Figure (f) shows the dependence of the signal integral on the transfer magnetic field (B), measured in situ with the "SHEATH-sudden-ZF" sequence. This field profile is expected for the SABRE-SHEATH process and it illustrates the efficiency of pumping Ŝz as a function of magnetic field applied during pH 2 bubbling, Fig. ). Optimal polarization transfer is achieved at approx. ±0.45 µT. This method of measuring the SABRE-SHEATH field dependence does not require sample shuttling and it is therefore ensures a cleaner way of studying nuclear spin dynamics in the system compared to approaches that require sample transfer.