to achieve simultaneous detection of HQ and CC in single-component or two-component solutions with satisfactory result. It has a low limit of detections (LOD = 3σ/k) (HQ: 0.14 μM, CC: 0.21 μM) and a wide detection range (HQ: 0.3–100.0 μM, CC: 0.5–100.0 μM). Meanwhile, the constructed sensor has been successfully employed for determination of HQ and CC in Yellow River water and tap water, and obtains good recovery rate. This work develops a new approach for design and engineering of MOF materials for electrochemical sensors and environmental monitoring.

Simultaneous Electrochemical Determination of Hydroquinone and Catechol by Lignocellulose Biopolymers Derived Porous Carbon

AbstractHemicellulose and lignin, which are main components of wood biomass with different structures, were carbonized and activated by KOH to prepare wood biomass‐derived porous carbons (WBM‐PCs). The resulting WBM‐PCs were characterized by SEM, XRD, Raman, FI‐IR, and N2‐adsorption/desorption isotherms, and successfully utilized as an effective modifier on the glassy carbon electrode surface (GCE) for simultaneous electrochemical determination of dihydroxybenzene isomers, i. e. hydroquinone (HQ) and catechol (CC), which are highly toxic and non‐degradable. The resulting WBM‐PCs‐modified GCEs allowed simultaneous determination of HQ and CC with cyclic voltammetry and constant‐potential amperometry. The linear range for determination of HQ by hemicellulose‐derived carbon (HC) was from 1.0 to 3000 μmol/L with the limit of detection (LOD) of 1.05 μmol/L, and that for CC was from 1.0 to 5000 μmol/L with LOD of 0.4 μmol/L. For lignin‐derived carbon (LC), the linear range for HQ was from 0.5 to 1000 μmol/L with LOD of 0.095 μmol/L, and that for CC was from 0.5 to 3000 μmol/L with LOD of 0.15 μmol/L. These results imply that wood biomass (hemicellulose and lignin), which is sustainable, renewable and environment‐friendly material, have potential as an effective precursor of electrochemically active porous carbon materials applicable to various electrochemical sensors.

Metal-organic framework (MOF)-derived flower-like Ni-MOF@NiV-layered double hydroxides as peroxidase mimetics for colorimetric detection of hydroquinone

BackgroundNanozymes are one of the ideal substitutes for natural enzymes because of their excellent chemical stability and simple preparation methods. However, due to the limited catalytic ability of most reported nanozymes, constructing nanomaterials with low cost and high activity is gradually becoming an exploration focus in the field of nanozymes. Heteroatom doping of metal-organic frameworks is one of potential approaches to design nanozymes with high catalytic performance. Due to their multiple valence states properties, V-doped metal-organic framework (MOF)-derived LDH is expected to be a good enzyme-like catalyst. To our knowledge, the V-doped MOF-derived LDH as nanozyme is not explored before. ResultsWe report the in-situ synthesis of NiV-layered double hydroxides (LDHs) on nickel-based MOF, i.e. Ni-MOF@NiV-LDHs. The MOF surface is covered by 2D nanosheets. This unique structural design increases the specific surface area of the material, enables more exposure of catalytic active sites to participate in reactions and accelerates the electron transfer rate. The Ni-MOF@NiV-LDHs have high peroxidase-like activity able to catalyze TMB oxidation by H2O2 via the generation of •OH and O2•−. Relative to Ni-MOF, the Ni-MOF@NiV-LDHs shows 47-fold peroxidase-like activity rise. It had good affinity to TMB and H2O2, with the Michaelis-Menten constants of 0.12 mM and 0.007 mM, respectively. The hydroquinone (HQ) consumed the reactive oxygen species generated in the TMB + H2O2+Ni-MOF@NiV-LDHs system to inhibit the TMB oxidation. On this basis, a sensitive and rapid assay for determining HQ was developed, with a linear range of 0.50–70 μM and a LOD of 0.37 μM. SignificanceThis work provided some clues for the further development of novel nanozymes with high catalytic performance via a strategy of heteroatom doping. And the constructed colorimetric analysis method was successfully utilized for the determination of HQ in actual waters, which has the potential for practical application in the analysis of environmental pollutants.

Electrochemical Sensor for Simple and Sensitive Determination of Hydroquinone in Water Samples Using Modified Glassy Carbon Electrode.

This study addressed the use of manganese dioxide nanorods/graphene oxide nanocomposite (MnO2 NRs/GO) for modifying a glassy carbon electrode (GCE). The modified electrode (MnO2 NRs/GO/GCE) was used as an electrochemical sensor for the determination of hydroquinone (HQ) in water samples. Differential pulse voltammetry (DPV), cyclic voltammetry (CV), and chronoamperometry were used for more analysis of the HQ electrochemical behavior. Analyses revealed acceptable electrochemical functions with lower transfer resistance of electrons and greater conductivity of the MnO2 NRs/GO/GCE. The small peak-to-peak separation is an indication of a rapid electron transfer reaction. Therefore, this result is probably related to the effect of the MnO2 NRs/GO nanocomposite on the surface of GCE. In the concentration range of 0.5 μM to 300.0 μM with the detection limit as 0.012 μM, there was linear response between concentration of HQ and the current. The selectivity of the modified electrode was determined by detecting 50.0 μM of HQ in the presence of various interferent molecules. At the end, the results implied the acceptable outcome of the prepared electrode for determining HQ in the water samples.

Quantitative determination of hydroquinone via electrochemical methods at nano-architecture platinum electrode

Hydroquinone (HQ) was electrochemically measured using convolutive cyclic voltammetry and differential pulse voltammetry (DPV) on a nano-architecture mesoporous platinum film electrochemically grown from a hexagonal liquid crystalline template of C16EO8 surfactant in 1.0 mol/l HClO4. The HQ cyclic voltammograms produced one oxidative peak in the forward sweep of potential and one reductive peak in the reverse sweep. The effect of HQ concentration was investigated using the different electrochemical methods mentioned above. The modified platinum electrode exhibits good sensitivity for the determination of the HQ compound in 1.0 mol/l HClO4. The best executive was found for the i-t curve method developed from cyclic voltammetry of HQ. It exhibits a linear peak current response over the concentration range of 8 to 55 µmol/l, with a detection limit of 0.5726 µmol/l and a quantification limit of 1.9088 µmol/l, confirming the accuracy and sensitivity of this quick, cheap, and easy method.