FT-IR analysis:
Spectrophotometers are devices that determine the absorption or passage of special radiant energy wavelengths (light) from an analyte in a solution. Due to the difference in the number and arrangement of groups, the double bonds of carbon atoms in each molecule absorb light at specific wavelengths with a specific spectrum pattern. According to the Beer-Lambert law, the light absorbed amount at this specific wavelength is directly proportional to the chemical sample concentration [32].
In laboratories, a large part of the measurements is based on absorbance reactions. The activity of most cholesterol, triglycerides, enzymes, lipoproteins, creatinine, urea, sugar and a wide range of analytes with research and clinical applications, drugs and metabolites can be measured by spectrophotometry. Investigating the molecular structure, identifying compounds, comparing structures and finding the maximum absorption wavelength are other spectrophotometry applications in research problems [32].
Figure 3 shows the FT-IR spectrum of VNPs@Salvia officinalis . In the FT-IR results of metallic nanoparticles the peaks in 400 to 700 cm-1 usually attributes to metal-oxygen bonds. Accordingly, for VNPs@Salvia officinalis , the peaks at 462, 538, and 725 cm-1 can be assigned for V-O bond. Similar peaks with a little difference in wavenumbers have been reported for green synthetic vanadium nanoparticles [32]. There are many points of similarity between vanadium nanoparticles spectrum and that of plant extract. The peaks at 3205 m-1 (of O-H), 1424 to 1665 cm-1 (C=C and C=O s), and 1120 cm-1(for the stretching vibration of C‐O), which belong to various functional groups, reveal the linkage of different organic compounds to the surface of VNPs@Salvia officinalis . These compounds have been reported as Salvia officinalis secondary metabolites previously [7-9].