Forensic Glass Classification according to ASTM E2926

Micro-XRF is the perfect pre-screening method. It does not require sample preparation, leaves the sample undamaged and it quickly reveals spatially resolved information on the elemental composition of the sample. These benefits make micro-XRF an ideal technique for forensic applications, and it is nowadays a well-established technique in this field.

For the Forensic Comparison of Glass, there is an ASTM test method for the use of micro-XRF (ASTM E2926-17). The comparison is based on measured element ratios, so it does not rely on a full quantification of the glass. The ASTM test method refers to the certified reference material NIST 1831 soda-lime glass. The polycapillary optic of the M4 TORNADO (PLUS) maintains a very high photon flux, even though the X-ray beam is focused onto a spot with < 20 µm diameter. With the high signal throughput capabilities of the SDD(s) up to 100000 counts per second can be used for the glass comparison of very small glass fragments. This advance in technology allows much better Signal-to-Noise Ratios and detection limits than stated in the ASTM E2926 document.