Spectrophotometric determination of tantalum(V) with 8-hydroxyquinoline-5-sulphonic acid

The formation of a yellow complex by the reaction between Ta(V) and 8-hydroxyquinoline-5-sulphonic acid (HQSA), has been studied spectrophotometrically in aqueous medium. At pH 6.5 the complex shows the maximum absorbance at 420 nm. The Beer's law is obeyed by the system within the concentration range of 1 mg to 6 mg per millilitre of Ta(V). The stoichiometry of the complex determined by the mole ratio and Job's method is 1:2 metal-ligand. The effect of ionic strength and temperature on chelate has been studied. The interference by various ions in the system and a probable structure of the complex are also suggested. (author)