枸杞子中红色素的提取及稳定性

枸杞子中红色素的提取及稳定性伍明，王杰，闪春霞，任仲皎，宋锡瑾，詹国庆（中南民族学院化学系武汉４３００７４）关键词枸杞，色素，液泛提取法枸杞子为茄科枸杞属植物的果实，具有补肾养肝，润肺明目以及调节机体免疫力，抑制肿瘤生长和细胞突变，延缓衰老及抗脂肪肝...     

Synthesis of anew siloxane-containing diamine and related polyimide

A novel siloxane-containing diamine, bis[4-(p-aminophenoxy)phenoxy]dimethylsilane (APPMS), was successfully synthesized in three steps using hydroquinone as starting material, which was reacted with 4,4'-oxydiphthalic anhydride (ODPA) via a conventional two-step thermal or chemical imidization method to produce a new siloxane-containing polyimide. The resulting polyimide exhibited excellent solubility, and film-forming capability.     

DNA-functionalized MFe2O4 (M = Fe, Co, or Mn) nanoparticles and their hybridization to DNA-functionalized surfaces

Magnetic MFe2O4 (M = Fe, Co, or Mn) nanoparticles with uniform diameters in the 4-20 nm range and with excellent material properties, reported previously, can be rendered soluble in water or aqueous buffers using a combination of alkylphosphonate surfactants and other surfactants such as ethoxylated fatty alcohols or phospholipids. Surfactant-modified oligonucleotides can be incorporated into the particles' organic shell. The particles can withstand salt concentrations up to 0.3 M, temperatures up to 90 degrees C, and various operations such as concentration to dryness, column or membrane separations, and electrophoresis. The particles can be selectively hybridized to DNA-functionalized gold surfaces with high coverages using a two-story monolayer structure. These particles may find valuable applications involving the magnetic detection of small numbers of biomolecules using spin valves, magnetic tunnel junctions, or other sensors.     

阻抑动力学光度法测定环境水样中的痕量苯酚

基于在稀硫酸介质中，痕量苯酚能灵敏地阻抑高碘酸氧化苯胺蓝褪色，研究了该阻抑褪色反应的最佳条件及动力学参数，建立了测定痕量苯酚的新方法。该方法的线性范围为0-40.0μg/L，线性回归方程为1g(A1/A2)=0.638c 0.00117，相关系数r=0.9996，检出限为1.2μg/L。该方法简便，灵敏，选择性好，用于环境水样中痕量苯酚的测定，结果准确。     

Study on Triplex DNA by Use of Molecular “Light Switch“ Complex of Ru(phen)2(dppx)^2

A new method for the study of triplex DNA is established according the fluorescence enhancement of molecular “Light Switch“ complex of Ru(phen)2(dppx)^2 when it intercalate into triplex DNA.Because the fluorescence intensity of Ru(phen)2(dppx)^2 bonded to triplex DNA is in ths case higher than that bonded to duplex DNA in certain range of DNA concentration,the method is much more sensitive than other methods reported previously.     

A new room temperature ionic liquid 1-butyl-3-trimethylsilylimidazolium hexafluorophosphate as a solvent for extraction and preconcentration of mercury with determination by cold vapor atomic absorption spectrometry

A new room temperature ionic liquid 1-butyl-3-trimethylsilylimidazolium hexafluorophosphate abbreviated as [C₄tmsim][PF₆] was synthesized and developed as a novel medium for liquid/liquid extraction of inorganic mercury in this work. Under optimal condition, o-carboxyphenyldiazoamino-p-azobenzene abbreviated as CDAA reacted with inorganic mercury to form a neutral Hg-CDAA complex, the complex was rapidly extracted into ionic liquid phase. After back-extracting into aqueous phase with sulfide sodium solution, the mercury concentration was detected by cold vapor atomic absorption spectrometry. The extraction and back-extraction efficiencies were 99.9 and 100.1% for 5.0 μg L⁻¹ standard mercury in 1000 mL of water solution, respectively. The detection limit, calculated using three times the standard error of estimate of the calibration graph, is 0.01 ng of mercury per milliliter water sample. The proposed method has been used to the determination of trace inorganic mercury in natural water with satisfactory results. Moreover, Zeta potential and surface tension of [C₄tmsim][PF₆] solution were measured and applied to explain the extraction mechanism of [C₄tmsim][PF₆] system.     

Conductivity of solvated electrons in hexane investigated with terahertz time-domain spectroscopy

We present investigations of the transient photoconductivity and recombination dynamics of quasifree electrons in liquid n-hexane and cyclohexane performed using terahertz time-domain spectroscopy (THz-TDS). Quasifree electrons are generated by two-photon photoionization of the liquid using a femtosecond ultraviolet pulse, and the resulting changes in the complex conductivity are probed by a THz electromagnetic pulse at a variable delay. The detection of time-domain wave forms of the THz electric field permits the direct determination of both the real and the imaginary part of the conductivity of the electrons over a wide frequency range. The change in conductivity can be described by the Drude model, thus yielding the quasifree electron density and scattering time. The electron density is found to decay on a time scale of a few hundred picoseconds, which becomes shorter with increasing excitation density. The dynamics can be described by a model that assumes nongeminate recombination between electrons and positive ions. In addition, a strong dependence of the quasifree electron density on temperature is observed, in agreement with a two-state model in which the electron may exist in either a quasifree or a bound state.     

Sensitive Determination of Cyanide in Cigarette Smoke by Capillary GC with a MicroECD

A sensitive method using capillary gas chromatography coupled with a micro electron capture detector (μECD) has been developed for the determination of cyanide in cigarette smoke. The procedure is based upon the conversion of cyanide to cyanogen chloride by chloramine-T. Cyanogen chloride, dissolved in n-hexane, was analyzed by GC–μECD. Under optimum conditions, the detector response was linear from 25.0 ng mL^?1 to 15.0 μg mL^?1 with relative standard deviation between 0.07 and 3.30%. Recovery ranged from 86.0 to 116.0%. The method was shown to be precise, accurate and linear over the range of concentration of analytes.     

Bandunamide, a Novel Cyclopeptide from the Streptomyces Griseovariabilis bandungensis

A new cyclic octapeptide, bandunamide, was isolated from the acetone extracts of streptomyces griseovariabilis bandungensis. This cyclic octapeptide exhibits strong antimicrobial activity against Phytophthora drechsleri (IC50=15 ng/mL), Colletotrchum higginsiannum(IC50=15.6 ng/mL), Piricularia oxyzae (IC50=0.2 μg/mL), and Fusarium oxysporum f. Sp.(IC50= 100μg/mL). The structure elucidation of bandunamide is herein reported.     

用高分辨率电感耦合等离子体-原子发射光谱仪测定高纯铬中的杂质元素

本文报道了高分辨率、高灵敏度的顺序扫描型电感耦合等离子体原子发射光谱仪(ICPS-8100)在高纯物质分析中的应用。对元素分析线进行优化选择;采用轴向观测方式,对高纯铬中μg/g级的杂质元素As、Sn、Sb、Pb进行直接同时测定,分析结果令人满意。