Adsorptive stripping voltammetric determination of quinoline yellow at the hanging mercury drop electrode

Adsorptive stripping voltammetry was used for the determination of trace amounts of dye Quinoline Yellow (E-104). Cyclic voltammetry was used to characterize its redox behavior in different pH media. Quinoline Yellow in 0.01 M HCl solution gave an adsorptive stripping voltammetric peak at the hanging mercury drop electrode at -0.73 V using an accumulation potential of -0.50 V. Parameters that affected this determination were optimized by square-wave mode. The calibration graph to determine Quinoline Yellow was linear in the range 1.0-38.5 mu g L-1, obtaining a relative standard deviation of 1.8 % for a solution of 25 mu g L-1 (n = 10). The determination limit was 1.0 mu g L-1 after 60 seconds of accumulation at -0.50 V. The proposed method was applied to determine this dye in several commercial refreshing drinks, which contained very small amounts of this compound. Measurements were made directly in the commercial samples. A comparison of the results in commercial analysis obtained by the proposed method with the provided by a HPLC method was also made. Results of the same order were obtained by voltammetric and chromatographic techniques.