μM For Catechol 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 Detection of Catechol and Hydroquinone Based on a Carbon Nanotube Paste Electrode Modified with Electro-Reduced Graphene Oxide.

Effectively detecting catechol (CC) and hydroquinone (HQ) simultaneously is crucial for environmental protection and human health monitoring. In the study presented herein, a novel electrochemical sensor for the sensitive simultaneous detection of CC and HQ was constructed based on an electrochemically reduced graphene oxide (ERGO)-modified multi-walled carbon nanotube paste electrode (MWCNTPE). Scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and electrochemical techniques were utilized to characterize the sensing interface and investigate the sensing mechanism. Under the optimal detection conditions, the oxidation peak currents of CC and HQ show a good linear relationship with their concentrations in the range of 0.4-400 μM with a detection limit of 0.083 μM for CC and 0.028 μM for HQ (S/N = 3). Moreover, the sensor exhibits good performance and can be applied successfully in the simultaneous detection of CC and HQ in tap water samples and urine samples with satisfactory results, indicating its promising application prospects.

A stable and efficient electrochemical sensor for hydroquinone and catechol detection in real-world water samples using mesoporous CaM@rGO nanocomposite

Hydroquinone (HQ) and catechol (CC) are widespread environmental pollutants known for their high toxicity and poor biodegradability. Herein, we devised an electrochemical sensor for sensitive and selective detection of HQ and CC. The glassy carbon electrode (GCE) was meticulously modified by using the Ca-perovskite (CaTiO3/GCE), zinc-based metal-organic frameworks (Zn-MOF/GCE), and their nanocomposite with reduced graphene oxide (rGO), i.e., CaTiO3-Zn-MoF@rGO/GCE (CaM@rGO/GCE). The CaM@rGO/GCE sensor showed stupendous electrochemical performance due to the synergistic effects of rGO's high conductivity and Ca-perovskite's electrocatalytic activity. Furthermore, the Zn-MOF component ensures the sensor's remarkable stability. The developed sensor boasts impressive selectivity towards HQ and CC, achieving exceptionally low detection limits (0.0086 µM (S/N = 3) for HQ, 0.0115 µM (S/N = 3) for CC), and broad linear ranges (0.05–105 µM for HQ, 0.05–120 µM for CC). The sensor shows better sensitivity to hydroquinone (HQ) than catechol (CC) due to the absence of intramolecular hydrogen bonding in HQ. The sensor's real-world applicability was validated by analyzing environmental water samples, demonstrating its immense potential for practical environmental monitoring.

Electrochemical detection of benzenediols using carbon-supported catalysts

A novel implementation of an electrochemical sensors making use of Screen-Printed Electrodes (SPE) has been discussed. SPE's modified with Carbon-supported Platinum (Pt/C) and Gold (Au/C) were used to detect the three benzenediol isomers, Catechol (CC), Hydroquinone (HQ) and Resorcinol (RS) in acidic media using traditional electrochemical analytical methods such as Cyclic Voltammetry (CV), Chronoamperometry (CA) and Differential Pulse Voltammetry (DPV). Detection of each benzenediol in isolation was possible by CV measurements, and peak oxidation potentials for each isomer were noted. Simultaneous detection of more than one, or all analytes in the same solution was also observed through DPV, once again noting the peak oxidation potentials. Quantification limits were observed using CA's across concentration values ranging from close to saturation down to 1 mM for CC and HQ, and 100 nM for RS, until the recorded current values were nearly indistinguishable to a blank 1 M HCl solution containing no analyte(s), and also evaluating the maximum possible linear range of sensing. The analytes were introduced to the sensor elements in controlled amounts and the electrochemical responses of the sensor elements were recorded and processed. Measurements were repeated across two potentiostats to ensure reproducibility. With these results, successful detection of benzenediols in acidic environment was possible using modified SPE's, proving a potential viable mechanism for quick, simple and inexpensive Volatile Toxic Organic Compounds (VTOC) detection and monitoring.

A bimetallic PtAu-modified carbon fiber electrochemical sensor for simultaneous and highly sensitive detection of catechol and hydroquinone in environmental water.

In this study, we report the development of a novel electrochemical sensor capable of the simultaneous detection of catechol (CC) and hydroquinone (HQ) through differential pulse voltammetry. The sensor is constructed using carbon fiber (CF) that has been intricately modified with bimetallic PtAu nanoparticles. The fabrication process involves subjecting CF to ultrasound treatment in an acidic mixture, resulting in the formation of activated carbon fiber (ACF). This activation step not only enhances surface roughness but also facilitates subsequent modification, ensuring the stability of the material. Bimetallic PtAu nanoparticles are then uniformly deposited onto the ACF surface through co-deposition from a metal precursor solution. The modified ACF, adorned with bimetallic PtAu nanoparticles, exhibits excellent conductivity and efficiently catalyzes both CC and HQ in a 10 mM phosphate-buffered saline solution at pH 7.0, thereby enabling their simultaneous detection. Under optimized experimental conditions, this electrochemical sensor achieves impressive detection limits of 0.019 μM for CC and 0.28 μM for HQ within the same concentration range of 0.5-50 μM, respectively. The practicality of the sensor is further demonstrated through recovery experiments using real water samples. This electrochemical sensor, with its superior performance and versatility, shows great potential for applications in analytical chemistry and environmental monitoring.

Fabrication and application of glutathione biosensing SPCE strips with gold nanoparticle modification.

Glutathione (GSH) is a major antioxidant in organisms. An alteration in GSH concentration has been implicated in a number of pathological conditions. Therefore, GSH sensing has become a critical issue. In this study, a disposable strip used for tyrosinase-modified electrochemical testing was fabricated for the detection of GSH levels in vivo. The system is based on tyrosinase as a biorecognition element and a screen-printed carbon electrode (SPCE) as an amperometric transducer. On the tyrosinase-SPCE strips, the oxidation reaction from catechol to o-quinone was catalyzed by tyrosinase. The tyrosinase-SPCE strips were modified with gold nanoparticles (AuNPs). In the presence of AuNPs of 25 nm diameter, the cathodic peak current of cyclic voltammetry (CV) was significantly enhanced by 5.2 fold. Under optimized conditions (250 μM catechol, 50 mM phosphate buffer, and pH 6.5), the linear response of the tyrosinase-SPCE strips ranged from 31.25 to 500 μM GSH, with a detection limit of approximately 35 μM (S/N > 3). The tyrosinase-SPCE strips have been used to detect real samples of plasma and tissue homogenates in a mouse experiment. The mice were orally administrated with N-acetylcysteine (NAC) 100 mg kg-1 once a day for 7 days; the plasma GSH significantly enhanced 2.8 fold as compared with saline-treated mice (1123 vs. 480 μM μg-1 protein). NAC administration also could alleviate the adverse effect of GSH reduction in the mice treated with doxorubicin.

N,Si co-doped GQDs: Facile green preparation and application in visual identifying dihydroxybenzene isomers and selective quantification of catechol, hydroquinone and antioxidants

A green economical procedure for preparing N,Si co-doped graphene quantum dots (N,Si-GQDs) using waste toners and ethylene diamine was reported, which not only minimizes waste and promotes recycling but also offers an alternative method for producing N,Si-GQDs. At a pH of 8.5, hydroquinone and catechol underwent oxidation in the presence of air, resulting in the formation of diquinones, specifically p-phenyldiquinone and o-phenyldiquinone. Resorcinol, on the other hand, was converted into monoquinone. The interaction between diquinones and N,Si-GQDs caused a linear fluorescence quenching effect when catechol and hydroquinone were present. However, this effect was minimal in the case of resorcinol. Furthermore, the antioxidants glutathione (GSH) and ascorbic acid (AA) were observed to disrupt the redox equilibrium of catechol and o-phenyldiquinone, leading to the activation of fluorescence. Conversely, hydroquinone and p-phenyldiquinone, due to the highly stable and symmetrical structure of p-phenyldiquinone, did not exhibit this fluorescence activation. Based on the described “Off-On” sensor system, it was possible to visually identify dihydroxybenzene isomers and selectively quantify catechol and hydroquinone in environmental samples, as well as GSH and AA in human serum. The method detection limits were 0.93, 1.35, 2.34, and 1.37 μM for catechol, hydroquinone, GSH, and AA, respectively. In conclusion, the presented procedure offers several advantages, including environmental friendliness, cost-effectiveness, and a means of recycling waste toners. It also demonstrates the successful synthesis of N,Si-GQDs, as well as the potential for their application in the “Off-On” sensor system for the detection and quantification of various analytes.

Synthesis of Graphene Oxide-Coupled CoNi Bimetallic MOF Nanocomposites for the Simultaneous Analysis of Catechol and Hydroquinone.

Herein, a three-dimensional flower-like cobalt-nickel bimetallic metal-organic framework (CoNi-MOF) coupled with two-dimensional graphene oxide (GO) nanocomposites was successfully synthesized for the selective and simultaneous electrochemical determination of catechol (CC) and hydroquinone (HQ). The three-dimensional flower-like structure of the CoNi-MOF/GO nanocomposite has a multilayer structure and a large surface area, which greatly improves its electrocatalytic activity towards CC and HQ. Differential pulse voltammetry (DPV) results showed that the peak-to-peak separation of CC (0.223 V) and HQ (0.120 V) was 103 mV at a CoNi-MOF/GO modified glassy carbon electrode (CoNi-MOF/GO/GCE), suggesting that the proposed modified electrode can selectively and simultaneously determine them. Under optimal conditions, the CoNi-MOF/GO/GCE showed an excellent analytical performance for the simultaneous determination of CC and HQ, including a wide linear range (0.1-100 μM), low detection limit (0.04 μM for HQ and 0.03 μM for CC) and high anti-interference ability. As expected, the developed modified electrode has been used to analyze CC and HQ in river water, with acceptable results.

Exploring the substrate scope of glycerol dehydrogenase GldA from E. coli BW25113 towards cis-dihydrocatechol derivatives

Glycerol dehydrogenase (GldA) from Escherichia coli BW25113, naturally catalyzes the oxidation of glycerol to dihydroxyacetone. It is known that GldA exhibits promiscuity towards short-chain C2-C4 alcohols. However, there are no reports regarding the substrate scope of GldA towards larger substrates. Herein we demonstrate that GldA can accept bulkier C6-C8 alcohols than previously anticipated. Overexpression of the gldA gene in the knockout background, E. coli BW25113 ΔgldA, was strikingly effective converting 2 mM of the compounds: cis-dihydrocatetechol, cis-(1 S,2 R)− 3-methylcyclohexa-3,5-diene-1,2-diol and cis-(1 S,2 R)− 3-ethylcyclohexa-3,5-diene-1,2-diol, into 2.04 ± 0.21 mM of catechol, 0.62 ± 0.11 mM 3-methylcatechol, and 0.16 ± 0.02 mM 3-ethylcatechol, respectively. In-silico studies on the active site of GldA enlightened the decrease in product formation as the steric substrate demand increased. These results are of high interests for E. coli-based cell factories expressing Rieske non-heme iron dioxygenases, producing cis-dihydrocatechols, since such sough-after valuable products can be immediately degraded by GldA, substantially hampering the expected performance of the recombinant platform.

Flexible electrochemical sensor constructed using an active copper center instead of unstable molybdenum carbide for simultaneous detection of toxic catechol and hydroquinone

A new electrochemical sensor based on a Cu-CuO@MoOx-modified polyethylene terephthalate electrode spin coated with PEDOT (Cu-CuO@MoOx-PEDOT/PET) was developed for simultaneous determination of catechol (CT) and hydroquinone (HQ). A zerovalent copper and copper(II) oxide intercalated molybdenum oxide MoOx (x = 2 or 3) hybrid nanomaterial (Cu-CuO@MoOx) by introducing active copper catalytic centers into the Mo2C@MoOx system based on unstable Mo2C, and replaced Mo2C using a simple hydrothermal method. At room temperature, the Cu-CuO@MoOx-PEDOT/PET electrode demonstrated the lowest detection limits of 0.216 and 0.221 μM for CT and HQ (S/N = 3), respectively. In addition, the applicability of this method was proven by the recovery of CT and HQ in spiked tap water samples. The Cu-CuO@MoOx-PEDOT/PET flexible electrode had strong anti-interference ability, good repeatability and long-term stability. It was used in the detection of CT and HQ in Nanjing tap water, the recoveries of CT and HQ calculated from the i–t curve were 99.36 % and 97.56 %, respectively. Most importantly, the flexible electrode could still maintain relatively stable electrochemical responses under different bending and folding conditions, and the obtained relative standard deviations (RSDs) were 2.78 % and 1.53 %, respectively. This flexible property holds promise for the construction of wearable electrochemical sensors.

Insights into the enhanced electrochemical sensing behavior of hydroquinone and catechol simultaneously enabled by ultrafine layer CoP-NiCoP heterostructure on graphene frameworks.

Hydroquinone (HQ) and catechol (CC), two major dihydroxybenzene isomers, are toxic pollutants coexisting and impeding each other in the process of sample identification. Well-defined nanostructure and interface engineering enable the optimization of electrocatalysts for constructing highly efficient electrochemical sensors to realize detection of HQ and CC simultaneously. Herein, CoP-NiCoP heterojunction nanosheet with ultrafine layer-like morphology is designed and synthesized using graphene frameworks (GFs) as supporter via a solid-state phase transformation strategy (defined as CoP-NiCoP/GFs). Notably, the CoP-NiCoP/GFs displays enhanced electrocatalytic activity toward both HQ and CC compared with CoP/GFs, NiCoP/GFs, and GFs. Density functional theory calculations prove that the CoP-NiCoP structure is more favorable for the adsorption and desorption of both HQ and CC than those of CoP and NiCoP, thus could accelerate the HQ and CC electrocatalytic oxidation reaction on CoP-NiCoP/GFs electrode. A novel electrochemical sensing platform is developed based on CoP-NiCoP/GFs for detection of HQ and CC with wide linear detection ranges and low detection limits (0.256 μM for HQ and 0.379 μM for CC). Meanwhile, the proposed sensor could effectively determine HQ and CC in actual river water. This work demonstrates the great potential of NiCo-based metal phosphide in constructing an efficient dihydroxybenzene electrochemical sensor.

Facile preparation of silver nanoparticle decorated RGO nanostructures with enhanced simultaneous detection property for hydroquinone and catechol

Well-dispersed reduced graphene oxide (RGO) nanostructures with uniform decoration of silver nanoparticles (AgNPs) on them have been prepared through a hydrothermal process followed by the freeze-drying method. The obtained graphene-layer-like structure with uniform distribution of AgNPs have then been applied on the glassy carbon electrodes (GCE) to detect different concentration of hydroquinone (HQ) and catechol (CC) in their mixed solutions. Because of such well-dispersed structure and uniform distribution of AgNPs, the AgNPs/RGO/GCE illustrated enhanced simultaneous detection performance for HQ and CC. In the HQ and CC mixed solution with pH of 6.0, the AgNPs/RGO/GCE electrode exhibits a wide linear range of HQ (0.18–130 μM) and CC (0.07–120 μM), and accurate limit of detection (2.37 × 10−2 μM for HQ and 5.8 × 10−2 μM for CC). Thus, it is believed that the AgNPs/RGO nanostructures shows a great potential of applying as possible probes for simultaneous detection of HQ and CC in real environment.

A Novel Sensor Based on Cu2O/Mo2C@C Derived from MOF Composites for Simultaneous Detection of Catechol and Hydroquinone

Herein, the copper-based metal organic framework (CuBDC) modified with MoO3 nanorods uniformly distributed on its surface (MoO3@CuBDC) was synthesized by a one-step solvothermal method, and then was treated with high temperature calcination. A series of characterizations demonstrate that MoO3@CuBDC was transformed into a ternary composite of Cu2O nanospheres, Mo2C, and carbon material (Cu2O/Mo2C@C) after the treatment. Moreover, a novel electrochemical sensor based on Cu2O/Mo2C@C modified glassy carbon electrode (GCE) was constructed for simultaneous sensitive detection of catechol (CC) and hydroquinone (HQ). Due to the excellent electrocatalytic ability of Cu2O/Mo2C@C, the prepared sensor exhibits good electroanalytical performance, which shows good linearity in the concentration ranges of 0.50–200.00 μM for CC and HQ with the limits of detection of 0.38 μM and 0.13 μM. In addition, this sensor can be used to detect CC and HQ simultaneously in real samples with satisfactory results.

Simultaneous Determination of Catechol and Hydroquinone using Gold Nanoparticles/Poly(p-aminobenzenesulfonic acid)/Multi-Walled Carbon Nanotubes Modified Glassy Carbon Electrode

Gold nanoparticles/poly(p-aminobenzenesulfonic acid)/multi-walled carbon nanotubes modified glassy carbon electrode (NanoAu/Poly(ABSA)/MWCNTs/GCE) was prepared for electrochemically determining catechol (CAT) and hydroquinone (HQ) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Results showed that CAT and HQ were electrochemically seperated well, and the difference between oxidation peak potentials of CAT and HQ was 111 mV. The redox currents of CAT and HQ were significantly enhanced on NanoAu/PABSA/MWCNTs/GCE, as compared with on bare GCE. The oxidation peak current (I pa) of 10 μM CAT was 0.24 μA, and there was almost no detected oxidation current response for 10 μM HQ on bare GCE. The I pa values on NanoAu/Poly(ABSA)/MWCNTs/GCE increased to 11.3 times for CAT as compared with on GCE, 1.5 times for CAT and 2.5 times for HQ as compared with on MWCNTs/GCE. The linear range of CAT and HQ measurments on NanoAu/Poly(ABSA)/MWCNTs/GCE was 2 ∼ 200 μM, and the limit of detection (LOD, S/N = 3) was 1.5 μM for CAT and 1.0 μM for HQ. This sensor showed high detection sensitivity for CAT (16.53 μA·μM–1·cm–2) and HQ (17.68 μA·μM–1·cm–2). The sensor had been applied for CAT and HQ measurement in lake water with satisfactory results.

Simultaneous detection of dihydroxybenzene isomers in the environment by a free-standing flexible ZnCo2O4 nanoplate arrays/carbon fiber cloth electrode

The simultaneous determination of dihydroxybenzene isomers is highly valuable for early environmental monitoring, but it is still a challenge. In this work, a free-standing flexible electrode was prepared for the simultaneous detection of hydroquinone (HQ), catechol (CC), and resorcinol (RC). The bimetallic zinc/cobalt zeolitic imidazolate frameworks nanoplate arrays (Zn/Co-ZIF NPAs) grown in situ on the carbon fiber cloth (CFC) was fabricated by a facile static synthesis method, and the porous ternary ZnCo2O4 NPAs derived from Zn/Co-ZIF NPAs were formed by annealing in air. Due to the fast electron transmission, abundant active sites and excellent electrocatalytic properties with enzyme-like kinetic performance of the ZnCo2O4/CFC electrode, the as-proposed sensor showed a wilder linear response (2–500 μM), a lower detection limits (0.03 μM HQ, 0.06 μM CC and 0.15 μM RC) and a higher sensitivity (23.58 μA μM−1 cm−2 HQ, 17.72 μA μM−1 cm−2 CC, and 15.18 μA μM−1 cm−2 RC), respectively. More importantly, the proposed electrochemical sensor exhibited excellent detection performance in complex water samples, providing a strategy for the detection of other toxic substances in the ecological environment.

Simultaneous electrochemical detection of antioxidants Hydroquinone, Mono-Tert-butyl hydroquinone and catechol in food and polymer samples using ZnO@MnO2-rGO nanocomposite as sensing layer

A sensing layer containing ZnO@MnO2-rGO nanocomposite was used for modification glassy carbon electrode (GCE) for monitoring some antioxidant molecules including Hydroquinone (HQ), Mono-Tert-butyl hydroquinone (MTBHQ) and catechol (CC). The resulting ZnO@MnO2-rGO/GCE exhibited significant electrocatalytic activities toward the electro-oxidation of MTBHQ, HQ, and CC in the linear range (LR) of 0.008 to 10 µM and 10 to 350 µM for MTBHQ, 0.008 to 10 µM and 10 to 320 µM for HQ, 0.008 to 8 µM and 8 to 330 µM for CC with the limits of detection (LOD) of 0.0011, 0.0012 and 0.001 µM, respectively by differential pulse voltammetric (DPV). The prepared sensor has been used to analysis of different real samples containing target analytes with satisfactory results. Based on the percentage of recovery range (95.5–104.4 %), Relative standard deviation (RSD%, below 3.51 %), and the obtained data from the HPLC method, the presented method are accurate with acceptable precision.

Longquan lignite-derived hierarchical porous carbon electrochemical sensor for simultaneous detection of hazardous catechol and hydroquinone in environmental water samples

Catechol (CC) and hydroquinone (HQ) featured with toxicity and wide application are regarded as organic pollutant in wastewater, so the detection of CC and HQ is very important. Besides, direct use of low-rank lignite for combustion is not only wasteful, but also leads to increased greenhouse gas production. Hence, its efficient and clean utilization accords with the process of social development and the concept of carbon neutrality. Based on the above two problems, a method of killing two birds with one stone was proposed to solve the clean utilization of lignite and be used to detect CC and HQ. Herein, a series of porous carbons derived from Longquan lignite with well-developed microporous and mesoporous structure were fabricated by pyrolysis, carbonization, and activation under various activation temperatures (600–900 °C). This combination of microporous and mesoporous structures can increase the surface area (3113 m2/g) and the active site of the porous carbon, improve its electrical conductivity and electron transport efficiency, and make it as a substrate for constructing electrochemical sensor (ECS) with excellent electrocatalytic activity, and successfully be applied in simultaneous detection of CC and HQ. Compared with some reported results, the prepared ECS exhibits satisfactory electrochemical sensing performance with wider linear concentration range and lower detection limits of 0.16 μM for CC and 0.16 μM for HQ, which is comparable to graphene-based sensors. Furthermore, the ECS possesses good stability, reproducibility, selectivity, and anti-interference, and shows practical applicability in environmental water samples.

N, S dual doped mesoporous carbon assisted simultaneous electrochemical assay of emerging water contaminant hydroquinone and catechol

Heteroatom doped mesoporous carbon materials are promising catalysts for the electrochemical sensing application. Herein, we report highly efficient dual heteroatom-doped hexagonal mesoporous carbon (MC) derived from Santa Barbara Amorphous-15 (SBA-15) hard template for the detection of phenolic isomers. The synthesis involves dopamine hydrochloride (DA)/thiophene complex, which helps to attain perfectly retained N and S dual doped mesoporous carbon (NS-MC) framework. NS-MC exhibits higher surface area (951 m2 g−1) as well as higher pore volume (0.12 cm3 g−1) with huge graphitic, pyridinic and thiophenic defective sites which facilitates the well-resolved simultaneous electrochemical detection of phenolic isomers hydroquinone (HQ) and catechol (CC). Our results demonstrate that as-synthesized NS-MC material had a LOD of 0.63 μM and 0.29 μM for HQ and CC, respectively. From the calibration curve, sensitivities of proposed sensor were found to be 9.44, 2.71 μA μM−1 cm−2 and 20.80, 10.02 μA μM−1 cm−2 for HQ and CC, respectively with good linear ranges of 10–45 μM and 45–115 μM for HQ; 2–16 μM and 16–40 μM for CC. The NS-MC modified electrode exhibited good selectivity over various possible interferences. The present investigation reveals that the proposed NS-MC material is a promising metal-free catalyst which boosted to electrochemically detect both HQ and CC, present in the municipal tap as well as natural river stream water samples.

Electrochemical detection of bisphenol A in presence of catechol and hydroquinone at copper oxide modified carbon paste electrode

Utilizing co-precipitation method copper oxide (CuO) nanomaterials are prepared and analyzed using X-ray diffraction (XRD), Scanning electron microscope (SEM), and Energy-dispersive X-ray Analysis (EDAX) technique. Copper oxide modified carbon paste electrode (CuOMCPE) were used as electrochemical sensor for the study of catechol, bisphenol A and hydroquinone using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The analyte species shows high reproducibility in voltammetric response because of his enhancement. The CuOMCPE exhibits the better electrocatalytic property for the oxidation of BPA, CC and HQ. Parameters like scan rate and concentration of Bisphenol A (BPA), catechol (CC) and hydroquinone (HQ) were studied by CuOMCPE. The effect of scan rate on CuOMCPE was studied individually for BPA, CC, and HQ and shows that the electrode process was adsorption-controlled. The modifier exhibits good limit of detection (LOD) and limit of quantification (LOQ) values are found at 2.48 μM and 8.26 μM for BPA, 3.22 μM and 10.73 μM for CC, 4.94 and 16.48 μM for HQ respectively. The CuOMCPE shows high stability and reproducibility compared to BCPE. DPV were studied using CuOMCPE gives three well defined peaks located at 0.4406(BPA), 0.1043 V (CC) and 0.0075 V (HQ) respectively. The simultaneous and interference study of analytes were studied using CuOMCPE. Hence, the modifier exhibits good selectivity and sensitivity for the study of BPA, HQ and CC.

Electrochemical sensors for hydroquinone and catechol based on nano-flake graphite and activated carbon sensitive materials

The nano-flake graphite and bamboo activated carbon composites (NFG-BAC) were obtained by simple ball-milling and carbonization of bamboo powder and flake graphite at high temperature, which was modified on the surface of the electrode to obtain an electrochemical sensor for the simultaneous separation and determination of hydroquinone (HQ) and catechol (CC). NFG-BAC showed good wettability to electrolyte solution and adsorption capacity to target analytes. NFC-BAC composites possess both the rich porosity and high specific surface area of activated carbon and the good conductivity of nano-flake graphite. Moreover, NFG-BAC composites show good wettability to electrolyte solution and adsorption capacity to target analytes. Compared with the gold-standard methodology for water analysis, electrochemical sensing has fast, sensitive and other advantages. When the NFG-BAC/GCE sensor is used for quantitative analysis of HQ and CC, the linear range is wide (2–1000 μM for HQ and 1–1000 μM for CC), the detection limit is low (0.4 μM for HQ and 0.2 μM for CC), and the detection accuracy of these two pollutants in environmental water samples is high. Due to the sensor fabrication is simple, low-cost and efficient, the NFG-BAC/GCE sensor can be used for real-time monitoring of the pollution of catechol in environmental water samples.