Latent fingerprints analysis using tape-lift, Raman microscopy, and multivariate data analysis methods

Area of Science:

• Forensic Science
• Analytical Chemistry
• Spectroscopy

Background:

• Latent fingerprints are crucial in forensic investigations.
• Analyzing trace materials within fingerprints presents significant challenges.
• Existing methods often struggle with complex mixtures and low analyte concentrations.

Purpose of the Study:

• To develop and validate a combined technique for chemical analysis of latent fingerprints.
• To extract and identify trace materials deposited on fingerprints.
• To determine the spatial distribution of identified components within fingerprints.

Main Methods:

• Utilized tape-lifting to collect trace particles and deposited materials.
• Employed Raman spectral mapping for localized chemical analysis.
• Applied band-target entropy minimization (BTEM) for spectral deconvolution of mixtures.

Main Results:

• Successfully recovered pure component spectra from complex mixtures of lifting media and lifted materials.
• Accurately identified various test substances including sebum, drug models, and food additives.
• Determined the spatial distribution of identified chemical components with high fidelity.

Conclusions:

• The combined Raman spectral mapping, tape-lifting, and BTEM technique offers a powerful new tool for forensic analysis.
• This method enables precise identification and spatial mapping of chemical evidence in fingerprints.
• The approach shows significant promise for enhancing the capabilities of forensic investigations.