Efficient and accurate determination of 13C T1 and T1? relaxation time constants of high-mobility polymers from limited-resolution spectra with optimized pulse sequences and data fitting
Publication date: December 2018
Source: Journal of Magnetic Resonance, Volume 297
Author(s): Kosuke Ohgo, Kristin K. Kumashiro
Abstract
The pulse sequences for the measurement of 13C
T1 and
T1? relaxation time constants in soft organic solids were modified to include steady-state nuclear Overhauser enhancement with direct polarization (ssNOE/DP). The increased signal intensities with ssNOE are particularly well-suited for highly mobile and structurally heterogeneous polymers and proteins like elastin. The phase cycling of these experiments was modified to yield datasets that require less time, with more accurate results. The “3D-fitting process” was developed and then optimized for natural-abundance 13C spectra of elastin, with its characteristic and significant overlap. A comparison of 3D-fitting with the similarly purposed SPORT (Geppi and Forte, 1999) illustrates that the former is more robust, with smaller uncertainty values and higher precision.
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