Novel Spectrophotometric Method for the Determination of Molybdenum in a PVA Medium

Abstract

A novel spectrophotometric method for the determination of trace molybdenum in the presence of a large amount of tungsten was developed. This proposed method was based on the formation of a green charge-transfer polyoxometalate, molybdo-11-tungstophosphate-3,3′,5,5′-tetramethylbenzidine-N-propanesulfonic, which was solubilized and stabilized in a PVA medium; the wavelength of the maximum absorption was at 660 nm. Beer’s law was obeyed in the Mo concentration range of 0.04 - 1.6 µg ml^-1. The molar absorptivity was 1.35 × 10⁴ l mol^-1 cm^-1. The developed method avoided the interference of W^VI, and was conveniently applied to analyses of some tungsten ores containing Mo^VI with satisfactory results.