Extraction and spectrophotometric determination of titanium(IV) with N-1-hydroxy-N-1, N-2-diphenylbenzamidine and thiocyanate

A precise, reliable, sensitive, and selective method for the determination of titanium(IV) is described. Titanium(IV) reacts with N-1-hydroxy-N-1, N-2-diphenylbenzamidine (HDPBA) and thiocyanate to form an orange-coloured mixed-ligand complex of stoichiometry 1:1:2 (Ti: SCN-: HDPBA). The complex is quantitatively extractable into toluene from 0.05-0.15 M hydrochloric acid. The spectrum of the complex exhibits an absorption maximum at 400 nm with a molar absorptivity of 20000 M(-1) cm(-1) and the coloured system obeys Beer's law in the concentration range 0.20-3.0 mu g ml(-1) titanium. The effects of foreign ions and of various experimental parameters have been studied to establish the optimum conditions for the extraction and determination of titanium. The precision of the method has been evaluated and the relative standard deviation has been found to be 0.53%. The method has been successfully applied to the determination of titanium in synthetic matrices corresponding to titanium-containing ores, minerals, and alloys.