3-Hydroxy-2-(2-thienyl)-4H-chromen-4-one as a new reagent for the extraction and trace determination of molybdenum(VI)

A simple, sensitive and selective method for the extraction and trace determination of molybdenum(VI) has been developed; it is based on its reaction with 3-hydroxy-2-(2-thienyl)-4H-chromen-4-one (HTC) in sulphuric acid medium. The 1:2 Mo (VI)-HTC yellow complex is quantitatively extractable into chloroform (_max 420 nm) and is stable for more than 4 h. The procedure eliminates the interference of a large number of metal ions and complexing agents. Beer's law is obeyed in the range of 0–2.85 g Mo/mL with a molar absorptivity, Sandell's sensitivity and standard deviation of 5.28×10⁴ L mol^–1 cm^–1, 0.0018 g Mo/cm² and ±0.0054, respectively. The method has successfully been used for the spectrophotometric determination of molybdenum in steel samples.