Electron microscopy characterization of biosynthesized iron oxide nanoparticles

We biosynthesized iron oxide nanoparticles with four different pH in the solution to see its influence in the oxides obtained. This method allowed for generating aggregates of 1–10 nm, and under optimal conditions (pH=10) we could control the size in the range of 1–4 nm. With the purpose to analyze the biosynthesized iron oxide clusters we employed electron transmission microscopy techniques. Because the biosynthetic method with alfalfa has been used, the presence of the biomass, which is dense and within which are contained the nanoparticles, makes their observation difficult. Using the HAADF (Z contrast) technique it is possible to locate the nanoparticles, which are then characterized using EDS and HRTEM.