Vertex 80v ir spectrometer

Infrared (IR) spectroscopy measurements were performed by using a Bruker Vertex 80v IR spectrometer. For scanning of the background and the sample, scan numbers of 128 and 512 scans were averaged, respectively. Measurements were performed at a spectral resolution of 2 cm⁻¹ under vacuum at the wavelength range of 4,000–400 cm⁻¹. Pristine MIL-53(Al) and [BMIM][PF₆]/MIL-53(Al) composite were directly placed between two KBr windows, while the bulk IL was mixed with KBr powder (>99%, purchased from Merck) beforehand. Deconvolution of the obtained IR bands was conducted by using Fityk (Wojdyr, 2010 (link)) software with the utilization of Voigt function.

MoPrP fibril samples were dialyzed into MilliQ water for 24 hours at 4 °C, then fibrils were separated from buffer solution by centrifugation at 20 000 x g for 30 min and resuspended in 1 mL of D₂O, the centrifugation-resuspension procedure was repeated three times. All samples were then sonicated for 60 s (MS-72 tip, 20% sonication strength). The FTIR spectra were recorded as described previously^{44 (link)} using Bruker Vertex 80 v IR spectrometer equipped with mercury cadmium telluride (MCT) detector. For all measurements, CaF₂ transmission windows and 0.05 mm Teflon spacers were used. Spectra were recorded at room temperature under near-vacuum conditions (~2 mBar). For each spectrum, 256 interferograms of 2 cm⁻¹ resolution were co-added. A D₂O spectrum was subtracted from each sample spectrum. All the spectra were normalized to the same area of amide I/I′ band (1700–1595 cm⁻¹). All data processing was performed using GRAMS software.