The DSS Chemistry Unit analyzes evidence in fire debris, gunshot residue (GSR), and explosives cases. The most common requests to the Chemistry unit are for:
- Ignitable liquid
- Elemental exams in GSR kits
Each case can use a mix of classical wet-bench chemical techniques and instrumental analyses.
Another task of the Chemistry Unit is to test for gunshot residue (GSR). Evidence is usually submitted as GSR kits. It includes swabbings taken by law enforcement. Clothing can also be submitted to see if a person was near a recently fired gun. The unit uses an instrument called a scanning electron microscopy with EDX to examine evidence. It uses energy-dispersive X-ray spectroscopy (SEM-EDX).
The Chemistry Unit also analyzes suspected arson and other cases where ignitable materials were used. The unit uses the headspace analysis technique. It removes volatile chemicals from evidence. Then, we analyze those chemicals with gas chromatography/mass spectrometry (GC/MS). This helps us identify the materials that may have been used to start or fuel fires. The unit also prepares ignitable liquid samples for the Canine Training Unit. Fire Debris Suspected arson and other cases involving ignitable materials are analyzed within the Chemistry Unit. A technique called headspace analysis is utilized to remove volatile chemicals from evidence. Such chemicals are trapped and subsequently analyzed by gas chromatography/mass spectrometry (GC/MS) in order to identify chemicals/material which may have been used to either start or accelerate fires. The Chemistry Unit assisted with ignitable liquid sample preparation for the Department’s Canine Training Unit.