Assessing phosphomolybdic acid as a fingermark enhancement reagent

© 2018 International Association for Identification. All rights reserved. The efficacy of an ethanolic solution of phosphomolybdic acid (PMA) was investigated as a latent fingermark visualization reagent, primarily on porous substrates. After treating samples and exposing them to ultraviolet radiation, the PMA solution was shown to develop fingermarks of high quality. Unlike the common amino acid reagents that are used for the development of fingermarks on porous substrates (e.g., ninhydrin and 1,8 diazafluoren-9-one), PMA stains a range of other compounds that are found in fingermark deposits, including lipids. The lysochrome diazo dye Oil Red O (ORO) was used for comparative purposes because of its application in staining some of the same components of fingermark residues for which PMA would be proposed. Initial results indicate that PMA is comparable to ORO at developing fingermarks on porous surfaces and may also have applications on nonporous surfaces

Introduction: Fingerprint Development Techniques: Theory and Application

© 2018 John Wiley & Sons Ltd. All rights reserved. A comprehensive review of the latest fingerprint development and imaging techniques. With contributions from leading experts in the field, Fingerprint Development Techniques offers a comprehensive review of the key techniques used in the development and imaging of fingerprints. It includes a review of the properties of fingerprints, the surfaces that fingerprints are deposited on, and the interactions that can occur between fingerprints, surfaces and environments. Comprehensive in scope, the text explores the history of each process, the theory behind the way fingerprints are either developed or imaged, and information about the role of each of the chemical constituents in recommended formulations. The authors explain the methodology employed for carrying out comparisons of effectiveness of various development techniques that clearly demonstrate how to select the most effective approaches. The text also explores how techniques can be used in sequence and with techniques for recovering other forms of forensic evidence. In addition, the book offers a guide for the selection of fingerprint development techniques and includes information on the influence of surface contamination and exposure conditions. This important resource: Provides clear methodologies for conducting comparisons of fingerprint development technique effectiveness; Contains in-depth assessment of fingerprint constituents and how they are utilized by development and imaging processes; Includes background information on fingerprint chemistry; Offers a comprehensive history, the theory, and the applications for a broader range of processes, including the roles of each constituent in reagent formulations. Fingerprint Development Techniques offers a comprehensive guide to fingerprint development and imaging, building on much of the previously unpublished research of the Home Office Centre for Applied Science and Technology

Chemical changes exhibited by latent fingerprints after exposure to vacuum conditions

The effect of vacuum exposure on latent fingerprint chemistry has been evaluated. Fingerprints were analysed using a quartz crystal microbalance to measure changes in mass, gas chromatography mass spectrometry to measure changes in lipid composition and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) to determine changes in the content of water, fatty acids and their esters after exposure to vacuum. The results are compared with samples aged under ambient conditions. It was found that fingerprints lose around 26% of their mass when exposed to vacuum conditions, equivalent to around 5 weeks ageing under ambient conditions. Further exposure to vacuum causes a significant reduction in the lipid composition of a fingerprint, in particular with the loss of tetradecanoic and pentadecanoic acid, that was not observed in ambient aged samples. There are therefore implications for sequence in which fingerprint development procedures (for example vacuum metal deposition) are carried out, as well as the use of vacuum based methods such as secondary ion mass spectrometry (SIMS) and matrix-assisted laser desorption ionisation (MALDI) in the study of fingerprint chemistry. © 2013

Chemical changes exhibited by latent fingerprints after exposure to vacuum conditions

The effect of vacuum exposure on latent fingerprint chemistry has been evaluated. Fingerprints were analysed using a quartz crystal microbalance to measure changes in mass, gas chromatography mass spectrometry to measure changes in lipid composition and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) to determine changes in the content of water, fatty acids and their esters after exposure to vacuum. The results are compared with samples aged under ambient conditions. It was found that fingerprints lose around 26% of their mass when exposed to vacuum conditions, equivalent to around 5 weeks ageing under ambient conditions. Further exposure to vacuum causes a significant reduction in the lipid composition of a fingerprint, in particular with the loss of tetradecanoic and pentadecanoic acid, that was not observed in ambient aged samples. There are therefore implications for sequence in which fingerprint development procedures (for example vacuum metal deposition) are carried out, as well as the use of vacuum based methods such as secondary ion mass spectrometry (SIMS) and matrix-assisted laser desorption ionisation (MALDI) in the study of fingerprint chemistry. © 2013