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

ABSTRACT

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 PO43-. Under acidic conditions, phosphomolybdic acid is formed by the reaction of PO43- 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 PO43- 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.