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Critical aspects of Raman spectroscopy as a tool for postmortem interval estimation
Guillaume Falgayrac1, Raffaele Vitale2, Yann Delannoy3
1Univ. Lille, CHU Lille, Univ. Littoral Côte D'Opale, ULR 4490, MABLab- Adiposité Médullaire et Os, F-59000, Lille, France.
Talanta
|June 12, 2022
Summary
Estimating postmortem interval (PMI) from bones is hard. Advanced analysis of Raman spectroscopy data, like ASCA, can quantify factors affecting bone spectra, improving PMI estimation accuracy.
Area of Science:
- Forensic Science
- Chemometrics
- Biomineralization
Background:
- Estimating postmortem interval (PMI) from skeletal remains is crucial but challenging.
- Extrinsic (environmental) and intrinsic (biological) factors significantly influence skeletal remains.
- Raman spectroscopy offers potential for PMI estimation but requires advanced data analysis to account for influencing factors.
Purpose of the Study:
- To evaluate the impact of intrinsic and extrinsic factors on Raman spectra of skeletal remains.
- To quantify the variability introduced by factors like the source body and burial time.
- To assess the utility of advanced multivariate data analysis for improving PMI estimation.
Main Methods:
- Designed a protocol simulating real-world forensic scenarios.
- Utilized ANOVA-simultaneous component analysis (ASCA) to deconvolve spectral variability.
- Analyzed Raman spectra from skeletal remains subjected to varying intrinsic and extrinsic conditions.
Main Results:
- Burial time was a significant source of spectral variability, with contributions from seasonal variations and diagenesis.
- Observed changes in bone spectra included decreased mineral and increased organic bands over time.
- Source body (bone composition) also contributed significantly to spectral variability, a factor not easily quantified by basic methods like PCA.
Conclusions:
- Advanced chemometric methods, specifically ASCA, are necessary to accurately quantify the effects of intrinsic and extrinsic factors on Raman spectra.
- This approach enhances the precision and reproducibility of postmortem interval estimation using Raman spectroscopy.
- The study underscores the need for sophisticated data analysis to overcome limitations in forensic skeletal analysis.
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