摘要：
A graphene oxide (GO) film coated glassy carbon electrode (GCE) was fabricated for sensitive determination of 4-nitrophenol (4-NP). The GO-based sensor was characterized by scanning electron microscope, atomic force microscopy and electrochemical impedance spectroscopy. The electrochemical behaviors of 4-NP at the GO-film coated GCE were investigated in detail. In 0.1 M acetate buffer with a pH of 4.8, 4-NP yields a very sensitive and well-defined reduction peak at the GO-modified GCE. It is found that the GO film exhibits obvious electrocatalytic activity toward the reduction of 4-NP since it not only increases the reduction peak current but also lowers the reduction overpotential. Based on this, an electrochemical method was proposed for the direct determination of 4-NP. Various kinetic parameters such as transfer electron number, transfer proton number and standard heterogeneous rate constant were calculated, and various experimental parameters were also optimized. Under the optimal conditions, the reduction peak current varies linearly with the concentration of 4-NP ranging from 0.1 to 120 mu M, and the detection limit is 0.02 mu M at the signal noise ratio of 3. Moreover, the fabricated sensor presented high selectivity and long-term stability. This electrochemical sensor was further applied to determine 4-NP in real water samples, and it showed great promise for simple, sensitive, and quantitative detection of 4-NP. (C) 2011 Elsevier B.V. All rights reserved.
摘要：
A new kind of nanocomposite based on silver nanoparticles (AgNPs)/graphene oxide (GO) was conveniently achieved through a green and low-cost synthesis approach using glucose as a reducing and stabilizing agent, and the synthetic procedure can be easily used for the construction of a disposable electrochemical sensor on glassy carbon electrode (GCE). The nanocomposite was detailedly characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR) and electrochemical impedance spectroscopy (EIS). The experimental results demonstrated that the nanocomposite possessed the specific features of both silver nanoparticles and graphene, and the intrinsic high specific area and the fast electron transfer rate ascribed to the nanohybrid structure could improve its electrocatalytic performance greatly. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were employed to evaluate the electrochemical properties of AgNPs/GO/GCE towards tryptophan, and the AgNPs/GO film exhibited a distinctly higher activity for the electro-oxidation of tryptophan than GO film with tenfold enhancement of peak current. The oxidation mechanism and the kinetic parameters were investigated, and analysis operation conditions were optimized. Under the selected experimental conditions, the oxidation peak currents were proportional to tryptophan concentrations over the range of 0.01 mu M to 50.0 mu M and 50.0 mu M to 800.0 mu M, respectively. The detection limit was 2.0 nM (S/N=3). Moreover, the proposed method is free of interference from tyrosine and other coexisting species. The resulting sensor displays excellent repeatability and long-term stability; finally it was successfully applied to detect tryptophan in real samples with good recoveries, ranging from 99.0% to 103.0%. (C) 2012 Elsevier B.V. All rights reserved.
摘要：
A highly sensitive and mercury-free method for determination of bisphenol A (BPA) was established using a glassy carbon electrode that was modified with carboxylated multi-walled carbon nanotubes. A sensitive oxidation peak is found at 550 mV in linear sweep voltammograms at pH 7. Based on this finding, trace levels of bisphenol A can be determined over a concentration range that is linear from 10 nM to 104 nM, the correlation coefficient being 0.9983, and the detection limit (S/N = 3) being 5.0 nM. The method was successfully applied to the determination of BPA in food package. A new electrochemical method was developed for the determination of bisphenol A based on carboxylated multi-walled carbon nanotubes modified electrode.
期刊：
GREEN CHEMISTRY,2012年14(5):1268-1271 ISSN：1463-9262
通讯作者：
Wang, DP
作者机构：
[Yu, Jiangxi; Li, Junhua; Zhang, Fuxing; Wang, Deping; Kuang, Daizhi] Hengyang Normal Univ, Dept Chem & Mat Sci, Hengyang 421008, Peoples R China.;[Yu, Jiangxi; Li, Junhua; Zhang, Fuxing; Kuang, Daizhi] Hengyang Normal Univ, Coll Hunan Prov, Key Lab Funct Organometall Mat, Hengyang 421008, Peoples R China.
通讯机构：
[Wang, Deping] Hengyang Normal Univ, Dept Chem & Mat Sci, Hengyang 421008, Peoples R China.
摘要：
6,7-Dihydroquinolin-8(5H)-one oxime (L3) was found to serve as a superior ligand for the CuI-catalyzed N-arylation of imidazoles with aryl iodides, bromides, and electron-deficient chlorides in water. Moreover, the CuI/L3 catalyst system enabled the coupling reactions to take place smoothly with high yields under a low catalyst loading (0.1-1 mol% CuI and 0.2-2 mol% L3).
摘要：
We report on a highly sensitive glucose biosensor that was fabricated from a composite made from mesoporous hydroxyapatite and mesoporous titanium dioxide which then were ultrasonically mixed with multi-walled carbon nanotubes to form a rough nanocomposite film. This film served as a platform to immobilize glucose oxidase onto a glassy carbon electrode. The morphological and electrochemical properties of the film were examined by scanning electron microscopy and electrochemical impedance spectroscopy. Cyclic voltammetry and chronoamperometry were used to characterize the electrochemical performances of the biosensor which exhibited excellent electrocatalytic activity to the oxidation of glucose. At an operating potential of 0.3 V and pH 6.8, the sensor displays a sensitivity of 57.0 μA mM−1 cm−2, a response time of <5 s, a linear dynamic range from 0.01 to 15.2 mM, a correlation coefficient of 0.9985, and a detection limit of 2 μM at an SNR of 3. No interferences are found for uric acid, ascorbic acid, dopamine and most carbohydrates. The sensor is stable and was successfully applied to the determination of glucose in real samples. Mesoporous hydroxyapatite, titanium dioxide and multi-walled carbon nanotubes were ultrasonically mixed to form a rough nanofilm, and a new glucose biosensor was fabricated based on this nanofilm. The biosensor had great bioelectrocatalytic activity to glucose oxidation, and it exhibited a high sensitivity, wide linear dynamic range and high selectivity for glucose determination.
期刊：
MATERIALS SCIENCE & ENGINEERING C-BIOMIMETIC AND SUPRAMOLECULAR SYSTEMS,2008年28(8):1516-1521 ISSN：0928-4931
通讯作者：
Xu, Z.(xuzhifenghw@163.com)
作者机构：
[Xu, Zhifeng; Wang, Jianqiu; Zhang, Fuxing; Kuang, Daizhi] Department of Chemistry and Material Science, Hengyang Normal University, Hengyang, 421008, China;[Xu, Li] Department of Applied Chemistry, College of Sciences, South China Agricultural University, Guangzhou, 510642, China
通讯机构：
[Xu, Zhifeng] Hengyang Normal Univ, Dept Chem & Mat Sci, Hengyang 421008, Peoples R China.
期刊：
CHINESE JOURNAL OF INORGANIC CHEMISTRY,2008年24(11):1907-1911 ISSN：1001-4861
通讯作者：
Chen Zhi-Min
作者机构：
[陈志敏; 邝代治] Department of Chemistry and Material science;[陈志敏; 邝代治] Hengyang Normal University;[李东平] Nanjing University;[李慧泉] Department of chemistry;[李慧泉] Fuyang normal university
通讯机构：
[Chen Zhi-Min] Hengyang Normal Univ, Dept Chem & Mat Sci, Hengyang 421008, Hunan, Peoples R China.
摘要：
A Manganese(Ⅱ) polymer {[Mn(bpdc)(bipy)(H_2O)]·4.5H_2O}_n has been synthesized (bpdc=2,2-bipyridine- 3,3-dicarboxylate,bipy=4,4-bipyridine) and characterized by IR, UV, elemental analysis and X-ray crystal structure determination . It crystallizes in Monoclinic system, space group P_2/n with a=1.010 13(8) nm, b=1.164 66(9) nm, c= 2.147 40(16) nm, β=98.22 20(10)°, V=2.500 4(3) nm~3, Z=4, D_c=1.467 g·cm~(-3), F(000)=1 144, R_1=0.049 0, wR_2= 0.141 2. The crystal structure shows that the Mn~(2+) ions have octahedral coordination geometry with two coordination situations. The Mn~(2+) (1) ion is coordinated with two N atoms of two bipy, and chelated by four O atoms from four carboxylate groups of two bpdc ligands. The neighbor Mn~(2+) (2) ion is coordinated with two oxygen atoms from two water, two N atoms of two 4,4-bipy and two O atoms from two carboxylate groups of two bpdc ligands. Mn(1) and Mn(2) ions are bridged by bpdc and bipy ligands, forming a novel 2D network. CCDC: 651043.
摘要：
We report on a glassy carbon electrode that was modified with a composite made from graphene oxide (GO) and multiwalled carbon nanotubes (MWCNT) that enables highly sensitive determination of L-tyrosine. The sensor was characterized by transmission electron microscopy and electrochemical impedance spectroscopy, and its electrochemical properties by cyclic voltammetry, chronocoulometry and differential pulse voltammetry. The GO/MWCNT hybrid exhibits strong catalytic activity toward the oxidation of L-tyrosine, with a well defined oxidation peak at 761 mV. The respective current serves as the analytical information and is proportional to the L-tyrosine concentration in two ranges of different slope (0.05 to 1.0 μM and 1.0 to 650.0 μM), with limits of detection and quantification as low as 4.4 nM and 14.7 nM, respectively. The method was successfully applied to the analysis of L-tyrosine in human body fluids. The excellent reproducibility, stability, sensitivity and selectivity are believed to be due to the combination of the electrocatalytic properties of both GO and MWCNT. They are making this hybrid electrode a potentially useful electrochemical sensing platform for bioanalysis. A new L-tyrosine electrochemical sensor was fabricated based on graphene oxide and multiwalled carbon nanotube. The prepared sensor exhibits excellent electro-catalysis to the oxidation of L-tyrosine, and can improve determination sensitivity and decrease detection limit. This sensor was successfully applied to detect L-tyrosine in human fluids with satisfactory results.
作者机构：
[Xu, Zhifeng; Zhang, Fuxing; Feng, Yonglan; Kuang, Daizhi] Department of Chemistry and Material Science, Hengyang Normal University, Key Laboratory of Functional Organometallic Materials, Hengyang, 421008, China
通讯机构：
[Xu, Zhifeng] Hengyang Normal Univ, Dept Chem & Mat Sci, Coll Hunan Prov, Key Lab Funct Organomet Mat, Hengyang 421008, Peoples R China.
摘要：
The combination of CuSO4 with naturally occurring sucrose in a biodegradable aqueous solution of PEG‐200 has been confirmed as a novel, recyclable, and environmentally benign homogeneous catalyst system for the direct amination of aryl halides with NH3·H2O. Electron‐rich, electron‐poor, and even ortho‐substituted aryl bromides and iodides could be aminated to provide the desired primary arylamines in high yields at 90 °C without the need of an inert atmosphere.
摘要：
A novel complex tri(o-bromobenzyl)tin ferrocenecarboxylate has been synthesized and its crystal structure was determined by X-ray diffraction. It belongs to orthorhombic, space group Pbca with a = 1.1340(3), b = 1.7823 (4), c = 3.0119(8) nm, V = 6.088(3) nm~3, M_r = 857.81, Z = 8, D_c = 1.872 g/cm~3, μ(MoKα) = 52.63 cm~(-1), F(000) = 3328, R = 0.0683 and wR = 0.1057. The tin atom adopts a distorted tetrahedral coordination geometry. Further studies on the title com- plex have been performed with quantum chemistry calculation at the Lanl2dz basis set level using G98W package. The stability of the complex, some frontier molecular orbital energies and com- position characteristics of some frontier molecular orbitals have been investigated.
摘要：
A novel organotin complex [(o-Cl-PhCH2)3SnOCOCioH8N]-0.5C6H6 has been synthesized, and its crystal structure was determined by X-ray diffraction. The crystal belongs to mo-noclinic, space group C2/c with a = 1.6214(5), b = 1.2033(3), c = 3.2873(10) nm, β= 91.467(5)°, V = 6.411(3) nm3, Mr = 1441.26, Z = 4, Dc = 1.493 g/cm3, μ(MoKa) = 10.79 cm-1, F(000) = 2904, R = 0.0500 and Rw = 0.0884. The bond lengths of Sn-C are 0.2150(5), 0.2157(4) and 0.2164(4) nm, and that of Sn-0 is 0.2043(3) nm. The tin atom adopts a distorted tetrahedral geometry.
