[Spectrophotometric study on the color reaction of multicomponent complex of tungsten-3,5-dibromosalicyl fluorone-CTMAB-Tween80].

In the presence of mixed surfactant cetyl trimethyl ammonium bromide(CTMAB) and Tween80, the photometric analysis properties of color reaction of 3,5-dibronosalicyl fluorone (DBSAF) with tungsten(VI) were studied. The experimental result showed that tungsten(VI) reacted with DBSAF to form a micelle complex with a maximum absorption at 527 nm in a 0.60 mol x L(-1) hydrochloric acid medium. The mixed surfactant remarkably improved the sensitivity of the method and the dissolubility of the complex. The apparent molar absorptivity of the complex is 2.64 x 10(5) L x mol(-1) x cm(-1) at 527 nm. Tungsten (VI) reacted with DBSAF to form a complex with a stoichiometric ratio of 1:2, which was determined by mole ratio method and continual method of transformation, respectively. Beer's law was obeyed in the range of 0-400 microg tungsten (VI) per L. The proposed method has been applied to the determination of trace amount of tungsten in alloy steel samples.