This implies that, for it to be truly analytically rigourous, the same sample prep must be applied to the actual sample. Obviously preparing in house standards with unprepared limestone is not possible due to porousity and mineralogy, implying that standards must be made of pulverised representative samples of the source rock. This, in turn, implies that all samples should be pulverised too. As we are taking invasive cores, it is unlikely we will have enough material to pulverise and sample for representative results but, on top of that, they will never be able to be reanalysed, which is surely another scientific concern