Reaction of p -carboxyphenylfluorone with molybdenum and its application

A method for spectrophotometric determination of molybdenum was developed with a new reagent p-carboxyphenylfluorone,which was synthesized in our laboratory. In phosphoric acid and cation surfactant CTMAB medium, p-carboxyphenylfluorone reacted with molybdenum to form a 1∶3 red complex with an absorption maximum at 530 nm. Under optimum conditions, the reaction completed rapidly and the absorbance remained stable for at least 12 h. Beer′s law was obeyed in the range of 0～50 μg for Mo(Ⅵ) in 25 mL of solution.The apparent molar absorption coefficient was found to be 1.03×10~5 L·mol~(-1)·cm~(-1). The effects of various foreign ions were examined in detail. The method was applied to determine molybdenum in steel samples with a high precision and accuracy.