Magnetic composites analysis

Both vapor-phase chromatography and high performance Hquid chromatography, along with nuclear magnetic resonance spectroscopy, have been used for isomer and composition analysis. 

Perhaps the most revolutionary development has been the application of on-line mass spectroscopic detection for compositional analysis. Polymer composition can be inferred from column retention time or from viscometric and other indirect detection methods, but mass spectroscopy has reduced much of the ambiguity associated with that process. Quantitation of end groups and of co-polymer composition can now be accomplished directly through mass spectroscopy. Mass spectroscopy is particularly well suited as an on-line GPC technique, since common GPC solvents interfere with other on-line detectors, including UV-VIS absorbance, nuclear magnetic resonance and infrared spectroscopic detectors. By contrast, common GPC solvents are readily adaptable to mass spectroscopic interfaces. No detection technique offers a combination of universality of analyte detection, specificity of information, and ease of use comparable to that of mass spectroscopy. 

Ohkoshi, M. and Kato, A. (1992). Distribution of substituents in acetylated wood as determined by nuclear magnetic resonance analysis. In Pacific Rim Bio-Based Composites Symposium Chemical Modification of Lignocellulosics, Plackett, D.V. and Dunningham, E.A. (Eds.). ERl Bulletin, 176, pp. 25-32. 

Laboratory analysis of flush water indicates that some non-magnetic iron oxide may also be retained by the EMF. The non-magnctic iron removal is believed to be due to the presence of magnetic/noii-magnetic composite particles, which are magnetically attracted by the filter. 

During the 1960s, high-resolution, double-focusing magnetic sector instruments became available from multiple manufacturers and were widely used in organic chemistry for exact mass measurements and elemental composition analysis. El was used for generating struc-... 

In addition to MS/MS with CID to obtain structural information, it is also useful to use high-resolution exact mass measurements to confirm the elemental compositions of ions. Essentially, exact mass measurements permit the unambiguous composition analysis of low-molecular-weight compounds (mol. wt. <500) through precise and accurate mlz measurements. The types of mass spectrometers capable of exact mass measurements include magnetic sector mass spectrometers, QTOF hybrid... 

Archaeologists have long sought methods for obsidian characterization that were rapid, reliable, non-destructive, and low-cost. Among the various methods investigated were visual techniques (79), density measurements (20), magnetic properties (27), thermoluminescence (22), fission-track analysis (25), Mossbauer spectroscopy (24), and natural radioactivity (25). Although some of the methods occasionally identified differences between sources, the overlap between sources was such that their overall reliability was unsatisfactory. The most successful method of characterization for obsidian provenance research has been compositional analysis (26). 

Tinsley, F. C., Taicher, G. Z. and Heiman, M. L. (2004) Evaluation of a quantitative magnetic resonance method for mouse whole body composition analysis. Obes Res 12, 150-160. 

J. E. Haw,T. E. Glass, and H. C. Dorn, Liquid chromatography/proton nuclear magnetic resonance spectrometry average composition analysis of fuels, Anal. Chem. 

Copolymer compositions were determined by a high resolution nuclear magnetic resonance spectrometer (180 HMz). Copolymers of methyl methacrylate and styrene were dissolved in deuterated chloroform for the analysis. Deuterated pyridine was the solvent for the methyl methacrylate - methacrylic acid copolymers. Elemental analysis was also used in copolymer composition analysis to complement the NMR data. 

Recurrent hepatitis was reported in a 5-year-old girl who had taken 3 tablets daily of shou wu pian, a product made from fo-ti tuber, for 4 months. Elevated serum levels of bilirubin and liver enzymes were observed, and viral markers were used to rule out a number of diseases. Symptoms disappeared and liver function tests were normal 1 month after cessation of the product. The girl experienced hepatitis again after being administered 2 tablets daily of the same product for 1 month (Panis et al. 2005). The product identity was confirmed by nuclear magnetic resonance analysis and showed 2,3,5,4 -tetrahydroxystilbene-2-O-P-D-glucopyranoside, a stilbene glycoside, to be the main constituent. The anthraquinone emodin was present in trace amounts (Panis et al. 2005). Such a chemical composition indicates that raw or incompletely processed fo-ti was used. 

M. C. Yappert, Compositional Analysis of Phospholipids by Mass Spectrometry and Phosphorus-31 Nuclear Magnetic Resonance Spectroscopy, in Methods in Pharmacology and Toxicology, ed. T. W.-M. Fan, R. M. Higashi and A. N. Lane, Handbook of Metabolomics, Springer, New York, N.Y.,... 

Taicher, G.Z., EC. Tinsley, A. Reiderman and M.L. Heiman, 2003. Quantitative magnetic resonance (QMR) method for bone and whole body composition analysis. Anal. Bioanal. Chem. 377, 990-1002. 

One of the principal applications of NMR spectroscopy is compositional analysis. The chemical shift reveals the nature of the nucleus, while integration of the area of each peak provides quantitative information about the relative content of each nucleus. Furthermore, it is possible to gain information about the local molecular environment because the magnetic fields of the neighboring nuclei will induce small changes in the chemical shift that can be detected by the NMR. 

Instmmental methods of analysis provide information about the specific composition and purity of the amines. QuaUtative information about the identity of the product (functional groups present) and quantitative analysis (amount of various components such as nitrile, amide, acid, and deterruination of unsaturation) can be obtained by infrared analysis. Gas chromatography (gc), with a Hquid phase of either Apiezon grease or Carbowax, and high performance Hquid chromatography (hplc), using siHca columns and solvent systems such as isooctane, methyl tert-huty ether, tetrahydrofuran, and methanol, are used for quantitative analysis of fatty amine mixtures. Nuclear magnetic resonance spectroscopy (nmr), both proton ( H) and carbon-13 ( C), which can be used for quaHtative and quantitative analysis, is an important method used to analyze fatty amines (8,81). 

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