Forensic analysis of burned fabrics through ATR-FTIR spectroscopy coupled with principal component analysis

Accurate identification of fabric evidence in fire-related forensic investigations can be challenging due to the physical and chemical changes induced by combustion. Traditional methods often fail to distinguish between fabric types when materials are charred or melted. This study investigates the effectiveness of Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy combined with Principal Component Analysis (PCA) in identifying five types of fabrics cotton, linen, nylon, polyester, and rayon in both unburned and burned conditions. Fabric samples were subjected to controlled burning and analysed using ATR-FTIR in the range of 4000–400 cm⁻¹. The spectral data were then processed using PCA to reveal patterns and differences between fabric types. Results showed distinct clustering of fabric types in both unburned and burned states, with burned fabrics forming tighter clusters due to consistent spectral changes post-combustion. These findings demonstrate that ATR-FTIR coupled with PCA is a valuable, non-destructive tool for differentiating fabric types in forensic fire investigations.