Microscopic and spectroscopic analyses of selected agricultural formulations containing various nanostructures

The aim of the present study was to analyse commercially available compounds containing nanoparticles in the form of Ag, Cu, and Ag sulphate colloids applied in agriculture. The compounds were analysed with TEM and FTIR spectroscopy, i.e., methods that can complement the commonly used research techniques such as EDX or Raman spectroscopy. The results of the microscopic examinations evidenced the presence of single spherical agglomerates (small granules) of the nanoparticle-containing products. Infrared spectroscopy revealed the presence of bands characteristic of vibrations that can be assigned to nanoparticle-X interactions, where X = S, C, or O in aqueous colloid solutions of the analysed samples. Additionally, bands characteristic for C-H stretching vibrations (probably associated with vibrations of the -CH₂ and -CH₃ groups) were observed as bands originating from compounds used as the carriers of the analysed systems. In the case of Ag sulphate, the most distinct band with a maximum at 2,863 cm⁻¹, which is characteristic of SH···Ag vibrations, can be observed, and its intensity may be associated with the nanostructure composition of the formulation, which is more diverse than that in the other two compounds.