On the autofluorescence of fingermarks

Area of Science:

• Forensic Science
• Biochemistry
• Analytical Chemistry

Background:

• Fingermark detection often relies on autofluorescence, but the specific chemical components responsible are not well understood.
• Identifying these components is crucial for enhancing fingermark visualization techniques and understanding their forensic significance.

Purpose of the Study:

• To identify the specific autofluorescent compounds present in fingermarks.
• To evaluate the forensic potential and origin of these identified components.

Main Methods:

• Thin layer chromatography (TLC) was employed to separate and visualize fluorescent components.
• Fluorescence spectroscopy was utilized to characterize the emission properties of these components.

Main Results:

• Tryptophan, particularly when integrated into peptides or proteins, was identified as a major contributor to fingermark autofluorescence.
• A kynurenine derivative was also found to contribute to the observed fluorescence.
• Pheophorbide A, a chlorophyll derivative, was inferred as a source of red fluorescence, suggesting a link to plant-based dietary intake.

Conclusions:

• The study elucidates the chemical basis of fingermark autofluorescence, highlighting the roles of tryptophan and its derivatives.
• The presence of chlorophyll metabolites like Pheophorbide A suggests the potential for retrieving dietary information from fingermarks.
• These findings can inform the development of more sensitive and specific fingermark detection methods.