Two-Dimensional Correlation Spectroscopy Analysis of Bloodstain Aging Using Fluorescence Spectral Data

Area of Science:

• Biochemistry
• Forensic Science
• Spectroscopy

Background:

• Accurate estimation of time since deposition (TSD) for bloodstains is crucial in forensic investigations.
• Fluorescence spectroscopy effectively tracks endogenous fluorophores (tryptophan, NADH, flavins) but faces challenges like spectral overlap and sample variability.
• Understanding bloodstain biochemical aging is key to developing reliable forensic methods.

Purpose of the Study:

• To investigate time-dependent fluorescence changes in bloodstains using advanced spectroscopic techniques.
• To gain molecular-level insights into the biochemical mechanisms of bloodstain aging.
• To establish a foundation for more accurate and robust forensic TSD estimation.

Main Methods:

• Utilized two-dimensional correlation spectroscopy (2D-COS) to analyze fluorescence spectral data.
• Employed 2D gradient mapping to visualize and quantify time-dependent spectral trends.
• Monitored bloodstain aging over a 24-hour period.

Main Results:

• 2D-COS identified hidden spectral components and sequential molecular changes, particularly in NADH and flavin bands.
• 2D gradient maps provided quantitative visualization of spectral changes during bloodstain aging.
• Demonstrated sequential biochemical alterations in bloodstains over 24 hours.

Conclusions:

• Advanced fluorescence techniques like 2D-COS offer deeper insights into bloodstain aging mechanisms.
• The study provides a fundamental understanding of ex vivo blood degradation.
• Findings support the development of improved forensic tools for TSD estimation.