33
Free Chlorine
Liquid reagents procedure
• To an empty cuvet add 3
drops of HI 93701A-F DPD1
indicator and 3 drops of
HI 93701B-F DPD1 buffer.
Swirl gently to mix, and
immediately add 10 mL of
unreacted sample. Replace
the cap and shake gently
again.
• Reinsert the cuvet into the instrument.
• Press READ DIRECT and the display will show “SIP” during
measurement.
• The instrument directly displays concentration in mg/L of free
chlorine on the Liquid Crystal Display.
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.
In case of water with alkalinity greater than 250 mg/L CaCO
3
or
acidity 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.
x 3
x 3
