Fig. 3. IR spectra from a bone sample, displayed in the range of 4000 cm–1 to 850 cm–1. Major absorption bands are indicated. Spectra demonstrate a slight increase in noise as the aperture size decreases. The C–H stretching vibrations between 2956 cm–1 and 2800 cm–1 can only be recorded by mapping with an aperture size of 140 μm × 140 μm. The absorption feature between 2300 and 2400 cm–1 is due to atmospheric CO2 and does not interfere with bands relevant in this study.
