A Novel Amperometric Nitric Oxide Sensor Based on Polythionine / Nation Modified Glassy Carbon Electrode

A novel amperometric sensor for the determination of nitric oxide was developed by coating polythionine / nafion on a glassy carbon electrode. This sensor exhibited a great enhancement to the oxidation of nitric oxide. The oxidation peak currents were linear to the concentration of nitric oxide over the wide range from 3.6×10-7 to 6.8×10-5 mol.L-1, and the detection limit was 7.2×10-8 mol.L-1. Experimental results showed that this nitric oxide sensor possessed excellent selectivity and longer stability. NO releasing from rat kidney was monitored by this sensor.     

Methanol Decomposition in a Water–Methanol Equimolar Mixture on a Nickel-Promoted Copper–Zinc–Cement Catalyst

Methanol decomposition in a water–methanol equimolar mixture is studied in the presence of a nickel-promoted copper–zinc–cement catalyst. Methanol decomposition at 200–300°C on the oxide and reduced forms of the catalyst yields a gas with an H₂/CO ratio close to two. The use of an equimolar CH₃OH–H₂O mixture under analogous conditions enables obtaining gaseous products with a hydrogen concentration up to 75 vol %.     

A Novel Electrochemical Sensor Based on Reduced Graphene Oxide–TiO2 Nanocomposites with High Selectivity for the Determination of Hydroxychloroquine

Russian Journal of Electrochemistry - A simply sensitive sensor based on a reduced graphene oxide–TiO2 nanocomposite modified glassy carbon electrode (RGO–TiO2/GCE) was developed for...     

Novel Electrochemical Sensor for Sunset Yellow Based on a Platinum Wire–Coated Electrode

Abstract

In this research, the construction and general performance characteristics of a sunset yellow sensor based on sunset yellow–cetyl pyridinum (SY-CPY) ion pair as an ion exchanger were described. A coated platinum wire electrode (CPE) was prepared and compared with coated graphite (CGE) and membrane electrode (PME). The CPE exhibited a rapid and Nernstian response (?29.77 ± 0.2 mV decade^?1) to SY concentration range from 3.16 × 10^?7 to 3.16 × 10^?3 mol dm^?3 within pH 4.5–9.5. Interfering effects of some foreign substances were reported. The optimized matrix was successfully applied to the determination of SY in artificial mixtures and commercial soft drinks. The results showed good agreements with the determination made by use of high-performance liquid chromatography.     

Electrochemical Sensor for Detection of p-Nitrophenol Based on Nickel Oxide Nanoparticles/α-Cyclodextrin Functionalized Reduced Graphene Oxide

p-Nitrophenol (p−NP) is a high priority toxic pollutant and that has harmful effects on human, animals and plants. Thus, the detection and determination of p−NP present in the environment is an urgent as well as highly important requisite. The present article, therefore focused on the construction of a novel electrochemical sensor based on NiO nanoparticles/α-cyclodextrin functionalized reduced graphene oxide modified glassy carbon electrode (NiO−NPs-α-CD-rGO-GCE) for the selective and sensitive detection of p−NP. UV-vis, high resolution transmission electron microscopy (HR-TEM), selected area electron diffraction pattern (SAED) and X-ray diffraction (XRD) analysis confirms the formation of highly pure NiO nanoparticles. Field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), and cyclic voltammetry (CV) were used to characterize the step-wise electrode modification process. DPV was carried out to quantify p−NP within the concentration range of 1−10 μM and found the detection limit of 0.12 nM on the basis of the signal-to-noise ratio S/N=3. The electrode can able to detect different isomers of nitrophenols. Interferences of other pollutants such as phenol, p-aminophenol, o- and m- nitrophenol, 4-chlorophenol, 2,6-dichlorophenol and ions like K⁺, Cd²⁺, Cl⁻, SO₄²⁻ did not affect the sensing of p−NP. The newly developed sensor exhibited diffusion controlled kinetics and had excellent sensitivity, selectivity and reproducibility for the detection of p−NP. The electrode showed good recoveries in real sample analysis.     

Electrochemical Determination of Copper(II) in Water Samples Using a Novel Ion-Selective Electrode Based on a Graphite Oxide–Imprinted Polymer Composite

A novel copper(II)-selective electrode based on graphite oxide/imprinted polymer composite was developed for the electrochemical monitoring of copper(II) (Cu²⁺) ions. The electrode exhibited highly selective potentiometric response to Cu²⁺ with respect to common alkaline, alkaline earth and heavy metal cations. The composite composition studies indicated that the most suitable composite composition performing the most promising potentiometric properties was 20.0% ionophore (Cu²⁺-ion imprinted polymer), 10.0% paraffin oil, 5.0% multiwalled carbon nanotubes, and 65.0% graphite oxide. The fabricated electrode exhibited a linear response to Cu²⁺ over the concentration range of 1.0?×?10^??6–1.0?×?10^??1?M (correlation coefficient of 0.9998) with a sensitivity of 26.1?±?0.9?mV decade^??1. The detection limit of the fabricated electrode was determined to be 4.0?×?10^??7?M. The electrode worked well in the pH range of 4.0–8.0. The electrode had stable, reversible and fast potentiometric response (3?s). In addition, the electrode had a lifetime of more than 1 year. The analytical applications of the proposed electrode were performed using as an indicator electrode for the potentiometric titration of Cu²⁺ with ethylene diamine tetraacetic acid solution and for the determination of Cu²⁺ of spiked river, dam, and tap water samples. The obtained results for potentiometric titration and water samples were satisfactory.     

Electrochemical Sensor Based on Magnetic Fe3O4–Reduced Graphene Oxide Hybrid for Sensitive Detection of Binaphthol

Russian Journal of Electrochemistry - Naphthol is an environmental pollutant with highly toxic and corrosive. Naphthol can be absorbed by the body easily through the skin, and can cause serious...     

A Frost-Resistant Structural Material Based on a High-Molecular-Mass Divinyl–Isoprene Copolymer

A new three-dimensionally cross-linked plasticized elastomer filled with polyfractional silicon dioxide was developed on the basis of a frost-resistant high-molecular-mass divinyl–isoprene copolymer. A quinol ether was suggested as an effective cross-linking agent. The envelopes of the experimental and calculated energies of mechanical failure at different temperatures as applied to uniaxial extension were constructed. The composite was recommended as a structural material for the development of wear-resistant parts and units of automobile and aviation transport intended for operation in a wide temperature range, including the Russian Extreme North and Arctic.     

A New Approach for Preparing Effective Inhibition Film on Copper Based on Self-assembled Process

A new method for preparing effective inhibition film on copper has been developed.Pheylthiourea(PT) was firest absorbed to copper surface to form a monolayer.1-Dodecanethiol(DT) was then assembled on the surface for modification.Finally,Ac voltage was loded on copper covered the mixed film to improve it further.After these processes,an effective inhibition film was gained because of its high charge transfer resistance and low corrosion current density shown in electrochemical impedance spectra and polarization.The inhibition efficiency was more than 97%.     

Silver(I) Oxide on Silver–Zinc Alloys: Anodic Formation and Properties

Russian Journal of Electrochemistry - Anodic formation in deoxygenated 0.1 М KOH solution of Ag(I) oxide on Ag–Zn alloys with zinc atomic fraction from 5 to 30 at % and its properties...     

A Novel Glucose Biosensor Based on Palladium Nanoparticles and Its Application in Detection of Glucose Level in Urine

IntroductionThelevelofglucoseinbloodorurineindicateshyper andhypoglycaemia ,bothofwhichcanresultfromavarietyofendocrinedisorders .1 4 Therapidandreliabledetermi nationofglucoselevelisaroutineprojectinclinicchem istry.Urinesamplesaresaferandmoreconvenientthanbloodones .Meanwhile ,theconcentrationofglucoseinserumiscloselyassociatedwiththatinurine .2 4 Eventhoughglucoseelectrodeshavebeensuccessfullyusedinseruminclinicalapplication ,thequestionstillremainedofhowtodetecttheglucoselevelinurine ,wh…     

A Novel Nano-Sensor Based on Rhodamine-β-Isothiocyanate – Doped Silica Nanoparticle for pH Measurement

A novel and simple enzymatic method for the determination of trace cyanide in marine fish is presented. This method is based on the conversion of metal-cyanide complexes by a fungal enzyme extract containing cyanide hydratase (E.C. 4.2.1.66; CyHT) and formamidase (E.C. 3.5.1.49) into formate and ammonia. The formate produced in the sample pretreated with the fungal enzymes was measured by adding formate dehydrogenase (E.C. 1.2.1.2; FDH) and excess NAD⁺. The NADH formed accordingly was monitored at 340nm. The cyanide calibration curve was found to be linear in the range of 10–100µM, and the detection limit was 1.1µM (0.0286ppm). The proposed biotest was successfully applied to the determination of trace cyanide in a tropical marine food fish species (Russells Snapper (Lutjamus russellii)) which had been exposed to cyanide.     

Amperometric Nitric Oxide Sensor Based on Poly(Thionine)/Nafion‐Modified Electrode and Its Application in Monitoring Nitric Oxide Release from Rat Kidney

Abstract

A novel amperometric nitric oxide (NO) sensor based on a glassy carbon electrode modified with thionine and Nafion films has been developed. The oxidation peak current of NO increased significantly at the poly(thionine)/Nafion‐modified glassy carbon electrode (GCE), which can be used for the detection of NO. The oxidation peak current was linear with the concentration of nitric oxide over the range from 3.6×10^?7 to 6.8×10^?5 mol · L^?1, and the detection limit was 7.2×10^?8 mol · L^?1. This nitric oxide sensor showed high selectivity to nitric oxide determination, and some potential interference could be eliminated effectively. The nitric oxide sensor has been applied to monitor NO release from rat kidney stimulated by L‐arginine. The results indicated the applicability of the NO sensor to biomedical samples.     

A Dicyanamido-bridged Zinc(Ⅱ) Complex Based on the Bis(4-pyridyl)ethane with a Three-dimensional Framework

A novel dicyanamido-bridged 3D polymeric complex {[Zn2(bpa)2(dca)]dca}n (1) (dca = dicyanamide anion,bpa = 1,2-bis(4-pyridyl)ethane) has been synthesized by reacting 1,2-bis(4-pyridyl)ethane with zinc salt in the presence of sodium dicyanamide,and characterized by elemental analysis,IR spectra and X-ray diffraction. It crystallizes in the monoclinic system,space group C2/c with a = 18.587(3),b = 20.070(3),c = 8.7957(13) ,β = 100.611(2)o,V = 3225.0(8) 3,Mr = 539.92,μ = 0.789 mm-1,F(000) = 1116,Z = 4,ρ = 1.112 (g/cm3),R = 0.0582 and wR = 0.1762. Complex 1 forms a 3D porous framework through the bpa and dca ligands,and gives 1-D coordination channels encapsulated by the guest dca molecules. Complex 1 also displays strong photo-luminescent properties in the solid state at room temperature.     

Sensitive Determination of 17β-Estradiol using a Magneto Sensor Based on Magnetic Molecularly Imprinted Polymer

The analysis of 17β-estradiol with high sensitivity and selectivity is extremely relevant to control the impacts that this compound can cause on health and the environment. Thus, we describe the development and application of a magneto carbon paste electrode based on magnetic molecularly imprinted polymer (MCPE-MMIP) for determination of 17β-estradiol. The analyte adsorbed on the MMIP was immobilized on the electrode surface by magnetic capture. The morphological and structural characterization of the obtained MMIP suggests that the material was effectively synthesized. MCPE-MMIP showed an improvement in the sensitivity for 17β-estradiol detection when compared to electrode configurations in the absence of this material. The optimum conditions (0.10 mol L⁻¹ phosphate buffer pH 7.0) were reached by differential pulse adsorptive stripping voltammetry (DPAdSV), in which the method presented linearity ranged from 0.06 to 175 μmol L⁻¹ with limits of detection and quantification of 0.02 and 0.06 μmol L⁻¹, respectively. The proposed sensor was applied effectively in the analysis of 17β-estradiol in river water and raw milk samples, exhibiting excellent recovery values (between 96.20 and 104 %), which were confirmed by HPLC analysis.     

A Multi-model,Large-range Flexible Strain Sensor Based on Carbonized Silk Habotai for Human Health Monitoring

In recent years, flexible strain sensors have received considerable attention owing to their excellent flexibility and multifunctionality.However, it is still a great challenge for them to accurately monitor multi-model deformations with high sensitivity and linearity. In this study, the industrial insulating silk habotai was successfully converted into carbonized silk habotai(CSH) for use in strain sensors. A strain sensor created using CSH exhibited excellent sensing performance under multi-mo...     

Study of Electrochemical Non-enzyme Glucose Sensor Based on Cu(Ⅱ)Co(Ⅱ) Bimetallic Carbon Nanosheets北大核心CSCD

CuCo-MOF nanofibers are synthesized by one-step solvent blending process at room temperature. Then CuCo-MOF nanofibers are used as the precursors,carbon nanosheets（Cu（Ⅱ）Co（Ⅱ）@C）uniformly loaded with nano-sized copper oxide and cobalt oxide are obtained by calcination at high temperature in air. Cu（Ⅱ）Co（Ⅱ）@C is modified on the glassy carbon electrode to directly catalyze glucose in alkaline solution. Because CuO and CoO are uniformly and firmly embedded on the carbon nanosheets,the agglomeration of catalyst is prevented,which greatly improves the specific surface area,and increases the catalytic active site. Meanwhile,due to the synergistic effect of copper and cobalt bimetals in the carbon nanosheet material,the enzyme free glucose sensor has excellent electrical conductivity and excellent catalytic performance. The detection range of the non-enzymatic electrochemical glucose sensors for glucose is 0. 03 µμmol/L~13. 6 mmol/L, the detection limit is 0. 01 µμmol/L（S/N=3）,and the sensitivity is 10. 56 mA·L/（cm2·mmol）. In addition, the non-enzyme sensor also has good anti-interference and high stability. © 2022, Science Press (China). All rights reserved.     

Novel Copper（Ⅱ） and Zinc（Ⅱ） 2-D Supramolecular Structures Based on Carboxylate and 1-Substitutedimidazole Mixed-ligands

Using the ligand bis(3-(1H-imidazol-1-yl)-1-phenylpropan-1-one) L, two novel com- plexes [CuL2(ph))]·H2O 1 and [ZnL2(tp)] 2 (ph = phthalic acid, tp = terephthalic acid) have been synthesized and their crystal structures were determined by single-crystal X-ray diffraction analysis. Crystal data for 1: triclinic, space group P1, a = 9.4300(17), b = 12.148(2), c = 13.721(2) , α = 109.620(2), β = 94.351(2), γ = 94.830(2)°, C32H30N4O7Cu, Mr = 646.14, V = 1466.2(4) 3, Z = 2, Dc = 1.464 g/cm3, μ(MoKα) = 0.801 mm-1, F(000) = 670, the final R = 0.0337 and wR = 0.0859 for 5122 observed reflections with I > 2σ(I). And those for 2: monoclinic, space group P2/n, a = 7.1866(11), b = 14.144(2), c = 14.407(2) , β = 101.427(2)°, C32H28N4O6Zn, Mr = 629.95, V = 1435.4(4) 3, Z = 2, Dc = 1.457 g/cm3, μ(MoKα) = 0.908 mm-1, F(000) = 652, the final R = 0.0438 and wR = 0.0821 for 2546 observed reflections with I > 2σ(I). In 1 and 2, ph or tp ligands bridge the six-coordinated copper(II) or four-coordinated zinc(II) ions forming 1D zigzag chains while L ligands act as the terminal monodentate ligand. It is noted that weak non-classical C–H···O plays the important and dominating roles in the formation of 2D supramolecular architectures of 1, but in 2 non-classical C–H···O and aromatic π-π stacking interactions are quite important and play dominant roles in the self-assembly of 2D supramolecular architectures.     

A Novel Two-dimensional Homochiral Zinc（II） Complex Constructed Based on In Situ Ligand Formation

A novel zinc(Ⅱ) complex, Zn(IBT) 2 (1, HIBT=5-(4-((1H-imidazol-1-yl)methyl)phenyl)-2H-tetrazole) has been synthesized with Zn(NO3)2·6H2O, 4-(imidazol-1-ylmethyl)benzonnitrile (IBN) and NaN 3 by the hydrothermal method, and characterized by elemental analysis, IR and single-crystal X-ray diffraction. Crystallographic data for 1:C22H18N12Zn, Mr=515.85, orthorhombic, Pbcn, a=16.0567(15), b=9.5316(9), c=14.6107(14) , V=2236.1(4)  3 , Z=4, D c=1.532 g/cm3 , μ=1.138 mm-1 , F(000)=1056, R=0.0350 and wR=0.0888 for 1438 observed reflections (I > 2σ(I)) and the goodness-of-fit S=1.002 on F2 . The crystal structural analysis revealed that complex 1 exhibits a rare two-dimensional homochiral wave-like layer structure. In addition, the photoluminescence of complex 1 was studied in the solid state at room temperature together with its theoretical analysis.