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961.
The BiCl3‐catalyzed reaction of pyrroles with electron‐deficient olefins generated the corresponding Michael adducts in high yields. 相似文献
962.
The Knoevenagel condensation of Meldrum's acid with aromatic aldehydes proceeded efficiently in a reusable ionic liquid, ethylammonium nitrate, at room temperature in the absence of any catalyst with high yields. 相似文献
963.
A small library of isocoumarin derivatives has been synthesized via K2CO3-catalyzed domino reactions of 2-carboxybenzaldehyde and ω-bromoacetophenones under microwave irradiation (MW). This strategy offers a simple, environmentally acceptable route to synthesize isocoumarin derivatives in moderate to excellent yields. All new compounds were characterized by 1H NMR, 13C NMR, infrared, and high-resolution mass spectroscopic techniques. 相似文献
964.
Terminal alkynes 1 react with Cp2Zr(H)Cl (Cp = η5-C5H5) and CO to give acylzirconocene chloride derivatives 2, which are trapped with arylsulfenyl chlorides to afford (E)-α,β-unsaturated thioesters. 相似文献
965.
Ethynylferrocene was prepared in satisfactory yield by reaction of formylferrocene with triphenylphosphine and carbon tetrachloride followed by dehydrohalogenation in presence of n-butyllithum. The reaction condition is mild and the reaction time is much shorter. The method is convenient and economical. 相似文献
966.
Zhihui Luo Wentao Li Donglian Lu Kun Chen Qigai He Heyou Han Mingqiang Zou 《Mikrochimica acta》2013,180(15-16):1501-1507
We report on a facile immunoassay for porcine circovirus type 2 (PCV2) based on surface enhanced Raman scattering (SERS) using multi-branched gold nanoparticles (mb-AuNPs) as substrates. The mb-AuNPs in the immunosensor act as Raman reporters and were prepared via Tris base-induced reduction and subsequent reaction with p-mercaptobenzoic acid (pMBA). They possess good stability and high SERS activity. Subsequently, the modified mb-AuNPs were covalently conjugated to the monoclonal antibody (McAb) against the PCV2 cap protein to form SERS immuno nanoprobes. These were captured in a microtiterplate via a immunoreaction in the presence of target antigens. The effects of antibody concentration, reaction time and temperature on the sensitivity of the immunoassay were investigated. Under optimized assay conditions, the Raman signal intensity at 1,076 cm?1 increases logarithmically with the concentrations of PCV2 in the concentration ranging from 8?×?102 to 8?×?106 copies per mL. The limit of detection is 8?×?102 copies per mL. Compared to conventional detecting methods such as those based on PCR, the method presented here is rapid, facile and very sensitive. Figure
A simple and novel approach to detect porcine circovirus type 2 using surface enhanced Raman scattering (SERS) of multi-branched gold nanoparticles is demonstrated, it has a higher sensitivity than polymerase chain reaction and ELISA. 相似文献
967.
We describe a molecularly imprinted polymer (MIP) for the solid-phase extraction of the skin protectant allantoin. The MIP was deposited on the surface of monodisperse silica microspheres possessing acroyl groups on the surface (MH-SiO2). The resulting MIP microspheres (MH-SiO2@MIP) showed a 3.4-fold higher adsorption capacity and a 1.9-fold better selectivity for allantoin than the respective non-imprinted polymer (MH-SiO2@NIP). The monolayer adsorption capacities of the MH-SiO2@MIP and the MH-SiO2@NIP were calculated with the help of the Langmuir model and found to be 6.8 and 1.9 mg?g?1, respectively. Adsorption kinetics fit a pseudo-second order rate mechanism, with an initial adsorption rate of 1.44 for the MH-SiO2@MIP, and of 0.07 mg?g?1?min?1 for the MH-SiO2@NIP. The material can be regenerated, and its adsorption capacity for allantoin remains stable for at least five regeneration cycles. It was successfully used as a sorbent for the selective solid-phase extraction of allantoin from Rhizoma dioscoreae. Figure
A molecularly imprinted polymer for the selective separation of allantoin was developed. It was successfully used as a sorbent for the selective solid-phase extraction of allantoin from Rhizoma dioscoreae. 相似文献
968.
Wei Xu Ping Liu Chunhui Guo Chao Dong Xiuhua Zhang Shengfu Wang 《Mikrochimica acta》2013,180(11-12):1005-1011
We describe a molecularly imprinted electrochemical sensor for selective and sensitive determination of β2-agonists. It is making use of a combination of single-wall carbon nanotubes (SWNTs) with a molecularly imprinted sol–gel. The SWNTs were introduced in order to enhance electron transport and sensitivity. The imprinted sol–gel film with its specific binding sites acts as a selective recognition element and as a preconcentrator for β2-agonists. The morphology of the imprinted film was characterized by scanning electron microscopy. The optimized sensor displays high sensitivity and excellent selectivity for the β2-agonists as shown for their determination in human serum samples. Figure
A molecularly imprinted electrochemical sensor was constructed for selective and sensitive determination of β2-agonists. The optimized sensor displays high sensitivity and excellent selectivity for the β2-agonists as shown for their determination in human serum samples. 相似文献
969.
A thin film of poly(eriochrome black T) was deposited on the surface of glassy carbon electrode by cyclic voltammetry, and this system is shown to enable the sensitive determination of adenine (A) and guanine (G). Scanning electron microscopy, Fourier transform infrared spectroscopy and electrochemical impedance spectroscopy were carried out to characterize the film which exhibits excellent electrocatalytic activity toward the oxidation of A and G in 0.1 M phosphate buffer solution (pH 4.0). Square wave voltammetry reveals an oxidation peak at 1084 mV whose current is linearly related to the concentration of A in the range from 0.05 to 1.00 μM. The oxidation peak for G occurs at 788 mV, and its current is linearly related to the concentration of G in the range from 0.025 to 1.00 μM. The detection limits are 0.017 μM for A and 0.008 μM for G (at S/N?=?3), respectively. The modified electrode displays good reproducibility and selectivity for the determination of A and G. The sensor was applied to quantify A and G in fish sperm DNA with satisfactory results. Figure
Square wave voltammograms of bare GCE (a), PEBT/GCE (b) in the presence of 1.00 μM adenine (A) and 1.00 μM guanine (G). 相似文献
970.
Zhongke Yan Jianwei Zhao Lirong Qin Fan Mu Ping Wang Xining Feng 《Mikrochimica acta》2013,180(1-2):145-150
Granular nanowires with a diameter of about 60 nm were fabricated from cuprous oxide (Cu2O) by an electrochemical method using anodic aluminium oxide as the template. A non-enzymatic sensor for hydrogen peroxide (H2O2) was then developed on the basis of a gold electrode modified with Cu2O nanowires and Nafion. The resulting sensor enables the determination of H2O2 with a sensitivity of 745 μA?mM?1?cm?2, over a wide linear range (0.25 μM to 5.0 mM), and with a low detection limit (0.12 μM). The results demonstrate that the use of such granular nanowires provides a promising tool for the design of non-enzymatic chemical sensors. Figure
A non-enzymatic sensor for hydrogen peroxide (H2O2) was developed on the basis of a gold electrode modified with Cu2O nanowires and Nafion. The resulting sensor enables the determination of H2O2 with a sensitivity of 745 μA mM?1 cm?2, over a wide linear range (0.25 μM to 5.0 mM), and with a low detection limit (0.12 μM). The results demonstrate that the use of such granular nanowires provides a promising tool for the design of non-enzymatic chemical sensors 相似文献