STOPPED-FLOW KINETIC SPECTROPHOTOMETRIC METHOD FOR THE SIMULTANEOUS DETERMINATION OF IRON, TITANIUM AND VANADIUM

A kinetic method for the simultaneous determination of iron, titanium and vanadium is proposed based on their inductive effects on the chromium(VI)-iodide-starch reaction in weakly acidic medium. The reaction was monitored with the stopped-flow spectrophotometric technique. The calibration graphs are linear in the ranges 0-2.2, 0-3.1 and 0-1.8 mug ml-1 for Fe(II), Ti(III) and V(IV), respectively, and the detection limits are 0.012, 0.020 and 0.018 mug ml-1, respectively. It was found that 100-1000 times higher concentrations of Co2+, Ni2+, Zr4+, Mn2+, Cd2+, Cu2+, Pb2+ and tervalent rare earths ions do not interfere with the determination. The method was applied to the determination of Fe, Ti and V in an aluminium alloy and a synthetic sample.