Epr100d x band spectrometer

The phase composition of BCFx powders was analyzed using an X-ray diffractometer (XRD, Bruker AXS D8 Advance) with a Cu-Kα radiation (λ = 1.5418 Å) source in the 2θ range of 20–80°. The microstructure of the cells was observed using scanning electron microscopy (SEM) (Supra 55 Sapphire Carl ZEISS). The conductivity of BCFx was measured using standard four-probe method with a Keithley 2700 digital multimeter. The BCFx powders were pressed at a pressure of 230 MPa and then sintered at 900 °C for 12 h to obtain the rectangular bars (12 × 2 × 1.5 mm). Thermal expansion coefficients (TECs) of BCFx were recorded with a dilatometer (SETARAMM Setsys 18) within a temperature range of 50–800. X-ray photoelectron spectra (XPS) were conducted on a Kratos Axis Ultra DLD instrument with a radiation source of Al Kα (1486.6 eV). Electron paramagnetic resonance (EPR) spectra were performed with Bruker EPR100d X-band spectrometer. Thermogravimetric (TG) tests were performed using TG/DTA 6300 thermal analyzer (PerkinElmer, USA) in air atmosphere in temperature range of 50–800 °C. The oxygen non-stoichiometry value (δ) of samples at elevated temperatures was calculated by thermogravimetric analysis (TGA) and iodometric titration data.

Antioxidative activity of bulk form and modified Vitamin B₁₂ was measured using the electron paramagnetic resonance (EPR) spectroscopy. EPR is a very sensitive technique for determining reactive oxygen species (ROS). To detect •OH, we used the EPR-spin trapping technique coupled with the spin traps 5,5-dimethyl-1-pyrroline N-oxide (DMPO, 0.02 M) (Sigma-Aldrich Co). The antioxidant activity was determined by measuring the amount of hydroxyl radical produced via the Fenton reaction before and after the addition of Vitamin B₁₂ or nano Vitamin B₁₂ (H₂O₂ + FeCl₂ + 4H₂O + DMPO + DDW/Vitamin B₁₂ [74 fM]). Fenton reagents with Vitamin B₁₂ were drawn by a syringe into a gas-permeable Teflon capillary (Zeus Industries, Raritan, NJ, USA) and inserted into a narrow quartz tube that was kept open at both ends. The tube was then placed in the EPR cavity, and the spectra were recorded on a Bruker EPR 100d X-band spectrometer (Bruker Corporation, Billerica, MA, USA). The conditions of the EPR measurement were as follows: frequency − 9.74 GHz; microwave power − 20 mW; scan width − 65 G; resolution − 1,024; receiver gain − 2×10⁵; conversion time − 8 ms; time constant − 655 ms; sweep time − 84 s; scans − 2; modulation frequency − 100 kHz.