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粒子束接口液相色谱—质谱应用 总被引:2,自引:0,他引:2
粒子束接口(BPI,Particle Beam Interface)是几种实现液相色谱-质谱联用的技术之一。本文结合FinniganMATSSQ710质谱仪及其粒子束接口与Waters液相色谱泵联用和近年来有关文献对仪器结构、分析条件选择、应用等方面进行讨论。 相似文献
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利用HPLC-ES/MS(高效液相色谱/电喷雾接口/质谱)联用技术,对国际奥委会规定禁用的药物精神刺激剂Mesocarb的标准品和阳性尿进行了分析实验。通过对分离条件、离子化条件等的选择,建立了一个可靠的Mesocarb的检测方法。 相似文献
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姜燕 《仪器仪表与分析监测》1998,(1):1-7
液相色谱—气相色谱联用技术的发展姜燕(山西经济管理学院城建系太原030006)关键词液相色谱毛细管气相色谱联用接口液相色谱和气相色谱联用技术(LC/GC)是一项新型多维色谱技术[1]。它兼有LC的高选择性和GC的高效率及高灵敏度,对复杂有机试样有较强... 相似文献
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HPLC与AAS,AFS联用技术在元素化学形态分析中的应用 总被引:1,自引:0,他引:1
本文介绍了高效液相色谱与原子吸收光谱、原子荧光光谱的联用技术及其应用于元素化学形态分析的现状、前景及存在问题。着重论述了用于元素形态分析的高效液相色谱分离方法及联用接口。 相似文献
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综合评述了各种分离/分析联用技术与仪器。重点论述的内容包括:气相色谱/质谱法各种类型接口和仪器,液相色谱/质谱法联用的困难和现有的六种接口,实现色谱/红外光谱法联用的各种方法和仪器,现有三种质谱/质谱联用仪器产品的型式,以及以上各种联用技术与仪器的发展趋势。此外,还对分离/分析联用技术和仪器的名词术语和符号的统一命名法提出了具体建议。 相似文献
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热喷雾接口是一种新型液相色谱/质谱联用接口。本文介绍热喷雾接口的结构、工作原理、操作方法和谱图特征.通过与其他接口的比较,说明其效率、方法的灵敏度和优缺点,热喷雾接口最适合于难汽化和热不稳定化合物,尤其是生物样品分析. 相似文献
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Chernetsova ES Revelsky AI Revelsky IA Mikhasenko IA Sobolevsky TG 《Mass spectrometry reviews》2002,21(6):373-387
Reagent gases that are used in mass spectrometry in the NCI mode for the determination of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) are discussed. Ion-molecule reactions and respective characteristic ions that form while using reagent gases (CH(4), O(2), i-C(4)H(10), NH(3), H(2), He, Ar, Xe, SF(6)) or gas mixtures (CH(4)/O(2), Ar/CH(4), CH(4)/H(2)O, Ar/O(2), i-C(4)H(10)/CH(2)Cl(2)/O(2)) are reviewed. It is shown that only CH(4), O(2), CH(4)/O(2), and CH(4)/N(2)O are widely used and well studied, even though-in the case of these reagent gases-there are contradictions between the publications of various authors. Such reagent gases as NH(3) and He are not well studied, but further investigations of their use for the determination of organochlorine pollutants could be of interest. The possibilities of more sensitive and selective determination of PCDDs, PCDFs, and PCBs are discussed. 相似文献
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Balamurugan A Benhayoune H Kannan S Laquerriere P Michel J Balossier G Ferreira JM 《Microscopy research and technique》2008,71(9):684-688
The present study deals with the short-term physicochemical reactions at the interface between bioactive glass particles [55SiO(2)-20CaO-9P(2)O(5)-12Na(2)O-4MgO. mol%] and biological fluid (Dulbecco Modified Eagle's Medium (DMEM)). The physicochemical reactions within the interface are characterized by scanning transmission electron microscopy (TEM) (STEM) associated with Energy-dispersive X-ray spectroscopy (EDXS). Microanalysis of diffusible ions such as sodium, potassium, or oxygen requires a special care. In the present investigation the cryo-technique was adopted as a suitable tool for the specimen preparation and characterization. Cryosectioning is essential for preserving the native distribution of ions so that meaningful information about the local concentrations can be obtained by elemental microanalysis. The bioglass particles immersed in biological fluid for 24 h revealed five reaction stages: (i) dealkalization of the surface by cationic exchange (Na(+), Ca(2+) with H(+) or H(3)O(+)); (ii) loss of soluble silica in the form of Si(OH)(4) to the solution resulting from the breakdown of Si--O--Si bonds (iii); repolymerization of Si(OH)(4) leading to condensation of SiO(2)); (iv) migration of Ca(2+) and PO(4) (3-) to the surface through the SiO(2)-rich layer to form CaO-P(2)O(5) film; (v) crystallization of the amorphous CaO-P(2)O(5) by incorporating OH-- or CO(3) (2-) anions with the formation of three different surface layers on the bioactive glass periphery. The thickness of each layer is approximately 300 nm and from the inner part to the periphery they consist of Si--OH, which permits the diffusion of Ca(2+) and PO(4) (3-) ions and the formation of the middle Ca--P layer, and finally the outer layer composed of Na--O, which acts as an ion exchange layer between Na(+) ions and H(+) or H(3)O(+) from the solution. 相似文献
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The micellar morphologies of well-defined amphiphilic block copolymers composed of 1H,1H-dihydroperfluorooctyl methacrylate (FOMA) and ethylene oxide (EO) blocks with different chain lengths were effectively investigated by using tapping mode-atomic force microscopy (TM-AFM). By spin-casting chloroform solutions, well-ordered spherical micellar films could be obtained for poly(FOMA(10k)-b-EO(10k)) and poly(FOMA(20k)-b-EO(20k)) copolymers. The atomic force microscopy (AFM) height and phase image analysis indicated that dark regions of the micelles corresponded to PEO blocks and the light regions were for PFOMA blocks. The spherical micelles with PEO corona and PFOMA core were also identified by transmission electron microscopy (TEM) and X-ray photoelectron spectrometer (XPS) analysis. The core diameters of the block-copolymer aggregates were 20nm for poly(FOMA(10k)-b-EO(10k)) and 30nm for poly(FOMA(20k)-b-EO(20k)) by TM-AFM, whereas slightly lower values of 17 and 26nm were obtained from TEM. A detailed study on the inverted morphological change observed in the micelles films after annealing above glass transition temperature (T(g)) was also presented. 相似文献
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针对数控强力切削中颤振问题,建立了包含切削过程颤振环节的数控强力切削伺服系统数学模型。对模型的理论分析、计算机仿真及正交试验验证表明:增大位置环增益KPP可以提高机床快速跟踪性能,减小速度环积分时间常数τs能迅速消除系统静差,但极限切削宽度blim会随之而下降;过大或过小的速度环增益KPS都会导致blim下;优化调节伺服系统KPP,τs和KPS可提高系统的动、静态特性及blim。正交实验优化伺服系统参数方法简单可行,能有效地提高切削系统稳定性和极限切削宽度,适用于重型机床的数控强力切削。 相似文献
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采用改进的固相反应法合成了锶、镁与铁或钴多元掺杂的LaGaO3基稀土复合氧化物La0.8Sr0.2Ga0.72Mg0.20Fe0.08O2.8(LSGMF)和La0.8Sr0.2Ga0.72Mgo.20Co0.08O2.8(LSGMC),利用EDS、XRD及SEM等方法对LSGMF和LSGMC的化学成分、物相组成及显微组织等进行了分析;采用直流四端子法测量了两者在350~850℃温度区间的电导率.结果表明:经1 400℃烧结后,LSGMF和LSGMC均形成单一正交钙钛矿结构;两者除含少量钙外,不舍其他杂质元素;在测试温度范围,材料的电导率与温度的关系分区间符合Arrhenius方程,在较低温阶段(350~500℃)具有较低的导电活化能(Ea<0.3 eV);与仅用锶、镁双掺杂的LSGM相比,LSGMF和LSGMC具有较高的电导率. 相似文献
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测出X80等5种材料常规机械性能及名义应力屈强比σs/σb和真实应力屈强比Ss/Sb。比较发现Ss/Sb较σs/σb小13%,表明高强度、高屈强比X80钢屈服后塑性变形裕度仍较大。还测出材料静力韧度、冲击韧性及断裂δR阻力曲线,并应用于X80钢管线安全性预测,可以认为,高屈强比对结构安全性的影响并非如通常认为的那么严重。最后讨论了屈强比对硬化指数n的影响。 相似文献
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用原位自生法制备了20%TiC/Fe复合材料,并以W替代部分Ti制备了两种20%(TiW)C/Fe复合材料,研究了它们的显微组织与性能。结果表明:在20%TiC/Fe和20%(Ti0.8W0.2)C/Fe复合材料中,TiC和(TiW)C分别是两种材料中唯一的第二相,它们呈枝晶、方块和条形等多种形态。在20%TiC/Fe中.由于TiC与铁熔体的密度相差较大,出现了第二相的分布不均现象。在20%(Ti0.7W0.3)C/Fe复合材料中,(TiW)C相是唯一的第二相,它呈细小等轴粒状和条状两种形态,均匀分布于基体中,它的硬度与耐磨性明显好于前两种复合材料。 相似文献
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Abstract The Oscosurvismeter is made of borosil glass material for measuring osmotic pressure (π), specific conductance (κ), viscosity (η), and surface tension (γ) of solutions. Solutions of different strengths are taken in two cells/compartments, partitioned by a semi‐permeable membrane (SPM). A concentration gradient makes the solvent move towards the concentrated solution to establish an equilibrium; this measures osmotic pressure (π). The Oscosurvismeter saves time and materials, and enhances accuracy and precision in measurements; the instrument consists of six parts: (1) survismeter; (2) osmometer; (3) electrode; (4) metallic clamp; (5) semipermeable membrane (SPM); and (6) high potential metallic springs. High accuracy data are noted with the instrument. 相似文献
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Cathodoluminescence study of semiconductor oxide micro- and nanostructures grown by vapor deposition
Nano- and microstructures of SnO(2), In(2)O(3) and ZnO have been grown during thermal treatment of compacted powders under argon flow. Indium-doped SnO(2) tube-shaped structures with rectangular cross-section are obtained by adding a fraction of In(2)O(3) to the starting SnO(2) powder. In-rich nanoislands were found to grow on some edges of the tubes. ZnO nanostructures doped with Sn or Eu were grown by adding SnO(2) and Eu(2)O(3) powder, respectively, to the ZnO precursor powder. All the samples have been characterized by the emissive and cathodoluminescence (CL) modes of scanning electron microscopy. CL images from SnO(2):In and In(2)O(3):Sn tubes and islands show a higher emission from the Sn-rich structures related to oxygen deficiency. CL of doped ZnO enables to detect the presence of dopant in specific regions or structures. CL appears to be a useful technique to study optical and electronic properties of semiconductor oxide nanostructures. 相似文献
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The topography of self-assembled viologen derivatives (VC(8)SH, VC(10)SH, HSC(8)VC(8)SH, and HSC(10)VC(10)SH) molecules on an octanethiol (C(8)) self-assembled monolayer (SAM) modified gold surface was measured using ultrahigh-vacuum scanning tunneling microscopy (UHV-STM). We demonstrate here a novel matrix SAM appropriate for isolation of the viologen molecules. The C(8) was used for a matrix SAM, in which the VC(8)SH, VC(10)SH, HSC(8)VC(8)SH, and HSC(10)VC(10)SH were inserted at molecular lattice defects. The isolated single molecules of viologen derivatives inserted in the matrix SAM were observed as protrusions in STM topography using a constant current mode. We measured the topographic heights (VC(8)SH: 1.53nm, VC(10)SH: 2.01nm, HSC(8)VC(8)SH: 2.71nm, and HSC(10)VC(10)SH: 3.3nm) of the molecular protrusions using STM. Also, changes in the central axis of viologen molecules were observed as VC(8)SH (0.5-0.73nm), VC(10)SH (0.4-0.74nm), HSC(8)VC(8)SH (0.67-0.84nm), and HSC(10)VC(10)SH (0.67-0.99nm), respectively. 相似文献