Escalab mk 2 spectrometer

We compounded the Fmoc-Sec (PMB)-OH with reference to the methods by Koide [30 (link)]. The GPx mimic was obtained by solid phase peptide synthesis [31 (link)]. The product was purified by reverse phase high-performance liquid chromatography (supplementary materials) and the yield was 21 mg (32.3%). The chemical state and percentage of selenium were measured by X-ray photoelectron spectroscopy (XPS) analysis in a Vacuum Generator (VG) ESCALAB Mk II spectrometer (VG Scientific, East Grinstead, UK) with an Mg Kα (1253.6 eV) achromatic X-ray source. The Se_3d electronic-binding energy of 5P is 54.8 eV, which approaches the binding energy of SeCys (55.1 eV), indicating that the selenium in 5P is present in the form of −1 valence (diselenium bridge, -Se-Se-). The experiment also gave a C/Se ratio of 20.7:1 (calculated 21:1), indicating that there was 2 mol of selenium per mol of [Arg-Gly-Sec-Arg-Asn]₂. Therefore, 5P existed in the dimer form [Arg-Gly-Sec-Arg-Asn]₂. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry showed an m/z of 651.5 (calculated for [M]⁺: 650.3).

The dry powders of samples ZnS(1) and ZnS(2) were used for X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and photocatalytic tests. They were redispersed in ethanol by means of sonication, after which they were drop-cast onto Si wafers for XRD, XPS, and SEM measurements, while more diluted dispersions were used for UV–Vis absorption spectroscopy.
The XRD patterns of the products were recorded on a Bruker instrument (D2 Phaser) with Cu/Ni radiation (λ = 0.154184 nm) at room temperature. UV–Vis absorption spectra were obtained on a BOECO S-220 spectrophotometer. Field-emission SEM (FE-SEM) images were taken on a Hitachi S-4800 microscope. The XPS measurements were carried out on an ESCAlab-MkII spectrometer (VG Scientific). The FTIR spectra of the samples in KBr tablets were recorded in the range 4000–400 cm⁻¹ at a resolution of 1 cm⁻¹ using a Nicolet 6700 FTIR spectrometer.

The surface morphology of the untreated and modified samples was observed by SEM (Quanta-250, FEI, Delmont, PA, USA) and AFM (Nanoscope IV, Veeco Instruments Inc., Plainview, NY, USA). The attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) of untreated and modified SFF was conducted on a Nicolet 6700 (Thermo Fisher Scientific Inc., Waltham, MA, USA) FTIR spectrometer over the range of 750–4000 cm⁻¹. X-ray Photoelectron Spectroscopy (XPS) test was performed using ESCALAB MKII spectrometer (VG Scientific, Montreal, QC, Canada). Measurements of elemental contents are based on the average of several measurements (Table 4).