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1.
龙耀庭  郭岩 《分析化学》1997,25(1):97-103
近年来离子淌度谱(IMS)在样品引入技术,信号采集和数据处理、离子源等方面都有了显著的进展,其中以IMS作为色谱检测器(IMD)进行的研究尤为重要,而IMS与J民喷雾郭子化(ESI)技术的联用扩大其在非挥发性化合物和生物物质检测方面的应用评论还综述了近年来IMS应用于环保、化学化工、违禁药物检测、爆炸物检测以及半导体表面挥发物分析等方面的最新研究成果。  相似文献   

2.
武轶  隋森芳 《分析化学》1995,23(11):1297-1300
本文制备了一系列富勒烯及其衍生物,并利用多种质谱技术进行了鉴定、表征、揭示了它们在离子源条件下的稳定性及解规律。这些富勒烯及其省生物在FDMS、ISMS中均得到了较强的准分子离子峰且碎片峰很少。结果表昨FDMS,LSIMS技术均适于富勒烯及其衍生物的定性分析,是目前富勒烯分析鉴定中较好的方法。  相似文献   

3.
有机显微组分的二次离子质谱研究   总被引:1,自引:1,他引:1  
采用二次离子质谱技术(SIMS)对煤及源岩中不同成熟度的镜质体、丝质体、沥青和笔石进行了详细研究。结果表明不同显微组分具有不同的SIMS谱图,反映出其化学组成和结构的差异性,且CH2^+/CH3^+参数变化趋势可以用来评价有机组分的热演化规律。同时说明SIMS技术是有机显微组分化学成分和结构研究的有效手段。  相似文献   

4.
用ESR方法研究了[Cu(IO5OH)2]^5-离子配合物中^127I核的超超精细相互作用,旨在证实在碘离子上存在未成对电子自旋和找到一种解释Cu^2+离子中电子离域的机制,根据ESR的参数的计算指出碘离子上自旋密度为0.77%。  相似文献   

5.
用ESR方法研究了[Cu(IO5OH)2]5-离子配合物中127I核的超超精细相互作用,旨在证实在碘离子上存在未成对电子自旋和找到一种解释Cu2+离子中电子离域的机制。根据ESR参数的计算指出碘离子上自旋密度为0.77%。  相似文献   

6.
碘代烷烃在532 nm激光作用下多光子电离解离机理   总被引:3,自引:0,他引:3  
利用532nm的激光对碘代烷烃(碘甲烷、碘乙烷、碘代正丙异丙烷)分子作了多光了电离解离(MPID)质谱(MS)研究,在532nm激光作用下,CH3I分子吸收532nm激光双光子的能量,进入A带的IA2态,继续吸收光子上泵浦至电离态形成母体离子CH3I,然后再形成碎片离子;而其它几个碘代烷烃吸收双光子的能量进入A带后均形成中性碎片,中性碎片再吸收光子经一系列电离解离形成碎片离子,此外,本文还通过对同  相似文献   

7.
3种羧酸类基质的基质辅助激光解吸/电离质谱行为   总被引:1,自引:0,他引:1  
郝春雁  刘志强 《分析化学》1998,26(2):241-241
1引言基质辅助激光解吸/电离质谱(MALDI-MS)这种新的“软电离”质谱技术,能够在短短10年间,得到广泛应用与迅速发展,很大程度上要归功于基质的辅助效应。基质在样品的解吸/电离过程中,起着关键作用。对基质本身MALDI-MS的研究,不仅可以、刻认识MALDI-MS中离子生成、碎裂的机制,在低分子量物质分析时更是必不可少。我们选择常用的3种羧酸类基质:2,5-二羟基苯甲酸(2,5-DHB)、芥子酸(SA)、α-CN-4羟基肉桂酸(ACHC),进行了其自身MALDI-MS的研究。2实验部分2.1…  相似文献   

8.
采用电子束蒸发的方法在200℃抛光的氮化铝(AlN)陶瓷衬底上淀积200nm的Cr膜,并在高真空中退火。利用MCs+-SIMS技术(在Cs+一次离子轰击下检测MCs+型二次离子)对样品进行了深度剖析,给出了界面组分分布随退火温度与时间的变化关系。结果表明,MCs+-SIMS技术是研究金属-陶瓷界面扩散与反应的有效方法。  相似文献   

9.
以FABMS、EIMS、FTIR等手段鉴定了从工业产品中分离得到的一种未知表面活性剂的化学结构为聚氧丙烯/聚氧乙烯共聚物,其商品名称为普鲁洛尼克型非离子表面活性剂。用FABMS谱观察到该表面活性剂系物的各种准分子离子峰呈近似的高斯分布,根据各种准分子离子峰的相对强度得出该表面活剂同系物的分子量分布及平均分子量。  相似文献   

10.
磷块岩含化学元素22-24种。对磷块岩和围岩的微量元素进行了比较,其中一些微量含量较高,若制成磷肥,Cr,Cu,Mn,Mo,As,Ni,Sr和V可通过食物链有益于人体健康,但U,Sr则可能带来环境问题。  相似文献   

11.
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%.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
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.  相似文献   

19.
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%).  相似文献   

20.
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.  相似文献   

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