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. Author manuscript; available in PMC: 2018 Jun 6.
Published in final edited form as: Angew Chem Int Ed Engl. 2017 May 12;56(24):6744–6748. doi: 10.1002/anie.201700032

Figure 2.

Figure 2

(a) DNP enhancement as a function of the contact time and the sweep width on a sample of 40 mM trityl-OX063 in glycerol-d8/D2O/H2O (60/30/10 volume ratio) at 80 K and ~0.35 T with microwave irradiation being on resonant. The microwave Rabi frequency was set to match the NOVEL condition corresponding to ω1S / 2π = 15 MHz. At each sweep width, there exists an optimum contact time. The corresponding maximum enhancement is normalized and plotted in (b) suggesting that a sweep width of ~50 MHz is sufficient. Similar results were obtained for sulfonated-BDPA (SA-BDPA)29 (Fig. 4). The correlation between the sweep width and the optimum contact time in (c) indicates a faster optimum sweep rate for SA-BDPA (50 MHz/µs) compared to trityl-OX063 (32 MHz/µs) due to stronger coupling in SA-BDPA.