Nicolet nexus 670 spectrometer

A transmission electron microscope (TEM, Jeol JEM-2100F, Tokyo, Japan), operating at 200 kV, was used to characterize the morphology and size of the CDs, MNPs, AuNPs and Fe₃O₄@Au nanocomposites. Samples for TEM were dropped on holey carbon-coated 400 mesh copper grids. A zeta potential analyzer (Brookhaven Omni, Austin, TX., USA) was used to measure the zeta potential. The morphology of nanoporous alumina membranes was observed by a scanning electron microscope (SEM, Hitachi SU8010, Tokyo, Japan), and the dry samples were coated with gold for 50 s. X-ray diffraction (XRD) patterns were collected on a PANalytical X’Pert PRO powder diffractometer (Almelo, The Netherlands) operated at 40 kV and 40 mA using Cu–Kα radiation. FTIR spectra were obtained with a Thermo Nicolet Nexus 670 spectrometer (Madison, WI. USA) employing KBr optics in the 4000–400 cm⁻¹ region with a resolution of 2.0 cm⁻¹.

Fourier transform infrared (FT-IR) spectra were recorded on a Nicolet Nexus 670 spectrometer (Thermo Fisher, Waltham, MA) by using powdered NPs (1 mg) dispersed in KBr (100 mg). Scans were recorded over 3500–1125 cm⁻¹ with the resolution of 2 cm⁻¹ and an average of 32 scans. ¹H spectral measurements were performed on a Bruker DRX 400 nuclear magnetic resonance spectrometer (Bruker, Fällanden, Switzerland) using D₂O or d₆-DMSO as solvent. The mean hydrodynamic particle size and the polydispersity index (PDI) were measured by dynamic light scattering (DLS, 90 Plus Particle Size Analyzer, Brookhaven Instruments, Holtsville, NY). Zeta potential (ZP) was measured by the same instrument equipped with a ZP analyzer as previously described (Song et al., 2017 (link)). The particle size, PDI, and ZP were measured in triplicate. Particle morphology was characterized with a scanning electron microscope (SEM) (FEI Nova TM Nano SEM, FEI, Hillsboro, OR) and transmission electron microscopy (TEM) (JEOL 2010F, Tokyo, Japan) operating at 200 kV using an aqueous solution of the sample (3 mg/mL) dropped onto a carbon-coated copper grid and air dried before TEM analysis.

Thermo Nicolet Nexus 670 Spectrometer was used for FT-IR analysis. Potassium bromide was used as beam splitter, the infra red (IR) with the wavelength of 4000 cm^-1 to 400 cm^-1, was used as a radiation source at mid IR region (Majzner et al., 2013[20 (link)]). DTGS potassium bromide with resolution of 4 cm^-1 was used as a detector.