GC和HPLC分析金银花多糖的单糖组成方法比较

目的:GC法和HPLC法分析金银花多糖的单糖组成,并对两种方法进行比较。方法:金银花多糖经2.0 mol·L-1的三氟乙酸水解后,用糖腈乙酸酯衍生化-GC法和1-苯基-3-甲基-5-吡唑啉酮(PMP)柱前衍生化-HPLC法分别测定其单糖组成及其比例。结果:GC法检测出金银花多糖由鼠李糖(L-Rha)、阿拉伯糖(D-Ara)、甘露糖(D-Man)、木糖(D-Xyl)、葡萄糖(D-Glc)、半乳糖(D-Gal)组成;HPLC法检测到金银花多糖中含有甘露糖(D-Man)、鼠李糖(L-Rha)、葡萄糖醛酸(D-GlcA)、葡萄糖(D-Glc)、半乳糖(D-Gal)、阿拉伯糖(D-Ara)和木糖(D-Xyl),其中半乳糖(D-Gal)与阿拉伯糖(D-Ara)的色谱峰重叠。结论:两种方法均能检测出中性糖,HPLC法不仅能测中性糖,还能检测出葡萄糖醛酸,对金银花多糖的单糖组成分析GC与HPLC联合使用较为合适。     

中药学专业分析化学实验教学改革初探

以提高中药学专业学生的分析化学实验能力为目的,从加强分析化学实验基础知识讲解以及加强实验的规范化操作训练入手,结合设计性实验与专业知识的融合及项目总数量的增加,同时注重考核机制对学生学习积极性的影响,探讨了增强实验教学效果的途径。实践证明,改革弥补了传统实验教学模式的部分不足,实际教学效果得到了很大的改善。     

仪器分析测试平台运行软环境建设研究

在学校硬件大为改善之际,我们提出软环境建设的概念,通过编写了仪器分析放培训教材、仪器操作规程及仪器操作注意事项等,既适应学校的快速发展,又加强了仪器分析测试平台的分析测试服务水平,保证了分析测试服务质量,建立了较为完善的仪器分析测试平台放软环境。     

无机阻燃剂研究进展

无机阻燃剂无毒或低毒,燃烧时能防流滴,不产生烟雾,很多还有抑制烟雾的作用,完全符合当今阻燃剂向环保型发展的大趋势。对无机阻燃剂的研究现状进行了综述,从而为其深入研究开发提供参考。     

ZnSiO_3-Mg(OH)_2复合阻燃剂在PVC中的应用研究

以ZnSiO3和Mg(OH)2按照1∶9的配料比复配成复合阻燃剂,添加到软PVC(聚氯乙烯)树脂中,进行了一系列的力学性能和燃烧性能的测试。结果表明,复合阻燃剂的添加对PVC的物理力学性能影响很少,阻燃性能优异,达到国家规定的难燃材料的标准。此复合阻燃剂低毒,由于复合使用,降低了生产成本。     

夏枯草指纹图谱研究概况

唇形科植物夏枯草Prunella vulgaris L.的干燥果穗是中国药典收载的常用中药。其清肝泻火,明目,散结消肿,常用于目赤肿痛,头痛眩晕乳房胀痛等症状。本文通过查阅文献对夏枯草的指纹图谱的研究现状进行了综述,从而为其质量控制的深入研究提供参考。     

Fabrication and photoluminescence properties of ridged TiO2 nanotube arrays

Highly-ordered ridged TiO₂ nanotube (TNT) arrays have been fabricated by a simple anodic method. Their structures have been systematically investigated using X-ray diffractometer, scanning electron microscope, energy dispersive spectrometer and HRTEM, and the results clearly presented the ridged morphologies with the outer diameters of about 200 nm. We also found that the annealing procedure induced the phase transformation from amorphous phase to anatase phase. The room-temperature photoluminescence (PL) properties were studied, and the much stronger PL emission for the anatase phase was observed compared to the amorphous counterparts. Furthermore, the broad emission for the anatase phase could be decomposed of three peaks locating at 540, 622 and 773 nm, respectively. The oxygen vacancies and the trapping of free excitons by TiO₆ octahedra near defects are the key factors to cause these peaks.     

Fe3O4/Ag microsheets assembled by interlaced nanothorns as high performance anode materials for lithium storage

Fe₃O₄/Ag nanocomposite is directly prepared by dealloying a well-designed FeAgAl source alloy in alkaline etching solution at room temperature. Selectively dissolving Al from FeAgAl alloy results in Fe₃O₄/Ag microsheets assembled by second order interlaced nanothorns. On account of the distinctive hierarchical micro-/nano-structure and the hybridization of well conductive Ag, Fe₃O₄/Ag composite shows much improved lithium storage performances with higher capacities, cycling stability, and coulombic efficiency compared with the pure Fe₃O₄ anode. Even the current rate is as high as 1 A g^?1, the capacity of Fe₃O₄/Ag composite still exceeds 600 mA h g^?1 after cycling 500 cycles compared with the remained value of only 294.8 mA h g^?1 for pure Fe₃O₄. Moreover, Fe₃O₄/Ag composite presents the excellent rate capabilities at whether low or high current densities. Owing to the superiorities of excellent properties and handy preparation, the Fe₃O₄/Ag anode exhibits encouraging prospect for lithium ion batteries.     

First-principles prediction of the transition from graphdiyne to a superlattice of carbon nanotubes and graphene nanoribbons

Graphdiyne is a recently-synthesized carbon allotrope with a framework of sp- and sp²-hybridized carbon atoms. From first-principles calculations, we propose a possible transition of graphdiyne to a novel carbon allotrope (h-carbon) whose structure is a superlattice of carbon nanotubes and graphene nanoribbons. The energy barrier of this endothermic transition was estimated to be 4.30 kcal/mol at zero pressure, which is much lower than that of the graphite–diamond transition at high pressure. First-principles calculations on the phonon spectrum and the elastic constants of the h-carbon revealed that it is kinetically and mechanically stable. This unique framework of sp²- and sp³-hybridized carbon atoms is energetically neutral versus diamond. The hardness of the h-carbon (35.52 GPa) is 1/3 that of diamond and very close to β-SiC crystal. Accurate electronic structure calculations based on the Heyd, Scuseria, and Ernzerhof approach and GW approximation indicate that the h-carbon is a semiconducting material with a band gap of 2.20–2.56 eV.     

痹病常用中成药的现代研究及合理应用

痹病是临床常见病、多发病,缠绵难愈。本文针对引发痹病的病因,分析总结了不同类型痹病常用中成药的药物组成、药理作用及应用注意,旨为合理应用中成药治疗痹病提供参考。