Universal atr sampling accessory

By using tetramethyl silane as the internal standard and DMSO‐d₆ as deuterium solvent, the ¹H NMR and ¹³C nuclear magnetic resonance (NMR) spectra were collected through a high‐resolution 400 MHz NMR spectrometer (Burker, Germany). The mass spectra were measured with a Q Exactive‐type four‐stage rod Orbitrap high‐resolution mass spectrometer (HRMS, UHPLC‐Q‐Orbitrap‐HRMS, Thermo Fisher Scientific, USA) and an Agilent Technologies 6530 TOF LC/MS (Agilent, Japan). The fluorescence spectra were collected on an Edinburgh FLS1000 fluorescence spectrophotometer (Edinburgh Instruments, UK). The colorimetric and fluorescent images were obtained by the iPhone 13 mini (Apple Inc., USA) or captured by an industrial camera (Vision Datum Mars 5000S‐20gc). Field‐emission scanning electron microscopy (FE‐SEM, JEOL JSM‐7610 F Plus, Japan) with a voltage of 4.0–6.0 kV was used for the morphology characterization of sensing substrate. Attenuated total reflection Flourier‐transformed infrared (ATR‐FTIR) spectra and Fourier‐transform infrared (FT‐IR) spectra were obtained by a PerkinElmer Frontier with a universal ATR sampling accessory from PerkinElmer (PerkinElmer, Japan). The RGB values were extracted using the software of Adobe Photoshop 2022.

The ATR-FTIR spectra of the EOs were obtained using a FT-IR spectrometer Spectrum Two, equipped with a Universal ATR sampling accessory (Perkin Elmer, Milano, Italy). One drop of each sample was deposited on the ATR diamond crystal cell. The spectra were acquired in the spectral range of 4000–450 cm⁻¹, with a spectral resolution of 4 cm⁻¹, averaging 16 scans per spectrum. The number of scans was selected for the optimal signal-to-noise ratio. The background spectrum of the empty ATR cell was obtained under the same instrumental conditions prior to the sample analysis. All samples were analyzed in duplicate.
For each EO, the absorbance percentages related to each wavenumber in the infrared range from 4000 to 450 cm⁻¹ (3551 points in total) were exported to create the datasets.

Experiments were carried out on Perkin-Elmer SPECTRUM 100 FT-IR Spectrometer equipped with the Perkin-Elmer Universal ATR Sampling Accessory. Samples were prepared as a 30 mM solution of interest compound dissolved in 1:1 MeOH and NaHCO₃ buffer (500 mM) at pH=7.8 (see Supplementary Material for further details). A drop of solution was deposed on the spectrometer ATR probe and let to completely evaporate in the air before scanning. The acquisition was performed between 4,000 and 650 cm⁻¹ with a resolution of 4 cm⁻¹.

Aqueous phase of the n-butanol extract of stems was pressed into pellets for the estimation of the infrared spectra with the scanned wave ranging from 4000 to 500 cm⁻¹. Spectra were recorded on a Perkin Elmer Universal ATR Sampling Accessory.

ATR-FTIR experiments (n = 2) were performed using a PerkinElmer Spectrum 100 FTIR spectrometer (Shelton, CT, USA) equipped with a PerkinElmer universal ATR sampling accessory. A spectral range of 650–4000 cm⁻¹, resolution of 4 cm⁻¹, accumulation of 10 scans and data interval of 1 cm⁻¹ were used. Spectrum software version 10.6.0 was used for background correction, normalization, and infrared spectra analysis.

Fourier transform infrared (FTIR) analysis was carried out on PBSA, bran, and PBSA/B pellets, dried at 40 °C for about 24 h to remove moisture. FTIR spectroscopy was used to evaluate the possible intermolecular interactions between the functional groups of PBSA and bran by monitoring the shifts of the typical absorption peaks of the two components in specific regions. The FTIR spectra were recorded using a Perkin Elmer Spectrum One FTIR Spectrometer (Perkin Elmer, Waltham, MA, USA) with a Perkin Elmer Universal ATR Sampling Accessory in the wavenumber range of 4000 to 650 cm⁻¹ at a 4 cm⁻¹ scanning resolution.