Figure 2
From: Microfluidic Overhauser DNP chip for signal-enhanced compact NMR
(a) Comparison between a thermal (160 averages, 10× scaled) and the ODNP enhanced \({}^{1}{\mathrm{H}}\) spectrum (130 nL of 15 mM TEMPOL in DI water, \(P_{\mathrm {MW}}\approx50\) mW, 16 averages). (b) Measured \({}^{1}{\mathrm{H}}\) ODNP enhancements as a function of the applied MW input power. Three concentrations of TEMPOL in DI water are shown (sample volume always 130 nL). (c) ODNP build-up curve as a function of MW radiation time (see text for details). (d) Measured \({}^{1}{\mathrm{H}}\) ODNP enhancement profile. Shown are the NMR signal peak values plotted versus the available \(\Delta B\)-field range of the \(B_0\)-field sweep coil (centre \(B_0\)-field strength was 4940 G).
