Abstract: A rapid, accurate, highly sensitive dual-wavelength Rayleigh light scattering method for quantifying Cu(II) was established. The Rayleigh light scattering spectral characteristics, the appropriate reaction conditions and the influence of coexisting substances were studied. At the maximum Rayleigh scattering wavelength of 528 nm and the second major Rayleigh scattering wavelength of 361 nm, the mass concentration of Cu(II) in the range of 0.003 to 0.21 mg/L was directly proportional to the Rayleigh light scattering quenching degree（ΔIRLS）of the system. The limits of detection (LOD) were 9.81 ng/mL (RLS, 361 nm), 8.62 ng/mL (RLS, 528 nm) and 4.61 ng/mL (DWO-RLS, 361 nm + 528 nm), and the limits of quantitation (LOQ) were 0.16 mg/100 g (361 nm), 0.14 mg/100 g (528 nm) and 0.077 mg/100 g (361 nm + 528 nm), respectively. The method can be used for the rapid determination of copper in various foods.

Key words: dual-wavelength, Rayleigh light scattering, copper, food