Free chlorine is the form of chlorine that is most effective at disinfecting water. It is also the most volatile form of chlorine, and can therefore be lost from water over time. Combined chlorine is formed when free chlorine reacts with organic matter in water. It is less effective at disinfecting water than free chlorine, but is more stable and can therefore last longer in water. Total chlorine is the sum of free chlorine and combined chlorine.
Chlorine analyzers typically use one of two methods to measure chlorine concentration: the DPD method or the amperometric method. The DPD method uses a chemical reaction between chlorine and a reagent to produce a colored compound. The intensity of the color is proportional to the concentration of chlorine in the sample. The amperometric method uses an electrode to measure the electrical current produced by the reaction between chlorine and the electrode. The current is proportional to the concentration of chlorine in the sample.
Chlorine analyzers can be used to monitor the chlorine concentration in a water supply to ensure that it is within the desired range. They can also be used to control the addition of chlorine to a water supply to maintain the desired concentration.
