| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 72815 | Microporous and Mesoporous Materials | 2015 | 5 Pages |
•DNP-enhanced 1H and 13C fast field cycling NMR relaxometry is presented.•A full 13C NMRD profile was measured in 2 h with 60 μl of 13C-enriched sample.•The scalar hyperfine coupling and DNP coupling factor of 13C were studied.•1H DNP experiments on polybutadiene provide an outlook for future applications.
Fast-field-cycling (FFC) NMR relaxometry experiments enhanced by in-situ Dynamic Nuclear Polarization (DNP) were performed for 1H and 13C nuclear spins with a setup based on a commercial electronically switching FFC relaxometer and a recently-built Alderman–Grant type microwave resonator for 2 GHz. DNP-enhanced 1H relaxation dispersion profiles were compared to reference measurements and literature data in order to prove the reliability of DNP-enhanced relaxometry data. The method was then used to investigate the paramagnetic nuclear spin relaxation of 13C in a benzene-13C6,D6 solution of nitroxide radicals. Dispersion profiles of good quality were obtained within 2 h of measurement time from a comparatively small sample of 60 μl. As a prospect for future applications, DNP experiments with a high-molecular weight Poly(butadiene-1,4) melt and BDPA radical were carried out at 2 GHz and 9.7 GHz microwave frequency, showing solid effect DNP enhancements. In-situ hyperpolarization by DNP may provide extended possibilities for FFC relaxometry, e.g. by allowing enhanced detection of dilute or insensitive nuclear spins, additional selectivity or faster measurements of small samples.
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