The COD Pack Test is a field-ready colorimetric test kit for rapid determination of Chemical Oxygen Demand in water samples. This portable system uses pre-measured reagent tubes with integrated color comparison charts to quantify organic pollutant levels without requiring laboratory infrastructure. The test employs dichromate oxidation chemistry in sealed reaction vessels, enabling on-site water quality assessment within minutes.
Designed for environmental monitoring professionals, wastewater treatment operators, and field researchers, this kit provides quantitative COD measurements through a standardized colorimetric procedure. The self-contained reagent tubes eliminate the need for volumetric glassware or analytical balances, making it suitable for remote sampling locations and rapid screening applications where immediate results guide sampling decisions.
The COD Pack Test utilizes dichromate oxidation chemistry in a closed system to quantify organic matter concentration. The pre-loaded reagent tubes contain potassium dichromate as the oxidizing agent, sulfuric acid to provide the acidic reaction environment, and silver sulfate catalyst to enhance oxidation efficiency. When the water sample is introduced, organic compounds are oxidized to carbon dioxide and water, with dichromate ions being reduced from Cr(VI) to Cr(III).
The color change from orange (unreacted dichromate) to green (chromium III) is proportional to the organic load in the sample. The reaction occurs at ambient temperature but requires a specified contact time for complete oxidation. Mercuric sulfate is typically included to complex chloride ions and prevent interference from inorganic chlorides that would otherwise consume dichromate and lead to falsely elevated COD readings.
Results are obtained by comparing the final tube color against a standardized color chart with predetermined COD concentration ranges. The colorimetric endpoint provides semi-quantitative results suitable for field screening, with accuracy dependent on proper sample preparation, reaction timing, and color comparison under appropriate lighting conditions.
| Feature | This Product | Category Context |
|---|---|---|
| Test Format | Pre-measured reagent tubes with integrated color chart | Test strips or separate reagent addition methods |
| Reaction System | Sealed tube chemistry preventing volatile losses | Open vessel reactions or strip immersion methods |
| Result Detection | Visual colorimetric comparison with reference chart | Digital photometric or reflectance measurement devices |
| Sample Handling | Direct sample aspiration into reagent tube | Pipetting or dropper bottle sample addition |
This COD Pack Test provides a self-contained colorimetric system optimized for field screening applications. The pre-measured reagent format and visual detection method offer operational simplicity for rapid water quality assessment without requiring laboratory infrastructure or electronic instrumentation.
Use natural daylight or full-spectrum fluorescent lighting when comparing colors to the reference chart for most accurate results.
Artificial lighting can shift color perception and lead to misinterpretation of COD concentration ranges.
Verify test performance using glucose or potassium hydrogen phthalate standards of known COD concentration before field deployment.
Standards validation ensures reagent activity and proper color chart interpretation for quality assurance.
Store reagent tubes in their original packaging away from temperature extremes and direct sunlight.
Reagent stability depends on proper storage conditions to maintain oxidizing capacity and color development.
Record ambient temperature and lighting conditions with each test result for data interpretation.
Environmental conditions affect both reaction kinetics and color perception, impacting result reliability.
If color development appears incomplete after the specified reaction time, verify sample mixing and reagent tube integrity.
Poor mixing or damaged seals can prevent proper reagent contact and lead to underestimated COD values.
Handle reagent tubes carefully to avoid breakage and potential exposure to dichromate and acid reagents.
Reagent tubes contain corrosive acids and toxic chromium compounds requiring appropriate personal protective equipment.
Analyze duplicate samples when COD levels are critical for decision-making or exceed expected ranges.
Duplicate analysis provides confidence in field results and identifies potential sampling or technique errors.
ConductScience provides standard manufacturer warranty coverage for reagent stability and performance specifications. Technical support is available for proper test procedures and result interpretation.
What is the measurement range and detection limit for this COD test?
Measurement range and detection limits are specified on individual product lots and should be confirmed from the product datasheet, as these parameters depend on reagent concentration and color chart calibration.
How does chloride interference affect results and what is the maximum tolerable chloride concentration?
Mercuric sulfate in the reagent formulation complexes chloride ions to minimize interference, but high chloride concentrations can still cause positive bias. Consult product specifications for chloride tolerance limits.
Can this test be used for both dissolved and total COD measurements?
The test can measure total COD if samples are properly homogenized, or dissolved COD if samples are filtered or settled to remove particulates before testing.
What is the shelf life and storage requirements for the reagent tubes?
Reagent tubes should be stored according to manufacturer specifications, typically in a cool, dry location away from direct sunlight. Expiration dates are printed on individual tubes.
How does temperature affect reaction kinetics and result accuracy?
While designed for ambient temperature operation, reaction rates may vary with temperature. Optimal results are obtained within the temperature range specified in the product documentation.
What quality control measures should be implemented when using these tests?
Use known COD standards or splits with laboratory methods for validation, maintain consistent reaction timing, ensure proper lighting for color comparison, and document ambient conditions.
How do results compare with standard laboratory COD methods?
Field colorimetric results provide screening-level accuracy suitable for preliminary assessment, but laboratory confirmation using EPA or ISO methods is recommended for regulatory compliance.
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