Bromine, a less volatile compound than chlorine is used as a sanitizing agent in drinking water systems, swimming pools, and spas.
The bromine test method employs the DPD chemistry. Potassium iodide is added to the sample before analysis. Bromine reacts with the iodide to liberate iodine. The iodine reacts with the DPD (N, N-diethyl-p-phenylenediamine) to form a pink color. Results are expressed in ppm (mg/L) bromine as Br2.