Using elemental analysis

Applications Over the last 20 years, ICP-AES has become a widely used elemental analysis tool in many laboratories, which is also used to identify/quantify emulsifiers, contaminants, catalyst residues and other inorganic additives. Although ICP-AES is an accepted method for elemental analysis of lubricating oils (ASTM D 4951), often, unreliable results with errors of up to 20% were observed. It was found that viscosity modifier (VM) polymers interfere with aerosol formation, a critical step in the ICP analysis, thus affecting the sample delivery to the plasma torch [193]. Modifications... 

The parent siliceous materials of the SBA-15 and MLV types were synthesised after typical procedures [2], The carbon replicas were prepared via polymerisation, catalysed by ferric chloride, of pyrrole introduced into the mesopores of matrices [3]. The products were characterised by the nitrogen adsorption, TEM, and thermal analysis (DTG, DTA). The nitrogen content in carbons was determined using elemental analysis, XPS, and EDX, while the Si and Fe contents, with XPS. The replicas of SBA-15 and MLV-0.75 are denoted as CMK-3Nx and OCM-.Nx, respectively, were x refers to the number of g of FeCl3 per 1 g of silica used for preparations. 

Exposure to inorganic chemicals in the workplace has been traditionally evaluated using elemental analysis. However, in recent years some attention has been given to the toxic effects of specific compounds rather than elements, e.g., chromic acid ( ), nickel subsulfide Q), zinc oxide (4.), and sodium hydroxide (5.). It is therefore important that the occupational health chemist develop the capability to identify and quantitate chemical compounds. To this end, X-ray powder diffraction (XRD) is a unique tool for... 

Concentrations of carbon and hydrogen on the catalysts (fresh, LP used and SCFP used) surface are measured by using element analysis (Italy). It is found that SCF used catalyst has a lower carbon content than that of the LP used, shown in Table 4. 

The principle of this technique is remarkably similar to that of global element analysis by X-ray fluorescence should. The essential difference between these two techniques is the energy source in the case of X-ray fluorescence, a collimated (but not focused) X-ray beam is used (elemental analysis in a volume of several cm ). In the case of the electron micro-... 

The structure of 33 has been supported by using elemental analysis, mass spectrometry and NMR spectroscopy [119]. However, the NMR spectra provided a more complex depiction. They indicated the presence of five species in a CDCI3 solution of sanguinarine fi ee base (I) a major bimole-cular stereoisomer, the racemate 6R,6"R + 6S,6 S, vsdiich is thermodynamically voured according to AMI calculations [120] (II) a minor isomer, a... 

Substitution of Fe for A1 was evidenced using elemental analysis and temperature programmed reduction of pillared clays prepared by various ways [4]. These authors claimed... 

According to these basic results, there is almost no chemical change detected by using elemental analysis and IR in the case of rapid heating (104 °C min-1). Many NMR techniques were applied to clarify the properties of coal changes by the rapid heating process from the standpoint of the physical and chemical structures. 

The characterization of arsenobetaine was performed using element analysis, H NMR, mass spectrometry, thermogravimetric/thermodifferential analysis and separative methods such as HPLC, GC and CZE. From all the results obtained it was concluded that the maximum amount of water present in the solid (if stored and handled under dry atmosphere) is 1% (w/w). In addition, arsenic impurities represent less than 0.15% (w/w) other impurities can be neglected. Therefore, the arsenobetaine purity of the calibrant obtained is >98.9%. 

Accuracy and Precision. In general, analysis by any of the three GC methods described produced ligand concentrations significantly lower than obtained using elemental analysis, even with carefully prepared monofunctlonal phases. As previously discussed, there are several possible sources for this discrepancy. 

High-iesolution scanning and transmission electron microscopy (HRSEM, HRTEM) can provide very specific information about surface films on any kind of particles. A comparison between pristine particles and particles scraped from cycled electrodes can provide very comprehensive information. Using element analysis, STEM techniques, and selected area electron diffraction (SAED), it is possible to map surface species in a nanometric scale [30]. 

A multidetector approach is often applied in FFF since all detection systems have some advantages and limitations over some size ranges, sample types, and detection limits. For example, the most common detector, the UV-VIS, has limitations that it is selective for both absorption and turbidity but it is still widely used. Elemental analysis of FFF fractions with ICPMS has been successfully developed during recent years, but other mass spectrometric hyphenations are stiU very few. On-line light scattering has proven to be a very valuable system to determine molecular weight and RMS radius distributions (MALS) as well as diffusion coefficients and hydrodynamic radius (DLS). 

The copolymers of acrylamide with sodium-3-acrylamido-3-methylbutanoate (NaAMB), as well as the homopolymer of NaAMB, were prepared in aqueous solution at 30 C using 0.1 mole percent potassium persulfate as the initiator. The feed ratio of AM NaAMB was varied from 95 5 to 25 75, and the total monomer concentration was held constant at 0.456 M. Following reaction, the polymers were purified by precipitation in acetone, dialysis, and lyophilization. Conversions were determined gravimetricallv and compositions were determined using elemental analysis and NMR. ... 

Terpolymer compositions were determined using elemental analysis for carbon, nitrogen, and sulfur. 

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