Chemical Imaging of Latent Fingerprint Residues

TLDR

Understanding fingerprint aging requires new analytical approaches, and ATR‑FT‑IR spectroscopic imaging provides a complementary method for studying the chemistry of pristine prints. The study used in situ ATR‑FT‑IR spectroscopic imaging on ZnSe crystals under controlled humidity and temperature to map lipid and amino acid distributions in fingerprints over time, analyzing the data with univariate and multivariate techniques. The imaging revealed temperature‑ and time‑dependent changes in lipid spectra, demonstrating the potential of spectroscopic imaging to visualize chemical fingerprint changes for forensic use.

Abstract

In situ attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectroscopic imaging has been used to obtain chemical images of fingerprints under controlled humidity and temperature. The distribution of lipid and amino acid components in the fingerprints from different donors left on the surface of the ZnSe crystal has been studied using an in situ FT-IR spectroscopic imaging approach under a controlled environment and studied as a function of time. Univariate and multivariate analyses were employed to analyze the spectroscopic dataset. Changes in the spectra of lipids with temperature and time have been detected. This information is needed to understand aging of the fingerprints. The ATR-FT-IR spectroscopic imaging offers a new and complementary means for studying the chemistry of fingerprints that are left pristine for further analysis. This study demonstrates the potential for visualizing the chemical changes of fingerprints for forensic applications by spectroscopic imaging.