Palintest AP060 Bromine Reagent Tablets 250 per box. The Palintest bromine test uses the DPD method now internationally recognised as the standard method of testing for disinfectant residuals. In the DPD method, the reagents are provided in tablet form for maximum convenience and simplicity of use. Bromine reacts with diethyl-p-phenylene diamine (DPD) in buffered solution to produce a pink coloration. The intensity of the colour is proportional to the total bromine concentration and is measured using a Palintest Photometer.