Fig. 11

Introducing dynamics-based ssNMR measurements at natural abundance. a Example of detecting molecular regimes based on dynamics: DP detects mobile molecules using a short recycle delay to capture signals from flexible regions, while T₁-filtered CP selectively enhances signals from rigid molecules, enabling differentiation between mobile and rigid molecular domains. The small panel illustrates the relationship between NMR relaxation times and molecular correlation times, highlighting how variations in relaxation behavior correspond to different dynamic regimes of the sample. Experiments were conducted on a 600-MHz spectrometer with a 4-mm HXY Phoenix probe, under 13.5-kHz MAS at 290 K, at NREL. b Representative ssNMR pulse sequences: ¹³C-detected ¹H T_1ρ and ¹³C-detected ¹H T₁ inversion recovery. Asterisk indicates that ¹³C-detected ¹H T_1ρ can be measured site-specifically. c Proton spin relaxation editing enhances resolution and improves baseline clarity. The graph indicates the enzymatic sugar yields versus X_NMR for all never-dried entries with various water/organic-cosolvent mixtures. Panel adapted with permission of ref [124]