A continuous forensic spectral analysis study to identify antemortem and postmortem muscle contusions by chemometrics

The differentiation between antemortem and postmortem mechanical injuries constitutes a critical challenge in forensic pathology, particularly given the scarcity of reliable diagnostic markers for severely autolyzed or decomposed cadavers. This study pioneers an integrative methodology combining advanced morphological characterization, infrared spectroscopy, and chemometric modeling to identify molecular signatures distinguishing antemortem from postmortem trauma. The spectral analysis revealed distinct biomarker patterns associated with proteins (1643 cm^-1 and 1560 cm^-1), phospholipids (1402 cm^-1), and carbohydrate complexes (1011 cm^-1). These molecular fingerprints demonstrate significant discriminative potential in trauma vitality assessment. Through systematic pattern recognition, we developed optimized partial least squares-discriminant analysis (PLS-DA) models achieving superior classification accuracy in both cross-validation and external validation cohorts. The established protocol demonstrates three critical advantages: enhanced diagnostic reliability in advanced decomposition states, quantitative spectral interpretation through chemometric processing, and methodological standardization for prolonged postmortem intervals. This multimodal approach addresses a persistent forensic limitation, offering a scientifically robust framework for trauma vitality determination in challenging postmortem contexts. In the future, by further simplifying the complexity of the method and integrating forensic examination comprehensive analysis, this method has promising applications in forensic investigations requiring vitality assessment with differentiation of antemortem from postmortem injury, including after extended postmortem intervals.