Simultaneous determination of titanium and molybdenum in alloy steels using derivative spectrophotometry in neutral micellar medium

A simple, selective and sensitive spectrophotometric method has been developed for the individual and simultaneous determination of Ti(IV) and Mo(VI) using salicylaldehyde p-hydroxybenzoylhydrazone (SAPHBH) in presence of Triton X100, without any prior separation. Beer’s law is obeyed between 0.15-2.0 and 0.20-2.51 μgmL concentration of Ti(IV) and Mo(VI) at 470 and 410 nm, respectively. The molar absorptivity and Sandell’s sensitivity of the coloured species at pH 2.6 are 2.0 × 10 and 3.5 × 10 Lmolcm and 2.5 and 2.7 ng cm for Ti(IV) and Mo(VI), respectively. The stoichiometry of the complexes were found to be 1:2 and 1:1 (metal : ligand) for Ti(IV) and Mo(VI), respectively. These metal ions interfere with the determination of each other in zero order spectrophotometry. The first derivative spectra of these complexes permitted a simultaneous determination of Ti(IV) and Mo(VI) at zero crossing wavelengths of 520 and 440 nm, respectively. The optimum conditions for maximum colour development and other analytical parameters were evaluated. The proposed method has been successfully applied for the determination of titanium and molybdenum in standard alloy steel and mineral samples.