Estimation of the post-mortem interval in human bones by infrared spectroscopy

Area of Science:

• Forensic Anthropology
• Biomineralization
• Skeletal Analysis

Background:

• Estimating the post-mortem interval (PMI) is challenging in forensic anthropology.
• Bone's mineral composition undergoes changes over time after death.
• Understanding these changes can improve PMI estimation accuracy.

Purpose of the Study:

• To investigate the correlation between bone mineral component changes and PMI.
• To identify specific bone mineral indices suitable for PMI estimation.
• To assess the influence of sex and age on these correlations.

Main Methods:

• Analysis of femur and humerus samples from 80 identified individuals with known PMIs.
• Application of Fourier Transform Infrared Spectroscopy in Attenuated Total Reflectance mode (FTIR-ATR).
• Quantification of bone mineral indices related to carbonate and phosphate content and crystallinity.

Main Results:

• Significant correlations were found between bone mineral indices and PMI.
• Increased carbonate content (BPI, API) and carbonate/phosphate ratio (C/P) with larger PMIs.
• Decreased crystallinity index (CI) and carbonate ratio (C/C) with larger PMIs.
• CI and C/C showed particular suitability for PMI estimation, especially in females, after controlling for sex and age.

Conclusions:

• Bone mineral analysis using FTIR-ATR provides a viable method for post-mortem interval estimation.
• Specific indices, particularly CI and C/C, are promising for improving PMI accuracy.
• The method shows potential for forensic anthropology, with enhanced utility in specific demographic groups.