Paramagnetic resonance spectrometry

A. Wennmalm, B. Lanne, and A.S. Petersson, Detection of endothelial-derived relaxing factor in human plasma in die basal state and following ischemia using electron-paramagnetic resonance spectrometry. Anal. Biochem. 187, 359-363 (1990). 

Various other techniques have been used to determine molybdenum, including adsorption voltammetry [510], electron-paramagnetic resonance spectrometry [512], and neutron activation analysis [513,514]. EPR spectrometry is carried out on the isoamyl alcohol soluble Mo(SCN)s complex and is capable of detecting 0.46 mg/1 molybdenum in seawater. Neutron activation is carried out on the /J-naphlhoin oxime [514] complex and the pyrrolidone dithiocar-bamate and diethyldithiocarbamate complex [513]. The neutron activation analysis method [514] was capable of determining down to 0.32 xg/l of molybdenum in seawater. 

Parman T, Chen G, Wells PG. Free radical intermediates of phenytoin and related teratogens. Prostaglandin H synthase-catalyzed bioactivation, electron paramagnetic resonance spectrometry, and photochemical product analysis. J Biol Chem 1998 273(39) 25079-25088. 

Ohnishi T, Lloyd D, Lindmark DC, Muller M. 1980. Respiration of Tritrichomonas foetus components detected by hydrogenosomes and in intact cells by electron paramagnetic resonance spectrometry. Mol Biochem Parasitol 2 39-50. 

In 1960 Rex (22) first reported the use of electron paramagnetic resonance spectrometry as a method for demonstrating the presence of stable organic free radicals in humic acid. We felt that this technique might provide useful information about the structure of humic acid which was not readily available by other physical methods, particularly if relations between EPR spectra and chemically modified humic acids could be demonstrated. Our preliminary studies (26) confirmed this presumption. 

Electron Paramagnetic Resonance studies Analysis by electron paramagnetic resonance spectrometry (EPR) showed the electrophoresis fraction to contain stable free radicals. A strong EPR signal was obtained at the g factor value of 2.0035-0.0003. The involvement of free radicals in the Maillard reaction has previously been reported (16). Recently also Lessig and Baltes (17) reported the content of extremely stable free radicals in melanoids obtained from the reaction between glucose and 4-chloroaniline. 

Kucherov and Slinkin reported solid-state reactions of H-mordenite and HZSM-5 zeolites with metallic oxides such as CuO (13), Cr2O-, Mo03, and V205 (14-17). The resulting samples were studied by EPR (electron paramagnetic resonance) spectrometry. The authors have shown that the metal cations migrate to cationic sites, where they are coordinately unsaturated. 

SANS, small-angle nuclear scattering EPR, electron paramagnetic resonance spectrometry NMR, nuclear magnetic resonance spectrometry FTIR, Fourier-transform infrared spectrometry SAXS, small-angle X-ray scattering. 

Phenytoin and related xenobiotics can be bioactivated by embryonic prostaglandin H synthase to a teratogenic free radical intermediate. Parman et al. (1998) evaluated the mechanism of free radical formation using photolytic oxidation with sodium persulphate and by electron paramagnetic resonance spectrometry. Incubation of 2 -deoxyguano-sine with phenytoin and prostaglandin H synthase-1 resulted in a 5-fold increase in the oxidation to 8-hydroxy-2 -deoxyguanosine. 

It should be possible to estimate values of Kby determining the concentrations of the radical intermediates in RAFT polymerization by EPR (electron paramagnetic resonance) spectrometry and some effort has been directed to this end. °- Coote and coworkers - have devised methods for calculating absolute values of K by applying ab initio methods. Values of K have also been estimated on the basis of simulation of the polymerization kinetics. Values of K estimated on the basis of the measured concentrations of the radical intermediates are suhstantially lower than those predicted by theoretical calculations. 

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