Exchange reactions of sulfates and arylazo sulfonates in organoaqueous solutions in the flow

The principles of the method of oriented graphs were used for the theoretic al description of the application of heterogeneous exchange reactions of su lfates with poorly soluble barium arylsulfonates in spectrophotometric flow -injection analysis. The capacity of poorly soluble barium salts of colored organic ate-dye sulfonates for participating in exchange reactions with su lfates in a flow system was studied. It was found that the reagent bearing only one o,o'-hydroxyazosulfonic group possesses the best properties. It wa s demonstrated how the theory predicts the necessity of using organoaqueous solutions. A method for determining low concentrations of sulfates by flow -injection analysis was proposed based on a heterogeneous displacement reac tion.