Visible and near-infrared chemical imaging methods for the analysis of selected forensic samples

This study investigated various chemical imaging methods for the forensic analysis of paints, tapes and adhesives, inks and firearm propellants (absorption and photoluminescence in the UV–vis–NIR regions). Results obtained using chemical imaging technology were compared with those obtained using traditional techniques. The results show that chemical imaging offers significant advantages in the forensic context, for example the ability to display visual and spectral results side by side and to reduce sample preparation, hence minimizing the risk of contamination. Chemical imaging produced a greater discriminating power than traditional techniques for most evidence types. Chemical imaging also eliminated different brands of ammunition based on the fluorescence characteristics of the propellant grains preserving the evidence for further analysis. It is expected that this technology will find broader forensic applications in the future.