Towards Onsite Age Estimation of Semen Stains Using Fluorescence Spectroscopy

Area of Science:

• Forensic Science
• Analytical Chemistry
• Biophysics

Background:

• Accurate age estimation of biological traces is crucial in forensic investigations.
• Current methods often rely on large, non-portable equipment, limiting in-situ analysis.
• Developing non-destructive, portable methods for biological stain aging is a significant forensic challenge.

Purpose of the Study:

• To develop and validate a portable fluorescence spectroscopy method for semen stain age estimation.
• To compare the accuracy of a portable fluorimeter with a traditional benchtop instrument.
• To assess the feasibility of in-situ forensic age determination of biological evidence.

Main Methods:

• Development of a portable fiber-based fluorimeter utilizing LEDs and spectrometers.
• Application of a stoichiometric aging model based on protein and fluorescent oxidation product (FOX) degradation/generation.
• Measurement of semen stain aging kinetics using both portable and benchtop fluorimeters.
• Non-destructive, in-situ measurement capability of the portable device.

Main Results:

• The portable fluorimeter achieved successful age estimation of semen stains up to 11 days.
• Mean absolute errors were 1.0 days for the portable and 0.9 days for the benchtop fluorimeter.
• The portable device demonstrated comparable accuracy to the benchtop instrument for age estimation.

Conclusions:

• The developed portable fluorimeter is a viable tool for in-situ age estimation of semen stains.
• This technology offers a non-destructive and efficient alternative for forensic analysis at crime scenes.
• The portable device shows significant potential to enhance forensic investigation capabilities.