Laser Ablation-Vacuum Capture System Can Identify Trace Substances in Fingerprints

Using IR laser ablation coupled with vacuum capture, a system of fingermark sampling has been developed that could be used for traditional fingerprint analysis and also to capture, filter and analyze biomolecules and trace substances such as DNA or explosives.

Laser ablation at three micrometer (µm) was performed in reflection mode with subsequent capture of the ejecta with a filter connected to a vacuum. The laser heated up any moisture present within the surface area, lifting biomolecules such as DNA off the surface.

After the laser ablated, a small vacuum pump system was used to pull the moisture and all molecules associated with it into a thimble-sized filter. Researchers flushed the contents of the filter into an analysis device to determine the mass of any compounds or molecules in the sample.

The technique was successfully tested on diverse materials, including glass, plastic, aluminum and cardboard — a material whose porosity makes substances from fingermarks difficult to capture.

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Source: Photonics