Ft ir prestige 21 spectrometer

FTIR spectra of neat and co-spray dried (CSD) drugs were recorded using a Shimadzu FT-IR-Prestige-21 spectrometer (Shimadzu Corporation, Tokyo, Japan) supported by software (Shimadzu IR solution 1.3, Shimadzu Europa GmbH, Duisburg, Germany) to see if there are any interactions between drugs and polymers. The instrument was attached to a horizontal Golden Gate MKII single-reflection ATR system (Specac, Kent, UK) equipped with a Diamond/ZnSe crystal (45° angle to the beam, 1.66 μm at 1000 cm⁻¹ depth of penetration, 2.4 refractive index, and 525 cm⁻¹ long wavelength cut-off). Samples were placed on the diamond disk using a sapphire anvil to restrain the powder. The spectra were average of 64 scans collected at 4 cm⁻¹ resolution.

Analysis of Fourir Transmission Infrared Spectroscopy (FTIR) was performed with a Shimadzu FTIR Prestige 21 spectrometer (Shimadzu, Tokyo, Japan) to determine the typical functional groups in curcumin and curcumin nanoparticles. Five milligram samples were prepared with the KBr discs method (160 mg). Wave numbers scanning was conducted with the range of 400–4500 cm⁻¹ with resolution of 2 cm⁻¹.

The structural analysis of products and the monitoring of epoxidation and carbonation reactions were studied using FT-IR, Carbon-13 nuclear magnetic resonance (¹³C-NMR), and proton magnetic resonance (¹H-NMR) spectroscopies. FT-IR spectra were obtained on an FT-IR Prestige 21 spectrometer, Shimadzu Scientific Instruments, Inc. in México (Tultitlán, EdoMex, México) equipped with a diamond crystal and a horizontal attenuated total reflectance (HART) module. The infrared spectra were obtained in absorbance mode with 64 scans and a resolution of 4 cm⁻¹ in the range of 560–4000 cm⁻¹. All FT-IR spectra were normalized to the signal at 1736 cm⁻¹ [37 ], corresponding to the triglyceride ester group’s carbonyl vibration. An Avance III spectrometer (Bruker Mexicana, S.A. de C.V, Cd. de México, México) was used for ¹³C-NMR and ¹H-NMR analysis. The analysis was performed at 300 MHz, with a spectrum width of 3689.22 Hz, a pulse width of 4.75 µs, 32 scans at 293 K, 90 pulse width of 9.5 µs. CDCl3 was used as the solvent, and tetramethylsilane was used as the internal standard. Through ¹H-NMR, the number of epoxide and carbonate groups was quantified, as well as conversion, epoxidation, carbonation, and selectivity values of the reactions [8 (link),13 (link),35 (link)].