Barium-dimethylsulphonazo

Air Barium-dimethylsulphonazo- III Photometry 0.2-14 mgr Hydrogen peroxide absorber... 

Other alternative spectrophotometric method of widespread use for sulfate monitoring is the dimethylsulphonazo(III) (DMSA(III)) approach. It has been automated in FIA [5] and SIA [6] and applied to the analysis of natural and residual waters. This method involves the reaction of sulfate with barium-dimethylsulphonazo(ni) complex, Ba-DMSA(111), displacing Ba from the complex and forming DMSA(III). 

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