Synthesis of [Dy(DPA)(HDPA)] and its potential as gunshot residue marker

The 2D metal-organic framework (MOF) [Dy(DPA)(HDPA)] (where H2DPA=dipicolinic acid) was synthesized under hydrothermal conditions and exhibited a whitish yellow color (CIE coordinates: 0.362, 0.416) when excited at 365 nm. This color arises from the simultaneous blue (4F9/2-6H15/2), yellow (4F9/2-6H13/2) and red (4F9/2-6H11/2) transitions of Dy3+. This MOF exhibited a high potential for use as a luminescent marker for gunshot residue (GSR) and in the ammunition encoding process because it was possible to observe visually the luminescent gunshot residue (LGSR) on the shooter's hands, both on the firearm and at the firing range, using an UV lamp. These particles were easily collected and characterized by photoluminescence spectroscopy and SEM-EDS. The particles exhibited a typical morphology and a composition, making them easy to differentiate from particles of occupational or environmental origin.