Application of Highly Selective and Sensitive 6-Chloro-3-hydroxy-2-(2í-furyl)-4-oxo-4H-1-benzopyran Reagent for Spectrophotometric Determination

A simple, fast, and highly selective method for spectrophotometric determination of trace tungsten has been presented. In the determination 6-chloro-3-hydroxy-2-(2i-furyl)-4-oxo-4H-1-benzopyran (CHFB) has been applied as a ligand to complex the analyte metal ion. The formed light-yellow complex was extracted into dichloromethane from 0.2 mol L n1 HCl solution. The Beeris law was obeyed in the concentration range of W(VI) of 0.0n2.0 mg mL n1 ; molar absorptivity and Sandellis sensitivity of the complex at 420 nm equaled 2.2 ◊ 10 4 L mol n1 cm n1 and 0.0083 mg W(VI) cm n2 , respectively. The method is free from the interference of many analytically important elements. The proposed system handles satisfactorily the analysis of several samples of various complexity. The obtained results were highly reproducible with a relative standard deviation of 0.08% for 10 mg of W(VI) per 10 mL of the aqueous volume.