Multifunctional Fe3O4 nanoparticles for highly sensitive detection and removal of Al(III) in aqueous solution

Fe3O4 nanoparticles (NPs) decorated with rhodamine 6G Schiff base, which exhibit high selectivity and sensitivity toward Al3+ over other common metal ions in aqueous media under a physiological pH window via a 1 : 1 binding mode, have been synthesized and characterized. The resulting conjugate 1c renders the rhodamine 6G Schiff base unit more water soluble, and the detection limit reaches 0.3 ppb in water. Moreover, 1c can detect Al3+ in a wide pH span (5.0–11.0) and enrich/remove excess Al3+ in water via an external magnetic field, which indicates that it has more potential and further practical applications for biology and toxicology. Furthermore, 1c provides good fluorescent imaging of Al3+ in living cells.