51
CHLORINE
, FREE
• Insert the cuvette into the instrument and close the lid.
• Press
Read
to start the reading. The instrument displays the results in
mg/L of chlorine (Cl
2
).
Note: Free and Total Chlorine have to be measured separately with fresh sample following
the related procedure if both values are desired.
INTERFERENCES
Interference may be caused by: Bromine, Iodine, Ozone, Oxidized forms of Chromium and
Manganese. In case of water with hardness greater than 500 mg/L CaCO
3
, shake the sample for
approximately 2 minutes after adding the powder reagent.
If the water used for this procedure has an alkalinity value greater than 250 mg/L CaCO
3
or acidity
value greater than 150 mg/L CaCO
3
, the color of the sample may develop only partially, or may
rapidly fade. To resolve this, neutralize the sample with diluted HCl or NaOH.
10 mL
• Swirl gently to mix.
• Add 10 mL of unreacted sample (up to the mark).
Replace the cap and shake gently.