A molecularly imprinted nanoprobe incorporating Cu₂O@Ag nanoparticles with different morphologies for selective SERS...

In a new method for the determination of trace levels of chlorophenols in river waters, detection via surface-enhanced Raman scattering (SERS) is combined with recognition by a molecularly imprinted polymer (MIP). Nanoparticles of type Cu₂O@Ag were synthesized by attaching silver particles to the surface of Cu₂O nanoparticles. The Cu₂O@Ag were then coated with a layer of a MIP that was obtained by atom transfer radical polymerization using from methacrylic acid as monomers and 2,6-dichlorophenol as the template. The morphology of Cu₂O is found to be flower-like. The Cu₂O@Ag-MIPs displays a strong SERS effect. Following removal of the template by rinsing with the mixture solution of methanol/acetic acid (9/1, v/v), the material was used to selectively bind 2,6-dichlorophenol, 2,4-dichlorophenol and 2,4-dichlorophenol. The SERS peak intensity at 1580 cm^-1 increases linearly with the concentration of the various chlorophenols in the range from 10 nM to 1 mM, and the detection limit is 5.8 nM. The imprinting factor is 4.62. The method was applied to the analysis of (spiked) river water, with recoveries ranging from 91.8 to 115.4% and relative standard deviations of <4.5%. Graphical abstract.