A novel sensor for the determination of warfarin based on a simple and sensitive method was developed on multiwalled-carbon-nanotube modified ZnCrFeO4 carbon paste electrodes（MWCNT/ZnCrFeO4/CPEs）. Cyclic voltammetry...A novel sensor for the determination of warfarin based on a simple and sensitive method was developed on multiwalled-carbon-nanotube modified ZnCrFeO4 carbon paste electrodes（MWCNT/ZnCrFeO4/CPEs）. Cyclic voltammetry, differential pulse voltammetry, chronoamperometry, and electrochemical impedance spectroscopy were used to investigate the electrochemical behavior of warfarin at the chemically modified electrode. According to the results, MWCNT/ZnCrFeO4/CPEs showed high electrocatalytic activity for warfarin oxidation, producing a sharp oxidation peak current at about ＋0.97 vs Ag/AgCl reference electrode at pH = 4.0. The peak current was linearly dependent on warfarin concentration over the range of 0.02–920.0 μmol/L with a detection limit of 0.003 μmol/L. In addition, chronoamperometry was also used to determine warfarin＇s catalytic rate constant and diffusion coefficient at MWCNT/ZnCrFeO4/CPEs.展开更多
This paper describes a facile in‐situ synthesis of palladium nanoparticles （Pd NPs） on silica gel/polydopamine composite（SiO2/PDA） without any stabilizer or reducing agent. In this approach, palladium ions were a...This paper describes a facile in‐situ synthesis of palladium nanoparticles （Pd NPs） on silica gel/polydopamine composite（SiO2/PDA） without any stabilizer or reducing agent. In this approach, palladium ions were adsorbed on SiO2/PDA surfaces by immersing the PDA‐coated SiO2 particles in a palladium plating bath. Then, they were reduced in situ to Pd nanoclusters by the reducing ability of PDA＇s N‐containing groups. The structure, morphology, and physicochemical properties of the synthesized nanocomposites were characterized by different analytical techniques such as high‐resolution transmission electron microscopy, field‐emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, X‐ray diffraction analysis, X‐ray photoelectron spectroscopy, inductively coupled plasma and Fourier‐transform infrared spectroscopy. The Pd NPs capped by the PDA groups had a strikingly small size（30–40 nm）. SiO2/PDA/Pd NPs exhibited high catalytic activ‐ity as a recyclable nanocatalyst in the aerobic oxidation of alcohols. Furthermore, recovery and multiple reuse of the catalyst revealed no detectable activity loss.展开更多
This report describes a new three‐component strategy for the regioselective synthesis of a series of tri‐substituted pyridazines via a 1,4‐diazabicyclo[2.2.2]octane （DABCO）‐catalyzed condensation of propiophenon...This report describes a new three‐component strategy for the regioselective synthesis of a series of tri‐substituted pyridazines via a 1,4‐diazabicyclo[2.2.2]octane （DABCO）‐catalyzed condensation of propiophenones, arylglyoxalmonohydrates and hydrazine hydrate in water. This method provides a green and convenient one‐pot route toward a diverse set of 3,6‐diaryl‐4‐methylpyridazines bearing various aryl substituents. This procedure is highly regioselective, operationally simple, uses water as a safe, environmentally friendly solvent, and DABCO as a green base‐organocatalyst, and affords good to excellent yields of products.展开更多
文摘A novel sensor for the determination of warfarin based on a simple and sensitive method was developed on multiwalled-carbon-nanotube modified ZnCrFeO4 carbon paste electrodes（MWCNT/ZnCrFeO4/CPEs）. Cyclic voltammetry, differential pulse voltammetry, chronoamperometry, and electrochemical impedance spectroscopy were used to investigate the electrochemical behavior of warfarin at the chemically modified electrode. According to the results, MWCNT/ZnCrFeO4/CPEs showed high electrocatalytic activity for warfarin oxidation, producing a sharp oxidation peak current at about ＋0.97 vs Ag/AgCl reference electrode at pH = 4.0. The peak current was linearly dependent on warfarin concentration over the range of 0.02–920.0 μmol/L with a detection limit of 0.003 μmol/L. In addition, chronoamperometry was also used to determine warfarin＇s catalytic rate constant and diffusion coefficient at MWCNT/ZnCrFeO4/CPEs.
基金Payame Noor University (PNU) for partial support of this work
文摘This paper describes a facile in‐situ synthesis of palladium nanoparticles （Pd NPs） on silica gel/polydopamine composite（SiO2/PDA） without any stabilizer or reducing agent. In this approach, palladium ions were adsorbed on SiO2/PDA surfaces by immersing the PDA‐coated SiO2 particles in a palladium plating bath. Then, they were reduced in situ to Pd nanoclusters by the reducing ability of PDA＇s N‐containing groups. The structure, morphology, and physicochemical properties of the synthesized nanocomposites were characterized by different analytical techniques such as high‐resolution transmission electron microscopy, field‐emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, X‐ray diffraction analysis, X‐ray photoelectron spectroscopy, inductively coupled plasma and Fourier‐transform infrared spectroscopy. The Pd NPs capped by the PDA groups had a strikingly small size（30–40 nm）. SiO2/PDA/Pd NPs exhibited high catalytic activ‐ity as a recyclable nanocatalyst in the aerobic oxidation of alcohols. Furthermore, recovery and multiple reuse of the catalyst revealed no detectable activity loss.
基金supported by the Research Council of Payame Noor University
文摘This report describes a new three‐component strategy for the regioselective synthesis of a series of tri‐substituted pyridazines via a 1,4‐diazabicyclo[2.2.2]octane （DABCO）‐catalyzed condensation of propiophenones, arylglyoxalmonohydrates and hydrazine hydrate in water. This method provides a green and convenient one‐pot route toward a diverse set of 3,6‐diaryl‐4‐methylpyridazines bearing various aryl substituents. This procedure is highly regioselective, operationally simple, uses water as a safe, environmentally friendly solvent, and DABCO as a green base‐organocatalyst, and affords good to excellent yields of products.
