User Manual

38 39
Chlorine Dioxide
CHLORINE DIOXIDE
SPECIFICATIONS
Range 0.00 to 2.00 mg/L
Resolution 0.01 mg/L
Accuracy ±0.10 mg/L ±5% of reading at 25 °C
Typical EMC ±0.01 mg/L
Deviation
Light Source Tungsten lamp with narrow band interference filter @ 575 nm
Method Adaptation of the Chlorophenol Red method. The reaction between chlorine dioxide and
reagents causes a colorless to purple tint in the sample.
REQUIRED REAGENT
Code Description Quantity
HI 93738A-0 Reagent A 1 mL
HI 93738B-0 Dechlorinating Reagent B 1 packet
HI 93738C-0 Reagent C 1 mL
HI 93738D-0 Reagent D 1 mL
REAGENT SETS
HI 93738-01 Reagents for 100 tests
HI 93738-03 Reagents for 300 tests
For other accessories see page 128.
MEASUREMENT PROCEDURE
• Select the Chlorine Dioxide method using the procedure
described in the Method Selection section (see page 12).
• Fill two graduated mixing cylinders (#1 & #2) up to the
25 mL mark with the sample.
• Add 0.5 mL of HI 93738A-0 Chlorine Dioxide Reagent to each cylinder (#1 & #2), close them and
invert several times to mix.
• Press Timer and the display will show the countdown prior to the measurement or, alternatively, wait
for 2 minutes and 30 seconds and press Read. When the timer ends the meter will perform the
reading.
• The instrument displays the results in mg/L of total chlorine.
Note: free and total chlorine have to be measured separately with fresh unreacted samples following
the related procedure if both values are requested.
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.
Total Chlorine
# 2
25 mL
# 1
25 mL
# 1 & # 2
# 1 # 2