Analysis and discrimination of single-layer white architectural paint samples.

Area of Science:

• Forensic Science
• Materials Science
• Analytical Chemistry

Background:

• Architectural paints are common in forensic investigations.
• Differentiating single-layer white paints presents analytical challenges.
• Standardized methods are needed for reliable paint comparison.

Purpose of the Study:

• To evaluate the discrimination power of various analytical techniques for single-layer white architectural paints.
• To establish a basis for assessing the significance of paint matches.
• To determine the effectiveness of combined analytical methods in forensic casework.

Main Methods:

• Fourier transform infrared spectroscopy (FTIR)
• Stereomicroscopy
• Scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and backscatter electron (BSE) imaging
• Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS)

Main Results:

• Initial FTIR analysis yielded 94.45% discrimination among 50 white architectural paint samples.
• Combining FTIR with stereomicroscopy, SEM-EDS/BSE, and Py-GC/MS increased discrimination to 99.35%.
• Blind verification replicates identified the only truly undifferentiable pairs, highlighting subtle differences detected by individual methods.

Conclusions:

• A multi-technique approach significantly enhances the discrimination power for single-layer white architectural paints.
• The applied methods are suitable for forensic science laboratories.
• This study provides a robust framework for paint evidence analysis and significance assessment.