Simultaneous first order derivative spectrophotometric determination of vanadium and zirconium in alloy steels and minerals.

A simple, selective and sensitive spectrophotometric method has been developed for the individual and simultaneous determination of trace amounts of vanadium(V) and zirconium(IV) in acetic acid medium using a newly synthesised reagent diacetylmonoxime salicyloylhydrazone (DMSH), without any prior separation. The molar absorptivity and Sandell's sensitivity of the coloured species are 1.30 x 10(4) and 1.82 x 10(4) L mol(-1)cm(-1) and 3.9 and 2.5 ng cm(-2) for V(V) and Zr(IV), respectively. Beer's law is obeyed between 0.26-2.80 and 0.30-3.20 μg mL(-1) concentration of vanadium (V) and zirconium (IV) at 405 and 380 nm respectively. The stoichiometry of the complex was found to be 1:1 (metal:ligand) for V(V) and 1:2 for Zr(IV) complexes. 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 V(V) and Zr(IV) at zero crossing wavelengths of 445 nm and 405 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 zirconium and vanadium in standard alloy steel samples, mineral and soil samples.