FTIR is able to provide accuracy, reproducibility, and also a favorable signal-to-noise ratio.
By using FTIR spectroscopy, it becomes possible to detect small absorbance changes on the order
of 10−3, which helps to perform difference spectroscopy, where one could distinguish the small
absorption bands of functionally active residues from the large background absorption of the
entire protein [122–128]. FTIR spectroscopy is frequently used to find out whether biomolecules
are involved in the synthesis of nanoparticles, which is more pronounced in academic and industrial research [10,68,129,130]. Furthermore, FTIR has also been extended to the study of nano-scaled materials, such as confirmation of functional molecules covalently grafted onto silver, carbon nanotubes, graphene and gold nanoparticles, or interactions occurring between enzyme and substrate during the catalytic process [68,131,132]. Furthermore, it is a non-invasive technique. Finally, the advantages of FTIR spectrometers over dispersive ones are rapid data collection, strong signal, large signal-to-noise ratio, and less sample heat-up . Recently, further advancement has been made in an FTIR method called attenuated total reflection (ATR)-FTIR spectroscopy [134–136]. Using ATR-FTIR, we can determine the chemical properties on the polymer surface, and sample preparation is easy compared to conventional FTIR [10,137–141]. Therefore, FTIR is a suitable, valuable, non-invasive, cost effective, and simple technique to identify the role of biological molecules in the reduction of silver nitrate to silver.