Spectrophotometric determination of vanadium in steels with o-phenylenediamine

Abstract

A simple method for the spectrophotometric determination of vanadium is described. The absorbance of the yellow colour obtained with vanadium(V) and o-phenylenediamine in the presence of acetic acid is measured at a wavelength of 400 nm between pH 2·5 and 3·2 and is found to obey Beer's law between concentrations of 0·5 and 10 p.p.m. of vanadium. The effect of iron, up to a level of 200 p.p.m., can be masked with fluoride ions. For steels containing less than 1 per cent. of vanadium a prior separation of iron, either by extraction into diethyl ether or by electrolysis at a mercury cathode, is advantageous. The method is found to be suitable for the determination of vanadium in high-speed steels and chromium-vanadium steels.