6-chloro-3-hydroxy-2-[2′-(5′-methylfuryl)]-4H-chromen-4-one as an analytical reagent for the spectrophotometric determination of tungsten(VI)

A 1:2 light yellow complex Of tungsten(VI) is formed with 6-chloro-3-hydroxy-2-[2'-(5'-methylfuryl)]-4H-chromen-4-one (CHMFC) in 0.18-0.32 M HClO4 medium. The complex is extractable into chloroform and absorbs maximally at 435 nm. The absorbance remains constant for more than 1 h with molar absorptivity, detection limit and Sandell's sensitivity as 2.16 x 104 L mol(-1) cm(-1), 0.131 mu g mL(-1) and 0.0085 mu g W cm(-2), respectively. Beer's law is obeyed in the concentration range of 0-2.6 mu g W mL(-1). the correlation coefficient is, r =1.001. Oxalate interferes in the tungsten determination. The method has been satisfactorily applied to the analysis of tungsten in various synthetic and technical samples.