A rapid spectrophotometric method for the determination of molybdenum using ferron in industrial and environmental samples

Abstract

Ferron has been used as an analytical reagent for the extractive spectrophotometric determination of molybdenum(V) obtained from the reduction of molybdenum(VI) with ascorbic acid. Molybdenum(V) in presence of a large number of cations, anions and complexing agents forms a yellow complex with ferron that is quantitatively extractable into tri-n-octylamine-chloroform from 1 M H₂SO₄ medium. The complex is stable for at least 24 h and shows an absorption maximum at 425 nm with molar absorptivity and Sandell’s sensitivity of 3.96×10³ l mol⁻¹ cm⁻¹ and 0.02525 μg cm⁻² Mo(V), respectively. The method obeys Beer’s law up to 31 μg ml⁻¹ Mo(V). For ten replicate determinations of 10 μg ml⁻¹ Mo(V), the relative standard deviation is found to be 0.54%. The method is simple, selective, precise and rapid, and has been satisfactorily applied to the determination of molybdenum in aqueous, synthetic and technical samples of diverse matrices.