Ft ir vertex 70 spectrometer

The common intermediate, 5-bromo-3-methyl-5H-furan-2-one 2, was obtained with good yield by the bromination of 3-methyl-5H-furan-2-one with N-bromosuccinimide in CCl₄, in the presence of benzoyl peroxide [73 (link)] and it was used as crude reaction product (94–95%).
The melting points (mp) were determined on a Boetius apparatus and are uncorrected. The IR spectra were registered on a Fourier-transform (FT)-IR Vertex 70 spectrometer (Bruker Optik GmbH, Ettlingen, Germany) in ATR modes. The NMR spectra were recorded on a Varian Gemini 300 BB instrument, operating at 300.1 MHz and 75.5 MHz for ¹H and ¹³C nuclei, respectively, or on a Bruker Avance III instrument, operating at 500 MHz, and 100 MHz, respectively. Chemical shifts are reported as δ (ppm) and were referenced to internal TMS for ¹H chemical shifts and to the internal deuterated solvent for ¹³C chemical shifts (CDCl3 referenced at 77.0 ppm) and unambiguously assigned based on additional COSY, HSQC/HETCOR and HMBC experiments. The elemental analysis was carried out on a COSTECH Instruments EAS32 apparatus. Satisfactory microanalyses for all new compounds were obtained.

Pullulan content of the hydrogels was determined by phenol-sulfuric acid assay [42 (link)] using glucose and pullulan for the calibration curve. Firstly, 25 mg of P/PVA hydrogels was refluxed in 50 mL of 0.5M H₂SO₄ at 100 °C for 17 h. Then, in a test tube over 2 mL of this solution, 1 mL of phenol 5% and 5 mL H₂SO₄ 96% were added, thoroughly mixed, and left for 10 min until the brown color appeared. After cooling at room temperature in an ice bath, the solution absorbance was read at 490 nm and the content of pullulan in the sample was calculated based on a calibration curve.
The chemical composition of the hydrogels with or without C. officinalis extract was confirmed by FT-IR spectra recorded in the 4000–400 cm⁻¹ range, using a FTIR Vertex 70 spectrometer (Bruker, Vienna, Austria). Lyophilized samples of hydrogels, unloaded or loaded with extracts, were mixed with KBr and pressed into pellets.

Elemental analysis of C, H and N was performed on a PE 2400 analyzer (Perkin Elmer) (Billerica, MA, USA). Infrared spectra were recorded on a FT-IR VERTEX 70 spectrometer (Bruker: Billerica, MA, USA), using KBr pellets. UV-visible-NIR spectra were recorded on solid probes, by diffuse reflectance method, using spectralon as a reference sample and without dilution, in the range of 200–2000 nm, on a V-670 spectrophotometer (Jasco: Tokyo, Japan). The conductivity was measured with a Consort C830 (Turnhout, Belgium) conductometer with an SK10T platinum electrode embedded in glass (cell constant 1.0 cm⁻¹) for 10⁻³ M solutions in DMSO. Fluorescence spectra were recorded using a Jasco FP 6500 spectrofluorometer. Thermal behavior (TG and DTA) was analyzed using a Labsys 1200 Setaram instrument, with a sample average mass of 12 mg, over the temperature range of 20–1000 °C, with a heating rate of 10 °C/min; measurements were carried out in a synthetic air atmosphere with a flow rate of 16.66 cm³/min by using alumina crucible. For high-resolution mass spectrometry (HRMS) the complexes were dissolved in DMSO and 1:10 (v:v) dilutions in MeOH were injected and analyzed on LTQ-Orbitrap Velos Pro with a nanoESI interface. The instrument was controlled using LTQ Tune v2.7 with manual data acquisition.

Fourier Transform infrared (FTIR) spectroscopy was used to chemically characterise microfibres, which were suggested to be of synthetic origin by their morphology. Measurements were carried out using a FTIR Vertex 70 spectrometer (Bruker) as beam source coupled with a Hyperion 3000 FTIR Microscope with a 15 x IR Objective (Bruker Corporation, Billerica, USA) and a 64 × 64 Focal Plane Array (FPA) detector. For analysis, fibres were uniformly spread on a KBr crystal and placed under a microscope equipped with a 15 × Objective (pixel resolution 2.7 µm). The measurements were performed in transmission mode in wavenumber range 3850–900 cm⁻¹ using a spectra resolution of 16 cm⁻¹. OPUS 7.2 Software was used to acquire and analyse data. Zero filling factor 2, Blackman Harris three term windows function were chosen. The background was measured with the same parameters against the KBr window. No transformation or post-processing of the spectra were conducted. To differentiate the fibres chemistry, the special integration was applied. For PP fibre CH-valence-stretching vibrations at 3000–2800 cm⁻¹ and for PAN fibres specific vibration of CN absorption band at 2260 cm⁻¹ were integrated.

Infrared spectra of GY785 DR and GY785 DRS were recorded with a FT-IR VERTEX 70 spectrometer (Bruker) in ATR mode in the range 4000–500 cm⁻¹.
NMR ¹H and ¹³C spectra were recorded using Bruker Avance 500 spectrometer (Bruker BioSpin, Wissembourg, France) equipped with a 5 mm ¹H/¹³C/¹⁵N TCI cryoprobe at 25°C. GY785 DR and GY785 DRS were dissolved in 700 μL of 99.96% deuterium oxide. Chemical shifts were expressed in parts per million (ppm) relative to tetramethylsilane (TMS) used as a reference.