To optimise the parameters of the two OPE sequences, experiments were performed on a sample of malate-D2 in D2O at thermal equilibrium (i.e. not generated from parahydrogen). A preparation rf pulse sequence known as the Sarkar sequence was applied to convert the thermal equilibrium 𝐼 1z + 𝐼 2z spin order into 𝐼 1z 𝐼 2z spin order between the protons, to mimic the initial density operator in an experiment using parahydrogen. Immediately after, an OPE sequence was applied. This experiment was repeated many times, with the delay in the OPE varied to find the optimum value. The pulse sequences and results for both the OPE-45 and OPE-s90 are shown in Fig. .