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Preparation
1.
Cleaning of vials:
As many household cleaners (e.g. dishwasher detergent) contain reducing
substances, this can lead to lower results with the determination of Chlorine.
To avoid measurement errors, the glassware used should be free of chlorine
consumption. To achieve this, all glassware should be placed in a sodium
hypochlorite solution (0.1 g/L) for one hour and then rinsed thoroughly with
deionised water.
2.
For individual testing of free and total Chlorine, the use of different sets of
glassware is recommended (EN ISO 7393-2, 5.3)
3.
The DPD colour development is carried out at a pH value of 6.2 to 6.5. The
reagents therefore contain a buffer for the pH adjustment. Strong alkaline or acidic
water samples must therefore be adjusted between pH 6 and pH 7 before the
analysis (use 0.5 mol/l Sulphuric acid or 1 mol/l Sodium hydroxide).
Notes
1.
After use, ensure the cuvettes are once again closed with the respective same-
coloured screw caps.
2.
Reagent sets are to be stored in the cool at +6 °C to +10 °C.
EN Method Reference Book 1.0
Chlorine L / M101
EN
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