Catalytic Fluorophotometric Determination of Trace Amount of Copper(Ⅱ)

Based on the catalytic action of Cu(Ⅱ) on the oxidation of indigo carmine in ammoniacal buffer medium, leading to enhancement of fluorescence of the reaction system, a fluorophotometric method for determination of Cu(Ⅱ) was proposed. Linear relationship was found between values of ΔF (F-F0) measured at wavelengths of 320 nm (λex) and 391 nm (λem) and concentration of Cu(Ⅱ) in the range of 0.2-100 μg·L-1. Limit of detection (3σ) of the method found was 0.05 μg·L-1. The proposed method was used in the determination of Cu(Ⅱ) in samples of rice, flour and tea, giving values of recovery ranged from 96.2% to 104.9%, and of RSD′s (n=5) ranged from 0.72% to 1.5%.