X-Ray Fluorescence (XRF) exposes the material to an X-Radiation beam that causes temporary excitation and emitting of secondary X-Radiation at levels characteristic for each element in the sample. Measurement and analysis of the secondary radiation provides the composition of the material under test. XRF testing leaves no mark or alteration of the tested material, allowing for measurement non-coated finished goods if necessary. However, XRF technologies cannot distinguish between material grades that differ in elements that it cannot measure, such as Carbon, Silicon, and others.

Optical Emission Spectroscopy (OES) exposes the test sample to excitation through an electrical spark between the sample and an electrode, most often in an atmosphere of high purification Argon.  The spark energy results in emitted light in wavelengths and intensity characteristic to the elements in the test sample. OES analysis offers the most complete view of elements in a test sample. It is the only method that can distinguish between the levels of Carbon in a sample. For example, the difference between 316L and 316H. Although OES is considered a nondestructive test method, the surface must be prepared by sanding or grinding and the material will show a small burn mark following a test.