What does a DPD test measure?

A DPD (N,N-diethyl-p-phenylenediamine) test specifically measures the concentration of chlorine and bromine in water. This test is commonly used in water sanitation, particularly in swimming pools and drinking water systems, as both chlorine and bromine are significant disinfectants that help maintain water quality and safety. The DPD method involves a colorimetric analysis; when DPD reagent is added to a water sample containing free chlorine or bromine, a color change occurs that can be measured to determine the concentration of these disinfectants. This makes the DPD test a crucial tool for ensuring that water is safe for recreational or consumption purposes by monitoring these important chemical levels.