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Transition metal ions instrumentation

Malct, P., Odriozola. J. A., Labajos, F. M., Rives, V. and Ulibarri, M. A. (1995).XAS study of transition metal ions in hydrotalcite-like compounds. Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms, 97, 16-19. [Pg.96]

Stripping voltammetry is an important, but limited technique, which uses a pre-concentration step to enhance the sensitivity of the voltammetric analysis step. This pre-concentration step is electrochemical using the same instrumentation as the subsequent voltammetric analysis. The simplest polarographic equipment can be used to obtain the highest sensitivity which depends on the length of the pre-concentration step as well as on the sensitivity of the voltammetric stripping step. Since the pre-concentration step requires the production of an insoluble product which can be reproducibly stripped from the electrode surface in the determination step, the use of stripping voltammetry is limited to a few analytes, eg transition metal ions, halides and pseudo-halides. [Pg.198]

On the other hand, it has proved possible to activate a C-C bond by using bare ( naked ) transition metal ions, generated by various ionization methods in the gas phase [165]. Using an ion-beam instrument, for example, Armentrout and Beauchamp [166] were able to show that the reaction of Co+ with -butane gives C0C2H4. An exothermic and quite facile C-C insertion by the metal is thought... [Pg.102]

Abstract The theoretical principles of the ESR technique and its application in the field of molecular sieve science are reviewed. The first part of this chapter focuses on the basic principles and instrumentation of the ESR, ENDOR, ESE and ESEEM techniques. Special attention will be given to spectral simulation and quantitative analysis of ESR spectra. In the second part, the general features of the ESR spectra of transition metal ions and paramagnetic clusters in molecular sieves are presented and discussed. In addition, some remarks will be made about the use of paramagnetic molecules, such as NO. [Pg.295]

This review deals with both the theoretical and practical aspects of the use of ESR spectroscopy in molecular sieve science. No attempt has been made to compile an exhaustive list of references to all the work that has been published so far. Rather, we have selected what, we feel, are the most important developments and also, where possible, we have drawn examples from our own work. In a first part, the ESR technique and its extensions such as ENDOR and ESEEM, will be highlighted with special emphasis on the principles of the techniques and the instrumental requirements. Attention will also be given to spectral simulation and to quantitative analysis. In a second part, the general features of ESR spectra of transition metal ions in molecular sieves are analyzed. In addition, some remarks will be made on paramagnetic metal clusters and on paramagnetic molecules. The chapter closes with general conclusions and an outlook into the future. For detailed explanations and discussions-in-depth, we refer to several excellent text books [1-9] and review papers [10-14]. [Pg.296]

Soon after the first experiments, studies on Mn " salts were performed by employing 10 cm microwaves, fed into the cavity containing the sample. The resonance was detected by readings on a d.c. instrument connected to the detector. In some following papers around 1948, single crystal studies were first reported. Systematic ESR studies of transition metal ions were initiated in a paper titled Paramagnetic Resonance in Salts of the Iron Group [3]. Many of these ions had... [Pg.18]

Electron spin resonance (ESR) spectroscopy a technique used for the study of substances that are paramagnetic, a property caused by the presence of unpaired electrons. In biological materials paramagnetism is principally found in two main types of molecular species, free radicals and those that contain a transition metal ion. Some spectroscopists confine the term ESR spectroscopy to the study of free radicals, because they have an identifiable electron spin, and use the term electron paramagnetic resonance (EPR) spectroscopy for the study of transition metals, where paramagnetism arises from the distribution of electrons in the d orbitals. However the spectra are taken with the same instrumentation and most authors use the terms ESR- and EPR spectroscopy either interchangeably or according to personal preference. [Pg.188]

Recently the compact time-resolved (TR) Raman, and fluorescence spectrometers suitable for planetary exploration under NASA s Mars Instrument Development Program have been developed (Sharma et al. 2012). The compact Raman and fluorescence spectrometers consist of custom miniature spectrographs based on volume holographic gratings, and custom miniature intensified CCD cameras. Using a small frequency-doubled Nd YAG pulsed laser (35 mJ/pulse, 20 Hz) and 50 mm camera lens, TR Raman and laser-induced fluorescence spectra of minerals from rare-earths and transition-metal ions in time domain and in the spectral range of 400-800 nm can be measured. [Pg.486]

Commercial CE instruments only became readily available in the late 1980s, however, a vast array of information about different applications has been published. As well as the dyes themselves, CE can be used, for example, for the analysis of low molecular weight/simple ions (such as small anions, e.g. chloride, bromide, nitrate, chlorite, acetate, phthalate or small cations, e.g. alkali -i- alkali earth metals, ammonium, transition metals) or for aromatic amines. [Pg.306]


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