Nuclear surfactants

W. Gozdz, R. Holyst. Distribution functions for H nuclear magnetic resonance band shapes for polymerized surfactant molecules forming triply periodic surfaces. J Chem Phys 706 9305-9312, 1997. 

Nuclear magnetic resonance (NMR) spectrometry has seldom been used as a quantitative analytical method but can have some practical importance in the characterization of surfactants [296-298]. 13C-NMR spectrometry has been used for the qualitative and also quantitative analysis of dodecyl, tetradecyl, and cetyl sulfates [299]. H- and, 3C-NMR spectra of sodium dodecyl sulfate are given by Mazumdar [300]. 

The best approach to the simultaneous determination of ingredients of a phosphorus-containing surfactant is by nuclear magnetic resonance [306]. To 1 ml of the solution of the sample exactly 1.7 ml tetrahydrofuran and 0.3 ml deuteroacetone, >99 %D, are placed into a homogeneously strong magnetic field and excited by a high-frequency radiation typical of phosphorus. 

A recent review of the detergent literature indicated the following trends (1) improvement in dodecyl maltoside surfactants (73), (2) expansion of the use of Triton detergents in biochemistry (74), and (3) the use of detergents for solution nuclear magnetic resonance studies (75). 

L.C.M. Van Gorkom and A. Jensen, In J. Cross (Ed.), Molecular Spectroscopy II—Nuclear Magnetic Resonance Spectroscopy, Anionic Surfactants, Analytical Chemistry, Surfactant Science Series, Vol. 73, Marcel Dekker, New York, USA, 1998, p. 169. 

In the series of microbubble experiments (ref. 394) included in this chapter, the actual film material, contained in compressed microbubble-surfactant monolayers, was collected for structural determinations using H-nuclear magnetic resonance (NMR) spectroscopy. The resulting spectrum is then compared to the H-NMR spectrum which was obtained beforehand from the partially purified, microbubble surfactant mixture prior to monolayer formation and compression. 

During the early years at McGill University, Whitehead s group concentrated on experimental nuclear quadrupole resonance spectroscopy123 and a variety of n- and all-valence electron semiempirical molecular orbital methods.124 His recent interests have included topics as diverse as density functional theory125 and related topics,126 and molecular models of surfactants. 

Leenheer, J. A., Wershaw, R. L., Brown, P. A., and Noyes,T. I. (1991). Detection of poly (ethylene glycol) residues from nonionic surfactants in surface-water by XH and BC nuclear-magnetic-resonance spectrometry. Environ. Sci. Technol. 25,161-168. 

Ramesh GT, Manna SK, Aggarwal BB, Jadhav AL (1999) Lead activates nuclear transcription factor-kappaB, activator protein-1, and amino-terminal c-Jun kinase in pheochro-mocytoma cells. Toxicol Appl Pharmacol 155 280-286 Xu KP, Li XF, Yu FS (2000) Corneal organ culture model for assessing epithelial responses to surfactants. Toxicol Sci 58(2) 306-314... 

At room temperature, these molecules occupy well-defined locations in their respective crystal lattices. However, they tumble freely and isotropically (equally in all directions) in place at their lattice positions. As a result, their solid phase NMR spectra show features highly reminiscent of liquids. We will see an illustration of this point shortly. Other molecules may reorient anisotropically (as in solid benzene). Polymer segmental motions in the melt may cause rapid reorientation about the chain axis but only relatively slow reorientation of the chain axes themselves. Large molecular aggregates in solution (such as surfactant micelles or protein complexes or nucleic acids) may appear to have solidlike spectra if their tumbling rates are sufficiently slow. There are numerous other instances in which our macroscopic motions of solid and liquid may be at odds with the molecular dynamics. Nuclear magnetic resonance is one of the foremost ways of investigating these situations. 

Freeze-fracture TEM combined with nuclear magnetic resonance and quasielastic light scattering was used to study the microstructure of surfactant-water systems and dynamics of o/w and bicontinuous ME systems [41], The authors reported a rather abrupt transition from a discontinuous droplet (o/w) to bicontinuous (oil-and-water) microstructure occurring at low surfactant concentration, close to a three-phase region in the constructed phase diagram of pentaethylene glycol dodecyl ether, water, and octane [41],... 

The sites of -glucosylation in the oxygenated surfactant metabolites are not known (see Figure 1). More details may come from MS of the conjugates or from nuclear magnetic resonance spectra of the conjugates and their aglycones. 

AD. Park et al. [530] investigated the effects of surfactin, a surfactant from Bacillus subtilis, on oligomeric Ap-induced microglial activation and neurotoxicity. Surfactin suppressed expression of MMP-9, iNOS, and COX-2, as well as production of ROS, NO, PGE2, TNF-a, IL-ip, IL-6, and MCP-1 in Ap-stimulated BV-2 microglial cells. Surfactin also inhibited Ap-induced nuclear translocation and activation of NF-kB as well as phosphorylation of JNK and p38 MAPK, and protected hippocampal HT22 cells from indirect neuronal toxicity mediated by A(3-treated microglial cells. 

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