Spectrophotometric Determination of Vanadium(V) Using Metanil Yellow Dye as an Analytical Reagent

A simple, rapid, selective and sensitive method for the spectrophotometric determination of microgram amount of Vanadium(V) utilizing the reaction between metanil yellow dye in 40 % ethyl alcohol medium. Metanil yellow reacts with vanadium (V) instantaneously at room temperature in slightly acidic medium. The complex exhibits an absorption maximum at 512 nm with a molar absorptivity 2.21 x 105 L mol(-1) cm(-1). The sensitivity is 4.52 n g of vanadium mL(-1) and the optimum range for the effective spectrophotometric determination is 0.05-0.41 mu g mL(-1). A five fold molar excess of the dye is necessary for the full development of the colour intensity. The influence of some common ions is reported.