SEDL / STP / STP949-EB / STP19440S

Considerations for Fiber Sampling with Infrared Microspectroscopy

Bartick, EG
Research chemist, Spectra-Tech, Inc., Stamford, CT
Forensic Science Research and Training Center, FBI Academy, Quantico, VA

Pages: 10    Published: Jan 1987

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Abstract

The sampling of fibers by infrared microspectroscopy is considered. Fibers are grouped into three categories: 30 to 50 µm diameter, less than 30 µm diameter, and small clumps of fibers. In the first type, rapid analysis can be easily accomplished without any preparation; however, the effects of the circular cross section of the fibers must be considered. In the second type, the best results are obtained by flattening the fibers. In the third type, the most reproducible results are acquired by pressing the clump into a potassium bromide substrate. When doing spectral subtraction, all categories require that the mixture and the subtracted spectra are obtained under the same sampling conditions. When applying these considerations to the analysis of fibers, microscopy combined with infrared (IR) spectroscopy should prove to be a very viable analytical method.