黄芪中铅的初级形态分析

黄芪是我国盛名的大宗传统中药材,也是常用的中药及食疗药膳品.关于黄芪的研究较多,但主要集中于有机成分与药理作用的研究.中草药药效不仅同药材中的有机成分有关,与微量元素之间关系已被越来越多的研究所证实[1,2].因此对中药微量元素的研究仅仅提供元素总量的信息是不够的,更需要对金属元素的存在化学形态进行分析[3].中药中微量元素的形态分析属一新研究领域,文献报道较少[4-7].本实验选取不同产地的黄芪药材,采用微波消解样品,氢化物发生-电感耦合等离子体原子发射光谱法(HG-ICP-AES)[8],对不同产地黄芪中重金属铅进行了形态分析,这对药材道地性研究,质量控制具有积极的意义.     

坩埚灰化-电感耦合等离子体原子发射光谱法测定催化油浆中微量钙、钠、铝、铁、镍、硅

目前,有不良商家为了追求经济效益,在减压渣油中掺入了一定比例的催化油浆,催化油浆中含有大量的铝、硅元素,容易造成装置炉管内及其余部位结焦,不利于装置长周期的运行。为了延长设备的使用寿命,需要建立方法来有效监测催化油浆中硅及铝等金属的含量。目前,油品中的微量元素常用的测定方法有原子吸收光谱法[1-3]、原子荧光光谱法[4]、紫外-可见分光光谱法[5-7]等。其中,电感耦合等离子体原子发射光谱法(ICP-AES)因具有多元素同时测定、线性范围宽、灵敏度高、基体效应小、精密度高、快速准确等特点在油品分析中得到广泛的应用[8-11]。本工作采用坩埚灰化-电感耦合等离子体原子发射光谱法同时测定催化油浆中6种非金属和金属元素含量,可为建立高效灵敏的日常生产检测方法提供依据。     

微波消解/湿法灰化-电感耦合等离子体原子发射光谱法测定原油重油中6种金属元素的含量

在石油炼制与加工过程中,原油重油中的微量金属元素容易引起管线设备结垢,反应器管线腐蚀,从而降低催化剂的使用寿命、影响产品的质量,因此对原油重油中微量金属元素的测定具有重要意义[1].目前油品中金属元素的测定方法主要有电感耦合等离子体原子发射光谱法(ICP-AES)[2]、原子吸收光谱法(AAS)[3]、电感耦合等离子体...     

四种补肾中成药微量元素含量的研究

从微量元素含量的角度,采用电感耦合等离子体发射光谱法,对四种常用补肾中成药中微量元素的含量进行了初步研究.研究结果表明,补肾阳药中钙、磷、镁、铁、钾含量普遍高于补肾阴药,与中医辨证施治的理论相一致.     

微波辅助消解ICP-AES法测定几种血藤中17种元素*

目的 建立电感耦合等离子体发射光谱(ICP-AES)法测定血藤类中药中K、Ca、Mg、P、Sr、Fe、Mn、Zn、Cu 、Co、Cr、Al 、Ba、Ni、As、Pb和Cd17种常量和微量元素含量的测定方法。方法 采用微波辅助消解样品,电感耦合等离子体发射光谱(ICP-AES)法测定几种血藤中17种元素的含量。 结果 该方法的检出限为0.00003~0.00981μg/mL,回收率88.37% ~110. 00%,相对标准偏差( RSD) 均小于5.0%。结论 该方法可快速、灵敏、准确测定血藤类中药中多种常量、微量元素的含量。血藤样品中除含有人体必需的常量元素K、Ca、Mg外,还含有Fe、Zn、Mn、Cr、Co等必需的微量元素和其它元素P、Ni、Ba、Al、Sr、Pb、Cd、Ba等。     

HG-ICP-AES测定马蹄金中As、Se含量

采用流动氢化物发生电感耦合等离子体-原子发射光谱法(HG-ICP-AES)分别对马蹄金在酸性条件下经超声煎煮后得到的酸提取液和滤渣中As、Se含量进行了测定。结果表明:(1)马蹄金中As含量较低,低于1.0μg/g,而Se含量则较高,可达6.298μg/g;(2)酸提取液中Se含量随煎煮时间延长有所增加,而As含量则有所降低。为进一步研究马蹄金的药理药效和合理开发利用药物资源提供了科学依据。     

样品基体化学改进剂-石墨炉原子吸收光谱法测定镍合金中痕量铋

镍基合金是航空工业的重要金属材料,合金中铋、铅、锡等易挥发元素的含量对合金材料性能影响很大[1,2].原子光谱法常被用于分析镍基合金中的痕量元素,如火焰原子吸收光谱法(FAAS)、氢化物发生-原子吸收(荧光)光谱法(HG-AAS/AFS) [3]、电感耦合等离子体-质谱法(ICP-MS).     

蔬菜中重金属含量测定方法的研究状况

综述了目前测定植株中重金属含量的4种主要方法,包括原子荧光光谱法(AFS)、原子吸收分光光度法(AAS)、电感耦合等离子体发射光谱法(ICP-AES)、电感耦合等离子体质谱法(ICP-MS)。分析了不同方法测定植株中重金属含量的原理、适用条件和研究现状,总结了其优缺点。得出电感耦合等离子体质谱法因其性能较强、实用性好的特点而在植株中的重金属含量测定方面具有明显的优势。同时展望了植株中重金属含量测定方法的发展前景。     

中药牛大力微量元素含量的测定

用电感耦合等离子体发射光谱仪(ICP)测定了湛江地区产的中药牛大力微量元素的含量,发现其Ca、Mg、Fe、Zn等元素的含量都比较丰富,相对标准偏差为0.32%~7.05%,回收率为93.0%~101%,结果令人满意。     

微波消解样品-电感耦合等离子体原子发射光谱法测定中草药中微量铜锌钴锰

采用微波消解样品,电感耦合等离子体原子发射光谱法(ICP-AES)测定了野菊花、菊花、蒲公英、枇杷叶和蝉蜕5种中草药中铜、锌、钴、锰4种微量金属元素的含量.在最佳仪器条件下,对野菊花样品平行测定6次,各元素的加标回收率在96.0%～106.5%之间,相对标准偏差(n=6)均小于2.0%.铜、锌、钴、锰4元素的检出限(3S/N)依次为0.011,0.018,0.001 1,0.024 mg·L-1.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.