加速溶剂萃取-固相萃取-硅胶吸附色谱-电喷雾质谱法测定纺织品中的烷基酚聚氧乙烯醚

建立了测定纺织品中壬基酚聚氧乙烯醚和辛基酚聚氧乙烯醚的硅胶吸附色谱-电喷雾质谱分析方法.不同类型的纺织品样品采用加速溶剂萃取法,以无水乙醇为提取溶剂,在10.3 MPa和100 ℃下静态循环提取2次,提取液经Sep-Pak Carbon/NH2石墨化碳黑/氨基复合型固相萃取柱净化,以Waters Spherisorb S3W(150 mm×2.0 mm, 3 μm)色谱柱为分离柱,乙腈-水体系为流动相梯度洗脱,在电喷雾质谱正离子模式下进行定性及定量分析.壬基酚聚氧乙烯醚的方法检出限为10～40 μg/kg,在1～20 mg/kg的3个添加水平范围内的平均回收率为81.4%～95.9%,相对标准偏差均小于12.5%.辛基酚聚氧乙烯醚的方法检出限为10～30 μg/kg,在1～20 mg/kg的3个添加水平范围内的平均回收率为80.2%～96.8%, 相对标准偏差均小于13.0%.本方法准确、简便、快速,可用于纺织品的实际检验工作.     

基于稳定同位素标记与质谱分析的蛋白质定量算法研究进展

蛋白质定量研究已成为蛋白质组学的热点,它是疾病相关生物标志物发现的重要途径.基于稳定同位素标记的质谱分析技术是蛋白质定量最常用的方法之一.随着实验方法的发展和改进,定量数据处理方法也在不断更新与完善.一般来说,定量数据处理包括四步:搜库鉴定、图谱定量信息提取与计算、肽段丰度比计算和蛋白质丰度比计算及差异显著性分析,其中后三步是数据处理的核心.目前,后三步中每步都有多种可选算法,这些算法一般都是针对特定实验技术而提出的,缺乏深入的工作对它们进行系统比较和优化.为此,在总结目前主要实验技术方法的基础上,论述了定量算法的现状和存在问题,并针对一些问题提出了可行的解决办法.     

Molecularly imprinted monolith in-tube solid-phase microextraction coupled with HPLC/UV detection for determination of 8-hydroxy-2′-deoxyguanosine in urine

Urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) has been widely used as a biomarker of oxidative DNA damage. Measurements of 8-OHdG in urinary samples are challenging owing to the low level of 8-OHdG and the complex matrix. In this study, a novel molecularly imprinted polymer (MIP) monolithic column was synthesized with guanosine as a dummy template which was used as the medium for in-tube solid-phase microextraction (SPME). In-tube SPME coupled with HPLC/UV detection for extraction and determination of urinary 8-OHdG was developed. The synthesized MIP monolithic column exhibited high extraction efficiency owing to its greater phase ratio with convective mass transfer and inherent selectivity. The enrichment factor for 8-OHdG was found to be 76 and the limits of detection and quantification of the method for urinary samples were 3.2 nmol/L (signal-to-noise ratio 3) and 11 nmol/L (signal-to-noise ratio 10), respectively. The MIP^’s selectivity also made the sample preparation procedure and chromatographic separation much easier. The linear range of the proposed method was from 0.010 to 5.30 μmol/L (r = 0.9997), with a relative standard deviation of 1.1–6.8%, and the recovery for spiked urine samples was 84 ± 3%. The newly developed method was successfully applied to determine urinary samples of healthy volunteers, coking plant workers, and cancer patients. The 8-OHdG level in cancer patients was significantly higher than that in healthy people.     

新型锂离子电池正极材料Li0.86V0.8O2的水热合成及性质

采用两步反应制备了新型锂离子电池正极材料Li0.86V0.8O2. 该材料具有六方层状结构, 空间群为R3m. 研究了在水热条件下溶液的碱度对于钒酸锂盐形成的影响, 在低碱度的条件下, 前驱体V2O3和LiOH·H2O并未发生反应, 只有在碱度达到2.5 mol/L时, 才能形成单相的Li0.86V0.8O2材料. X射线光电子能谱分析发现, V2p的结合能位于516.4 和523.1 eV, 分别对应于四价钒离子的V2p3/2 和V2p1/2, 这说明在Li0.86V0.8O2中V离子主要价位为+4价. 在电流密度为7.4 mA/g的充放电中, Li0.86V0.8O2初始充电容量达到163 mA·h/g, 首次放电容量也能达到113 mA·h/g, 20次循环后放电容量仍然可以达到80 mA·h/g, 表现出较好的循环性能.     

化妆品中碘丙炔醇丁基氨甲酸酯的高效液相色谱检测及质谱确证

建立了高效液相色谱(HPLC)-二极管阵列检测器(DAD)测定化妆品中碘丙炔醇丁基氨甲酸酯的方法.化妆品样品经超声提取后,高效液相色谱-二极管阵列扫描检测,并在235 nm波长进行分析.用保留时间结合紫外光谱定性,外标法定量,并采用液相色谱-质谱法确证.碘丙炔醇丁基氨甲酸酯的回收率为92.7%～99.8%,相对标准偏差在0.8%～2.1%之间,定量限为20 mg/kg.     

Homo-timeric structural model of human microsomal prostaglandin E synthase-1 and characterization of its substrate/inhibitor binding interactions

Inducible, microsomal prostaglandin E synthase 1 (mPGES-1), the terminal enzyme in the prostaglandin (PG) biosynthetic pathway, constitutes a promising therapeutic target for the development of new anti-inflammatory drugs. To elucidate structure–function relationships and to enable structure-based design, an mPGES-1 homology model was developed using the three-dimensional structure of the closest homologue of the MAPEG family (Membrane Associated Proteins in Eicosanoid and Glutathione metabolism), mGST-1. The ensuing model of mPGES-1 is a homo-trimer, with each monomer consisting of four membrane-spanning segments. Extensive structure refinement revealed an inter-monomer salt bridge (K26-E77) as well as inter-helical interactions within each monomer, including polar hydrogen bonds (e.g. T78-R110-T129) and hydrophobic π-stacking (F82-F103-F106), all contributing to the overall stability of the homo-trimer of mPGES-1. Catalytic co-factor glutathione (GSH) was docked into the mPGES-1 model by flexible optimization of both the ligand and the protein conformations, starting from the initial location ascertained from the mGST-1 structure. Possible binding site for the substrate, prostaglandin H₂ (PGH₂), was identified by systematically probing the refined molecular structure of mPGES-1. A binding model was generated by induced fit docking of PGH₂ in the presence of GSH. The homology model prescribes three potential inhibitor binding sites per mPGES-1 trimer. This was further confirmed experimentally by equilibrium dialysis study which generated a binding stoichiometric ratio of approximately three inhibitor molecules to three mPGES-1 monomers. The structural model that we have derived could serve as a useful tool for structure-guided design of inhibitors for this emergently important therapeutic target.     

(±)-Yaequinolone A2的简洁全合成

由廉价的邻氨基苯甲酸为起始原料经6步反应以27.8%的总产率首次合成了2-喹啉酮类生物碱(±)-yaequinolone A2,关键步骤为MOM保护的α-羟基酰胺进行的高非对映选择性分子内aldol 反应。     

唾液酸糖苷化反应研究新进展

唾液酸是一类重要的具有多种生物学功能的糖酸化合物. 唾液酸糖苷化反应条件较一般糖苷化反应苛刻, 立体选择性通常较差, 端基碳的立体构型较难控制. 在唾液酸糖苷化反应中能否高效地得到α糖苷键是评价该反应优劣的重要标志之一. 唾液酸苷化方法的研究一般涉及以下几个方面: C-2上的离去基团的运用, C-1, C-3上辅助基团的参与作用, C-5上氨基保护基团的修饰, 以及一些新的糖苷化反应催化剂的发展. 近些年来, 这些研究领域, 尤其是C-5上氨基保护基团的研究, 取得了重要进展. 将着重对唾液酸糖苷化方法的新进展做一总结和评述.     

Synthesis of micron-sized hollow silica spheres with a novel mesoporous shell of MCF

Micron-sized hollow silica spheres whose shells are made up of mesocellular silica foams(MCFs) have been synthesized by one-pot sol-gel method in benzene/water/P123 emulsion.The material is characterized with SEM,TEM,BET and ~(29)Si MAS NMR. The results show that the MCFs of the unique shell of hollow silica spheres were connected by large windows with a narrow distribution of～10 nm in diameter,the inner space of the hollow sphere is accessible.And the formation mechanism of the hollow silica spheres is ...     

Theoretical study of interaction of 2,6-dithiopurine with Li+, Na+, K+, Be2+, Mg2+, and Ca2+ metal cations

The geometries of the complexes of Li⁺, Na⁺, K⁺, Be²⁺, Mg²⁺, and Ca²⁺ metal cations with different possible 2,6-dithiopurine anions (DTP) were studied. The complexes were optimized at the B3LYP level and the 6-311++G(d, p) basis set. The interactions of the metal cations at different nucleophilic sites of various possible 2,6-dithiopurine anions were considered. It was revealed that metal cations would interact with 2,6-dithiopurine anions in a bicoordinate manner. In the gas phase, the most preferred position for the interaction of Li⁺, Na⁺, and K⁺ cations is between the N₃ and S₂ sites, while all divalent cations Be²⁺, Mg²⁺, and Ca²⁺ prefer binding between the N₇ and S₆ sites of the corresponding 2,6-dithiopurine. The influence of aqueous solvent on the relative stability of different complexes has been examined using the Tomasi’s polarized continuum model. The basis set superposition error (BSSE) corrected interaction energy was also computed for complexes. The AIM theory has been applied to analyze the properties of the bond critical points (electron densities and their Laplacians) involved in the coordination between 2,6-dithiopurine anions and the metal cations. It was revealed that aqueous solution would have significant effect on the relative stability of complexes obtained by the interaction of 2,6-dithiopurine anions with Mg²⁺ and Ca²⁺ cations. The effect of metal cations on different NH and CS stretching vibrational modes of 2,6-dithiopurine has also been discussed.