β-丙氨酸-银复合膜修饰电极用于循环伏安法测定对乙酰氨基酚

制备了β-丙氨酸-银复合膜修饰电极(Ag-Ala/GCE),采用循环伏安法研究了对乙酰氨基酚在修饰电极上的电化学行为。结果表明:在pH 4.0的磷酸盐缓冲液中,对乙酰氨基酚在修饰电极上呈现一对灵敏的氧化还原峰,提出了用循环伏安法测定对乙酰氨基酚的含量。对乙酰氨基酚浓度在6.0×10-7～7.0×10-4 mol.L-1范围内与氧化峰电流呈现线性关系,检出限(3S/N)为2.0×10-7 mol.L-1。修饰电极用于药剂中对乙酰氨基酚的测定,并用标准加入法测得方法的回收率在95.1%～101.6%之间。     

分散液相微萃取-高效液相色谱法测定水和土壤中多环芳烃

以二硫化碳为萃取剂,丙酮为分散剂对水样和土壤样中残留的多环芳烃进行分散液相微萃取。提取液供高效液相色谱仪的二极管阵列检测器和荧光检测器测定。选用LiChrospherPAH色谱柱作为固定相,用乙腈和水以不同比例混合的溶液作为流动相进行梯度淋洗。在优化的试验条件下,对合成水样中多环芳烃的富集倍数达220～560倍,16种多环芳烃可有效分离并测定。16种多环芳烃的检出限(3S/N)在0.002～0.05μg.L-1之间。用标准加入法测得回收率在64%～108%之间,测定值的相对标准偏差(n=7)在2.0%～7.8%之间。     

头孢唑林钠与DNA相互作用的紫外吸收光谱法研究

利用紫外-可见分光光度法研究了头孢唑林与鲱鱼精DNA的相互作用并考察了影响两者相互作用的条件(如pH、温度、作用时间等)。实验发现头孢唑林与鲱鱼精DNA主要通过嵌入式结合。根据试验结果利用双倒数分析法计算出头孢唑林与DNA相互作用的结合常数为3.38×102mL/mg。     

鸡蛋壳膜蛋白在生物相容性材料中的应用研究

鸡蛋壳是一种天然产物,作为食品工业和人类生活的废弃物大量存在.鸡蛋壳膜作为蛋壳的重要组成部分,具有重要的生理作用,同时也是一种性能优异、具有开发价值的天然生物材料.本文介绍了作者课题组近年来在鸡蛋壳膜蛋白方面的相关工作,这些工作围绕可溶性鸡蛋壳膜蛋白的提取及其在生物相容性材料制备方面的应用展开,有望将蛋壳膜蛋白应用于组...     

THERMAL DEGRADATION AND FLAME RETARDANCY OF CALCIUM ALGINATE FIBERS

Calcium alginate fibers were prepared by wet spinning of sodium alginate into a coagulating bath containing calcium chloride.The thermal degradation and flame retardancy of calcium alginate fibers were investigated with thermal gravimetry(TG),X-ray diffraction(XRD),limiting oxygen index(LOI) and cone calorimeter(CONE).The results show that calcium alginate fibers are inherently flame retardant with a LOI value of 34,and the heat release rate(HRR),total heat release(THR),CO and CO_2 concentrations during ...     

镧与邻菲咯啉和联吡啶的混配物的合成及其与DNA作用的研究

合成了稀土镧 (La)与 2 ,2 联吡啶 (dpy) ,1,10 邻菲咯啉 ( phen)的混配物 ,并进行了红外和热分析的表征 ,证实了其混配物的结构为La(dpy) ( phen)Cl3 。并对其与DNA作用的紫外 可见光谱和共振光散射光谱作了初步的研究。研究结果表明 ,混配物的吸收峰随着DNA的加入而发生减色效应 ,而DNA浓度继续增高 ,吸收峰又增高 ,说明此混配物与DNA先是嵌入结合 ,而后伴随有静电结合。而此混配物在 4 70nm处的共振光散射峰随着DNA的加入增强 ,则表明混配物在DNA分子表面进行长距离自组装。研究证明所合成的配合物能够与DNA作用 ,可作为DNA的荧光探针     

SURFACE MODIFICATION OF CaCO_3 WITH DENDRITIC CARBOXYLIC ACIDS

Nanometer calcium carbonate was modified with Frechet type polyether dendrons bearing a COOH group at thefocal point by a wet-coating technique in dichloromethane at room temperature. The interaction between CaCO_3 and thedendritic modifier was proven by IR and mass spectroscopy of the modified CaCO_3 after thorough extraction withdichloromethane. The amount of tightly bonded organic modifier was estimated by TGA. It was shown that the amount ofbonded molecules decreased with increasing generation number due to the larger number of branches. Compared tounmodified CaCO_3, the modified CaCO_3 possess different dispersibility in water and in organic solvents.     

GRAFTING OF POLYSTYRENE ONTO A NANOMETER SILICA SURFACE BY MICROEMULSION POLYMERIZATION

The grafting of polystyrene onto a nanometer silica surface by microemulsion polymerization is described. Silicawas functionalized with 3-methacryloxypropyltrimethoxysilane coupling agent before polymerization. A mixture of ionic andnon-ionic surfactants as well as water-soluble and oil-soluble initiators were used. The effect of the amount of silica and ionicsurfactant on the graft polymerization was studied. The graft polymerization procedure for styrene was also applied to methylmethacrylate. Composite particles with a core-shell structure were obtained and the yield and grafting efficiency of monomerwere high.     

DIBUTYLTIN DILAURATE-CATALYZED DIISOCYANATE COUPLING—GRAFTING OF POLY(ETHYLENE GLYCOL) ONTO NANO-SILICA SURFACE THROUGH A ONE-STEP PROCEDURE

Grafting polymer glycols onto nano-silica surface through one-step procedure was investigated. The major characteristic of this procedure is that all the materials and reagents (silica, PEG, TDI, DBTDL, solvent) required for grafting were added simultaneously into the reaction vessel. TDI and DBTDL were used as coupling agent and catalyst, respectively.The products were characterized by FTIR, TGA, elemental analyses and TEM, giving evidence for successful grafting of PEG. Possible mechanism of this grafting was studied and two grafting processes were proposed. The process through which the grafting proceeds depends on the reaction temperature. Effect of molecular weight of PEG on grafting was also investigated.     

NETWORK ENCAPSULATION OF NANOMETER CaCO_3

The encapsulation of stearic acid coated nanometer CaCO3 by a polystyrene (PS) network via emulsion polymerization is described, where γ-methacryloxypropyltrimethoxysilane (MPS) was used as an efficient crosslinker. The important factors such as the type and amount of surfactant and initiator and the content of CaCO3 are investigated as well as the role of MPS. It has been shown that little PS was extractable with only 0.6 wt% of MPS (relative to styrene). The cationic surfactant cetyl trimethylammonium bromide (CTAB) proved more effective than the anionic surfactant sodium dodecyl sulfonate (SDS). The yield rises, particles become smaller and size distribution broadens with increased amount of CTAB. It is also found that either 2,2′-azobis(isobutyronitrile) (AIBN) or ammonium persulfate (APS) is suitable for attaining high monomer conversion. With increased amount of CaCO3, the encapsulation ratio can be varied from 17.9 to 3.6, while monomer conversion and yield decrease slightly. FT-IR spectra of the products after extraction indicate tight encapsulation between PS and CaCO3, and TEM photographs of composite particles with well-defined core-shell structure give direct evidence of encapsulation.