DR/2400
Oxygen Demand, Chemical
OxygenCOD_None_Mid_RCD_Eng_Ody.fm Page 1 of 8
• Some of the chemicals and apparatus used in this procedure may be hazardous to the health and safety of the user if
inappropriately handled or accidentally misused. Please read all warnings and refer to Waste Management and Safety on
page 55 of this manual.
• Wear appropriate eye protection and clothing for adequate user protection. If contact occurs, flush the affected area with running
water. Follow instructions carefully.
• Place a safety shield in front of the COD reactor to prevent injury if splattering occurs.
• The reagent mixture is light-sensitive. Keep unused vials in the opaque shipping container. Refrigerate if possible.
• Spilled reagent will affect test accuracy and is hazardous to skin and other materials. Wash spills with running water.
• Run one blank with each set of samples. Run all tests (the samples and the blank) with the same lot of vials. The lot number
appears on the container label. See Blanks for Colorimetric Determination on page 4.
• For greater accuracy, analyze a minimum of three replicates and average the results.
Oxygen Demand, Chemical
(Method 8000
Reactor Digestion Method*
* Jirka, A.M.; Carter, M.J., Analytical Chemistry, 1975, 47(8), 1397
(3 to 150, 20 to 1500, and 200 to 15,000 mg/L COD)
Scope and Application: For water, wastewater, and seawater; digestion is required;
3–150 mg/L and 20– 1500 mg/L COD ranges are USEPA approved for wastewater analyses**;
200–15,000 mg/L COD range is not USEPA approved.
** Federal Register, April 21, 1980, 45(78), 26811-26812
1. Homogenize 100 mL
of sample for 30 seconds
in a blender. (For samples
containing large amounts
of solids, increase the
homogenization time.)
Note: If the sample does not
contain suspended solids, omit
step 1 and step 2.
2. For the
200–15,000 mg/L range
or to improve accuracy
and reproducibility of the
other ranges, pour the
homogenized sample
into a 250-mL beaker and
gently stir with a
magnetic stir plate.
3. Turn on the COD
Reactor. Preheat to
150 °C. Place the safety
shield in front of the
reactor.
4. Remove the caps
from two COD Digestion
Reagent Vials. (Be sure to
use vials for the
appropriate range.)
Tips and Techniques
Digestion Procedure Method 8000
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