In this paper, we report the fabrication of an amplified sensor to determine dopamine in the presence of morphine based on nano-MgO, multiwall carbon nanotubes, and an oxadiazole derivative. The electrochemical behavior and electrocatalyic activity of the sensor toward the oxidation of dopamine were investigated. Cyclic voltammetry was used to study the redox features of the sensor, and the results have shown that dopamine overpotential oxidation at the surface of the sensor was reduced to nearly 460 mV. The diffusion coefficient was estimated by chronoamperometry. Three segmented linear dynamic ranges over the range 0.05–5175.0 and detection limit of 0.021 μM for the quantification of dopamine were obtained using differential pulse voltammetry (DPV). The modified nanocomposite carbon paste electrode, which showed excellent sensitivity, selectivity, repeatability, and reproducibility, was satisfactorily employed to determine dopamine and morphine in actual samples. 相似文献
Nanostructures from natural sources have received major attention due to wide array of biological activities and less toxicity for humans, animals, and the environment. In the present study, silver nanoparticles were successfully synthesized using a fungal nitrate reductase, and their biological activity was assessed against human pathogenic fungi and bacteria. The enzyme was isolated from Fusarium oxysporum IRAN 31C after culturing on malt extract-glucose-yeast extract-peptone (MGYP) medium. The enzyme was purified by a combination of ultrafiltration and ion exchange chromatography on DEAE Sephadex and its molecular weight was estimated by gel filtration on Sephacryl S-300. The purified enzyme had a maximum yield of 50.84 % with a final purification of 70 folds. With a molecular weight of 214 KDa, it is composed of three subunits of 125, 60, and 25 KDa. The purified enzyme was successfully used for synthesis of silver nanoparticles in a way dependent upon NADPH using gelatin as a capping agent. The synthesized silver nanoparticles were characterized by X-ray diffraction, dynamic light scattering spectroscopy, and transmission and scanning electron microscopy. These stable nonaggregating nanoparticles were spherical in shape with an average size of 50 nm and a zeta potential of ?34.3. Evaluation of the antimicrobial effects of synthesized nanoparticles by disk diffusion method showed strong growth inhibitory activity against all tested human pathogenic fungi and bacteria as evident from inhibition zones that ranged from 14 to 25 mm. Successful green synthesis of biologically active silver nanoparticles by a nitrate reductase from F. oxysporum in the present work not only reduces laborious downstream steps such as purification of nanoparticle from interfering cellular components, but also provides a constant source of safe biologically-active nanomaterials with potential application in agriculture and medicine. 相似文献
An efficient and simple method for the synthesis of bis(4‐hydroxycoumarin)methanes has been achieved through a one‐pot condensation of aryl aldehydes and 4‐hydroxycoumarin in the presence of nanoporous solid acid catalyst of SBA‐Pr‐SO3H with pore size of 6 nm. Excellent yields, short reaction times, reusability of the catalyst and simple workup are advantages of this synthetic procedure. 相似文献
Densities (ρ) and viscosities (η) of ternary mixtures of 2-methylbutan-2-ol (1) + trichloroethylene (2) + acetonitrile (3) and the related binary mixtures of {2-methylbutan-2-ol (1) + trichloroethylene (2)}, {2-methylbutan-2-ol (1) + acetonitrile (3)}, and {trichloroethylene (2) + acetonitrile (3)} have been measured over the whole composition range at 298.15 K and at ambient pressure (81.5 kPa). Excess molar volumes $ V_{\text{m}}^{\text{E}} $, viscosity deviations Δη, and excess Gibbs energies of activation ΔG*E were derived from the experimental data. The binary and ternary data of $ V_{\text{m}}^{\text{E}} $, Δη, and ΔG*E for the binary and ternary mixtures were correlated as functions of the mole fraction by using the Redlich–Kister and the Cibulka equations. Kinematic viscosities of the binary mixtures were correlated by means of several semi-empirical equations to determine the fitting parameters and the SDs. The experimental results are analyzed to discuss the nature and strength of intermolecular interactions in these mixtures. 相似文献
The complexation reactions of Mn2+, Co2+, Y3+, and ZrO2+ cations with the macrocyclic ligand, 4′-nitrobenz-15-crown-5 (4′-NB15C5), in acetonitrile (AN), methanol and AN-MeOH binary mixtures have been studied at various temperatures using the conductometric method. The conductance data stand for the Me : L stoichiometric ratio 1 : 1. Values of the formation constants of the complexes were accumulated by plotting molar conductivity curves using the computer program, GENPLOT. The order of stability of the metal-ion complexes in pure AN at 15°C was found to be: (4′-NB15C5 · ZrO)2+ > (4′-NB15C5 · Mn)2+ ≈ (4′-NB15C5 · Co)2+ > (4′-NB15C5 · Y)3+. In the case of AN-MeOH binary solvent solutions with 50 and 75 mole percent of AN at the same temperature, the sequence of stability of the complexes was the following: (4′-NB15C5 · Mn)2+ > (4′-NB15C5 · ZrO)2+ ≈ (4′-NB15C5 · Co)2+ 〉 (4′-NB15C5 · Y)3+, and (4′-NB15C5 · Mn)2+ > (4′-NB15C5 · Y)3+ ≈ (4′-NB15C5 · Co)2+ > (4′-NB15C5 · ZrO)2+, respectively. The complexes formed are entropy stabilized in all cases. 相似文献
Abstract On-chip integrated photonic circuits are crucial for further progress toward quantum technologies and in the science of quantum optics. The quantum controlled-Z gate is an example of the maximally entangling gate, which is universal for quantum computing when coupled with single-qubit gates. This article demonstrates a deterministic controlled-Z photonic quantum gate based on titanium in-diffused channel waveguides in which polarization and modal degrees of freedom of a single photon are used for encoding the control and target qubits, respectively. 相似文献
27Al NMR spectroscopy is a powerful tool for the study of coordination and solvation in both aqueous and nonaqueous solutions.
In this study, the complexes coexisting upon dissolution of AlCl3 in acidic acetone + methanol solutions are shown to consist essentially of mixed hexacoordinated species of the general formula
[Al(CH3OH)6−n(CH3COCH3)n]3+ (n=1,2 and 3), all exhibiting distinctly different 27Al shielding effects. The relative populations of the various mixed species are found to be highly dependent upon the acetone:methanol
mole ratio that in the more acetone-rich mixtures with aluminum become appreciably coordinated by acetone. The results demonstrate
that the key factor for the formation of acetone-containing species in acidic methanolic solutions is having the CH3COCH3:CH3OH mole ratio at 3:1. 相似文献
In this study, we report the synthesis of MIP-coated hybrid NPs by “semi-covalent” imprinting technique throught a thermally reversible covalent bond and application for biochemical separation of β-estradiol (E2). A moleculary imprinted polymer (MIP) were synthesized using 3-(triethoxysilyl) propyl isocyanate and dibutyltin dilanurate as a functional monomer and cross-linking agent and β-estradiol as template. The removal of the template by a simple thermal reaction produced specific β-estradiol recognition sites on the surface of silica shell. Meanwhile, a solid-phase extraction (SPE) based on E2- MMIPs has been established for efficient separation and fast enrichment of E2 from the plasma. Recoveries of E2 from two kinds of plasma spiked at different concentration levels ranged from 86.9 to 103.3 with RSD <1.76 %.In this manner LOD was 0.0019 and LOQ was 0.0057 (µmol L?1), capacity factor and selectivity factor were 3.05 and 1.099 respectively. Also E2- MMIPs was used for selective separation of E2 from drugs mixture. 相似文献
A co-crystal of cobalt(II) complexes, Co(AMTTO)2(CH3CN)2]2+(NO3)2. [Co(AMTTO)2(H2O)2]2+(NO3)2, compound (1) was isolated from the reaction of Co(NO3)2?6H2O and 4-amino-3-mercapto-6-methyl-5-oxo-1,2,4-triazine (AMTTO) in acetonitrile as solvent. Isolated crystals were characterized by elemental analyses, IR spectroscopy as well as X-ray diffraction studies. Crystal data for 1 at 95 K revealed a monoclinic space group P21/n, a?=?11.7903(5), b?=?12.1279(5), c?=?14.1443(6) Å, β?=?99.244(4)°, Z?=?2, R1?=?0.0339. Compound 1 consists of two co-crystallized Co(II) complexes [Co(AMTTO)2(CH3CN)2]2+ and [Co(AMTTO)2(H2O)2]2+ and four nitrate counter anions In both complexes, cobalt(II) ions are in an octahedral arrangement. Two S, N bidentate AMTTO ligands are coordinated to both Co(II) ions. The coordination sphere of Co1 is completed by two acetonitrile molecules, and these positions are occupied by water molecules for Co2.
Graphic Abstract
A co-crystal of cobalt(II) compound was isolated from the reaction of Co(NO3)2?6H2O and 4-amino-3-mercapto-6-methyl-5-oxo-1,2,4-triazine in acetonitrile as solvent.
The reaction of 4‐amino‐5‐methyl‐2H‐1,2,4‐triazole‐3(4H)‐thione (AMTT, 1 ) with 4‐methoxy benzaldehyde and 3‐methoxybenzaldehyde in methanol led to the iminic derivatives 4‐(4‐methoxybenzylideneamino)‐5‐methyl‐2H‐1,2,4‐triazole‐3(4H)thione ( 2 , L1) and 4‐(3‐methoxybenzylideneamino)‐5‐methyl‐2H‐1,2,4‐triazole‐3(4H)‐thione ( 3 , L2). The reaction of the latter with [(PPh3)2CuCl] in methanol solution gave the first CuI complex of 3 , [(PPh3)2CuCl(L2)] ( 4 ) and in chloroform solution the complex [(PPh3)2CuCl(L2)]·2CHCl3 ( 5 ). All compounds were characterized by infrared spectroscopy, elemental analyses as well as by X‐ray diffraction studies. Crystal data for 2 at ?80 °C: space group P21/c with a = 1351.3(3), b = 399.4(1), c = 2225.2(5) pm, β = 96.50(2)°, Z = 4, R1 = 0.0667, for 3 at ?80 °C: space group R3c with a = b = 3020.4(2), c = 708.2(1) pm, Z = 18, R1 = 0.0435, for 4 at ?80 °C: space group P21/c with a = 1427.8(1), b = 1129.0(1), c = 2622.8(2) pm, β = 97.19(1)°, Z = 4, R1 = 0.0517 and for 5 at ?80 °C: space group with a = 1280.5(1), b = 1316.1(1), c = 1731.4(1) pm, α = 78.14(1)°, β = 86.06(1)°, γ = 64.69(1)°, Z = 2, R1 = 0.0525. 相似文献