Mid infrared throughout with 5 μm aperture for H₂O determination of an andesitic glass: Comparison of synchrotron radiation source at SPring-8 with conventional light sources

Mid infrared throughput using 5 μm apertures was investigated using micro-FTIR spectrometers with conventional light sources at two laboratories and the synchrotron radiation infrared (SR-IR) light source at SPring-8. With both the light sources micro-FTIR microscopy can analyze the fundamental O-H vibration in andesitic glass with 1 weight % H₂O through 5 μm apertures. Spectra obtained at SPring-8 show better relative standard deviations due to the brighter and more highly collimated nature of SR-IR compared to conventional light sources. The spectra with 100 and 1000 scans at SPring-8 have similar relative standard deviations to those with 1000 and 10200 scans, respectively, at laboratories. The successful analysis with 5 μm apertures using both light sources shows the potential for an improvement in the spatial resolution of micro-FTIR analyses.