Technology - Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) Spectroscopy for Gunshot Residue Analysis

Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) Spectroscopy for Gunshot Residue Analysis

Gunshot residue (GSR) particles are the chemical remains of ammunition expelled from a firearm discharge. GSR can assist investigators in shooting incident reconstruction. Recovery, detection, and preservation of these discharge samples are often challenging. At present, scanning electron microscopy combined with energy dispersive X-ray spectroscopy (SEM/EDS) is the most widely accepted technique for GSR detection. Unfortunately, the collection of debris and fibers from certain surfaces can inhibit SEM analysis. In addition, this method requires expensive instrumentation and time-consuming analysis (several hours or more).

Technology Overview:

This technology, developed by University at Albany researchers, is based on microscopic-attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopic imaging. This technology rapidly and automatically scans large areas of the tape collection substrate and detects varying morphologies of GSR (microscopic, macroscopic, organic and inorganic). The “spectroscopic fingerprint” of each GSR type provides unique vibrational modes. IR images (maps) target the detection of these unique chemical markers over the mapped area. The hues of the IR images are determined by the intensity of the signal for the chemical marker of each analyte. The spatial resolution of the technique is 4.7 mm.

Advantages:

Nondestructive, with analysis times competitive to current methodologies. Provides a molecular “fingerprint” of the detected GSR. Targets a wider range of chemicals compared to current methodologies, increasing the selectivity of the method. Enhanced spatial resolution.