where ε is the signal enhancement obtained by comparing the signal integrals of the hyperpolarized sample with that of the highly concentrated sample prepolarized at 2 T. Compared to prepolarization at 2 T, the sodium formate signal enhancement translates into a spin polarization enhancement of ε = 5000. Indeed, the peak shows a signal enhancement ε = 44 with a concentration of formate in the dissolved sample of HP1 determined to be 45 mM by high-field NMR, while the reference sample was at a higher concentration of 5.2 M.