Determination of sulphonated dyes in water by ion-interaction high-performance liquid chromatography

An ion-interaction high-performance liquid chromatography method for quick separation and determination of the sulphonated dye Acid Yellow 1, and the sulphonated azo dyes Acid Orange 7, Acid Orange 12, Acid Orange 52, Acid Red 2, Acid Red 26, Acid Red 27 and Acid Red 88 has been developed. An RP-ODS stationary phase is used, and the mobile phase contains an acetonitrile–phosphate buffer (27:73, v/v) mixture at pH 6.7, containing 2.4 mM butylamine as ion-interaction reagent. Good separations were obtained using isocratic elution and spectrophotometric detection at 460 nm. The detection limits for the eight dyes ranged from 7 to 28 μg/l for an injection volume of 100 μl. Spiked tap water samples (100 ml), containing different concentration levels (0.3–1.2 μg/l) of the dyes were analyzed after acidification (pH 3) and preconcentration in disposable solid-phase extraction C18 cartridges.