Forensic Float Glass Fragment Analysis Using Single-Pulse Laser Ablation Inductively Coupled Plasma Time of Flight Mass Spectrometry
Float glass fragments are common pieces of evidence produced in different crimes, including vandalism, burglaries, and traffic accidents. Forensic elemental analysis can test whether glass fragments found with the suspect match the broken glass found at the crime scene. The most discriminating method in forensic elemental analysis of glass is laser ablation with quadrupole or sector field based inductively coupled plasma mass spectrometry (LA-ICP-MS). Due to the sequential nature of these spectrometers, however, a certain minimum sample size is required which is determined by the laser spot size, number of laser pulses per replicate, and number of replicate measurements.
In this study, a single-pulse laser ablation inductively coupled plasma time-of-flight mass spectrometry (single-pulse LA-ICP-TOFMS) method, using the icpTOF, was developed for forensic float glass the analysis. 110 laser pulses with a spot size of 90 µm were applied to float glass fragments < 400 µm in diameter. A total of 18 elements were quantified in the signal from each individual laser pulse. The results highlight new capabilities when using quasi-simultaneous signal detection with TOFMS. Most importantly, the required sample material was reduced by more than 1 order of magnitude, which allows the measurement of significantly smaller fragments than previously possible.