A Highly Sensitive and Selective Spectrophotometric Determination of Vanadium(V) Using 6-Chloro-3-hydroxy-7-methyl-2-(2-thienyl)-4H-chromen-4-one

Abstract

A simple, rapid, highly sensitive and selective method for the extractive spectrophotometric determination of micro amounts of vanadium(V) has been worked out using 6-chloro-3-hydroxy-7-methyl-2-(2-thienyl)-4H-chromen-4-one (CHMTC) as a complexing agent in a weakly acidified (HCl, pH 0.84 - 1.09) medium. The greenish-yellow complex is quantitatively extractable into carbon tetrachloride, and shows maximum absorbance at 417 - 425 nm. The method obeys Beer’s law up to 0.9 μg V ml^-1, having molar absorptivity and Sandell’s sensitivity of 8.26×10⁴ dm³ mol^-1 cm^-1 and 0.0006 μg V cm^-2, respectively. As many as 39 cations and 14 anions and/or complexing agents do not interfere. The method has good reproducibility and can be satisfactorily applied to the determination of vanadium in steels, reverberatory flue dust and water samples.