Delving into the aqueous coprecipitation synthesis of Fe-oxide nanoparticles with a real time AC susceptometer

We herein present the potentiality of a simple and desktop AC susceptometer to explore easily and in real time the influence of different alkaline agents on the coprecipitation reaction of Fe-oxide NPs. We have studied the aqueous coprecipitation reaction of Fe-oxide nanoparticles with three different chemical basis: NH 3 , NaOH and 1-amino-2propanol (MIPA). We conclude that ammonia leads to the fastest chemical reactions because the slope of the real time X ( t ) curves are the largest ones. On the other hand, the smallest NPs would be obtained with NaOH because the in-phase curve values are one order of magnitude smaller than those obtained with NH 3 and MIPA and also, because there is no signal in the out-of-phase curves obtained with some concentrations of NaOH. Finally, we also corroborate that even though the NPs obtained with organic MIPA would be smaller than those found with traditional inorganic bases [ q ( t ) θ(t) curves of MIPA exhibit lower values than those of NH 3 ], the magnetic properties of the NPs synthesized with these new alkalonamines would be enhanced [ X ( t ) curves of MIPA are one order of magnitude larger than those obtained with NaOH]. This work put on view the potentiality of our AC susceptometer to predict in situ and in less than 30 min how the dynamic of the chemical reaction together with the polydispersity and magnetic saturation of the NPs, are being influenced by the type of chemical base and its concentration.