A new strategy for RRS-based determination of phosphate with a bifunctional Fe₃O₄ magnetic nanoparticle surface...

In this paper, a magnetic nanoparticle surface molecularly imprinted polydopamine RRS probe Fe₃O₄@MIP was prepared using phosphomolybdic acid (PMo) as the template, Fe₃O₄ magnetic nanoparticles as the substrate and dopamine hydrochloride (PD) as the monomer and crosslinking agent for the determination of PO₄^3-. Under acidic conditions, phosphomolybdic acid is formed by the reaction of PO₄^3- with ammonium molybdate (MSA), which can be imprinted with the Fe₃O₄@MIP probe surface and reduced to phosphomolybdic blue (PMoB) by ascorbic acid (Aa). Strong resonance Rayleigh scattering energy transfer (RRS-ET) occurs between the probe and PMoB, resulting in a decrease in the RRS signal value. A new, simple and selective RRS method for the determination of PO₄^3- in water samples was developed. The linear range of this method is 1-22.5 μmol L^-1, and the detection limit (DL) is 0.49 μmol L^-1. Furthermore, the magnetic enrichment ability of Fe₃O₄@MIP is discussed. Experimental data show that even 0.2 μmol L^-1 of phosphate can be detected within a 20% error range.