First, we examined trimethyl phosphate solutions prepared with a procedure that involves a different number of freezepump-thaw cycles. As trimethyl phosphate consists of nine equivalent protons coupled to phosphorus (with coupling constant J HP =11 Hz), its zero-field spectrum consists of peaks at J HP , 2J HP , 3J HP , 4J HP , and 5J HP (see detailed discussion of trimethyl phosphate spectrum at zero field in Ref. ). Here, due to the relatively low amplitude of the peaks at 11 and 55 Hz, we only analyzed the peaks at 22, 33, and 44 Hz. As demonstrated in Fig. , a substantial increase in the amplitude of the peaks and a decrease in their linewidth were observed up to two freeze-pump-thaw cycles. Although cycling initially helps to reduce the peak linewidth, the results also show that no significant differences in the signal parameters were observed by increasing the number of cycles above two (Fig. ). Changes in peak linewidths and therefore molecule relaxation time T 2 are associated with the reduction of paramagnetic oxygen in the sample. Most likely, after two cycles, an oxygen level in the solution is small (potentially negligible) in terms of its contribution to relaxation. Therefore, no improvement in the signal was achieved after the second cycle. Alternatively, even though the vacuum pump can reduce pressure over the frozen liquid to about 10 -6 mbar, it might be insufficient to remove remaining dissolved oxygen any further after two cycles.