Abstract: In a tris-hydrochloric acid medium of pH 3.87 and in the presence of cetylpyridine bromide (CPB), Cu(Ⅱ) combines with fast green FCF to form ionic association complexes, which distinctly enhances Rayleigh light scattering (RLS) signal of the system and generates a new Rayleigh light scattering spectrum. The maximum Rayleigh scattering peak is located at 366 nm. The mass concentration of copper(Ⅱ) in the range of 0.01 to 0.22 mg·L-1 has linear relationship to the Rayleigh scattering enhanced intensity (ΔIRLS) of system with the detection limits at 0.009 5 mg·L-1 and the quantitative limit at 0.013 mg·L-1. Based on the results, a highly sensitive, rapid, accurate and new Rayleigh light scattering method for detecting Cu(Ⅱ) is established. The spectrum characteristics of Rayleigh light scattering of the system and the suitable reaction conditions are discussed. The standard addition recovery rate and RSD (n=5) of this method are in the range of 98.0%-101% and 1.8%-2.4% respectively. This method is suitable for the determination of copper in beverages in the market.
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