A method for preparing a sample of organic material for laser induced breakdown spectroscopy (LIBS) may include obtaining granular organic material, forming a portion of the granular organic material into a sample pellet, and searing the organic material. The searing may include searing only an exposed end surface of the sample pellet on which LIBS analysis is to be performed. The method may include pressing the seared sample pellet to consolidate the material comprising the seared end surface.

A method of quantitative X-ray analysis includes capturing X-ray fluorescence data from a pressed powder sample including a binder. A quantity and/or distribution of binder is assumed and the concentration of various components of the sample is calculated from the measured data and the assumed quantity of binder. Then, the concentration of binder is adjusted and the calculation step repeated until the method converges. The method is allowed to take widely different values of quantity of binder, which may be the concentration of the binder in the sample or alternatively the thickness of an assumed thin layer at the surface of a model used for calculation.