Fingerprints, or the impressions left by the unique patterns of ridges on an individual’s fingers, are a fundamental tool in forensic science for identification purposes. These patterns, consisting of loops, whorls, and arches, form during the embryonic development stage and are influenced by genetic and environmental factors, making each fingerprint unique. The use of fingerprints for the identification of criminals was first proposed in 1880 by Dr. Henry Faulds, and the United States adopted a fingerprint system in 1903. Despite the widespread acceptance of fingerprint analysis, the process remains lengthy and subjective, as experts rely on their judgment to match prints without firm guidelines or numerical thresholds for identification. Efforts to introduce objectivity, such as Bruce Comber’s mathematical test and the Automated Fingerprint Identification System (AFIS), have made improvements but still require human verification and struggle with partial or blurred prints. The limitations of current fingerprint analysis have sparked interest in developing techniques that analyze the chemical compounds in fingerprints to reveal physical traits and lifestyle habits of individuals, offering a new direction for forensic research.
Mass Spectrometry
Mass spectrometry, particularly methods such as GC-MS (Gas Chromatography-Mass Spectrometry), LC-MS (Liquid Chromatography-Mass Spectrometry), MeV-SIMS (Mega Electron Volt Secondary Ion Mass Spectrometry), DESI (Desorption Electrospray Ionization), MALDI (Matrix-Assisted Laser Desorption/Ionization), SALDI (Surface-Assisted Laser Desorption/Ionization), and DART-MS (Direct Analysis in Real Time Mass Spectrometry), is used to identify the chemical components of fingerprints. GC-MS, for example, is widely used for this purpose and even features dedicated laboratory experiments for fingerprint analysis, demonstrating its popularity and effectiveness.
Optical Spectroscopy
Optical spectroscopy, including techniques like FTIR (Fourier Transform Infrared Spectroscopy) with and without ATR (Attenuated Total Reflectance) mode, offers non-destructive ways to analyze fingerprints by allowing chemical analysis along with pictorial comparison. The choice of spectroscopic method depends on the characteristics of the surface where the fingerprint is found, making it versatile for various forensic applications.
Nanotechnology
Research in nanotechnology has led to the development of methods to enhance the visualization of latent fingerprints, often difficult to detect at crime scenes. This includes the study of nanoparticles, such as gold nanoparticles, that interact with substances like cellulose found in paper, to improve the consistency and reliability of latent fingerprint detection.
Combinatorial Methods for the Analysis of Authentic Fingerprints
Combinatorial approaches integrate various analytical techniques, including the non-destructive methods DESI, MALDI, SALDI, and DART-MS in mass spectrometry, to facilitate both imaging and chemical detection of fingerprints. These methods are particularly valuable as they can be applied outside of laboratories and offer practical solutions for the analysis of authentic fingerprints in forensic investigations.
Huynh, C., & Halámek, J. (2016). Trends in fingerprint analysis. Trends in Analytical Chemistry: TRAC, 82, 328–336. https://doi.org/10.1016/j.trac.2016.06.003
