Elemental Analysis by Optical Spectrometry

Very often, techniques for direct solid analysis are classified into two groups according to whether they provide bulk information (of interest for homogeneous samples) or analytical information with lateral and/or depth resolution. 

As for XRF, gas atoms are not formed during EPXMA. In EPXMA, an electron probe is used to excite and eject electrons from the solid, yielding excited ions which relax and emit X-radiation. Electron guns can be focused easily on small areas of the solid surface, although exciting electrons cannot go too deep into the solid. Hence this technique obtains analytical information with some spatial resolution. The technique is prone to serious matrix interferences, like XRF. 

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