纳米醋丙乳液的合成与性能表征

以醋酸乙烯酯(VAc)为原料,丙烯酸丁酯(BA)和丙烯酸(AA)为改性单体,过硫酸钾(KPS)为引发剂,OP-10,SDS和可聚合乳化剂丙烯氧基壬基酚聚氧乙烯(10)醚硫酸铵为乳化剂体系,采用半连续种子乳液聚合法制备了纳米粒径的醋丙乳液.对得到的乳液进行了分子量,热性能,红外光谱,乳液稳定性等测试,用激光散射粒度仪和透...     

光谱法研究盐酸麻黄碱及盐酸伪麻黄碱与人血清白蛋白的键合

在模拟人体生理条件下,采用紫外光谱法、荧光光谱法和同步荧光光谱法研究盐酸麻黄碱及盐酸伪麻黄碱与人血清白蛋白(HSA)的结合作用.实验表明:盐酸麻黄碱和盐酸伪麻黄碱对HSA的荧光猝灭机制均为静态猝灭,盐酸麻黄碱和盐酸伪麻黄碱与HSA均形成1∶1复合物,结合常数K分别为2.53×104 L·mol-1和2.02×104 L...     

猪肉中二甲胺四环素的反相-高效液相色谱测定

建立了一种测定猪肉中二甲胺四环素的反相-高效液相色谱(RP-HPLC)分析方法.目标物经EDTA-Mcllvaine提取,用Oasis HLB固相萃取小柱净化,流动相为甲醇-咪唑缓冲溶液,体积比20:80,荧光检测器检测,外标法定量.平均添加回收率在89.6％～94.0％之间,相对标准偏差(RSD)在3.1％～6.5％...     

恒电流电解-BCO分光光度法测定纯铜中铜含量不确定度的评定

对采用恒电流电解-BC0分光光度法测定纯铜中铜含量的不确定度进行了评定.对测量重复性、电解重量法、光度法等影响测量结果的不确定度分量进行了分析和量化.当纯铜中铜的质量分数为99.93%时,扩展不确定度为0.01%,k=2.     

Fluorescence properties and antiproliferative effects of mono-, bis-, and tris- thiophenylnaphthalimides: results of a comparative pilot study

A series of mono-, bis- and trisnaphthalimides with different substituents on the naphthalimide ring system was prepared. For compounds containing a thiophenyl substituent fluorescence spectroscopic measurements were performed and unexpectedly showed an increase in fluorescence emission for the bis- and trisnaphthalimide derivatives in phosphate buffered saline. Additional fluorescence microscopic experiments indicated an efficient cellular uptake of the thiophenyl substituted compound 1c into cultured tumor cells. Experiments on the inhibition of tumor cell proliferation were performed in MCF-7 breast adenocarcinoma and HT-29 colon carcinoma cells and confirmed derivatives containing a nitro substituent as the most active compounds. Compound 1c demonstrated potential as photoinducable antitumor agent.     

Simultaneous determination of benzimidazoles and their metabolites in plasma using high-performance liquid chromatography/tandem mass spectrometry: application to pharmacokinetic studies in rabbits

An HPLC/MS/MS method was developed for the simultaneous determination of the following benzimidazole anthelmintics and metabolites in plasma: flubendazole, albendazole, fenbendazole, mebendazole, thiabendazole, hydrolyzed flubendazole, albendazole sulfoxide, albendazole sulfone, albendazole aminosulfone, oxfendazole, fenbendazole sulfone, aminomebendazole, hydroxymebendazole, and 5-hydroxythiabendazole. The sample preparation process involved a pH-dependent extraction of the analytes. Chromatographic separation was performed on a C18 column with a mobile phase gradient starting with methanol-water (20 + 80, v/v) containing 0.1% formic acid. The overall average recoveries of the analytes based on a matrix-matched calibration ranged from 75.0 to 120.0%, with RSD values of <20.0%. The LODs ranged from 0.08 to 2.0 microg/kg and the LOQs from 0.3 to 5.0 microg/kg. The validated method was used in pharmacokinetic studies of benzimidazole compounds in rabbits, and the elimination of the metabolites was measured quantitatively.     

Synthesis and characterization of a 'fluorous' (fluorinated alkyl) affinity reagent that labels primary amine groups in proteins/peptides

Strong non-covalent interactions such as biotin-avidin affinity play critical roles in protein/peptide purification. A new type of 'fluorous' (fluorinated alkyl) affinity approach has gained popularity due especially to its low level of non-specific binding to proteins/peptides. We have developed a novel water-soluble fluorous labeling reagent that is reactive (via an active sulfo-N-hydroxylsuccinimidyl ester group) to primary amine groups in proteins/peptides. After fluorous affinity purification, the bulky fluorous tag moiety and the long oligoethylene glycol (OEG) spacer of this labeling reagent can be trimmed via the cleavage of an acid labile linker. Upon collision-induced dissociation, the labeled peptide ion yields a characteristic fragment that can be retrieved from the residual portion of the fluorous affinity tag, and this fragment ion can serve as a marker to indicate that the relevant peptide has been successfully labeled. As a proof of principle, the newly synthesized fluorous labeling reagent was evaluated for peptide/protein labeling ability in phosphate-buffered saline (PBS). Results show that both the aqueous environment protein/peptide labeling and the affinity enrichment/separation process were highly efficient.     

DFT study on the mechanism for the substitution of F(-) into Al(III) complexes in aqueous solution

The mechanisms for the substitution of an aqua ligand with F(-) in monomeric Al complexes were studied with density functional theory (DFT). Typical mechanisms are modeled to determine the preferred substitution pathway according to the activation energy barriers. The present computational results are in favor of interchange associative (I(a)) mechanism for the substitution of F(-) into Al(H(2)O)(6)(3+), whereas interchange dissociative (I(d)) mechanism is preferred for the substitution into Al(H(2)O)(5)(OH)(2+), which is in agreement with the previous experimental findings. This implies the mechanistic changeover from I(a) to I(d) induced by the spectator hydroxyl ligand. Like the water-exchange reaction, the substitution rate is accelerated by OH(-) ligand. The difference of the computational and experimental activation enthalpy values is interpreted as the DFT errors in energy and the deviation of transmission coefficient from unity.     

A ratiometric fluorescent probe for oxalate based on alkyne-conjugated carboxamidoquinolines in aqueous solution and imaging in living cells

A novel ratiometric fluorescent probe for oxalic acid was designed and synthesized, based on the zinc-containing [DAQZ@2Zn(2+)] complex. It shows highly selective "on-off" fluorescence changes with a more than 20 nm blue shift in wavelength for oxalic acids in aqueous solution. Moreover, it can fluorescently respond to oxalic acid in living cells.     

DFT study on the interaction between monomeric aluminium and chloride ion in aqueous solution

The interaction of monomeric aluminium and chloride ion in aqueous solution is investigated by density functional theory (DFT) calculations. The computational results show that it is difficult for Cl(-) to enter the inner-coordination shell of aluminium complexes by replacing the bound water molecules, independent of pH and the concentration of Cl(-). However, pH and the concentration of Cl(-) might influence the conformations, bond lengths and natural charge populations of monomeric aluminium complexes to a given extent. Based on the computed Gibbs energies, pK(a) values of various hydrolysis species in the presence and absence of Cl(-) are evaluated, respectively. It is concluded that pK(a) increases with the introduction of Cl(-).