Frontier ftir nir spectrometer

The NIR spectrum of the oat flour sample was measured by using Frontier FT-IR/NIR Spectrometer (PerkinElmer Inc., Waltham, MA, USA) using a NIR infrared reflectance accessory—NIRA (PerkinElmer Inc., Waltham, MA, USA) equipped with a spinning sample module and Spectrum-V.7.3.1.1023 (PerkinElmer Inc., Waltham, MA, USA) software. The spectrum was recorded in diffuse reflectance mode from 700 to 2500 nm using 32 scans at 1 nm intervals. The measurements were performed in duplicate, and the average spectrum was used for further analysis.

Fourier-transform infrared spectroscopy (Frontier-FTIR/NIR Spectrometer, PerkinElmer, MA, USA) was used to quantify secondary structures in the protein backbone. Scanning was conducted at wavelengths ranging from 4000 to 400 cm⁻¹. Graphs were created by arranging the wavelength range from 1450 to 1750 cm⁻¹, representing the secondary structure of the protein matrix.

The FTIR measurements were performed
using a PerkinElmer Frontier FTIR/NIR spectrometer. All of the measurements
were performed in the mid-IR spectral range (7800–400 cm^–1, the optimum scan range) in transmission mode. Thin-film
NIR (15000–2000 cm^–1, the optimum scan range)
was also performed for stitching to give a broader picture of the
CNT film optical density or −log(T). Stitching
in Figure 3a was simply
done by matching absorbance at the edge of each respective spectrum
by normalization.

ATR-FTIR spectra of all powder samples were measured directly without any pretreatment. A Frontier FT-IR/NIR spectrometer with a universal ATR sampling accessory (PerkinElmer, Waltham, MA, USA) was used to collect the spectra. The internal reflection element (IRE) of the ATR accessory was a diamond/ZnSe composite crystal and the angle of incidence was 45°. The powder sample was placed on the top surface of the IRE crystal and pressed by a lever to ensure tight and consistent contact. Each spectrum was the average of 16 scans in the range of 4000–650 cm⁻¹ with a spectral resolution of 4 cm⁻¹. The influence of water vapor and carbon dioxide was subtracted automatically.
The software Spectrum v10.4.3 (PerkinElmer, USA) was used to control the spectrometer and process the spectra. First, the spectral ordinate was transformed into absorbance. Next, ATR correction with a contact factor of zero and automatic baseline correction were applied. Finally, the spectrum was normalized to set the maximum and minimum absorbance in the range of 1800–800 cm⁻¹ at 1 and 0, respectively. Triplicates of each sample were measured and the average spectrum was used.