An alternative approach to the detection of latent fingermarks using [Eu2(BDC)3(H2O)2], a luminescent non-toxic MOF powder.

Abstract

Fingermarks are important forensic evidence for identifying people. In this work, luminescent MOF [Eu₂(BDC)₃(H₂O)₂] (herein referred as EuBDC) was tested as a potential latent fingermark (LF) luminescent developer powder and its acute toxicity evaluated following OECD protocol 423. The results showed that the powder can develop groomed LF on materials such as leather, plastic, metal, glass, cardboard, and aluminum. LFs aged up to 30 days, left on glass slides were developed and classified as level-3. The images presented high quality, enabling correct donor identification as well as through an Automated Fingerprint Identification System (AFIS) search. EuBDC also showed useful results as secondary technique for fixed cyanoacrylate LFs, especially on a reflective, multicolored and non-flat surfaces. Additionally, the EuBDC was tested on ungroomed fingermarks, developed on a split depletion series of successive deposits and compared to a commercially available luminescent powder. Development also occurred on ungroomed aged fingermarks; as a secondary technique for cyanoacrylate fuming; and on transparent adhesive tape when used as a suspension for the latter. Considering that development powders are frequently handled by Papilloscopists and that this may pose a health risk, the acute toxicity and of EuBDC and histopathological analysis were evaluated. The tests showed no signs of toxicity. Therefore, the EuBDC was classified in category 5 in the Globally Harmonized System classification, the least toxic category, with an LD₅₀ >5000 mg/Kg. The set of results shows that EuBDC powder has the potential use as a fingermark developer, as well as being suitable for applications for non-toxic material.