We propose the unit molar polarization, which is a useful measure of the signal one might expect from a hyperpolarized sample in a fixed-volume detector. This is more comprehensive than reporting signal enhancement or polarization alone, which can in many hyperpolarization experiments be improved by using lower and lower substrate concentrations , without increasing the observable NMR signal. We report 50 mM molar polarization (assuming [1- C] isotopic enrichment of the starting material) from the control samples which used a 60 s hydrogenation reaction. For the purification step the hyperpolarized reaction samples were mixed with a 1 M sodium fumarate solution to raise the overall fumarate concentration, and speed up the rate of precipitation. This diluted the concentration of hyperpolarized fumarate molecules, and hence reduced the molar polarization to 16 mM. This was a convenient method for achieving fast precipitation in this initial demonstration, but is not expected to be necessary for future experiments. With higher parahydrogen pressures, fumarate can be formed in higher concentrations on a similar timescale, and at concentrations of ~200 mM or higher the precipitation is fast. Additional experimental steps such as performing the precipitation at lower temperature and optimizing the volume of acid added should aid in direct precipitation of hyperpolarized fumarate from the reaction solution.