A rugged flow-based procedure for spectrophotometric determination of molybdenum in steel

Original Paper

Abstract

The novel reagent 3,5-dibromo-4-hydroxyphenylflurone (DBHF) is exploited in order to design a rugged sequential injection procedure for spectrophotometric determination of molybdenum in steels. DBHF interacts with Mo(VI) under acidic conditions yielding a 1:2 reddish complex (λmax = 530 nm). Beer’s law is followed up to 100 mg l^-1 Mo (r > 0.998; n = 5). Sensitivity and detection limit were estimated as 0.007 absorbance l mg^-1 and 0.05 mg l^-1 Mo, respectively, this latter value corresponding to 0.002 % (w/w) in the steel. Measurement frequency is 60 h^-1, and reagent consumption is 250 mg DBHF per determination. Results are precise (r.s.d. < 0.5 %) and in agreement with ICP-OES and with certified values of standard reference materials.