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Construction of an oxygen detection-based optic laccase biosensor for polyphenolic compound detection
摘要： A fiber optic biosensor was constructed from Pleurotus ostreatus laccase for the detection of polyphenolic compounds. Laccase was immobilized on the surface of the commercially available fiber optic oxygen sensor spots by using 3-aminopropylsilanetriol, tetramethyl orthosilicate (TMOS), glutaraldehyde, and amino-modified carboxycellulose. A diffusion layer containing trimethoxymethylsilane (Tri-MOS), and polyvinyl alcohol (PVA) was added to the immobilized laccase layer. The consumption of oxygen as a result of laccase activity was monitored using a fiber optical measuring setup with catechol as a model substrate. The optimal enzyme amount was determined as 1.5 mg per 50 μL of enzyme layer mixture, and with one diffusion layer and at pH 6.9, optimum detection conditions were attained. The biosensors have high reproducibility, stability (at least 85 days if stored in PBS at 4 °C), and convenient measurement duration (ca. 25 min between two successive measurements). The biosensor was found to have a broad linear working range for catechol (40–600 μM) and to be applicable to a flow-through system. In summary, an easy-to-produce, reproducible, and stable laccase sensor with a broad linear working range was produced. The sensor has potential in the food industry as well as in environmental monitoring for the detection of phenolic compounds.
关键词： catechol,phenolic compounds,oxygen-based optic sensor,Laccase biosensor
更新于2025-09-23 15:23:52
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A novel non-enzymatic zinc oxide thin film based electrochemical recyclable strip with device interface for quantitative detection of catechol in water
摘要： Catechol, one of the major effluents released by various chemical and metal processing industries, causes severe pollution of groundwater. Monitoring of catechol in water using cost-effective, handheld sensor is demanding for the safety of the environment. In this work, non-enzymatic zinc oxide thin film based electrochemical strip sensor is developed on conducting glass substrate for detection of catechol. The preparation of strip without employing standard Pt or Ag/AgCl electrodes and simply depositing ZnO through wet chemical process represents a cost-effective innovative technique. The ZnO thin film is characterized using field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM) and grazing incidence X-ray diffractrometer (GIXRD). Catechol is electrochemically detected by means of cyclic voltammetry and amperometry. A prominent redox peak of the developed strip attributed to the detection of catechol is observed at -0.26 V in cyclic voltammetry. The strip is integrated with readout meter and an algorithm is built based on the experimentally observed linear variation of amperometric current with catechol concentration. The quantitative detection performance is demonstrated by testing 0.1-12 ppm catechol solutions.
关键词： Zinc oxide,Catechol,Electrochemical strip sensor,Amperometry,Cyclic voltammetry
更新于2025-09-23 15:23:52
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Highly selective and sensitive detection of catechol by one step synthesized highly fluorescent and water-soluble silicon nanoparticles
摘要： Because the chemical properties and structures of catechol and its analogues (hydroquinone and resorcinol) are similar, it still is a great challenge to detect catechol from other hydroxybenzene isomers with high accuracy and reliability. Herein, a selective and sensitive method based on the water soluble silicon nanoparticles (Si NPs) was established for catechol detection, and to the best of our knowledge, this is the first time using Si NPs for catechol measurement. The synthesis of Si NPs was very cheap and simple, no time-consuming, and no need for high temperature processing, or special instrument. The as-synthesized Si NPs, with high salt and temperature stabilities emitted yellow-green fluorescence (540 nm). A good linear relationship was observed from 0.06 to 40 μM and the limit of detection (based on 3s/k) was calculated as 20 nM, and the sensor displayed a significant selectivity toward catechol over other dihydroxybenzene isomers. Moreover, the Si NPs were applied in tap water, human serum samples and Yellow River water for catechol measurement.
关键词： Silicon nanoparticles,Catechol,Fluorescence
更新于2025-09-23 15:21:01
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A sensitive method to monitor catechol by using graphitic carbon nitride quantum dots as coreactants in Ru(bpy)32+-based electrochemiluminescent system
摘要： Graphitic carbon nitride quantum dots (g-CNQDs) with special structures have exhibited fascinating advantages over the common QDs. In this work, we report a novel Ru(bpy)3 2+/g-CNQDs electrochemiluminescence (ECL) system, and the effect of g-CNQDs on the ECL signal of Ru(bpy)3 2+ was discussed. It was found that g-CNQDs containing in proposed ECL system played an important coreactant role in ECL signal enhancement of Ru(bpy)3 2+, which was proved by electrochemical, ultraviolet, and ECL experiments. Based on the quenching effect of catechol on the ECL signal of Ru(bpy)3 2+/g-CNQDs, a quenching-based ECL system was designed for catechol determination. The ECL sensing system demonstrated high sensitivity to catechol, with a linear range from 10 nM to 2 mM and a detection limit of 2.5 nM (S/N = 3). The sensor was adopted for catechol analysis in tea samples with satisfactory results.
关键词： Detection,Ru(bpy)3 2+,Electrochemiluminescence,Graphitic carbon nitride quantum dots,Catechol
更新于2025-09-23 15:19:57
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Off-on fluorescent switching of boron-doped carbon quantum dots for ultrasensitive sensing of catechol and glutathione
摘要： A signal-off-on probe of B-doped carbon quantum dot (B-CQD) is developed for ultrasensitive detection of catechol (CC) by fluorescence quenching and glutathione (GSH) by fluorescence recovering without any auxiliary of biomolecules or labeled materials. In this sensing system, the B-CQDs with a high quantum yield of 42% are prepared via a facile hydrothermal method with precursors of citric acid as C source and sodium tetraphenylborate as B source. The microstructure and fluorescence stability of the B-CQDs are investigated. Under the optimum conditions, the B-CQDs are highly sensitive for detecting CC with a linear range of 1-50 nM and a detection limit of 0.25 nM under a typical signal-to-noise ratio of 3 to 1 (S/N=3), and for sensing GSH with a linear range of 2-100 nM and a detection limit of 0.5 nM (S/N=3). Meanwhile, the developed B-CQDs show a good selectivity for sensing CC and GSH under high concentrations of interfering substances, such as biological thiols and amino acids. The B-CQDs are successfully applied to determination of CC in river water and GSH in human serum, where the recoveries are 103.3%-106.0% and 99.8%-106.3% for CC and GSH sensing, respectively. The signal-off-on mechanisms of the B-CQDs sensor are discussed.
关键词： Glutathione,B-doped carbon quantum dot,Sensitivity,Fluorescent sensing,Catechol
更新于2025-09-23 15:19:57
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Optical Fiber Probe for the Selective Plasmonic Sensing of Catechol Utilizing ZnO Decorated MWCNTs
摘要： The widespread use of dihydroxybenzenes in various industries like photography, pesticides, dyes, antioxidants and medicines has lead their inadvertent disposal in soil and water. Catechol is an isomer of dihydroxybenzene whose disposal in ground and river water has necessitated requirement of its highly sensitive sensor due to its toxic effects. Being of polar nature it is easily uptaken by cells but not released properly leading to its accumulation in cells. It is regarded as human group 2B carcinogen by IARC with severe effect on central nervous system. Due to its toxicity, co-carcinogenic activity and low biodegradability it is declared as serious threat for ecology by USEPA and Europian Union [1, 2]. Therefore, we report, here, a selective and sensitive surface plasmon resonance (SPR) based catechol sensor utilising zinc oxide decorated multi-walled carbon nanotubes (MWCNTs) functionalised with CTAB (cetyl trimethyl ammonium bromide) as a sensing layer on an optical fiber probe. Surface plasmon technique makes the sensor highly sensitive, whereas use of an optical fiber provides the advantage of miniaturised probe with facility of continuous online monitoring. The sensor fabrication broadly consists of three steps. The first step involves the chemical route for the preparation of nanocomposite. Firstly, ZnO nanoparticles were prepared through the reduction of zinc acetate by NaOH. Then the nanoparticles were decorated on sidewall functionalised MWCNTs followed by functionalization with CTAB [3]. The TEM image of ZnO decorated MWCNTs is shown in fig.1(a). The second step involves the thermal deposition of silver on 1 cm uncladded region of the fiber probe. Finally, the nanocomposite was coated on the fiber probe by dip coating method. All the steps of probe fabrication are schematically depicted in fig.1(b). To characterize, the probe was fixed in a flow cell having the facility of inlet and outlet for the samples. Polychromatic light was launched from one end of the probe and the SPR spectrum of the catechol sample of a given concentration in the flow cell was recorded by the spectrometer at the other end.
关键词： surface plasmon resonance,optical fiber probe,CTAB,catechol,ZnO decorated MWCNTs
更新于2025-09-16 10:30:52
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Catechol oxidase mimetic activity of cadmium sulfide nanoparticles for the oxidation of L- 3,4 -dihydroxyphenylalanine
摘要： In the present work we have investigated the oxidation of L-3,4 -dihydroxyphenylalanine (L-Dopa) using colloidal cadmium sulfide nanoparticles (CdS NPs) as a photocatalyst. The CdS NPs were synthesized and characterized using UV-visible absorption spectroscopy, transmission electron microscopy (TEM) and powder X-ray diffraction (XRD). It was demonstrated that the as-prepared CdS NPs mimiced the activity of the catechol oxidase enzyme. To the best of our knowledge, this is the first report on the oxidation of L-Dopa using semiconductor NPs. The kinetic analysis was carried out using the Michaelis-Menten equation. The results observed that the CdS NPs oxidized L-Dopa within 30 min of irradiation using a 200 W Hg(Xe) arc lamp. The oxidation product was identified using high performance liquid chromatography (HPLC). The HPLC analyses were carried out on a reverse-phase C18 column under isocratic conditions using methanol/water (10/90) as the mobile phase. The retention time of the product matched with that of dopachrome. The mechanistic studies indicated the participation of hydroxyl radicals (?OH) in the photocatalytic oxidation of L-Dopa.
关键词： CdS NPs,semiconductor,irradiation,photocatalytic,catechol oxidase
更新于2025-09-09 09:28:46
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Silicon tris(perchloro)dioxolene: a neutral triplet diradical
摘要： The reaction of ortho-quinone with silicon tetraiodide leads to neutral silicon trisdioxolenes in high yield – delivering the unknown oxidized form of triscatecholatosilicate dianions and the first example of open shell semiquinonates connected via a single non-metal center. Silicon tris(perchloro)dioxolene is a stable diradical with a triplet ground state, as supported by X-ray diffraction, IR-, resonance Raman, UV/Vis-, (VT)EPR-spectroscopy and Kohn-Sham broken symmetry computations. Preliminary results suggest that the preferred magnetic ground state can be altered by choice of the substituents.
关键词： hypercoordination,catechol,diradical,redox active substituents,silanes
更新于2025-09-04 15:30:14