Elements Analysed

Oelert, H.H. (1971) "Entwicklung und Anwendung einer auf IR-NMR Spektroskopie und elemental Analyse beruhenden Strukturgruppenanalyse fiir hohersiedende Kohlenwasserstoffgemische und Mineralolanteile". Z Anal. Chem., Vol. 255, p. 177. 

Selected Elemental Analyses Based on Acid-Base Titrimetry ... 

Microscopes are also classified by the type of information they present size, shape, transparency, crystallinity, color, anisotropy, refractive indices and dispersion, elemental analyses, and duorescence, as well as infrared, visible, or ultraviolet absorption frequencies, etc. One or more of these microscopes are used in every area of the physical sciences, ie, biology, chemistry, and physics, and also in their subsciences, mineralogy, histology, cytology, pathology, metallography, etc. 

The two most useful supplementary techniques for the light microscope are EDS and FTIR microscopy. Energy dispersed x-ray systems (EDS) and Eourier-transform infrared absorption (ETIR) are used by chemical microscopists for elemental analyses (EDS) of inorganic compounds and for organic function group analyses (ETIR) of organic compounds. Insofar as they are able to characterize a tiny sample microscopically by PLM, EDS and ETIR ensure rapid and dependable identification when appHed by a trained chemical microscopist. 

The infrared spectra of PVDC often show traces of unsaturation and carbonyl groups. The slighdy yeUow tinge of many of these polymers comes from the same source the pure polymer is colorless. Elemental analyses for chlorine are normally slightly lower than the theoretical value of 73.2%. 

Table 7. Elemental Analyses of Representative Petroleum Asphalts...

Composition. The results of elemental analyses are almost always included among the specifications for a commercial catalyst. Depending on the accuracy desired and whether or not the catalyst can be rendered soluble without great difficulty, elemental analysis may be performed by x-ray methods, by one of the procedures based on atomic absorption, or by traditional wet-chemical methods. Erequentiy it is important to determine and report trace element components that may have an effect on catalyst performance. 

Application of these tests at successive steps will give a good indication of whether or not the purification is satisfactory and will also show when adequate purification has been achieved. Finally elemental analyses, e.g. of carbon, hydrogen, nitrogen, sulfur, metals etc. are very sensitive to impurities (other than with isomers), and are good criteria of purity. 

MPI is especially valuable for elemental analyses with typical useful yield of 10 . Because SALI is laser-based, expected improvements over the next few years, in particular for vacuum-ultraviolet laser technology, should have a significant impact. High repetition rate Nd—YAG systems with sufficient pulse energy are already available to 50 Hz, and probably can be extended to a few hundred Hz. 

Yields were determined by %NMRvs benzomfluonde, isolated yields are given in parentheses All products exhibited spectral data in accord with the assigned structure and gave satisfactory elemental analyses... 

A mixture of 24 g of 1,3-dimethyladamantane and BO ml of bromine was refluxed for 6 hours. The reaction product mixture was cooled, taken up in about 200 ml of chloroform, and poured onto ice. The excess bromine was removed by adding sodium hydrosulfite. The chloroform layer was separated from the aqueous layer, dried, concentrated in vacuo, and distilled at reduced pressure to yield 30.5 g of product having a boiling point of about 11B°C at 5-6 mm np = 1.5169-1.51B2. The product was identified by nuclear magnetic resonance (NMR) and elemental analyses as 1-bromo-3,5-dimethyladamantane. 

Multi-element analyses involving solvent extraction and high performance liquid chromatography (HPLC) have also been described. The extracts, containing metal-chelate complexes with sulphur-containing reagents, such as dithizone and diethyldithiocarbamate, were used directly for determination of the metals by HPLC.14... 

For laboratories required to do a large number of heavy-element analyses, particularly those where interferences with the L spectra are present, the purchase of a 100-kv source may well be justified. Two examples to illustrate this are shown in Figure 9-3, furnished by M. L. Salmon. 

The free ligands were obtained by visible photolysis in acetonitrile and were characterized by elemental analyses and H- and 13C-NMR spectroscopies. Low-temperature reduction in ESR tubes also provided the green Fe1 19e complexes which gave the characteristic 3g values typical of the rhombic distortion of Fe1 [77],... 

Note The elemental analyses were difficult to perform due to the tendency of the compd to expld in the combustion tube (Ref 1)... 

F.17 In determining the composition of an unknown compound, elemental analyses are often considered to have an error of 0.5%. With the use of elemental analyses alone, would it be possible to determine whether a sample was glucose (QHt2OJ or sucrose (C12H22On) ... 

Arrhenius, B. 1990 Trace element analyses of human skulls. In Arrhenius, B., ed., Laborativ Arkeologi. Stockholm, Stockholm University 15-19. 

Gilbert, R.l. 1975 Trace Element Analyses of Three Skeletal Amerindian Populations at Dickson Mounds. Ph.D. dissertation. University of Massachusetts, Amherst. 

C and 5 N values were determined by mass spectrometry (MM 903, VG Isogas), equipped with a CN elemental analyzer (Roboprep CN, Europa Scientific). As control for sample purity, C N ratios from the elemental analyser were compared with C N ratios as calculated from the amino acid profile of the same sample. 

Advanced Seminar volume reflects the greatly expanded awareness of the importance of diet reconstruction for understanding past human health and behavior. It also reflects the growing number of applications of stable isotope and trace element analyses of bones and teeth. 

DBpD was prepared by slowly heating a mixture of o-chlorophenol (480 mmoles), potassium carbonate (240 mmoles), and purified copper powder (50 mmoles) in a 500-ml Erlenmeyer flask to 160°-180°C and maintaining this temperature for 6 hours. DBpD, which sublimed to the walls of the flask as it was formed, was recovered by scraping and was recrystallized from absolute ethanol (14% yield white needles, mp 119°-120°C reported 120°-122°C (7) elemental analyses—calcd. C = 78.26, H = 4.34, found C = 77.98, H = 4.48). 

Compared to polycarbonates, little work has so far been published on the synthesis of poly(iminocarbonates). The first attempted synthesis of a poly (iminocarbonate) was reported by Hedayatullah (44), who reacted aqueous solutions of various chlorinated dipheno-late sodium salts with cyanogen bromide dissolved in methylene chloride. Unfortunately, Hedayatullah only reported the melting points and elemental analyses of the obtained products which, according to Schminke (40), were oligomers with molecular weights below 5000. 

The presentation in this paper concentrates on the use of large-scale numerical simulation in unraveling these questions for models of two-dimensional directional solidification in an imposed temperature gradient. The simplest models for transport and interfacial physics in these processes are presented in Section 2 along with a summary of the analytical results for the onset of the cellular instability. The finite-element analyses used in the numerical calculations are described in Section 3. Steady-state and time-dependent results for shallow cell near the onset of the instability are presented in Section 4. The issue of the presence of a fundamental mechanism for wavelength selection for deep cells is discussed in Section 5 in the context of calculations with varying spatial wavelength. 

A cationic molybdenum sulfide cluster [Mo3S4(H20)9] " with incomplete cubane-type structure and a cationic nickel-molybdenum mixed sulfide cluster [Mo3NiS4Cl(H20)9p " with complete cubane-type structure were introduced into zeolites NaY, HUSY and KL by ion exchange. Stoichiometry of the ion exchange was well established by elemental analyses. The UV-visible spectra and EXAFS analysis data exhibited that the structure of the molybdenum cluster remained virtually intact after ion exchange. MoNi/NaY catalyst prepared using the molybdenum-nickel sulfide cluster was found to be active and selective for benzothiophene hydrodesulfurization. 

The NMR spectrum of 4 showed signals at 7-9 (m,9H,ArH) and 10.5 (s,lH,NH). Data from the elemental analyses have been found to be in conformity with the assigned structures. Furthermore, the molecular ion recorder in the mass spectrum is also in agreement with the molecular weight of the compound. 

There have been no reports of complexes of " JV-substituted thiosemicarbazones derived from 2-formylpyridine, but 2-acetylpyridine JV-methyl-thiosemicarbazone, 3a, formed [Fe(3a-H)2]C104 and [Fe(3a-H)2]FeCl4 [117]. The nature of these two species was established by partial elemental analyses, molar conductivities, magnetic moments, electronic, infrared, mass and electron spin resonance spectra. A crystal structure of a related selenosemicarbazone complex confirmed the presence of a distorted octahedral iron(III) cation coordinated by two deprotonated anions so that each ligand is essentially planar and the azomethine nitrogens are trans to each other the pyridyl nitrogen and selenium donors are both cis. 

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