DR/2400
Oxygen Demand, Chemical
OxygenCOD_Other_Other_MN3_Eng_Ody.fm Page 1 of 2
• For information about sampling, storage, accuracy checks, interferences, method summary, reagents and apparatus, see
Manganese III Reactor Digestion Method (with optional chloride removal).
• If the sample contains chloride, use the chloride removal method. To determine if the sample contains chloride, use Quantab
®
Titrator Strips for low range chloride (Cat. No. 27449-40).
• If the sample COD value is not between 30 and 1000 mg/L, dilute the sample with deionized water to obtain this range. Multiply
the final result by the dilution factor.
• Blending the sample promotes even distribution of solids and improves accuracy and reliability.
• Stability of the reagent blank allows for reuse. Verify the reagent blank quality by measuring the absorbance of the blank vs. a
clean COD vial filled with deionized water. The absorbance range should be about 1.4–1.5.
• If the sample boils during the digestion, the vial is not properly sealed. Test results will be invalid.
• Place a safety shield in front of the COD reactor to prevent injury if splattering occurs.
• Spilled reagent will affect test accuracy and is hazardous. Do not run tests with spilled vials.
Oxygen Demand, Chemical
Method 10067
Manganese III Reactor Digestion Method
(without chloride removal)*
* U.S. Patent 5,556,787
(30 to 1000 mg/L COD Mn)
Scope and Application: For water and wastewater
1. Touch
Hach Programs.
Select program
432 COD Mn III.
Touch
Start.
2. Turn on the COD
Reactor and heat to
150 °C. Place the safety
shield in front of the
reactor.
3. Homogenize 100 mL
of sample for 30 seconds
in a blender.
If suspended solids are
present, continue to mix
the sample while
pipetting.
4. Pipet 0.5 mL of
homogenized sample
into one Mn III COD vial
(the prepared sample)
and 0.5 mL of deionized
water into another Mn III
COD vial (the blank).
Tips and Techniques
Without Chloride Removal Method 10067
Hach Programs
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