作者机构：
[Liu, GD] New Mexico State Univ, Dept Chem & Biochem, Las Cruces, NM 88003 USA.;Hunan City Coll, Dept Environm Chem & Engn, Yiyang 413049, Peoples R China.
通讯机构：
[Liu, GD] N;New Mexico State Univ, Dept Chem & Biochem, Las Cruces, NM 88003 USA.
摘要：
An amperometric immunosensor was constructed by dispersing graphite, schistosoma-japonicum antigen (SjAg) and silica sol-gel at low temperature. The performance characteristics of the prepared immunosensor were examined in the buffered solution of o-aminophenol (o-AP) used as a substrate. It exhibited excellent physical and electrochemical stability with a renewable external surface. A competitive binding assay was employed to determine schistosoma-japonicum antibody (SjAb) with the aid of horseradish peroxidase labeled SjAb (HRP-SjAb). The experimental parameters for SjAb assay were optimized, including the amount of labeled SjAb in incubation solution, incubation time, temperature and the pH of solution. The use of o-AP substrate and amperometric detection at -250 mV (vs. SCE) results in a determination limit of 0.32 μg/ml and a linear range extending up to 0.18 μg/ml. The results of SjAb assay in serum samples demonstrate the feasibility of using the proposed immunosensor for clinical analysis.
摘要：
A highly selective and sensitive electrochemical sensor modified with carboxymethylated, beta-cyclodextrin (CM-beta-CDP) polymer film was fabricated for the determination of dopamine (DA) in the presence of ascorbic acid (AA). The electrochemical behavior of DA and AA at the chemically modified electrode was investigated by cyclic voltammetry (CV) and differential pulse voltammetry. The response mechanism of CM-beta-CDP film for DA was based on the combination of electrostatic and inclusion interaction of CM-beta-CDP for DA, which was distinguished from the response mechanism of the charged polymer film modified electrode that only relied upon the electrostatic interaction between charged polymer film and DA (or AA) to realize the separation of overlapping peak potential of DA and AA. The CM-beta-CDP film showed preferable analytical performance characteristics in catalytic oxidation of DA compared with the beta-CDP polymer film. Under optimized conditions, it was feasible for the electrode modified with the CM-beta-CDP film to selectively determine DA in the presence of a large excess of AA. A linear calibration plot was obtained over the range 0.8-60 muM with a sensitivity of 65 nA/muM and a detection limit (signal/noise (S/N) = 3) of 0.2 muM in the presence of 1.0mM AA. This electrochemical sensor showed excellent sensitivity, repeatability, stability, and recovery for the determination of DA. The interference of AA with the determination of DA could be efficiently eliminated.
摘要：
A new enzyme-based amperometric biosensor for hydrogen peroxide was developed relying on the efficient immobilization of horseradish peroxidase (HRP) to a nano-scaled particulate gold (nano-Au) film modified glassy carbon electrode (GC). The nano-Au film was obtained by a chitosan film which was first formed on the surface of GC. The high affinity of chitosan for nano-Au associated with its amino groups resulted in the formation of nano-Au film on the surface of GC. The film formed served as an intermediator to retain high efficient and stable immobilization of the enzyme. H2O2,was detected using hydroquinone as an electron mediator to transfer electrons between the electrode and HRP. The HRP immobilized on nano-Au film maintained excellent electrocatalytical activity to the reduction of H2O2. The experimental parameters such as the operating potential of the working electrode, mediator concentration and pH of background electrolyte were optimized for best analytical performance of amperometry. The linear range of detection for H2O2 is from 6.1 x 10(-6) to 1.8 x 10(-3) mol L-1 with a detection limit of 6.1 mumol L-1 based on signal/noise = 3. The proposed HRP enzyme sensor has the features of high sensitivity (0.25 Almol(-1)cm(-2)), fast response time (t(90%) less than or equal to 10 s) and a long-term stability (> 1 month). As an extension, glucose oxidase (GOD) was chemically bound to HRP-modified electrode. A GOD/HRP bienzyme-modified electrode formed in this way can be applied to the determination of glucose with satisfactory performance.
摘要：
Benzil is an important photosensitive initiator of organic synthesis intermediates,medicinal intermediates and ultraviolet solidified resin (UVresin),and is usually prepared by oxidizing benzoin, The oxidizers and methods reported are mainly;(PhCH_2Et_3N)~+Br~-/(PhCO)_2O_2/MeCN~[1],DMSO/(COCL)_2 CH_2CL_2~[2],CrO_3·CH_3NH_2·HCl/Al_2O_3~[3], the metallorganic compound~[4],microwave radiation~[5],etc.The reaction conditions of some methods are harsh, the toxicity is heavy, the reaction reagent is expensive, the preparation is difficult, the aftertreatment is tedious or the conversion ratio of materials is low.Cupric compound is a kind of weak oxidizer.Up till now there is only the report of oxidizing benzoin with cupric sulfate-pyridine~[6] with cupric acetate-acetic acid~[7].This paper studies the problem of oxidizing benzoin by using cupric nitrate, cupric chloride, cupric sulfate,cupric acetate and cupric subcarbonate as oxidizers.The experimental results indicate that these cupric compounds can all oxidize benzoin into benzil in acetic acid solutions, and cupric nitrate is the best one.Its product has these adventages of fine color and luster,high yield, available raw material and simple and easy operation and it has the prospects of being used widely.
作者机构：
[张鲁西; 管仕斌; 俞善信] Department of Chemistry, Coll. of Chem. and Chem. Engineering, Hunan Normal University, Changsha 410081, China;[文瑞明] Dept. of Chem./Environmentally Eng., Hunan City University, Yiyang 413049, China
摘要：
1 INTRODUCTION
Catalytic hydrodechlorination is an elegant reaction for disposal of environmentally hazardous chlorocarbons,such as chloro-benzene[1].Development of a new catalyst with excellent stability is necessary due to the deactivation of supported noble metal catalysts[1].However the modification of catalytic properties of catalysts in hydrodechlorination reaction by introducing stable ligands to noble metals has been the least studied.Here the synthesis of Pd(Ⅱ) 2,9,16,23-symetrically tetrasubstituted phthalocyanines PdPTX4 (where X=-H,-NO2,-NH2 respectively) from phthalimide derivatives is reported,and their application as catalysts in hydrodechlorination of chlorobenzene,which is a representative environmentally hazardous materials is discussed.
