Similar observations are made for the pH-dependent T 1 values at 16.5 T and 2 T with an overall decrease in T 1 as the magnetic field strength increases. This is consistent with a dominant CSA relaxation mechanism, proportional to the square of the magnetic field strength. O:D2 O squarate at pH = 14.0 (black line). The spectrum was acquired at 16.5 T using the pulse sequence protocol shown in figure with no evolution delay. The blue line shows the spectrum after application of a single π 2 pulse. Both spectra are referenced to a carrier frequency of 203.05 ppm.