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131.
Preparation, characterization and properties studies of quinine-imprinted polymer in the aqueous phase 总被引:4,自引:0,他引:4
The uniform-sized spherical molecularly imprinted polymers were successfully prepared through molecular imprinting technology
by two-step seed swelling and mini-emulsion polymerization in the aqueous condition using quinine as template molecules and
methacrylic acid (MAA) as functional monomer. The polymers were characterized by IR spectra, thermal-weight analysis, scanning
electron microscope and laser particle size analysis. The properties of imprinted polymers were investigated in different
organic phases and aqueous media. In the organic media, results suggested that polar interactions (hydrogen bonding, ionic
interactions) between acidic monomer/polymer and template molecules are mainly responsible for the binding and recognition;
whereas in the aqueous medium, a considerable recognition effect was also obtained where the ionic (electrostatic) interaction
and hydrophobic interaction play an important role. The experiments of binding different substrates indicated that the MIPs
possessed an excellent rebinding ability and inherent selectivity to quinine.
__________
Translated from Zhongshan Dcocue Xuebao/Acta Scientianum Natralium University Sunyatseni, 2005, 44(3)(in Chinese) 相似文献
132.
Xu X Zhao J Jiang D Kong J Liu B Deng J 《Analytical and bioanalytical chemistry》2002,374(7-8):1261-1266
A novel hydrogen peroxide biosensor was developed based on the immobilization of horseradish peroxidase (HRP) in a TiO(2) sol-gel matrix on an electropolymerized phenazine methosulfate (PMS) modified electrode surface. Such membranes are of interest due to their high surface area, biological compatibility, and ease of fabrication. HRP entrapped in the TiO(2) matix was stable and retained its activity to a large extent. Cyclic voltammetry and amperometric measurements were employed to demonstrate the feasibility of electron transfer between immobilized HRP and the glassy carbon electrode via electropolymerized PMS. The influence of various experimental parameters such as operating potential, pH, temperature, and stability was investigated for optimum analytical performance. The biosensor provided a wide linear calibration range from 4.0x10(-6) M to 1.0x10(-3) M, with a detection limit of 8.0x10(-7) M at a signal-to-noise ratio of 3. The sensor retained 80% of its original activity after two months of operation. 相似文献
133.
Qiutian Liu Chunxi Zhang Changneng Chen Hongping Zhu Yuheng Deng Jinhua Cai 《中国科学B辑(英文版)》1997,40(6):616-623
In a reaction system consisting of FeCl2, tetrathiometallate and cycloalkylthiolate, two Fe4S4 cubanelike cluster compounds were obtained with the following crystallographic data: (PhCH2NMe3)2 [ Fe4S4 (SC5H9)4] (I), monoclinic space groupP21/c,a = 1.632 7(4),b=1.122 9(3),c = 2. 802 5(10) nm, β= 94.63(2)°, Z=4, andR= 0.074; (Et4N)2[F4S4(SC6HlI)4] (II), tetragod space group
,a = l.167 05(9),b = 1.167 06(2),c = 2.063 26(5) nm,Z = 2, Dobs = 1. 28 g/cm3, andR = 0. 078. The participation of cycloalkylthiolate ligand does not obviously arouse the change of the Fe4S4 core structure. Meanwhile, the influence of the cation on the structural symmetry of the Fe4S4 cluster dianion is also discussed.
Project supported by the National Natural Science Foundation of China and the Climbing Program Foundation of China. 相似文献
134.
Simple interface for capillary electrophoresis-inductively coupled plasma atomic emission spectrometry 总被引:4,自引:0,他引:4
A simple interface has been developed to couple capillary electrophoresis (CE) to inductively coupled plasma atomic emission spectrometry (ICP-AES) for metal speciation. A concentric glass nebulizer with elongated tip is used as the CE-ICP interface. The CE capillary is the central tube of the nebulizer. A platinum wire is wrapped across the exit end of the CE capillary to provide electrical connection to the CE power supply. No sheath flow of buffer solution is needed. A simple cooling system has also been developed. A peristaltic pump circulates water through a plastic tube that encloses the section of the CE capillary between the CE instrument and the ICP spectrometer. Characteristics of the CE-ICP interface, e.g., elution time, nebulization and transport efficiency and peak broadening, versus carrier gas flow-rate have been studied. Comparisons to a previous design with the Pt electrode inserted into the end of the CE capillary are made where appropriate. The reproducibility (RSD) in ICP emission intensity of the system is <4%. Detection limits of Cr and Cu are approximately 5 ng/ml. 相似文献
135.
136.
Rapid determination of volatile constituents of Michelia alba flowers by gas chromatography-mass spectrometry with solid-phase microextraction 总被引:12,自引:0,他引:12
The volatile constituents of Michelia alba flowers, including fresh flowers, frozen flowers and withered flowers, were investigated by GC-MS. The volatiles in a simulated natural environment were sampled by solid-phase microextraction (SPME), with a 100 microm polydimethylsiloxane fiber at 25+/-5 degrees C for 4 h. The fibers were desorbed in a GC injection liner at 250 degrees C for 3 min. With headspace SPME-GC-MS analysis, 61 peaks were separated. The main compounds in headspace of fresh Michelia alba flowers included alpha-myrcene, (S)-limonene, (R)-fenchone, linalool, camphor, caryophyllene, germacrene D, etc., a greater number of compounds than for frozen flowers and withered flowers. At the same time, the biomarkers of fresh flowers were compared with the frozen flowers and withered flowers. In this study, headspace SPME-GC-MS afforded a simple and more sensitive sampling method for fresh Michelia alba flowers and other fresh flowers. 相似文献
137.
138.
Xu X Zhao Z Song P Zhou G Xu J Deng P Bourdet G Chanteloup JC Zou JP Fulop A 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(11-12):2444-2447
Infrared (1.2-1.6 microm) luminescence in a ytterbium aluminium garnet (YbAG) crystal, doped with Cr (0.05at.%) ions, was investigated under CW laser diode pumping (lambda=940 nm). The Cr4+ emission band was observed with its peak at 1.34 microm and measured to be about 1.3 times with respect to Yb3+ IR luminescence (lambda=1.03 microm). We demonstrate that for the excitation wavelength of 940 nm Yb3+ ions act as sensitizers of the 3B2(3T2)-3B1(3A2) emission of Cr4+ ions. This crystal is promising as a high-efficient system for tunable laser (1.2-1.6 microm) output. 相似文献
139.
Behaviors and mechanisms of copper adsorption on hydrolyzed polyacrylonitrile fibers 总被引:6,自引:0,他引:6
Polyacrylonitrile fiber (PANF) was hydrolyzed in a solution of sodium hydroxide and the hydrolyzed polyacrylonitrile fiber (HPANF) was used as an adsorbent to remove copper ions from aqueous solution. Scanning electron microscopy (SEM) showed that the hydrolysis process made the surface of HPANF rougher than that of PANF. Fourier transform infrared (FTIR) spectroscopy revealed that the HPANF contained conjugated imine (-Cz=Nz-) sequences. Batch adsorption results indicated that the HPANF was very effective in adsorbing copper, and the adsorption equilibrium could be reached within 10-20 min. Atomic force microscopy (AFM) showed that some aggregates formed on the surface of the HPANF after copper ion adsorption and the average surface roughness (R(a)) value of the HPANF changed from 0.363 to 3.763 nm due to copper adsorption. FTIR analysis indicated that copper adsorption caused a decrease of the light adsorption intensity of the imine (-Cz=Nz-) groups at 1573 and 1406 cm(-1) wavenumbers, and X-ray photoelectron spectroscopy (XPS) showed that the binding energy (BE) of some of the nitrogen atoms in the HPANF increased to a greater value due to copper adsorption. The FTIR and XPS results suggest that the adsorption of copper ions to the HPANF is attributed to the imine groups on the surface of the HPANF. 相似文献
140.
The Staudinger reaction of fluoroalkylazides were studied. A series of N-fluoroalkylimines were synthesized via aza-Wittig reaction of N-fluoroalkyliminophosphoranes. The N,N′-difluoroalkylated carbodiimide was also synthesized via the reaction of N-fluoroalkyliminophosphoranes with carbon dioxide or carbon disulfide. 相似文献