高效液相色谱法分离/蒸发光散射和紫外检测法测定天麻中天麻甙含量

天麻（Gastrodia elata Blume）系兰科多年生寄生植物,用于治疗头错、眩晕、肢体麻木等症,冯孝章和周俊等分离并鉴定出天麻的活性成分有天麻甙（对羟甲基苯β－D－吡喃葡萄糖式,亦称天麻素）、天麻甙元（对羟基苯甲醇）等,其中天麻甙为主要成分,一些药理实验也证实了这一点,在测定天麻甙含量的方法中,采用高效液相色谱法9HPLC）最多,正相PHLC和反相HPLC都可用于天麻及其占天麻甙的分离,-通常采用紫外检测法,检测波长在220nm或270nm处。     

天麻的化学研究——Ⅰ.天麻化学成分的分离和鉴定

从中药天麻的乙醇提取物中分离得到7个化学成分。根据红外光谱、核磁共振谱、质谱分析,衍生物制备,以及已知样品对照,证明为天麻苷(天麻素)(Gastrodin)、对羟基苯甲醇、对羟基苯甲醛、琥珀酸、β谷甾醇、蔗糖及一微量而未确证的1,4-二取代芳环化合物。其中天麻素的化学结构为对羟甲基苯β-D-吡喃葡葡糖苷。     

HPLC-DAD分析金线莲中天麻素和天麻苷元

研究超声-微波协同法提取金线莲中的天麻素和天麻苷元,并对提取条件进行了优化.应用高效液相-二极管阵列检测法分析提取物中的天麻素和天麻苷元.研究结果表明:金线莲中天麻素、天麻苷元和其他杂质成分能够很好的分离,且两者的含量分别为1.430及0.562 mg/g,相对标准偏差为0.94%和0.25%.方法准确、快速、灵敏度高、重现性好.     

三维荧光二阶校正法测定天麻中天麻素的含量

中药天麻背景复杂,对天麻素的激发-发射光谱(270nm/295nm)干扰特别大。本文利用三维荧光结合化学计量学二阶校正自加权交替三线性(SWATLD)算法对其进行解析,在不经分离的情况下测定了中药天麻中天麻素的含量。计算得到中药天麻中天麻素的平均含量是0.3766%,平均回收率为104.6%,分辨得到的天麻素解析光谱与真实光谱几乎完全重合。说明这种方法可用于中药天麻中天麻素含量的测定。     

高效液相色谱法测定天麻中4种化合物的含量

采用高效液相色谱法同时测定天麻中天麻素、对羟基苯甲醇、对羟基苯甲醛和巴利森苷的含量。样品(1.000 0 g)经60%(体积分数)乙醇40 mL于90℃回流提取1.0 h后进行色谱分离,以Syncronis C18色谱柱为固定相,以不同体积比的甲醇和0.05%(体积分数)磷酸溶液的混合液为流动相进行梯度洗脱。4种化合物的进样质量在一定范围内与其峰面积呈线性关系,检出限(3S/N)在0.003~0.012μg之间。按标准加入法进行回收试验,回收率在96.4%~98.4%之间,测定值的相对标准偏差(n=6)均小于1.5%。     

利用鲁米诺—H2O2—Co（Ⅱ）化学发光体系测定天麻素的研究

天麻为兰科天麻属植物天麻(Gastrodia elata Blume)的块茎,性味甘平有祛风定惊之功效。其主要成分为天麻素(Gastrodia)。对天麻素的测定,作者用酶促化学发光法进行了研究,已撰文报道。为了降低分析成本,避免用造价高、难保存的葡萄糖氧化酶,作者利用过氧化氢能够氧化天麻素的水解产物一对羟基苯甲醇的酚羟基,而消耗鲁米诺-H_2O_2-Co~(2+)化     

悬浮液进样火焰原子吸收光谱法测定高锌天麻中锌

天麻中含有大量人体必须的微量元素 ,利用人工强化载培方式 ,增加天麻中锌的含量 ,在医学上具有重大的应用前景。天麻中锌的测定 ,一般采用消化后原子吸收光谱法测定[1] 。但这种方法费时费事 ,又宜造成污染。悬浮液石墨炉原子吸收光谱法在固体样品分析中取得了满意的结果。但悬浮液火焰原子吸收光谱法直接测定固体样品时存在一些困难 ,主要是颗粒样品传输和原子化时间不充分问题 [2 ] 。本文对悬浮液天麻样品中锌含量的火焰原子吸收光谱法进行了研究。结果表明 ,天麻样品中含有很多可溶性物质 ,样品溶解后 ,可形成较均匀的悬浮液 ,用原子吸…     

高效液相色谱法测定山楂中的苦杏仁甙

 建立了从山楂中提取苦杏仁甙的方法,样品先用石油醚脱脂，然后用甲醇进行索氏提取。用高效液相色谱法定量测定了山楂中的苦杏仁甙,色谱条件如下：反相C18柱,流动相为15%的甲醇水溶液,检测波长为215 nm。测定了含不同比例山楂籽的山楂样品,结果表明含山楂籽比例高的山楂样品中苦杏仁甙的含量高,且山楂粗粒样品中苦杏仁甙的提取量比粉末样品的提取量高。     

微柱高效液相色谱法测定金银花中的多酚类物质

研究了用微柱高效液相色谱法测定金银花中的几种多酚类物质 (氯原酸、木犀草黄素、木犀草黄素 7 葡萄糖甙、木犀草黄素 7 半乳糖甙、槲皮素及槲皮素 3 葡萄糖甙)的方法。金银花样品中的多酚类物质用甲醇加热回流提取,然后以WatersXterraTMRP18 (1. 0mm×50mm, 2. 5mm)微柱为固定相, 1%的醋酸和甲醇梯度洗脱为流动相分离,在该色谱条件下,金银花中 6种多酚类成分在 4min内可达到基线分离;用紫外二极管矩阵检测器检测。方法标准回收率为 97% ~104%;相对标准偏差为 1. 6% ~2. 3%。测定了几种金银花样品中的多酚类物质,结果满意。     

化学发光法测定天麻素

天麻为兰科天麻属植物天麻Gastrodia elata Blume的块茎,性味甘平,有祛风定惊之功效,以天麻素为有效成分应用于临床。对天麻素的测定多用薄层层析-紫外分光光度法,而用化学发光法却未见报道。本文使用鲁米诺-过氧化氢-高锰酸钾发光体系,对天麻素进行了定量分析,取得了良好的效果。     

X-ray diffraction study of the structure of Al-Co melts

The structure of Al-Co melts with 0 at.%, 10 at.%, 18 at.%, 23.5 at.%, 26 at.%, 80.7 at.%, and 100 at.% Co has been studied by X-ray diffraction. Inverse Monte Carlo simulation using the experimental curves of the structural factor was employed to reconstruct the models of melts, analyzed by the Voronoi-Delaunay technique. The dependence of parameters that define short-and longer range ordering of atoms is nonmonotonous in the range 85–74 at.% Al and is extremal in the vicinity of a melt with 76.5 at.% Al. In the stated range of concentrations, the cobalt atoms basically lie at distances of ≈4.2 Å in the pentagonal rings of icosahedral type polytetrahedral clusters. Therefore one can speak about correlation in the character of atomic ordering in melts and corresponding periodic and quasiperiodic phases.     

Photoluminescence Properties of Silica Aerogel During Sintering Process

We report photoluminescence spectra measured for two series of silica aerogel sintered at 1000°C in different time intervals. In the photoluminescence spectra of nonsintered sample, bands at 1.8, 2.0 and 2.2 eV are identified. During sintering process, the bands at 1.8 and 2.0 eV decrease and vanish, while the band at 2.2 eV shows more complicated behavior. According to infrared spectra of the same samples we find that the photoluminescence band at 1.8 eV originates from nonbridged oxygen hole center defect, and that at 2.0 eV originates from silane in the gel network. Nonstoichiometric SiOx causes photoluminescence band at 2.2 eV.     

Fluorescence anisotropy of acridinedione dyes in glycerol: Prolate model of ellipsoid

Time-dependent reorientations of resorcinol-based acridinidione (ADR) dyes in glycerol were studied using steady-state and time-resolved fluorescence studies. The difference between fluorescence anisotropy decays recorded at 460 nm when exciting at 250 nm and those obtained when exciting at 394 nm are reported. When exciting at 394 nm, the fluorescence anisotropy decay is bi-exponential, while on exciting at 250 nm a mono-exponential fluorescence anisotropy decay is observed. We interpret this in terms of different directions of the absorption dipole at 394 and 250 nm with the emission dipole respectively, which is experimentally validated and further analysed as a prolate model of ellipsoid.     

Dynamic Visualization of Free Radicals at Single Oxygen Bubbles using Chemiluminescence

The generation of free radicals is a key process in the formation and the collapse of the bubbles in water, however, the direct and dynamic observation of the radicals in this process at single bubbles has never been achieved. Here, the hydroxyl (OH^.) and oxygen (O₂^.−) radicals at single oxygen bubbles are continuously traced using chemiluminescence (CL), in which these radicals at the bubble react with the surrounding luminol in the solution emitting the light. Varied increase trends of luminescence are observed in the generation of a bubble, floating, short parking at the water/air interface and the final explosion, revealing the complexity in the distribution of radicals at the bubble unprecedentedly. Despite more radicals are observed at the bubble generated at a deep position under the water for the stabilization, almost the same amount of radicals are included in the bubbles that is independent on the water pressure during the production of the bubble. This rich information collected from the dynamic study of bubbles illustrates the complicated generation and distribution process of radicals at the bubbles, and will facilitate the understanding of the function about the bubbles.     

三苯胺-噁二唑超支化共轭聚合物的多光子泵浦绿色荧光

采用钯催化Heck反应制备了一种新型三苯胺-噁二唑超支化荧光聚合物PI. 用飞秒Ti:sapphire激光研究了PI的三光子和双光子上转换荧光光谱, 激发波长位于近红外区(800~1350 nm). 在1280 nm和80 fs激光激发下, PI的三光子上转换荧光发射波长分别为525 nm(THF), 534 nm(CH2Cl2)和578 nm(DMF). 在800 nm和150 fs激光激发下, PI的双光子上转换荧光发射波长分别为527 nm(THF), 532 nm(CH2Cl2)和573 nm(DMF). 采用非线性透过率法测定荧光聚合物PI的三光子和双光子吸收系数. 系统研究了PI的线性吸收和透过、单光子荧光、荧光寿命、前线轨道能级及热稳定性. 实验结果表明, 三苯胺-噁二唑超支化共轭聚合物的多光子吸收和上转换荧光发射性能比树型分子或线型聚合物更为优异.     

原位拉曼技术研究Mo催化剂的还原和硫化

运用原位激光拉曼技术研究了Mo/Al_2O_3和Mo/TiO_2-Al_2O_3催化剂的氢还原和硫化行为．结果清楚显示，两种载体上不同配位形态的Mo物种的氢还原能力有明显差异，其硫化性能也不相同．TiO_2对Al_2O_3表面的复盖可显著促进Mo物种的还原和硫化。     

界面光化学反应研究进展

本文介绍了在气液界面上和LB 膜中的光化学反应特点及不同的类型, 从界面光聚合、界面光致变色、界面光致电子转移、光电转化等几个方面对最近几年来在界面光化学领域内的重要成果及最新进展进行了综述, 并对这一领域的发展和应用前景进行了展望。     

STUDY ON THE PROPERTIES OF BLEND OF NATURAL RUBBER LATEX/METHYL METHACRYLATE GRAFTED RUBBER LATEX BY GAMMA RADIATION

Natural rubber latex(NRL)and methyl methacrylate(MMA)grafted rubber latex were blended in different ratios and irradiated at various absorbed doses by gamma rays from Co-60 source at room temperature.The tensile properties, swelling ratio and permanent set were measured.The maximum tensile strength and modulus at 500% elongation were obtained at an absorbed dose of 8 kGy.Modulus increases from 6.99 MPa to 9.87 MPa for an increase in proportion of MMA grafted rubber from 40% to 60% in the blend at similar absorbed dose.Elongation at break and swelling ratio decrease with increasing absorbed dose as well as the MMA grafted rubber content in the blends.The decreasing trend of permanent set is high up to 5 kGy absorbed dose,and beyond that dose,it becomes almost flat.     

Preparative scale mass spectrometry: A brief history of the calutron

Calutrons were developed in the laboratory of E. O. Lawrence at the University of California at Berkeley. They were a modification of the cyclotrons he had invented and used in his Nobel Prize‐winning investigations of the atomic nucleus. At the time their construction was undertaken, calutrons represented the only certain means of preparing enriched uranium isotopes for the construction of a fission bomb. The effort was successful enough that every atom of the 42 kg of ²³⁵U used in the first uranium bomb had passed through at least one stage of calutron separation. At peak production, the first stage separators, α tanks, yielded an aggregate 258‐g/day ²³⁵U enriched to about 10 at. % from its natural abundance level of 0.72 at. %. The second stage separators, β tanks, used the 10 at. % material as feedstock and produced a total 204‐g/day ²³⁵U enriched to at least 80 at. %. The latter, weapons grade, material was used in fission bombs. Under typical operating conditions, each α tank operated at a uranium beam intensity at the collectors of approximately 20 mA and each β tank at a beam intensity of approximately 215 mA at the collectors. Bulk separation of isotopes for bomb production ceased in 1945. Since that time calutrons have been used to separate stable isotopes, but on a more limited scale than wartime weapons production. Stable isotope separations since 1960 have taken place using one modified β tank.