Nuclear magnetic resonance, surface acidity

The photochemical and thermal stabilities of Ru complexes have been investigated in detail [8,153-156]. For example, it has been reported that the NCS ligand of the N3 dye, cri-Ru(II)(dcbpy)2(NCS)2 (dcbpy = 2,2 -bipyridyl-4,4 -dicarboxylic acid), is oxidized to produce a cyano group (—CN) under irradiation in methanol solution. It was measured by both ultraviolet-visible (UV-vis) absorption spectroscopy and nuclear magnetic resonance (NMR) [8,153]. In addition, the intensity of the infrared (IR) absorption peak attributed to the NCS ligand starts to decrease at 135°C, and decarboxylation of N3 dyes occurs at temperatures above 180°C [155]. Desorption of the dye from the 2 surface has been observed at temperatures above 200°C. 

SpA, Staphylococcal protein A PpL, protein L from Peptostreptococcus Magnus IgG, immunoglobulin G Gla, y-carboxyglutamic acid SPR, surface plasmon resonance ELISA, enzyme-linked immunosorbent assay FITC, fluorescein isothiocyanate NMR, nuclear magnetic resonance... 

Chemiluminescence is a very sensitive and selective technique. Reagent types, analytes, and detection limits have been summarized in a review by Imai.56 Chemiluminescence has been applied to the analysis of compounds that exhibit low UV absorbance, including metal ions, amino acids, fatty acids, and bile acids. Other detectors include detectors for radioactivity, nuclear magnetic resonance (NMR), and surface-enhanced Raman spectroscopy. Radioactivity detection is one of the most selective detectors, as only components that have been radiolabeled will be detected. The interface of NMR with HPLC and has been discussed in detail by Grenier-Loustalot et al.57 Surface-enhanced Raman spectroscopy is another technique that... 

Various physical techniques, i.e., nuclear magnetic resonance (NMR), x-ray diffraction, and chemical probes (exchange of H by D), indicate that there is a layer of water bound to protein molecules, phospholipid bilayers, and nucleic acids, as well as at the surface of the cell membranes and other organelles. 

When surface active agents are considered, a further complication may be encountered. Because of their surface active nature, the surfactants not only emich at the surfaces, but also form extended structures themselves. At low concentrations, the surfactants remain as dissolved monomers or asssociate to oligomers. However, when the critical micellization concentration (cmc) is surpassed, a cooperative association is activated to micelles (1 to 10 nm) consisting typically of some 50 to 100 monomers. At stiU higher concentrations, or in the presence of cosurfactants (alcohols, amines, fatty acids, etc.), liquid crystalline phases may separate. These phases have an infinite order on the x-ray scale, but may remain as powders on the NMR (nuclear magnetic resonance) scale. When the lamellar liquid crystalline phase is in equilibrium with the liquid micellar phase the conditions are optimal for emulsions to form. The interface of the emulsion droplets (1 to 100 pm) are stabilized by the lamellar liquid crystal. Both the micelles and the emulsions may be of the oil in water (o/w) or water in oil (w/o) type. Obviously, substances that otherwise are insoluble in the dispersion medium may be solubilized in the micelles or emulsified in the emulsions. For a more thorough analysis, the reader is directed to pertinent references in the literature. ... 

Investigations of the acidity of specific surface sites may be accomplished by studies coordinated with spectroscopic methods, such as infrared (JR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, or mass spectrometry (MS). Surface characterization with Fourier transform infrared (FTIR) spectroscopy can provide quantitative results with experimental methods that are easily performed. However, the transmission sampling techniques traditionally employed for infrared studies may introduce experimental artifacts on the analyzed surface (10,... 

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