What is the main purpose of performing the DPD test?

The DPD test is primarily designed to measure residual chlorine levels in water. Chlorine is a common disinfectant used in water treatment processes to eliminate pathogens and ensure that drinking water is safe for human consumption. The DPD (N,N-diethyl-p-phenylenediamine) method is a widely accepted colorimetric technique where DPD reacts with free chlorine to produce a pink color, the intensity of which is proportional to the concentration of chlorine present in the water sample.

Measuring residual chlorine is critical for public health because it ensures that sufficient disinfectant levels are maintained to prevent microbial contamination. This is particularly important in water distribution systems and swimming pools, where maintaining proper chlorine levels is vital for ensuring the safety and quality of the water. Understanding the levels of residual chlorine helps water treatment professionals make informed decisions about chemical dosing and overall water quality management.