Which test is specifically used for measuring free available chlorine?

The test specifically used for measuring free available chlorine is the DPD Test. This method utilizes a chemical reagent called N,N-diethyl-p-phenylenediamine (DPD), which reacts with chlorine to produce a pink color, the intensity of which corresponds to the concentration of free available chlorine in the sample. This test is widely recognized for its sensitivity, accuracy, and ease of use in water quality monitoring.

The FACTS Test is designed for different applications, including assessing overall water quality but is not specifically focused on free chlorine measurement. Similarly, while the Colorimetric Test is a general methodology that can be modified for various compounds, it does not specifically identify free available chlorine as its primary function. Lastly, the Syringalazine Test is not a standard procedure for chlorine measurement and is instead used for different analytical purposes. Thus, the DPD Test is the standout choice for determining free available chlorine levels in water samples.