Reagent A Bromine T DPD/P comes in a 10 g powder form and is designed for accurate bromine testing. It reacts with diethyl-p-phenylene diamine (DPD) in a buffered solution to produce a pink coloration, with the intensity of the color being proportional to the total bromine concentration, allowing for precise measurement using a colorimeter or photometer. For optimal performance, store reagents consistently between 36°F and 85°F (2°C and 29°C), avoid extreme temperature fluctuations, and protect them from prolonged direct sunlight.