FT-Raman spectroscopy of wool—I. Preliminary studies

The FT-Raman spectrum of wool has been obtained using near-IR excitation. No significant fluorescence was observed and the spectra could be obtained routinely. No sample damage was observed for laser powers up to 400 mW. Several methods of sample presentation for both wet and dry wool were investigated and the optimum data collection conditions were determined for each. Dry dense plugs of wool fibers (∼0.16 g cm⁻³) were found to provide the best spectra. Due to improvements in band resolution and signal-to-noise ratio, several previously unobserved spectral features in the wool spectrum have become apparent. The assignment of the Raman-active vibrational modes of wool are reviewed and updated to include these features. Raman spectra obtained from chlorinated and untreated wool samples did not exhibit any significant differences. In contrast, the ATR spectra obtained from these samples exhibited significant differences in the SO stretching region.