Chlorine DPD XF (Free), Photometer Reagents, 0 - 10 mg/L Cl2

  • 50 tests per pack (PM013)
  • 250 tests per pack (AP013)

This Palintest Chlorine/10 test uses the DPD method developed by Dr A T Palin and now internationally recognised 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 buffered solution to produce a pink coloration. The intensity of the colour is proportional to the free chlorine concentration.

Subsequent addition of excess potassium iodide induces a further reaction with any combined chlorine present. The colour 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 colour intensities are measured using a Palintest Photometer.

The DPD Oxystop tablet is added after measurement for free chlorine but before the DPD XT tablet. It prevents the reaction between shock treatment chemicals and potassium iodide which would give a positive response.

Chlorine DPD XF (Free), Phot Reagents, 0 - 10 mg/L


Chlorine DPD 1 (0-10) Photometer Reagent Instructions

Download step-by-step instructions for using this test with a Palintest Photometer.


Photometer Reagents

Download the brochure section to view the full range of Palintest Photometer Reagents


Safety Data Sheets

Search our online database to download Safety Data Sheets

Filter searches by Part Code, Product Name or UN Code, then select the desired language. This link takes you to an external website.

Search SDS Website

Research & Insights

Free and combined chlorine - understand the difference

Testing the water for both free and combined chlorine allows you to know whether the water you've chlorinated is of sufficient quality to drink or disinfect your process, depending upon your application.