Omnic 7

Fourier-transform infrared (FTIR) spectra of the polysaccharides from T. suecica were obtained by using self-supporting pressed discs of 13 mm in diameter of a mixture of polysaccharides and KBr (1% w/w) with a hydrostatic press at a force of 15.0 tcm⁻² for 2 min. The FTIR spectra were obtained with a Thermo Nicolet Avatar 360 IR spectrophotometer (Thermo Electron Inc., Franklin, MA, USA) having a resolution of 4 cm⁻¹ with a deuterated triglycine sulfate (DTGS) detector and using Omnic^TM 7.2 software (bandwidth 50 cm⁻¹ and enhancement factor 2.6) in the 400–4000 cm⁻¹ region. Baseline adjustment was performed using the Thermo Nicolet OMNIC software to flatten the baseline of each spectrum. The OMNIC correlation algorithm was used to compare sample spectra with those of the spectral library (Thermo Fisher Scientific, San Jose, CA, USA).

Fourier-transformed infrared (FTIR) spectrophotometry was employed to determine chemical changes among the extracts and their fractions [32 (link)]. FTIR spectra were recorded in a Bruker FT-MIR model Vertex 70 V spectrometer. Wave number range was set in the range of 800 to 4000 cm⁻¹. Samples were blended with KBr and compressed into disks. FTIR spectra analysis was carried out by using Omnic 7.1 software (Thermo Fisher Scientific, USA).

AF–CS samples at the intermediate ratio (1:1) were analyzed by FT-IR to characterize the AF–CS interactions. FT-IR spectra were recorded with a Bruker FT–MIR model Vertex 70 V spectrometer. The wave number range was set in the range of 4000 to 50 cm^–1. Samples were blended with KBr and compressed into disks. FT-IR spectra treatment was carried out with Omnic 7.1 software (Thermo Scientific, Waltham, MA, USA).

The Fourier transform infrared analysis of all studied materials was performed by means of a Nicolet iS10 (Thermo Fisher Scientific, Waltham, MA, USA). The spectra were recorded in the frequency range of 500–4000 cm⁻¹ at a resolution of 4 cm⁻¹ and scanned 64 times. The spectrum of quercetin in KBr disc form was obtained in the same conditions. All spectra were analyzed using the OMNIC 7.0 software (Thermo Fisher Scientific, Waltham, MA, USA).

The Fourier transform infrared—Attenuated Total Reflectance (FTIR-ATR) spectra, obtained using zinc selenide crystal, of Ch and ChQ films were registered within the frequency range of 500–4000 cm⁻¹. The FTIR spectra of squaric acid (H₂SQ) were recorded in KBr disc form using a device working in transmittance mode. Final spectra are a result of 64 scans at the spectral resolution of 2 cm⁻¹. In each of the (FTIR and FTIR-ATR) analyses Nicolet iS10 (Thermo Fisher Scientific, Waltham, USA) was applied. OMNIC 7.0 software (Thermo Fisher Scientific, Waltham, USA) was also employed for spectra analysis.

The study of the impact of the introduction of berberine on the structure of the obtained films was conducted using a Nicolet iS10 (Thermo Fisher Scientific, Waltham, MA, USA). The frequency range of 500–4000 cm⁻¹, and a resolution of 4 cm⁻¹ were applied in all of the 64 scans during the recording of the spectra. With the aim of analyzing the obtained data, the OMNIC 7.0 software (Thermo Fisher Scientific, Waltham, MA, USA) was applied.

The chemical structure of the studied films was characterised by Fourier transform infrared spectroscopy (FT-IR). The spectra of individual samples were recorded in the frequency range between 650 and 4000 cm^–1. Analyses were performed on a Nicolet iS10 spectrometer (Thermo Fisher Scientific, Waltham, MA, USA). The final spectra are the result of the application of a 4 cm⁻¹ resolution and 64 scans for each sample. All spectra were analysed using OMNIC 7.0 software (Thermo Fisher Scientific, Waltham, MA, USA).