Nano-scale composition of commercial white powders for development of latent fingerprints on adhesives

Abstract

Abstract.Titanium dioxide based powders are regularly used in the development of latent fingerprints on dark surfaces. For analysis of prints on adhesive tapes, the titanium dioxide can be suspended in a surfactant and used in the form of a powder suspension. Commercially available products, whilst having nominally similar composition, show varying levels of effectiveness of print development, with some powders adhering to the background as well as the print.X-ray fluorescence (XRF), analytical transmission electron microscopy (TEM), X ray photoelectron spectroscopy (XPS) and laser particle sizing of the fingerprint powders show TiO 2 particles with a surrounding coating, tens of nanometres thick, consisting of Al and Si rich material, with traces of sodium and sulphur. Such aluminosilicates are commonly used as anti-caking agents and to aid adhesion or functionality of some fingerprint powders; however, the morphology, thickness, coverage and composition of the aluminosilicates are the primary differences between the white powder formulations and could be related to variation in the efficacy of print development.

Effect of substrate surface topography on forensic development of latent fingerprints with iron oxide powder suspension

“…Forensic casework and research laboratory studies show that latent fingerprint development efficiency can be affected by characteristics of the deposition surfaces as well as the donors [1][2][3][4][5][6][7][8][9][10][11][12].…”

“…Powder suspensions, fine particles suspended in a surfactant, are increasingly used in development of latent fingerprints [1][2][3][4]. Powders may be based on titanium dioxide, aluminium, iron oxide or a range of carbon based materials, allowing choice of technique that is optimum for a particular sample.…”

“…Advances in nanotechnological techniques enable the use of new methodologies for making and augmenting crime scene identifications [13][14][15]. Research into nanostructured particles [4, 16,17] has helped develop techniques with improved latent fingerprint development, though efficacy remains surface dependent [4,17]. Development efficacy of powders and suspensions is related to lack of development agent adhering to deposited print as well as excess background staining; different powders and powder suspension formulations have been shown to have optimum efficacy depending on the surface on which the print is deposited [4,5,8,18].…”

“…Research into nanostructured particles [4, 16,17] has helped develop techniques with improved latent fingerprint development, though efficacy remains surface dependent [4,17]. Development efficacy of powders and suspensions is related to lack of development agent adhering to deposited print as well as excess background staining; different powders and powder suspension formulations have been shown to have optimum efficacy depending on the surface on which the print is deposited [4,5,8,18]. This demonstrates that an understanding of the substrate surface properties, beyond a broad classification, is important in forensic development of latent fingerprints.…”

Synthesis of Composite Particles with Fe3O4core and Ag Shell for the Development of Fingerprints

“…3 However, this type of technique is limited in many aspects, especially in health and safety, selectivity, sensitivity.…”