Electron Emission Spectrometric Analysis

Other broad signals are often observed in the energy range 403 to 405 eV. Peaks near 403 eV are usually assigned to nitrogen atoms bound as in pyridine-N-oxides. Pyridine-N-oxides are easily formed from pyridine or substituted 

The ratio of the nitrogen species also changes during gasification of the N-doped carbons with oxygen, carbon dioxide, and so on. This is shown in the following example. An activated carbon was prepared by CO2 activation at 1173 K of a carbonized mixture of sucrose with uracil (carbonization at 1373 K). This activated carbon, with a bum-off of 23% and a nitrogen content of 1275 ttmol/g, was further activated with CO2 at 1073 K or with 5% O2 in He at 853 K to 70 to 75% bum-off levels. 

Further, it is very likely that N-Q nitrogen atoms near the edge become N-6 when two of the adjoining carbon atoms are removed by gasification. 

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The prepared catalysts were analyzed by X-ray powder diffraction (XRD), Diffuse Reflectance Spectra (DREAS), Inductive coupled plasma-atomic emission spectrometric analysis (ICP-AES) and scanning electron microscopy (SEM). The catalysts were characterized by XRD before and after calcination, using a Philips PW 1877 automated powder diffractometer with CuKa radiation. DREAS measurements were recorded on a Varian Cary-1 spectrophotometer using BaS04 as a reference. ICP-AES measurements were recorded on a Perkin-Elmer Plasma 40 (ICP) or Perkin-Elmer 1100 (AES). SEM measurements were recorded on a Philips XL-20 microscop. 

In this connection investigations are to be mentioned in which a mass-spectrometric analysis has been made of neutral radicals, e.g., CHjCO, split off from acetone by u.v. photons in the ordinary range.27-28 In the first a flash lamp has been used and the radicals were ionized as usual by electron impact. In the second the same radical ionized at a field emission electrode. Recently, several alkyl radicals generated by pyrolysis have been studied. Their values of lv and of the photoionization cross sections could be obtained in the mass spectrometer under monochromatic vacuum u.v. irradiation.29... 

NMR) [24], and Fourier transform-infrared (FT-IR) spectroscopy [25] are commonly applied methods. Analysis using mass spectrometric (MS) techniques has been achieved with gas chromatography-mass spectrometry (GC-MS), with chemical ionisation (Cl) often more informative than conventional electron impact (El) ionisation [26]. For the qualitative and quantitative characterisation of silicone polyether copolymers in particular, SEC, NMR, and FT-IR have also been demonstrated as useful and informative methods [22] and the application of high-temperature GC and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) is also described [5]. 

The most frequently applied analytical methods used for characterizing bulk and layered systems (wafers and layers for microelectronics see the example in the schematic on the right-hand side) are summarized in Figure 9.4. Besides mass spectrometric techniques there are a multitude of alternative powerful analytical techniques for characterizing such multi-layered systems. The analytical methods used for determining trace and ultratrace elements in, for example, high purity materials for microelectronic applications include AAS (atomic absorption spectrometry), XRF (X-ray fluorescence analysis), ICP-OES (optical emission spectroscopy with inductively coupled plasma), NAA (neutron activation analysis) and others. For the characterization of layered systems or for the determination of surface contamination, XPS (X-ray photon electron spectroscopy), SEM-EDX (secondary electron microscopy combined with energy disperse X-ray analysis) and... 

In this review results from two surface science methods are presented. Electron Spectroscopy for Chemical Analysis (ESCA or XPS) is a widely used method for the study of organic and polymeric surfaces, metal corrosion and passivation studies and metallization of polymers (la). However, one major accent of our work has been the development of complementary ion beam methods for polymer surface analysis. Of the techniques deriving from ion beam interactions, Secondary Ion Mass Spectrometry (SIMS), used as a surface analytical method, has many advantages over electron spectroscopies. Such benefits include superior elemental sensitivity with a ppm to ppb detection limit, the ability to detect molecular secondary ions which are directly related to the molecular structure, surface compositional sensitivity due in part to the matrix sensitivity of secondary emission, and mass spectrometric isotopic sensitivity. The major difficulties which limit routine analysis with SIMS include sample damage due to sputtering, a poor understanding of the relationship between matrix dependent secondary emission and molecular surface composition, and difficulty in obtaining reproducible, accurate quantitative molecular information. Thus, we have worked to overcome the limitations for quantitation, and the present work will report the results of these studies. 

Plsko E (1988) Analysis of water using optical emission spectrometry with arc and spark excitation. In Butler LRP and Strasheim A, section editors. Atomic-, mass-, X-ray-spectrometric methods, electron paramagnetic and luminescence methods. In West TS and Niimberg HW, eds. The determination of trace metals in natural waters. 

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