Fig. 15

Future directions in advanced natural abundance biomass analysis. a ¹H detection in solids achieved through ultrafast MAS, with resolution improving at higher spinning speeds. Panel adapted with permission of ref [188]. b ¹H{¹³C} CP-HETCOR spectra of spruce at varying spinning frequencies and fields show improved resolution with higher spinning rates and field strengths. Panel adapted with permission of ref [189]. c Chemical structures of symmetric and asymmetric biradicals employed in DNP polarizing agents. d DNP sensitivity enhancement through polarization transfer via biradicals. Panel adapted with permission of ref [47]. e DNP-enhanced 2D ¹³C–¹³C refocused-INADEQUATE of biomass and resistant starch at natural abundance. Panel adapted with permission of ref [116]