Model a300 spectrometer

The analysis of hydroxyl radical’s formation was performed by fluorescence technique using terephthalic acid, which readily reacted with hydroxyl radical to produce highly fluorescent products of 2-hydroxyterephthalic acid.27 (link) Typical reactions were started by adding 1.0 mL terephthalic acid (500 µM final concentration) to 2.0 mL solutions containing 50 mM phosphate buffer (pH 7.4), 100 µM CuCl₂, and 0, 50, 100 µM baicalein. Reactions were carried out for 30 min at room temperature and were recorded on a Hitachi F-4500 fluorescence spectrophotometer with excitation setting of 315 nm.
Additionally, the electron spin resonance (ESR) spectra were used to analyze the hydroxyl radical generation in the baicalein- Cu(II) system on a Bruker model A300 spectrometer, in which 5,5-dimethyl-l-pyrroline N-oxide (DMPO) was chosen as hydroxyl radical spin-trapping reagents.28 The basic system used in this study consisted of 50, 100 µM baicalein, and 50 mM DMPO in 50 mM phosphate buffer solution (pH7.4) at room temperature.

Solid-state cross-polarization magic angle spinning (CP/MAS) NMR spectra of the polymers and composite were obtained on a Bruker Avance III 400 Nuclear Magnetic Resonance (NMR) spectrometer (Bruker Daltonics Inc., Switzerland). The infrared (IR) spectra were obtained from a Fourier transform infrared (FTIR) spectrometer (PerkinElmer, USA). Transmission Electron Microscope (TEM) observations were obtained using a Tecnai G² 20 S-TWIN microscope (FEI, USA) at the accelerating voltage of 200 kV. Nitrogen sorption–desorption isotherm was measured at 77 K using a Micromeritics 2020M + C system after the sample was degassed at 120 °C overnight and the surface areas were determined by Brunauer–Emmett–Teller(BET) method. (Micromeritics Instrument Corporation, USA). The Pore Size Distribution (PSD) was calculated by Non-local density functional theory (NLDFT). Electron paramagnetic resonance (EPR) measurements were carried out on a Bruker model A300 spectrometer with a 300 W Xenon lamp. All Gas Chromatography (GC) experiments were carried out and recorded with a SHIMADZU GC-2010 with flame ionization detector (FID) detector.