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HIGH SENSITIVITY FOURIER TRANSFORM NMR. INTERMOLECULAR INTERACTIONS BETWEEN ENVIRONMENTAL TOXIC SUBSTANCES AND BIOLOGICAL MACROMOLECULES
Citation:
Levy, G. HIGH SENSITIVITY FOURIER TRANSFORM NMR. INTERMOLECULAR INTERACTIONS BETWEEN ENVIRONMENTAL TOXIC SUBSTANCES AND BIOLOGICAL MACROMOLECULES. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/1-77/045 (NTIS PB274011), 1977.
Description:
This project explored the feasibility of developing new techniques for evaluation of the effects of environmental toxic materials on complex biopolymer systems using high sensitivity Fourier transform nuclear magnetic resonance (nmr) spectroscopy. Commercial instrumentation available in 1974-75 did not possess adequate sensitivity, and thus one goal of this project was to increase spectral sensitivity, especially for the 13C and other nuclides having low magnetogyric ratios. Initially, modifications to an existing Bruker HX-270 spectrometer provided moderate improvement in sensitivity for 13C and substantial sensitivity increase for 15N observation. During the second (last) year of this grant, a new instrument design was initiated. Several studies were begun to elucidate the nature of chlorophenol interactions in liquids, and when incorporated into lecithin bilayer membrane models. Variable frequency 13C spin lattice relaxation time measurements were used to probe cooperativity of molecular chain dynamics in some simple molecules and in two complex synthetic polymers. A new theoretical modification involving a non-exponential autocorrelation function and also allowing for multiple independent internal rotations, allowed effective analysis of a large experimental set.