Spectrophotometric determination of barium in Si-Al-Ba alloy with dibromo-p-methylsulfonazo

The chromogenic reaction of the new reagent dibromo-p-methylsulfonazo with barium?was studied.In 0.36 mol/L H_3PO_4 medium,barium reacted with the reagent to form a blue complex with maximum absorption at 624 nm.The apparent molar absorptivity of the complex with a stoichiometric ratio of 1∶5,was 4.38×10~4 L·mol~(1)·cm~(-1).Beer's law is obeyed in the range of 0-25 μg/25 mL for barium.Most of common co-existing ions didn't cause interferences during the determination of barium.The results obtained by this method in the analysis of some Si-Al-Ba alloy samples were agreement with the certified values.