Extractive spectrophotometric determination of trace amounts of molybdenum using thiocyanate and ethylisobutrazine hydrochloride

Abstract

An extractive spectrophotometric method for the determination of trace amounts of molybdenum in hydrochloric acid medium has been developed using potassium thiocyanate and ethylisobutrazine hydrochloride in the presence of ascorbic acid. The ternary complex that is extracted into chloroform has a molar absorptivity of 3.86 × 10⁴ l mol^–1 cm^–1 at 460 nm. Beer's law is obeyed in the concentration range 0.05–5.6 p.p.m. The complex is stable for over 1 week. The effects of acid and reagent concentrations, time, temperature and foreign ions were investigated. The method has been applied to the determination of molybdenum in steel samples.