This study aims to address the limitations of relying solely on the visual comparison of overall infrared (IR) or Raman spectral shapes for the forensic analysis of paint evidence. It seeks to establish a more reliable identification method by systematically summarizing and interpreting the characteristic peaks and their corresponding chemical bond assignments in automotive coatings.
The research is based on the analysis of the 8 major types of paints and 22 kinds of additives commonly used in automotive coatings in China. The complementary nature of IR and Raman spectroscopy is leveraged. IR spectroscopy is used to distinguish the main paint types, while Raman spectroscopy provides more detailed chemical structural information. The core of the approach involves the systematic identification and assignment of main and auxiliary diagnostic peaks in the spectra.
The results demonstrate that IR and Raman techniques are complementary. Their combined use provides more secure and reliable detection outcomes in practical casework by revealing subtle characteristic peaks that might be overlooked when either technique is used alone. The systematic interpretation of these peaks effectively mitigates the risk of forensic misjudgment.
The present study offers a clear and systematic interpretation of characteristic peaks for automotive paint analysis, moving beyond simple spectral shape comparison. The findings furnish fundamental information that facilitates the broader application of these techniques not only in forensic science but also in related fields such as production, quality supervision and testing.
