title: Extractive spectrophotometric determination of tungsten(VI) using 3-hydroxy-2-(2'-thienyl)-4-oxo-4H-1-benzopyran.
abstract: A simple, rapid, highly sensitive and selective spectrophotometric method for the determination of tungsten(VI) in trace amounts is developed using 3-hydroxy-2-(2'-thienyl)-4-oxo-4H-1-benzopyran (HTB) as a reagent for the complexation of metal ion and extracting the 1:2 (metal:ligand) complex into dichloromethane from 0.2 M HCl solution. It obeys Beer's law in the range 0-2.8 microg Wml(-1) with molar absorptivity and Sandell's sensitivity at 415 nm as 6.45 x 10(4) L mol(-1) cm(-1) and 0.0029 microg W(VI) cm(-2), respectively. The method is free from the interference of a large number (39) of elements and handles satisfactorily the analysis of various samples of varying complexity.
authors.affiliation: Department of Chemistry, Kurukshetra University, Kurukshetra-136 119, Haryana, India.
authors.forename: Nivedita
authors.initials: N
authors.lastname: Agnihotri
authors.forename: Jaswant R
authors.initials: JR
authors.lastname: Mehta
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000379:methods; D008024:Ligands; D012680:Sensitivity and Specificity; D013053:Spectrophotometry / Q000379:methods; D014414:Tungsten / Q000032:analysis*
chemical_list: D008024:Ligands; D014414:Tungsten