A single blue synthetic fibre recovered from a victim's sweater must be identified as to its polymer type for comparison with fibres from a suspect's garment. Which analytical technique provides a rapid, essentially non-destructive identification of the fibre's chemical composition?

• A Pyrolysis gas chromatography-mass spectrometry
• B Scanning electron microscopy with energy dispersive X-ray spectroscopy
• C Fourier transform infrared microspectrophotometry ✓
• D Thin layer chromatography of extracted dyes

Explanation

Fourier transform infrared microspectrophotometry gives the characteristic absorption spectrum of the polymer, allowing nylon, polyester, acrylic and other fibre classes to be distinguished on a single small fibre without destroying it. Pyrolysis GC requires heating the sample and destroys it, SEM-EDX identifies only elemental composition such as delustrant metals, and TLC addresses dye components rather than polymer identity.

Reference: Parikh's Textbook of Medical Jurisprudence, Forensic Medicine and Toxicology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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