Fig. 1.
Sensitivity enhancement from Dynamic Nuclear Polarization (DNP). The DNP-enhancement spectra measured with microwave irradiation provide sensitivity enhancement of 23 and 18-fold for (a) Wiley-milled cotton and (b) ball-milled samples, respectively. The εon/off is the enhancement factor by comparing spectra recorded with microwave on and off. In contrast, the non-DNP spectra have very low intensities even with the same number of scans and measurement time. The representative positions for Iα and Iβ cellulose and their non-equivalent glucose units are labeled in magenta