TEST METHOD FOR FREE CHLORINE IN INDUSTRIAL WATER (Range: 0-5.0 mg/L as Cl2)
BACKGROUND OF THE TEST:
There are numerous applications where chlorine is dosed as disinfectant because it is a strong
oxidizing agent and is considered as one of the most powerful and economical disinfectant at all.
Consequently, chlorine residuals are maintained in water based on a specific application.
Nuclotrasis offers user friendly test method with ease of handling the relevant reagents and other
Chlorine in the sample as hypochlorous acid or hypochlorite ion (free chlorine or free
available chlorine) is first buffered and then is allowed to react with DPD (N, N-diethyl-pphenylenediamine) indicator which immediately forms a pink color, the intensity of which is
proportional to the chlorine concentration. The measurement wavelength is 530 nm for
spectrophotometers or 520 nm for colorimeters.
REAGENTS/EQUIPMENTS/APPARATUS:
Provided 10 mL marked glass vial (Item Code: 02-01)
NUCLOTRASIS DPD FREE CHLORINE-I REAGENT (Item Code: 01-16-1)
NUCLOTRASIS DPD FREE CHLORINE-II INDICATOR (Item Code: 01-16-2)
SAMPLE COLLECTION & PREPARATION
Make sure to immediately analyze the sample after collection of sample.
Ensure to collect sample in a suitable and designated bottle for a specific sample.
Thoroughly rinse the sample bottle with current sample and fill the sample by allowing slight
overflow and immediately tighten the cap.
Prevent agitation of the sample and exposure to air as the test is sensitive to the air.
TEST PROCEDURE:
1. Use the provided glass vial for sample analysis and rinse it by sample to be analyzed and take
sample to 10 mL mark in the given vial, call it as “A”.
2. Similarly take 10 mL deionized water in a cuvette used with photometer for reagent blank
and call it as “B”.
3. In the sample, add nine (09) drops of DPD FREE CHLORINE-I REAGENT (Item Code: 01-16-1).
4. Then add one (01) drop of DPD FREE CHLORINE-II INDICATOR (Item Code: 01-16-2).
5. The solution will turn purple upon addition of indicator while color intensity is proportional to
concentration of DPD Free Chlorine concentration in the sample.
6. Meanwhile, select DPD Free Chlorine specific channel/test in the spectrophotometer.
7. First run reagent blank “B” to achieve blanking.
8. Then run test sample “A” and note the Photometer display reading in µg/L or mg/L. In case
photometer is not available, match the developed color with the provided soft copy color
comparator of this DPD FREE CHLORINE test kit.
9. Multiply the reading with dilution factor 1.05.