Spectrophotometric determination of bromate ions using phenothiazines

A highly sensitive spectrophotometric method for the determination of bromate ion is described. The method is based on the reduction of aqueous bromate ion by a phenothiazine in acidic conditions to produce a colored species. The method is suitable for bromate ion determination in the 1–700 μg/l range. For the most sensitive reagent, trifluoperazine, the limit of detection and limit of quantitation were calculated to be 0.67 and 2.25 μg/l, respectively.