Emx 10 12 spectrometer

Transmission electron microscopy (TEM) was conducted on a JEM-2100 transmission electron microscope (JEOL Ltd., Tokyo, Japan) at the operating voltage of 200 kV. The chemical composition of was performed by X-ray photoelectron spectroscopy (XPS) with PHI5300 electron spectrometer using 250 W, 14 kV, Mg Ká radiation (PE Ltd., Boston, MA, USA). UV-Vis absorption spectra were recorded on UV-2450 spectrophotometry (Shimadzu Corporation, Honshu Island, Japan). Electron paramagnetic resonance (EPR) measurements were recorded using an EMX-10/12 spectrometer (Bruker, Karlsruhe, Germany).

5,5-dimethyl-1-pyrroline N-oxide (DMPO) was used to capture the instable hydrogen radical to form the DMPO-H adduct to generate EPR spectra⁶⁴ . In the experiments, 5 ml electrolyte was mixed with 10 μL DMPO and was deoxygenated by bubbling Ar. The potentiostatic electrolysis was carried out for 5 min in the H-type cell under the protection of Ar. EPR measurement was performed by Bruker EMX-10/12 spectrometer operating at a frequency near 9.5 GHz, sweep width of 200 G and power of 20 mW.

SEM images were acquired from a SU‐70 electron microscope (Japan). TEM images, high‐angle annular dark‐field images, EDS element mappings were obtained on a Talos F200 electron microscope (US). Nitrogen adsorption–desorption isotherm and pore‐size distribution were performed by a Tristar 3000 system (US). XRD was tested on an Ultima IV X‐ray diffractometer (Japan). XPS spectra were recorded by Thermo Fisher Scientific K‐Alpha+ (US). FTIR spectra were recorded by a Nicolet Avatar 360 spectrometer (US). UV–vis–NIR absorption spectra were performed on a UV‐3600 spectrometer (Japan). Element concentration was determined by an Agilent 5100 inductively coupled plasma optical emission spectrometer (Switzerland). ESR spectra were performed on a Bruker EMX‐10/12 spectrometer (Germany). CLSM images were acquired on a Leica TCS SP5 CLSM (Germany). NIR fluorescence images were acquired by a Series II 900/1700 NIR‐II small animal imaging system (China). NIR photoacoustic images were acquired by a VisualSonics Vevo‐2100 system (Canada).

Transmission electron microscopy (TEM) images were obtained at 200 kV from a transmission electron microscope (JEM-2100; JEOL, Japan). Freshly peeled mica was used as the substrate to deposit NGQDs for atomic force microscopy (AFM) measurement. Tapping mode was employed to obtain AFM images on a Bruker Multimode 8 (Bruker, United States). X-ray photoelectron spectroscopy (XPS) was obtained with Mg Ká radiation (250 W, 14 kV) on an electron spectrometer (PHI5300; Perkin-Elmer, United States). The ultraviolet-visible (UV-Vis) absorption and fluorescence spectra were taken by a UV-Vis spectrometer (UV-2450; Shimadzu, Japan) and a fluorescence spectrometer (RF-5301PC; Shimadzu), respectively. The fluorescence emission spectrum was obtained when excited at 465 nm, and the fluorescence excitation spectrum was measured using an emission wavelength of 520 nm. The absolute photoluminescence (PL) quantum yield was determined by a fluorescence spectrometer (FL 3C-11; Hariba Scientific, United States). Electron paramagnetic resonance (EPR) spectrum was recorded on an EMX-10/12 spectrometer (Bruker, Germany).

Room temperature: 30 μL of purified TbMscL samples at monomer concentrations of ~450 µM were loaded into glass capillary tubes. Spectra were recorded on a Bruker EMX 10/12 spectrometer operating at ~9 GHz with 100 kHz modulation frequency using an ELEXSYS Super High Sensitivity Probehead (Bruker ER4122SHQE). Spectra were averaged for 20 scans with a modulation amplitude of 0.2 mT, magnetic field sweep width of 16 mT and magnetic field center at 350.5 mT. X-axis resolution was set to 512, microwave bridge power to 1 mW and both time constant and conversion time were set to 40.96 ms.
Low temperature (i.e., 80 K). Sample preparation was identical to the one described for PELDOR. Measurements were carried out using a Bruker ELEXSYS E580 X-band spectrometer with an Oxford Instruments CF935 helium flow cryostat operating with liquid nitrogen and Flexline probehead housing 5 mm dielectric ring resonator (MD5) that was critically coupled. Spectra were taken as single scans with a modulation amplitude of 0.2 mT, magnetic field sweep width of 20 mT and magnetic field center at 346.0 mT. X axis resolution was set to 1024, microwave bridge power to 1.5 µW, time constant to 40.96 ms and conversion time was set to 346 ms.

Room-temperature CW EPR measurements to assess labelling efficiency were performed using a Bruker EMX 10/12 spectrometer equipped with an ELEXSYS Super Hi-Q resonator at an operating frequency of ∼9.9 GHz (X-band) with 100 kHz modulation. Samples were recorded using a 120 G field sweep centred at 3505 G, a time constant of 20.48 ms, a conversion time of 18.67 ms, and 1714 points resolution. An attenuation of 20.0 dB (2 mW power) and a modulation amplitude of 0.7 G were used. Csx23 samples were measured in 20 μl capillaries at ∼30 μM monomer concentration and double integrals were compared to 4-hydroxy-TEMPO (4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl; Acros) as a standard. Labelling efficiency was ∼63% for the N62R1 mutant and ∼73% for both V52R1 and N59R1 mutants; samples showed negligible free spin label contribution and the shape of the spectra suggested low mobility of the label (Supplementary Figure S9).

The samples were characterized using different techniques. X-ray diffraction (PAN analytical Empyrean CuKα = 0.15406 nm, 40 kV, 40 mA) from 5° to 90° was used for phase and crystal structure studies. The morphology of samples was identified by scanning electron microscopy (SEM, Hitachi, Ltd., S4700). Reflectance spectroscopy was analyzed by a UV-3600 spectrophotometer (Shimadzu Corporation) in the wavelength range of 200–800 nm with barium sulphate as the reference. X-ray photoelectron spectroscopy (XPS) characterization was carried out on an ESCALAB 250Xi (Thermo Fisher Scientific Inc.) spectrometer using an Al Kα source. Specific surface areas were measured by Brunauer–Emmett–Teller (BET) nitrogen adsorption–desorption at 77 K on Micromeritics ASAP-2010. The electrochemical workstation CH1760E equipped with a Xe lamp (AM 1.5G) was used for photoelectron measurements. Electron spin-resonance spectroscopy (ESR) was conducted on a Bruker model EMX 10/12 spectrometer (Bruker, Germany) equipped with a Hg lamp for the measurement of the signals of radicals spin-trapped by 5,5-dimethyl-1-pyrroline N-oxide (DMPO) at a microwave frequency of 9.77 GHz.