Hanna Instruments HI 83099 User Manual
Page 50
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98
Blank
Sample
Blank
Sample
Blank
D.I. Water
Sample
Sample
COD MR
• Select the
Oxygen Demand, Chemical
MR (COD) method following one of the
procedures described in the
Method
Selection section (see page 12).
• Place the COD vial adapter in the cuvet
holder and ensure that the adapter is
well fit inside.
• Place the blank vial into the holder and push it completely down.
• Press the Zero key and the instrument will perform a zero sequence. If the zero sequence was
successfully done, the display will show “
-0.0-”. Now the meter is zeroed and ready for measurement.
• Remove the blank vial.
• Place the sample vial into the holder and push it completely down.
• Press
Read and the instrument will perform the reading.
• The instrument displays concentration in
mg/L of oxygen demand on the LCD.
INTERFERENCES
Interference may be caused by:
Chloride (Cl¯) above 2000 mg/L.
Samples with higher chloride concentration should be diluted.
• Choose a homogeneous sample. Samples containing settleable solids need to be homogenized with a
blender.
• Preheat the Hanna Reactor HI 839800 to 150 °C (302°F). For correct use of the reactor follow Reactor
Instruction Manual.
Use of the optional HI 740217 safety shield is strongly recommended.
DO NOT USE AN OVEN OR MICROWAVE samples may leak and generate a corrosive and possibly explosive
atmosphere.
• Remove the cap from two Reagent Vials.
• Add exactly 2.0 mL of sample to one vial (sample vial), and 2.0 mL of deionized water to the other
vial (blank vial), while keeping the vials at a 45-degree angle. Replace the cap tightly and mix by
inverting each vial a couple of times.
Warning: the vials wil become very hot during mixing, be careful when handling them.
• Insert the vials into the reactor and heat them for 2 hours at 150°C.
• At the end of the digestion period switch off the reactor. Wait for twenty
minutes to allow the vials to cool to about 120°C.
• Invert each vial several times while still warm, then place them in a
test tube rack.
Warning: the vials are still hot, be careful when handling them.
• Leave the vials in the tube rack to cool to room temperature. Do not shake
or invert them, the samples may become turbid.