Palintest AP011 Palintest AP011 Free Chlorine / Bromine Reagent (DPD 1), 250 tablets

Test for free, Combined, and total Chlorine in Water Chlorine and chlorine-release compounds are widely used for the disinfection of drinking water and swimming pools, for the control of microbiological growth in cooling water, and in many other water treatment systems. Accurate measurement of the chlorine residual is an essential aspect of the control of these chlorination processes. The chlorine level can be expressed in terms of the free chlorine, combined chlorine, or total chlorine residuals, for the majority of applications measurement of the free chlorine residual is the most important. The Palintest DPD chlorine method provides a simple means of measuring free, combined, and total chlorine residuals over the range of 0 – 5 mg/l. It is recommended that if any shock treatment compounds are known to have been used in the treatment of the water to be tested, a DPD Oxystop tablet be included in the test procedure as outlined below. Method This Palintest chlorine test uses the DPD method developed by Dr A T Palin and is now internationally recognized as the standard method of testing for chlorine and other disinfectant residuals. In the Palintest DPD method, the reagents are provided in tablet form for maximum convenience and simplicity of use. Free chlorine reacts with diethyl-p-phenylene diamine (DPD) in a buffered solution to produce a pink coloration. The intensity of the color is proportional to the free chlorine concentration. Subsequent addition of excess potassium iodide induces a further reaction with any combined chlorine present. The color intensity is now proportional to the total chlorine concentration; the increase in intensity represents the combined chlorine concentration. In this way, it is possible to differentiate between free and combined chlorine present in the sample. The color intensities are measured using a Palintest Photometer. The DPD Oxystop tablet is added after measurement for free chlorine but before the DPD No 3 tablet. It prevents the reaction between shock treatment chemicals and potassium iodide which would give a positive response.