In an embodiment a method is described which includes emplacing a sample within a measurement cell, wherein two or more electrodes are configured in the measurement cell; introducing a reactive fluid into the measurement cell; reacting the sample with the reactive fluid, wherein reacting the sample with the reactive fluid results in a change in an ion concentration in the reactive fluid; and measuring the resistivity of the reactive fluid using the two or more electrodes, wherein the resistivity is proportional to the ion concentration in the reactive fluid.