Abstract:

Objective: To develop a method for the determination of copper in food samples. Methods: Resonance lightscattering
technique was used. Results: The resonance light-scattering signal at 589 nm was observed when a ion-associated
complex was formed among Cu2+, tungstate and rhodamine 6G in the presence of polyvinyl alcohol (PVA). The lightscattering
intensity increased linearly with increasing concentration of Cu2+ in the range of 0.05–1.0 ng/mL. The linear
regression equation was ΔI = 4.38 + 77.12c (r = 0.997 1), and the detection limit was 0.026 ng/mL. The relative standard
deviations and recovery rates of the proposed method for the determination of copper in flour and tea were less than 3.5%
and in the range of 96.7%–104.1%, respectively, suggesting that this method was free from the interference of significant
amounts of other common ions. Conclusion: The proposed method possesses the advantages of simple operation, rapid
determination, excellent reproducibility, high sensitivity and good selectivity so that it can be used for the determination of
copper in food samples.

Key words: resonance light-scattering technique, copper, rhodamine 6G, flour, tea