58
59
Dissolved Oxygen
• Let the sample stand and the flocculent agent will start to settle.
• After approximately 2 minutes, when the upper half of the bottle becomes
limpid, add 10 drops of HI 93732C-0.
• Replace the cap and invert the bottle until the settled flocculent dissolves completely. The sample is
ready for measurement when it is yellow and completely limpid.
• Fill the cuvette up to the mark with 10 mL of the unreacted (original)
sample, and replace the cap. This is the blank.
• Place the cuvette into the holder and close the lid.
• Press ZERO key. The display will show “-0.0-” when
the meter is zeroed and ready for measurement.
• Remove the cuvette.
• Fill another cuvette up to the mark with 10 mL of the reacted sample and
replace the cap.
• Reinsert the cuvette into the instrument.
• Press READ to start the reading. The instrument will display the results in mg/L of dissolved oxygen.
10 mL
x 10
INTERFERENCES
Interferences may be caused by reducing and oxidizing materials.
Dissolved Oxygen
SPECIFICATIONS
Range
0.0 to 10.0 mg/L
Resolution
0.1 mg/L
Accuracy
±0.4 mg/L ±3% of reading
Typical EMC
± 0.1 mg/L
Deviation
Light Source
Tungsten lamp with narrow band interference filter @ 420 nm
Method
Adaptation of the
Standard Methods for the Examination of Water and Wastewater,
18
th
edition
,
Azide modified Winkler method. The reaction between dissolved oxygen
and the reagents causes a yellow tint in the sample.
REQUIRED REAGENTS
Code
Description
Quantity
HI 93732
A
-0
Reagent A
5 drops
HI 93732
B
-0
Reagent B
5 drops
HI 93732
C
-0
Reagent C
10 drops
REAGENT SET
HI 93732-01
Reagents for 100 tests
HI 93732-03
Reagents for 300 tests
For other accessories see page 73.
MEASUREMENT PROCEDURE
• Select the
Dissolved Oxygen
method using the procedure described in
the
Method Selection
section (see page 12).
• Fill one 60 mL glass bottle completely with the unreacted sample.
• Replace the cap and ensure that a small part of the sample spills over.
• Remove the cap and add 5 drops of HI 93732A-0 and 5 drops of
HI 93732B-0.
• Add more sample, to fill the bottle completely. Replace the cap again
and ensure that a part of the sample spills over. This is to make sure
that no air bubbles have been trapped inside, which could alter the
reading.
• Invert several times the bottle. The sample becomes orange-yellow and a
flocculent agent will appear.
x 5
x 5
DISSOLVED OXYGEN