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71.
o-Dianisidine (ODA)-H2O2-horseradish peroxidase (HRP) voltammetric enzyme-linked immunoassay system has firstly been used for the detection of tobacco mosaic virus (TMV). HRP catalyzes strongly the oxidation reaction of ODA by H2O2, the product of which produces a sensitive second order derivative linear sweep voltammetric peak at potential of −0.56 V (versus SCE) in Britton–Robinson (BR) buffer. HRP activity has been measured with this voltammetric peak and TMV detected through immunoreaction. The detection limit for HRP is 9.25×10-7 mU l−1 and the linear range is 2.5×10−6–5.0×10−4 mU l−1. The detection limit for the clarified TMV is 0.25 ng ml−1 and the highest dilution ratio detected for the infected leaf sap is 1:8×105. The sensitivity for TMV detection with this method is higher than that with the enzyme-linked immunosorbent spectrophotometric assay (ELISA) using ODA-H2O2-HRP system. The processes of the enzyme-catalyzed reaction and the electro-reduction of the product of the enzyme-catalyzed reaction have been described. 相似文献
72.
Chang Xiu Han Ji Li Ren Xue Jiao Tang Bao Gui Zhang 《中国化学快报》2007,18(10):1285-1288
A new ternary Fe-based alloy catalyst FeCuP applied to decompose PH_3 was prepared with low-cost material by chemical reduction deposition method.The properties of it were characterized by XRD,ICP and SEM.Its catalytic activity on the decomposition of PH_3 and the decomposition conditions were studied.FeCuP alloy exhibits high thermal stabilities and high catalytic activity.Using it as catalyst,the decomposition temperature of phosphine decreases from over 800℃to 400-500℃.The decomposition rate of phosphine achieved 100%. 相似文献
73.
Cyanex301的纯化及其特性 总被引:7,自引:0,他引:7
研究了用Cyanex301[TM]铵盐在苯中重结晶以纯化Cyanex301的方法,该法收率62.4%,产品纯度>99%。测定了经纯化后产品的红外光谱,研究了纯化产品在-水正庚烷体系中的分配平衡及其在正庚烷中的缔合,浓度在0.2~1.0mo1/L范围,Cyanex301主要以二聚形式存在。 相似文献
74.
An improved method has been developed for the determination of acrylamide in infant powdered milk and baby foods in jars, a particular class of foodstuffs which represent an important source of nutrition for young infants and babies. This method uses isotope dilution liquid chromatography coupled to a tandem mass spectrometer with electrospray ionization and is significantly more sensitive than previous published methods with a limit of quantification estimated at 1 microg kg(-1). The new method offers effective sample preparation procedures including defatting with petroleum ether, extraction with aqueous solution of sodium chloride, further liquid-liquid extraction with ethyl acetate and clean-up by solid-phase extraction (SPE) with HLB 200 mg cartridges. The analytical method was well validated and good results were obtained with respect to repeatability (RSD < 5%) and recovery (86-97%) which fulfilled the requirements defined by European Union (EU) legislation. The acrylamide level in infant powdered milk and baby foods in jars were 3.01-9.06 microg kg(-1) and 6.80-124.93 microg kg(-1), respectively. Especially, this new method is successfully applied to the trace quantification of acrylamide in infant/baby foods, the content of which is less than 10 microg kg(-1). 相似文献
75.
The electrochemical enzyme-linked immunoassay increases the sensitivity of the detection of cucumber mosaic virus (CMV) by 5-fold compared with the spectrophotometric o-phenylenediamine (OPD) enzyme-linked immunosorbent assay (ELISA). The detection limit for the purified CMV is 1.0 ng/mL and the highest dilution ratio of the infected leaf sap is 1:5.0 x 10(4). The method is based on coupling the oxidation reaction of o-aminophenol (OAP)-H2O2 catalyzed by HRP-IgG conjugate with the electro-reduction of the enzymatic product. The enzymatic product 2-aminophenoxazine-3-one exhibits a sensitive second order derivative linear-sweep voltammetric response at the potential of -0.65 V (vs. Ag/AgCl) in pH 8.0 Britton-Robinson (B-R) buffer solution. So it can be applied to the detection of the plant virus with highly improved sensitivity. 相似文献
76.
Electrochemical studies on the interaction of heparin with crystal violet and its analytical application 总被引:1,自引:0,他引:1
In this paper, crystal violet (CV) was used to determine heparin concentration by linear sweep voltammetry on a dropping mercury
electrode (DME). In Britton-Robinson (B-R) buffer solution, pH 3.0, CV had a well-defined second-order derivative linear sweep
voltammetric reductive wave at −0.74 V (vs. SCE). After the addition of heparin to the CV solution, the reductive peak current
decreased greatly with the positive movement of the peak potential and without appearance of new peaks in the scanning potential
range. Based on the decrease in the reductive peak current, a new voltammetric method for the determination of heparin was
established. The conditions for the interaction and the electrochemical detection were optimized, and interfering substances
were investigated. Under the optimal conditions, the decrease in reductive peak currents of CV was proportional to heparin
concentration in the range 0.1–8.0 mg/L with the linear regression equation Δip″(nA) = 400.42 + 1563.11c (mg/L), (n = 14, γ = 0.993). The detection limit was 0.092 mg/L. This new method was further successfully applied to the determination of heparin
content in heparin sodium injection samples with satisfactory results. The binding ratio and binding mechanism were also studied
by the electrochemical method.
The text was submitted by the authors in English. 相似文献
77.
Pt微粒修饰纳米纤维聚苯胺电极对甲醇氧化电催化 总被引:9,自引:0,他引:9
以脉冲电流法制备的纳米纤维状聚苯胺(PANI)为Pt催化剂载体,用它制备了甲醇阳极氧化的催化电极Pt/(nano-fibular PANI).研究结果表明, Pt/(nano-fibular PANI)电极对甲醇氧化具有很好的电催化活性,并有协同催化作用.在相同的Pt载量条件下, Pt/(nano-fibular PANI)电极比Pt微粒修饰的颗粒状聚苯胺电极Pt/(granular PANI)具有更好的电催化活性.此外, Pt的电沉积修饰方法同样影响Pt/(nano-fibular PANI)电极对甲醇氧化的催化活性.脉冲电流法沉积Pt形成的复合电极较循环伏安法电沉积得到的Pt复合电极具有更优异的催化活性. 相似文献
78.
The synthesis of derivatives of 3-β-D-xylopyranosyl-1,2,4-oxadiazolesis accomplished by condensing protected β-D-xylopyranosyl amidoxime with acidanhydrides or various substituted benzoyl chlorides in good yield.Thestructures of now derivatives were identified by spectra and elemental analysis.The stability of 1,2,4-oxadiazole ring and mechanism of cyclization were.investigated. 相似文献
79.
Chen Z Heine T Jiao H Hirsch A Thiel W Schleyer Pv 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(4):963-970
Hybrid B3LYP and density-functional-based tight-binding (DFTB) computations on the solid-state structures and electronic properties of the C(20) fullerene monomer and oligomers are reported. C(20) cages with C(2), C(2h), C(i), D(3d), and D(2h) symmetries have similar energies and geometries. Release of the very high C(20) strain is, in theory, responsible for the ready oligomerization and the formation of different solid phases. Open [2+2] bonding is preferred both in the oligomers and in the infinite one-dimensional solids; the latter may exhibit metallic character. Two types of three-dimensional solids, the open [2+2] simple cubic and the body-centered cubic (bcc) forms, are proposed. The energy of the latter is lower due to the better oligomer bonding. The open [2+2] simple cubic solid should be a conductor, whereas the bcc solids are insulators. The most stable three-dimensional solid-state structure, an anisotropically compressed form of the bcc solid, has a HOMO-LUMO gap of approximately 2 eV and a larger binding energy than that of the proposed C(36) solid. 相似文献
80.
Xu J Jiao P Deng D Zhang Q Tsang CW Chan AS 《Rapid communications in mass spectrometry : RCM》2002,16(12):1174-1179
The mass spectrometric fragmentation behaviour of five pairs of (R,R)- and (S,S)-4,5-bis(benzoxazol-2-yl)-2,2-dimethyl-1,3-dioxolane derivatives, one pair of (R,R)- and (S,S)-4,5-bis(benzothiazol-2-yl)-2,2-dimethyl-1,3-dioxolanes, and three pairs of (R,R)- and (S,S)-N,N'-bis(2-hydroxyaryl)-2,2-dimethyl-1,3-dioxolane-4,5-dicarbamides, all important compounds for asymmetric catalysis (P. Jiao et al., Tetrahedron Asymmetry 2001; 12: 3081), has been studied with the aid of mass-analyzed ion kinetic energy spectrometry and accurate mass measurements under electron impact ionization conditions. The spectral observations have been rationalized in terms of fragment ion structures and fragmentation mechanisms that will provide an aid to spectral interpretation for new compounds of this type. 相似文献