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91.
Cunninghmia lanceolata Hook. is a traditional Chinese medicine used for thetreatment of hernia, arthritis and strangury. its chemical constituents have beenexamined]' 2' 3' '. In a previous paper we reported a bislabdane-type diterpenoidlanceolatic acid from the roots of the plant 5. Further chemical studies on this plantled to the isolation of another new bislabdane-type diterpenoid, named lanceolatin(I ).Compound I was obtained as white amorphous powder. mp 232-234 'C, [a]."-24 (c 0. 10, C… 相似文献
92.
本文从顺序扫描式双通道电感耦合等离子体原子发射光谱仪(ICP-AES)的特点出发,对微克级介形虫壳体样品中的低含量元素选择最灵敏谱线和最佳通道,对各项条件进行最优化。Mg、Sr、Mn、Fe、Ba、Zn的检测限分别为0.6~5.2μg/L,Ca和Na的检测限分别为16μg/L和52μg/L,测定了微克级样品的多元素含量,回收率为90%~106%。 相似文献
93.
Wang M Wang BM Shi L Tu YQ Fan CA Wang SH Hu XD Zhang SY 《Chemical communications (Cambridge, England)》2005,(44):5580-5582
A quinine/Selectfluor combination inducing rearrangement reaction of allylic alcohols was discovered, which involved a moderate yield with good enantioselective construction of alpha-quaternary carbon center and beta-fluoro aldehyde under base condition. 相似文献
94.
六氰合铁酸铜钴在蜡浸石墨电极表面的电化学沉积 总被引:3,自引:0,他引:3
首次报道了电化学沉积的混合金属六氰合铁酸盐修饰电极作为电流型传感器的研究。针对六氰合铁酸盐修饰电极在中性和碱性条件下的不稳定性,采用混合金属电沉积的方法,成功地提高了电极的稳定性,所得到的修饰电极在 pH 4~10之间均表现出良好的稳定性。该电极的响应时间(t95%)为 0.5s,并对Fe3+/Fe2+电对表现出良好的电催化作用。催化氧化峰电流与Fe2+的浓度在1.0×10-4~6.5×10-2mol/L范围内呈很好的线性关系,检测下限为 1.4×10-6mol/L。 相似文献
95.
The method describes the use of a piezoelectric quartz crystal (PQC) as a substitute for ion-selective electrodes. The approach is feasible when the membrane materials are electrically non-conductive and membrane potential measurements are consequently not possible. An ion-selective piezoelectric sensor sensitive to atropine sulfate was constructed by coating a PVC membrane containing activant on one the side of a PQC. On the basis of selective adsorption of atropine ions across the modified film and the sensitive mass response of PQC, the method exhibits a sensitive, rapid response and is easy to operate without pretreatment of the sample. The logarithm of the frequency shift gave a linear relationship with the logarithm of atropine sulfate concentration in the 1.0 x 10(-8)-1.0 x 10(-3) M range with a detection limit of 5.0 x 10(-9) M at pH 7.0. Recoveries were from 98.7-102.2%. Two activants, atropine tetraphenylborate and atropine dipicrylaminate, were synthesized and investigated. Influencing factors were also examined and optimized. The results for real samples obtained by the proposed method agreed with those obtained by conventional methods. 相似文献
96.
SyntheticinterestsinhighlyfunctionalizedacyclicandcyclicamineshavecontributedtothewealthofexPerimentalmethodologydeveloPedfortheadditionofcarbanionstothecarbon-nitrogendoublebondofimines.Generally,organometallicreagentsorilltermedi-atesareusedascarbanionsandadditionofallylicorganometallicspeciestothenieconshtutesavaluablemethodforthesynthesisofhomoallylamines.'Amongthese,allyLlithium,'-magnesium,'-zinc,'-boraneandboronate,'-silaneand-stannane'havebeenusedforallylationofdriines.Ontheotherhand,… 相似文献
97.
用水合五氧化二锑分离放射性母子体的研究─—一个新的~(201)Pb—~(201)T1发生器的制备 总被引:1,自引:0,他引:1
本文研究了无机离子交换剂—水合五氧化二锑(Sb2O5·nH2O)的制备,并用它分离了放射性母子体,制备了一个新的201Pb—201Tl放射性发生器。结果表明,末发生器具有高效、快速、简便的特点,此外还讨论了离子交换反应的机理。 相似文献
98.
Zheng-Zhong Lin Rui-hu Wang Lei Han Rong Cao 《Journal of solid state chemistry》2004,177(7):2494-2498
The indium(III)-organic compound [In(HBtc)2(4,4′-bpy)](4,4′-Hbpy)(H2O)0.5 (Btc=1,3,5-benzenetricarboxylate, 4,4′-bpy=4,4′-bipyridine) has been synthesized under hydrothermal condition and characterized by IR, fluorescent spectroscopy, TGA and single-crystal X-ray diffraction analyses. The compound crystallizes in monoclinic, space group P2(1)/c, a=17.0884(2) Å, b=12.28390(10) Å, c=17.9456(4) Å, β=104.1920(10)°, V=3652.03(10) Å3, Z=4, R1=0.0572 and wR2=0.1116 [I>2σ(I)]. All the indium atoms in the compound are hepta-coordinated and link 1,3,5-benzenetricarboxylate forming a 2-D layer structure with rhombus grids. 相似文献
99.
100.
Purification of astilbin and isoastilbin in the extract of smilax glabra rhizome by high-speed counter-current chromatography 总被引:2,自引:0,他引:2
Purification of astilbin from the rhizome extract of Smilax glabra was conducted using a high-speed counter-current chromatograph equipped with a 700 mL column. In a single operation, 1.5 g of crude sample was separated to yield 105 mg of component astilbin and 48 mg of isoastilbin while the upper phase of the two-phase solvent system composed of n-hexane-n-butanol-water (1:1:2, v/v/v) was used for stationary phase. The chemical structures of the two flavonoid glycosides were confirmed by electrospray ionization ion trap multiple mass spectrometry and nuclear magnetic resonance experiments. 相似文献