超声提取-反相高效液相色谱法测定黄姜中薯蓣皂甙元

以超声萃取-酸水解-超声萃取进行预处理,结合RP-HPLC测定黄姜中薯蓣皂甙元含量。色谱条件为:采用AglilengtHC-C18色谱柱,流动相为甲醇∶水=95∶5(V∶V),流速为1.0mL/min,UV检测波长为203nm。结果表明,在40—1000μg/mL范围内,薯蓣皂甙元峰面积与其质量浓度具有良好的线性关系(r=0.9996),样品平均加标回收率为99.8%,RSD为1.1%。与直接酸水解-萃取预处理方式进行对比,本方法测得薯蓣皂甙元含量提高了32%。采用本方法对黄姜芽,根茎,表皮及不定根中的薯蓣皂甙元含量进行测定:根茎1.69%,芽0.19%,表皮0.15%,不定根部分含量为0.36%。     

一系列薯蓣皂甙元-β-D葡萄糖基-(1→2)和(1→3)-β-D葡萄糖甙的1H和13C NMR归属

用同核和异核二维核磁共振方法全归属了一系列合成的薯蓣皂甙元-β-D葡萄糖甙的¹H和¹³C核磁共振谱线.这些薯蓣葡萄糖甙是薯蓣皂甙元-β-D葡萄糖甙(1),薯蓣皂甙元-β-D葡萄糖基-(1→2)-β-D葡萄糖甙(2),薯蓣皂甙元,-β-D葡萄糖基-(1→3)-β-D葡萄糖甙(3),薯蓣皂甙元[-β-D葡萄糖基-(1→2)-β-D葡萄糖基(1→3)-β-D葡萄糖甙(4)以及薯蓣皂甙无[-α-L鼠李糖基-(1→2)]-β-D葡萄糖基-(1→3)-β-D葡萄糖甙(5).     

一系列薯蓣皂甙元-α-L鼠李糖基-(1→2)和(1→4)-β-D葡萄糖甙的1H和13C NMR归属

用同核和异核二维核磁共振方法全归属了一系列合成的薯蓣皂甙元-α-鼠李糖基-β-D葡萄糖甙的¹H和¹³C核磁共振谱线.这些薯蓣葡萄糖甙是薯蓣皂甙元-β-D葡萄糖甙(1),薯蓣皂甙元-α-L鼠李糖基(1→2)-β-D葡萄糖甙(2),薯蓣皂甙元-α-L鼠李糖基(1→4)-β-D葡萄糖甙(3),薯蓣皂甙元[-α-鼠李糖基-(→2)]-α-L鼠李糖基→-(1→4)-β-D葡萄糖甙(4)以及薯蓣皂甙元[-α-L鼠李糖基-(1→2)]-β-D阿拉伯糖基-(1→4)-β-D葡萄糖甙(5).     

胡芦巴中总皂苷的含量测定

选用薯蓣皂苷元为对照品,以高氯酸显色,分光光度法测定胡芦巴总皂苷含量。薯蓣皂苷元在410nm处有最大吸收,在0.0163—0.0357mg.mL-1范围内吸光度与薯蓣皂苷元浓度呈良好的线性关系(r=0.9996),方法的平均回收率为98.0%(n=9),RSD为0.6%。该方法简便、准确、稳定,是一种快速测定胡芦巴总皂苷的有效方法。     

一系列薯蓣皂甙元-β-D葡萄糖基-(1→2)和(1→3)-β-D葡萄糖甙的1H和13C NMR归属

用同核和异核二维核磁共振方法全归属了一系列合成的薯蓣皂甙元-β-D葡萄糖甙的1H和13C核磁共振谱线．这些薯蓣葡萄糖甙是薯蓣皂甙元-β-D葡萄糖甙（1）,薯蓣皂甙元-β-D葡萄糖基-（1→2）-β-D葡萄糖甙（2）,薯蓣皂甙元,-β-D葡萄糖基-（1→3）-β-D葡萄糖甙（3）,薯蓣皂甙元[-β-D葡萄糖基-（1→2）-β-D葡萄糖基（1→3）-β-D葡萄糖甙（4）以及薯蓣皂甙无[-α-L鼠李糖基-（1→2）]-β-D葡萄糖基-（1→3）-β-D葡萄糖甙（5）．     

菝葜中薯蓣皂苷元提取工艺的研究

探讨了索氏提取法提取菝葜中薯蓣皂苷元的提取工艺。通过单因素试验和正交试验,研究了提取工艺对薯蓣皂苷元提取率的影响。在不同条件下,提取率不同。确定了最佳提取工艺参数为:甲醇浓度为50%,固液比为1∶10(g∶mL),提取时间2.5h,提取次数1次,薯蓣皂苷元得率为0.421mg/g。该方法简便,可行。     

火焰原子吸收法测定栽培柴胡中六种金属元素含量的研究

采用浓硝酸-高氯酸(V:V=4:1)常压微沸条件下消解柴胡样品,应用火焰原子吸收法测定栽培柴胡中的金属元素Ca,Mg,Fe,Cu,Zn,Pb的含量.研究了测定不同元素的仪器最佳工作条件及溶液介质对测定结果的影响,并做了方法的准确性和精密度考察.结果表明,栽培柴胡中Ca,Mg,Fe,Cu,Zn的含量分别为5 588.9,1 790.5,869.3,78.4,44.3μg·g-1,Pb未检出.方法的加标回收率为99.57%～102.10%,相对标准偏差(n=9)为0.18%～2.26%.测定方法简单易行,方便快捷,结果可靠.     

HPLC测定怀菊花中的总黄酮

建立了HPLC测定怀菊花中总黄酮含量的方法.采用Agilent C18柱(150mm×4.6mm,5μm),以甲醇(A)-超纯水(0.2％的冰乙酸)(B)(25∶75,V/V)为流动相,流速:0.5mL·min-1;柱温为20℃,检测波长:260nm;进样量:10μL.结果:回归方程为y=33.29x-8.284,r=0.9993(n=6),线性范围0-20μg,平均回收率为102.63％,RSD为5.56％.样品总黄酮含量为7.51mg/g.方法简便、灵敏、快速、准确、重现性好,可用于怀菊花中总黄酮含量的质量控制.     

火焰原子吸收光谱法测定栽培甘草中6种金属元素

浓硝酸 -高氯酸 (V∶V=4∶ 1 )常压微沸条件下消解甘草样品 ,火焰原子吸收法 (FAAS)测定甘草中的金属元素 Ca、Mg、Fe、Cu、Zn、Pb的含量 ,研究了测定不同元素的仪器最佳工作条件及溶液介质对测定结果的影响及方法的准确性和精密度研究。栽培甘草中 Ca、Mg、Fe、Cu、Zn的含量分别为 4 0 4 5 .5、71 5 .4、2 79.8、1 2 .6、1 0 .4 μg/g,Pb未检出。方法的加标回收率为 99.38%— 1 0 2 .30 %,相对标准偏差 (n=9)为0 .4 1 %— 1 .6 8%。本法简单易行 ,方便快捷 ,结果可靠。     

电感耦合等离子体发射光谱法测定烟道灰中的铟

铟是一种银白色稀有稀散金属,在地壳中的平均质量分数为0.000 01%,为了准确测定烟道灰样品中低含量的铟,通过对样品成分的初步分析,确定实验中溶解样品所用的酸及其比例。依次逐步加入HCl, HNO3, HF和HClO4(V∶V∶V∶V=15∶5∶2∶2),将样品完全溶解后,冷却至室温并移入分液漏斗,在HBr介质中,以溴化铵做盐析剂(溶液体积控制在25 mL左右);移取25 mL乙酸乙酯作为萃取剂和稀释剂,萃取液直接导入配备有机进样系统的电感耦合等离子体原子发射光谱仪(ICP-AES),选择In 230.606 nm为分析谱线,对烟道灰样品中的铟进行测定,从而建立了电感耦合等离子体原子发射光谱法(ICP-AES)测定烟道灰样品中铟的方法。实验样品溶解后,采用萃取分离法消除基体元素及共存元素的干扰。通过对萃取酸度、萃取剂、萃取方法、盐析剂、分析谱线等条件试验,确定了最优的实验条件。铟的质量浓度在0.25~4.00 mg·L^-1范围内与其发射强度呈线性关系,校准曲线线性相关系数为0.999 3,检出限为0.03 mg·L^-1,测定结果的相对标准偏差(n=11)小于5%,回收率在92%~102%之间。按照上述试验步骤测定5个烟道灰样品中的铟含量,其测定结果与ICP-MS法比较吻合。另外,与现有的分析方法(EDTA滴定法、分光光度法、原子吸收光谱法、 X射线荧光光谱法、电感耦合等离子体原子发射光谱法及质谱法等)相比,该法具有简便,快速,灵敏,准确度较高的优点,可用于铟含量在0.000 8%~0.10%之间烟道灰样品的批量检测。     

Linear and Nonlinear Raman Spectroscopy onⅡ-Ⅵ Semiconductor Quantum Wires and Dots

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Of heat capacity at homologous temperatures for metals showing h.c.p. ⇄ b.c.c. transformation

Some interesting aspects of the temperature dependence of the Planck’s functionφ and heat capacities of metals exhibiting the h.c.p. ⇄ b.c.c. transformation have been brought to light by the use of reduced temperature (T*) and Planck’s function (-φ T*). It has been shown that tangents drawn to the -φ T* vsT* plots of these metals at any chosen value ofT* intersect at a point whose coordinates are defined by the slope and intercept ofφ vs entropy plots at any homologous temperature and the selectedT* value. A generalized expression obtained for the temperature dependence ofφ has been used to demonstrate that the heat capacity of these metals may be visualized to have structural and material components.     

Photolysis and E. S. R. Studies on Triphenylphosphinecarbethoxymethylene

Although several different groups have studied the photolysis of phosphorus ylides, none have utilized e. s. r. to support the postulated decomposition mechanisms. The fundamental question which awaits a definitive answer is which bond breaks first upon photolysis. Tschesche¹ and de Silva² utilizing the ylides (1) and (2) suggested that the carbon-phosphorus double bond was initially broken while Nagao³ using (3) proposed phenyl-phosphorus bond cleavage.     

A. C. conductivity due to intimate pairs of charged defect centres

The influence of the association of charged defects into intimate pairs on a.c. conduction is discussed in the light of the fundamental mechanism being that of the simultaneous hopping of two electrons over the barrier separating two oppositely charged defect centres, the barrier height being correlated with the intersite separation via the Coulomb interaction. The behaviour of chalcogenide glasses is discussed in terms of the present theory, and it is concluded that the existence of two classes of a.c. conductivity behaviour into which these materials generally fall can be simply explained by the predominance of either intimate pairs or non-intimate pairs of charged defect states according to the conditions of preparation.     

威耳逊对云室的实验研究

介绍了C.T.R.威耳逊的主要贡献和发明云室的过程.他由研究水滴的凝结规律入手,不断改进实验装置,拍摄了带电粒子的径迹照片,从而证明了康普顿效应;还分析了威耳逊取得成功的几个重要因素.     

凹叶厚朴各部位挥发油成分比较研究

采用顶空固相微萃取(HS-SPME)提取凹叶厚朴不同部位的挥发油成分,气相色谱-质谱(GC-MS)分析其组成.结果显示:根鉴定出19个化合物,其中4(14),11-桉叶二烯(26.04％),(1S-顺)-1,4-二甲基-7-(1-甲基亚乙基)-奠(24.94％),石竹烯(9.41％),β-桉叶醇(7.28％)为主要成分...     

W.R. Grove and the fuel cell

Though known these days largely because he invented the fuel cell, Grove also had many other distinguished achievements to his credit. His monumental book On the Correlation of Physical Forces contained all the arguments that led to the enunciation of the first law of thermodynamics. He was also an extremely versatile natural philosopher who was, in addition, well versed in classical literature, particularly the works of the eminent scholars of ancient Greece and Rome. This article touches upon these qualities, but is predominantly concerned with the emergence and modern aspects of the H₂/O₂ fuel cell and its potential for the clean generation of energy.     

E.S.R. Spectra of the Cyclobutanesemidiones Derived from Three Tricyclo[4. 4. 2. 01,6,]Dodecane-11-OL-12-Ones

The semidione radical anions derived from a variety of alicyclic ketones and α-hydroxyketones have been extensively investigated via esr by Russell and co-workers.¹Studies of the chemistry and spectra of the 1, 2-cyclobutanediones derived from the tricyclo[4. 4. 2. 0^1,6] dodecane-11-o1-12-one system²suggested that an examination of the esr spectra of the related semidiones would be of considerable interest. The recent reports on the esr spectra of cyclobutanes emidione^1cand several substituted cyclo-butanes emidiones^1bfurther prompt this communication.     

Bulk viscous L.R.S. Bianchi type V tilted stiff fluid cosmological model in general relativity

Locally rotationally symmetric (L.R.S.) Bianchi type V bulk viscous tilted stiff fluid cosmological model is investigated. To get the deterministic model of the universe, we have also assumed a condition A=Bⁿ between metric potentials A, B where n is the constant. The behaviour of the model in presence and absence of bulk viscosity and singularities in the model are also discussed. In general, the models represent accelerating, shearing, tilted and non-rotating universe. The models have point type singularity in presence and absence of bulk viscosity both.