X-Ray Fluorescence Microspectroscopy
Micro x-ray fluorescence (micro-XRF) utilizes a rhodium x-ray tube in an evacuated sample chamber to excite the sample using a collimated (1 or 2 mm) or focused (via polycapillary to 30 micrometers) x-ray beam. The emitted x-rays are quantitatively or semi-quantitatively related to the concentration of elements in a sample. Micro-XRF provides detection limits on the order of a few ppm to a few hundred ppm, depending on the element and sample matrix. Comparison of glass samples by micro-XRF has been shown to be one of the most reliable approaches in forensic work and is supported by years of research by the NIJ FIU elemental analysis working group (EAWG) (of which Microtrace was a contributing member), which published the first ASTM test method for the analysis of glass by micro-XRF.
Related standardized methods: ASTM E2926