Vertex 70v ftir spectrometer

The transmittance measurements were performed by using Bruker Vertex 70 V FTIR spectrometer integrated with silicon photodetector working in visible and near-IR. We worked in the wavelength range between 400 nm to 1100 nm. We biased the graphene based transistors using Keithley 2400 source measure unit during the transmittance measurements. The leakage current is also recorded during the measurement.

A Bruker Vertex 70 V FT-IR spectrometer (Bruker Optics, Germany), equipped with a Hyperion microscope attachment was used. The bacterial coated CaF₂ slides were placed under the microscope objective and IR spectra were recorded in transmission mode from 4000 to 850 cm^-1 at a spectral resolution of 4 cm^-1. Fifteen spectra for each sample were obtained at room temperature. A total of 45 spectra (3 × 15) for each treatment were obtained. Experiments were performed in triplicate. OPUS software version 6 was used to perform data analysis. Spectra were smoothed with a Savitsky-Goly function algorithim with 25 smoothing points, base-line corrected and normalized. Principle component analysis (PCA) was used on raw data to separate and group control and GCE-treated bacterial spectra to illustrate differences between the two data sets.

Polysaccharide powders were cast into KBr pellets and analyzed by a VERTEX 70v FTIR spectrometer (Bruker, Germany) [3 (link)]. For the monosaccharide composition analysis, polysaccharides were hydrolyzed with 4 M of trifluoroacetic acid and separated on a CarboPac PA1 column integrated to a Dionex ED50 Detector (HPAEC-PAD) (Dionex, Sunnyvale, CA, USA). A standardized monosaccharide mixture was used as the reference standard [3 (link)].

Chemical structures and purity of the polymer and monomer were determined by ¹H NMR spectroscopy using CDCl₃, deuterium or DMSO-d₆ as solvents in the Bruker Ascend^TM 400 MHz Spectrometer. The polymer coating was confirmed by Bruker’s VERTEX 70v FT-IR Spectrometer in range of 4000–500 cm⁻¹ with resolution of 2 cm⁻¹. SEM analysis was done to study the homogeneity of the coating.

Fourier transform infrared spectroscopy was performed on oven-dried (70 °C) leaf samples with a Bruker Vertex 70v FTIR spectrometer (Bruker Optik GmbH, Ettlingen, Germany, DEU) equipped with A225/Q Platinum attenuated total reflectance (ATR) with a single reflection diamond crystal (Bruker Optik GmbH, Rosenheim, Germany, DEU). The spectra were obtained from 4000 to 400 cm⁻¹ wavenumbers with a spectral resolution of 4 cm⁻¹. Two replications were performed for each spectrum, which were collected from an average of 300 scans sample⁻¹ at room temperature (25 °C). All spectra were equally corrected by baseline using OPUS software (Bruker Optik GmbH, Rosenheim, DEU), and the intensity was normalized at 3270 cm⁻¹ (OH stretching band).

UV–VIS absorption spectra were recorded in chloroform, acetone, DMSO, acetonitrile, and methanol (3.323 × 10⁻⁶ M) solutions on a Hitachi spectrophotometer. The fluorescence spectra were recorded on a spectrofluorometer Gildenpλotonics 700 (Dublin, Ireland) in the range 900–200 nm (grating 1, bandpass 5 and 8, integration time 100 ms, chloroform, acetone, DMSO, acetonitrile, and methanol solution of compounds the same as in the case of the UV–VIS studies or silicon slides). The elemental analysis was carried out using a Vario EL III Elemental analyzer. The thermal analysis (TG, DTG, DTA) was performed on an SDT 2960 TA analyzer under air, a heating rate of 10 °C min⁻¹, and a heating range of up to 1000 °C and a Jupiter STA 449 F5 thermoanalyzer from Netzsch (Selb, Germany) with an automatic sample feeder coupled to a Vertex 70V FT-IR spectrometer from Bruker Optik (Ettlingen, Germany). After combustion, the residue of the sample was analyzed by an XRD analysis performed with a Philips X’Pert equipped with an X’Celerator Scientific detector. The IR spectra were recorded on the Bruker instrument using the ATR technique in the range of 70–4000 cm⁻¹. Circular dichroism spectra were recorded with a Jasco J-815 spectropolarimeter (Jasco Inc.) in the range of 310–700 nm wavelengths. The solution of K1 and K2 complexes (≈1 × 10⁻⁴ M) was prepared by dissolving it in a CHCl₃ solution.