Fingerprints

Tool Pinpoints When Fingerprints Were Left (+Video)

American Chemical Society | August 13, 2015

The investigators on TV's popular CSI: Crime Scene Investigation series seem able to solve any mystery thanks to a little science and a lot of artistic license. But, now there is a real-life technique that could outperform even fictional sleuths' crime-busting tools. Scientists report in ACS' journal Analytical Chemistry a way to tell how old fingerprints are. This could help investigators determine which sets are relevant and which ones were left long ago.

<more at http://www.laboratoryequipment.com/videos/2015/08/tool-pinpoints-when-fingerprints-were-left; related link: http://www.acs.org/content/acs/en/pressroom/presspacs/2015/acs-presspac-august-12-2015/a-new-csi-tool-could-pinpoint-when-fingerprints-were-left-behind-video.html (A new CSI tool could pinpoint when fingerprints were left behind (video) "Strategies for Potential Age Dating of Fingerprints through the Diffusion of Sebum Molecules on a Nonporous Surface Analyzed using Time-of-Flight Secondary Ion Mass Spectrometry". August 12, 2015) and http://pubs.acs.org/doi/abs/10.1021/acs.analchem.5b02018 (Strategies for Potential Age Dating of Fingerprints through the Diffusion of Sebum Molecules on a Nonporous Surface Analyzed Using Time-of-Flight Secondary Ion Mass Spectrometry. Anal. Chem., 2015, 87 (16), pp 8035–8038 DOI: 10.1021/acs.analchem.5b02018 Publication Date (Web): July 17, 2015. [Abstract: Age dating of fingerprints could have a significant impact in forensic science, as it has the potential to facilitate the judicial process by assessing the relevance of a fingerprint found at a crime scene. However, no method currently exists that can reliably predict the age of a latent fingerprint. In this manuscript, time-of-flight secondary ion imaging mass spectrometry (TOF-SIMS) was used to measure the diffusivity of saturated fatty acid molecules from a fingerprint on a silicon wafer. It was found that their diffusion from relatively fresh fingerprints (t ≤ 96 h) could be modeled using an error function, with diffusivities (mm2/h) that followed a power function when plotted against molecular weight. The equation x = 0.02t0.5 was obtained for palmitic acid that could be used to find its position in millimeters (where the concentration is 50% of its initial value or c0/2) as a function of time in hours. The results show that on a clean silicon substrate, the age of a fingerprint (t ≤ 96 h) could reliably be obtained through the extent of diffusion of palmitic acid.])>