Resonance Rayleigh scattering method for highly sensitive detection of copper ions in water based on salicylaldeoxime-copper (Ⅱ)- 2-methylimidazole supramolecular

Abstract

In weakly acidic BR buffer solution, a convenient and sensitive resonance Rayleigh scattering (RRS) method for the detection of Cu(Ⅱ) was developed based on the formation of salicylaloxime-Cu(Ⅱ) supramolecular complex by complexation reaction. The coordination reaction of salicylaldehyde oxime with Cu(Ⅱ) led to the significant enhancement of the resonance Rayleigh scattering intensity of the solution, and the increase of the resonance Rayleigh scattering intensity was proportional to the concentration of Cu (Ⅱ). When organic compounds with different molecular structures were introduced into the system, the resonant Rayleigh scattering intensity of the solution system changed differently. The interaction between the compounds and the spatial structure of the complexes were characterized by transmission electron microscopy (TEM), Fourier real-time infrared spectroscopy (FT-IR), zeta potential and particle size. The results showed that when 2-methylimidazole was introduced, the layered texture of Cu(Ⅱ)-CH3COO--H2PO4- -salicylaldoxime system changed to porous reticular spatial structure, and the RRS value increased significantly. Under the optimal conditions, in the range extending from 0.08 to 2.81 µmol/L, the equation of linear regression was ΔI = 3202c + 10.88 (c, µmol/L) with a correlation coefficient 0.9996, and the detection limit was estimated to be 4.23 × 10-2 µmol/L. The method was successfully applied for the determination of Cu(Ⅱ) in tap and river water sample, suggesting its great potential toward Cu(Ⅱ) analysis.