A Generalized Approach to Forensic Dye Identification: Development and Utility of Reference Libraries

Area of Science:

• Forensic Science
• Analytical Chemistry
• Materials Science

Background:

• Dye analysis in forensic trace evidence is challenging due to small sample sizes and complex dye mixtures.
• Existing literature often lacks generalized methods applicable to forensic constraints.

Purpose of the Study:

• To develop a generalized, scalable approach for identifying dyestuffs in textile fibers.
• To overcome limitations of current dye analysis methods in forensic casework.

Main Methods:

• Development of a reference collection of 300 commercial textile dyes.
• Characterization using microanalytical methods: HPTLC, Raman, infrared, UV-Vis, and visible microspectrophotometry.
• Application of a combined analytical strategy to forensic-sized samples.

Main Results:

• A reproducible approach combining multiple robust analytical methods was established.
• The method is broadly applicable to various dye chemistries, application classes, and fiber types.
• Reference libraries aid in constraining and identifying dyes in trace samples.

Conclusions:

• The presented generalized approach enables reliable dye identification in forensic fiber analysis.
• This method significantly advances the capabilities for analyzing trace amounts of dyes.
• It provides a valuable tool for forensic trace evidence examinations.