High pressure capillary NMR probe, with stripline chip detection and hyphenation with supercritical solvent manager for automated sample loading and radical addition.

In situ diffusion measurements using B1 gradients.

Relaxation measurements as function of solvent mixture and radical concentration with analysis of relaxivity at 600 MHz, using Overhauser hard sphere model, indicating a fixed TEMPO–toluene contact distance of about 2.4 Å (similar to that found for water–TEMPOL) and in quantitative agreement with in situ diffusion measurements.

Short translational correlation times (2–4 ps) confirm potential applications at high magnetic field.

Extension of DNP enhancements towards high pressure/temperature for water at 3.4 T, showing unprecedented enhancements at this field. Preliminary qualitative enhancement measurements for CO₂/toluene confirm high enhancement levels, but additional measurements are needed to fully quantify this.