NCJ Number
192030
Journal
Journal of Forensic Sciences Volume: 46 Issue: 6 Dated: November 2001 Pages: 1309-1314
Date Published
November 2001
Length
6 pages
Annotation
Infrared microspectroscopy has been used by forensic chemists to characterize polymer fibers by using both transmission and internal reflection methods. This study demonstrated that nylon, acrylic, cotton, polyester, and olefin fibers too thick for transmission could be analyzed readily by attenuated total reflection (ATR) microspectroscopy.
Abstract
Single-fiber ATR spectra have been reported in the past; however, this study focused on using ATR spectroscopy to learn about surface treatments. This information could potentially be used in forensic science to determine matches or mismatches of fibers found at different locations. A transmission spectrum from a single fiber shows mostly the chemical characteristic of the fiber itself. Because surface treatment represents a small percent of the overall content of the fiber, seeing those bands superimposed on the strong bands of the fiber itself may be difficult; however, the ATR spectrum of a surface-treated fiber can reveal spectral features of the surface treatment chemicals. This study also shows that ATR can be used with transmission spectra in determining the identity of the core and sheath portions of a bicomponent fiber. This was done by using ATR to obtain the spectrum of sheath and subtracting the ATR spectrum from the transmission spectrum of the combined sheath and core. When different spectra of the three bicomponent fibers were subjected to a computer spectral library search, polyethylene trerphthalate core was correctly identified. Although this work analyzed commercial surface treatments, the micro-ATR method can be used to analyze residual artifacts on fabrics and fibers. 11 figures, 2 tables, and 14 references