Nicolet 5700 ftir spectrometer

The morphology and microstructure of the products were characterized using field emission scanning electron microscopy (FE-SEM; Hitachi S-4800, Hitachi, Ltd., Chiyoda-ku, Japan) and transmission electron microscopy (TEM; JEOL JEM-2100 F, JEOL Ltd., Akishima-shi, Japan) with an accelerating voltage of 200 kV. The crystal structure of the prepared powders was analyzed with an X-ray diffractometer (D8-Discover, Bruker AXS, Billerica, MA, USA), using Cu Kα radiation. Fourier transform infrared spectroscopy (FT-IR) was performed using a Nicolet 5700 FTIR spectrometer (Thermo Electron Corp, Waltham, MA, USA) with KBr pellets. Thermogravimetric analysis (TGA) was carried out in nitrogen atmosphere from room temperature to 700°C at a heating rate of 5°C/min using a SDTA851e analyzer (Mettler-Toledo, Greifensee, Switzerland).
The composite samples used for electromagnetic measurements were prepared by loading the products in paraffin wax. The powder-wax compound was then pressed into toroidally shaped samples (φ_out = 7 mm, φ_inner = 3 mm, H_thickness = 2 mm) for complex relative permittivity ε (ε = ε′ − jε″) and magnetic permeability μ (μ = μ′ − jμ″) measurements with a vector network analyzer (37247D, Anritsu Co., Ltd., Atsugi-shi, Japan) in the 0.5 to 15 GHz range.

The UV-vis absorption spectra were recorded at room temperature on a Lambda 650S UV-vis spectrometer (PerkinElmer, USA). The excitation and emission spectra were carried out using a Cary Eclipse luminescence spectrometer (Varian, USA). FT-IR spectra were measured using a Nicolet 5700 FTIR spectrometer (Thermo-Electron Corp., USA) with the KBr pellet technique in the range of 400–4000 cm⁻¹. TEM images were performed on a JEM-2100 transmission electron microscope operated at an acceleration voltage of 200 kV. XPS analysis was performed at an X-ray photoelectron spectrometer (ESCALAB 250Xi, Thermo Scientific). Fluorescence lifetime was investigated using a FLS 980 fluorescent spectrofluorimeter (Edinburgh Instrument, UK). The QY of CQDs was calculated using quinine sulphate (in 0.1 M H₂SO₄) as a reference. Photostability tests were performed at room temperature using the light of 365 nm from an ultraviolet lamp (16 W, CBIO-UV3A, Beijing CBIO Bioscience Technology Co. Ltd., Beijing, China). Photographs were taken using a Canon 700 D digital camera.

According to the KBr disk method to prepare the infrared spectrum for SSPs powder [11 (link)], the dried SPs (1.0 mg) was mixed with KBr powder (100 mg), then ground and pressed into pellets. By applying a Nicolet 5700 FT-IR Spectrometer (Thermo Electron, Madison, WI, USA), the FT-IR spectrum of the SPs was collected over the frequency range of 4000–400 cm⁻¹.

Fourier-transform infrared spectroscopy (FTIR) was used to provide spectra analysis of the dried PLLA resin and extruded tubing from Batch A. FTIR spectra were recorded using a Thermo Electron Corporation Nicolet 5700 FTIR spectrometer (Madison, WI, USA) equipped with a universal attenuated total reflectance. The spectra were recorded between 4000 and 500 cm⁻¹ frequency ranges. The number of scans was 64, with a wavelength resolution of 4 cm⁻¹.

Microcapsules were characterized by Fourier transform infrared spectroscopy (FTIR) to confirm the absence of chemical interactions between vitamins and polymer and to assess the formation of the microparticles. The FTIR spectra were recorded in a Thermo Nicolet 5700 FT-IR spectrometer equipped with an attenuated total reflectance unit (ATR) (Thermo Electron Corporation, Madison, WI, USA). The spectra were collected in triplicate in the region between 4000 cm⁻¹ and 400 cm⁻¹ with a resolution of 4 cm⁻¹ and 64 accumulations. A previous air-background correction was considered. The spectral analysis was performed by means of the Omnic^TM v7.0 software.

The CFPS-1 sample (2 mg) was pressed into a KBr pellet at room temperature. Infrared spectroscopy was performed within the range of 400–4000 cm⁻¹ on a Nicolet 5700 FT-IR spectrometer (Thermo Electron, Madison, WI, USA) and analyzed with OMNIC 7.0 software. For the NMR measurements, CFPS-1 was dissolved in D2O to exchange its active hydrogen and was then lyophilized. This procedure was repeated several times. In total, 40–50 mg of deuterium-exchanged CFPS-1 sample was dissolved in 0.5 mL of D₂O in an NMR tube to detect the NMR spectra. The NMR spectra (¹H NMR and ¹³C NMR) were recorded on a Bruker Avance^™ 600 spectrometer (600 MHz) at 60°C.