Nxr ft raman module nicolet series

Raman spectroscopy was performed with a Thermo Scientific NXR FT-Raman Module Nicolet Series TM equipped with an InGaAs detector (ThermoFisher Scientific, Waltham, USA), a CaF 2 beamsplitter and a 1064 nm laser line. Raman spectra were collected using a laser (power 0.9 W) in the spectral range 200 to 4000 cm -1 with a resolution of 4 cm -1 . 256 scans were collected to obtain S/N ratio higher than 15. Samples were analyzed in 4 ml glass vials positioned vertically on a motorized stage.

Thin self-consistent tablets for Raman analysis were prepared using a laboratory press. This method is very rapid and safe in comparison with microscope glasses preparation since solvents and drying time are avoided. This is a very useful condition for Raman imaging, as in flat tablets all fragments lied exactly at the same distance from the laser source, and each spectrum of a Raman map can be collected in suitable focus conditions. In this way focus was set only once before the Raman mapping analysis. Raman spectroscopy analysis was performed with a NXR FT-Raman Module Nicolet Series TM (Thermo Fischer Scientific, Waltham, USA) equipped with an InGaAs detector. The laser power of 0.8 W was used for the calibration set collection, whereas 0.3 W was used for the Raman mapping of contaminated feed samples. Raman spectra collection was optimized using 1064 nm excitation laser mounted on a Fourier Transform Raman instrument to minimize the fluorescence phenomena in competition with Raman signal. The wavenumbers range considered was 200 cm -1 -4000 cm -1 . A resolution of 8 cm -1 was applied, and 256 scans were collected for each map point to obtain a S/N ratio higher than 10. For rapid screening tests fast Raman mapping was performed with 1 mm diameter laser spot (instead of 50 µm) and 64 scansions for each map point, instead of 256.