SQUARE-WAVE ADSORPTIVE VOLTAMMETRIC DETERMINATION OF SUNSET YELLOW

Square wave adsorptive stripping voltammetry was used for determining trace amounts of dye Sunset Yellow (E-110) for the first time. Its ads orptive voltammetric behaviour followed by a square wave mode step was investigated at different pH media. Sunset Yellow in 0.5 M NH4Cl/NH3 buffer solution gave an adsorptive stripping voltammetric peak at the hanging mercury drop electrode at -0.60 V using an accumulation potent ial of -0.40 V. The effect of experimental parameters that affected th is determination are discussed. The calibration graph to determine Sun set Yellow was linear in the range 5-90 mu g l(-1), obtaining a relati ve standard deviation of 2.2% for a solution of 30 mu g l(-1) (n = 10) in the same day. The determination limit was 5 mu g l(-1) after 15 s of accumulation at -0.40 V. The proposed method was applied to determi ne this dye in several commercial refreshing drinks, which contained s mall amounts of this compound. Measurements were made directly over di luted solutions of commercial samples. Similar results were obtained b etween adsorptive stripping square-wave voltammetric values and the ob tained by application of a HPLC method with spectrophotometric detecti on. (C) 1997 Elsevier Science B.V.