3-HYDROXY-2-(2-THIENYL)-4H-CHROMEN-4-ONE AS AN ANALYTICAL REAGENT FORSPECTROPHOTOMETRIC DETERMINATION OF VANADIUM(V)

3-Hydroxy-2-(2-thienyl)-4H-chromen-4-one (HTC) forms a dark yellow 1 : 2 (V : HTC) complex with V-V species in 0.04-0.30 M CH3COOH medium, w hich is extracted in benzene and has lambda(max) at 415-425 nm, The mo lar absorptivity, Sandell's sensitivity and standard deviation are 3.2 7 x. 10(4) dm(3) mol(-1) cm(-1), 0.0016 mu g V cm(-2) and +/-0.0015, r espectively at 420 nm. Beer's law is obeyed over the concentration ran ge of 0-1.3 mu g V ml(-1) solvent phase. The method has been satisfact orily applied for the determination of vanadium in a wide variety of s ynthetic and technical samples.