Figure 5. FT-IR Spectrum of silver nanoparticles.
FTIR analysis was performed to investigate possible organic compounds involved in the synthesis of nanoparticles. According to Figure 5, after the reaction with Ag salt, there is some shift in the location and height of the peaks. This shift is related to the breaking of the bonds of hydroxyl and carbonyl groups, the release of hydrogen and carbon, and their role in reducing the charge and regenerating iron ions. The results of this research showed that the OH and CO groups in the water extract of the plant are possible compounds for reducing iron salt to silver nanoparticles. The definitive mechanism of the nanoparticle formation during green formulation has not yet been determined. Despite this, some researchers believe that the active surface of terpenoid molecules causes the regeneration of metal ions and stabilizes the synthesized nanoparticles [43,44]. Probably, these molecules with or without other reducing agents (sugars) are effective in this process. Terpenoids are a large and diverse group of metabolites that are made of five carbon isoprene structural units and have different types. Since these substances are the largest group of natural products that exist in almost all living organisms, it is likely that many plant extracts can be used in the metal nanoparticle synthesis because of the presence of terpenoids and reducing sugars in them [45].