Photometric Determination of Chemical Oxygen Demand (COD)

This test is suitable for the photometric determination of the chemical oxygen demand (COD). The test is equivalent to the methods EPA 410.4, APHA 5220D, DIN ISO 15705-H45 and DIN 38409-H41-1. This test is suitable for water, wastewater and sludge.

Measuring Range

1.0-15.0 mg/L O₂ (method 0281)
1000-15000 mg/L O₂ (method 0282)

Test Specifications

Number of tests: 20
Wavelength for photometric determination: 595 / 605 / 620 nm
Shelf life: 12 months
Storage temperature: 15-25 °C
Storage conditions: protected from sunlight, upright.

Method

The organic compounds of a sample are oxidized by heating the sample in a mixture of sulphuric acid and potassium dichromate. The chemical oxygen demand (COD) of a water sample is the concentration of oxygen that is equivalent to the amount of potassium dichromate consumed. The change in the potassium dichromate concentration is determined via the change in absorbance after digestion.

Interferences

The foreign materials shown here do not interfere with the test up to the indicated concentrations (in mg/L). The cumulative effect of different interfering ions has not been tested.

Data in mg/L:

Cl⁻: 15000

Important: For samples in which the chloride content is high, shake the tube to suspend the precipitate prior to adding the sample. If the chloride content is greater than 15,000 mg/L, you must dilute the sample or use a chloride masking agent (REF 918911). Once it has reacted in the heating block, the solution must not be cloudy; turbidity can result in high COD values. This method is not suitable for analyzing seawater.

Reagents and Accessories

Contents of reagents set:

20 test tubes R0

Required devices:

MACHEREY-NAGEL photometer
MACHEREY-NAGEL heating block
Digital piston pipette 100-1000 µL (REF 91677) with pipette tips (REF 91667)
Safety bottle for shaking COD tubes (REF 91637)

Standards

NANOCONTROL COD 15000 (REF 92528)
NANOCONTROL Multistandard Sewage outflow 1 (REF 925011)
NANOCONTROL Multistandard Sewage (REF 925013)

Sampling and Preparation

See DIN EN ISO 5667-3-A 21 and DIN 38409-H41-1.

Quality Control

The measurement of a blank value and a standard is recommended before every measuring series as a quality control measure.

	NANOCOLOR COD 40: Photometric Test for Chemical Oxygen Demand MACHEREY-NAGEL's NANOCOLOR COD 40 is a photometric test kit for determining chemical oxygen demand (COD) in water, wastewater, and sludge, compliant with various international standards. Includes overview, method, interferences, reagents, procedure, and quality control data.
	NANOCOLOR Aluminum 07 Test Kit (REF 985 098) - MACHEREY-NAGEL MACHEREY-NAGEL's NANOCOLOR Aluminum 07 test kit (REF 985 098) enables photometric determination of aluminum in water samples. This kit utilizes the eriochrome cyanine R method and provides a measurement range of 0.02-0.70 mg/L Al³⁺. It includes detailed procedures, reagent contents, interference information, and quality control recommendations.
	NANOCOLOR® Ammonium 100 Test Kit - MACHEREY-NAGEL MACHEREY-NAGEL NANOCOLOR® Ammonium 100 test kit (REF 985008) for photometric determination of ammonium (NH4+/NH3) in water. Includes overview, method, procedure, and quality data.
	NANOCOLOR® Nitrate 50 Test Kit - MACHEREY-NAGEL Technical datasheet for the NANOCOLOR® Nitrate 50 test kit by MACHEREY-NAGEL, detailing its application, method, procedure, and quality control for nitrate determination in water.
	MACHEREY-NAGEL PF-3 Sol and VISOCOLOR® NANOCOLOR® Soil Analysis MACHEREY-NAGEL's PF-3 Sol and VISOCOLOR® NANOCOLOR® systems offer reliable and efficient soil analysis. The compact PF-3 Sol photometer, resistant to water and shocks, combined with VISOCOLOR® ECO and NANOCOLOR® reagents, provides accurate measurements of essential soil parameters like ammonia, potassium, nitrates, and phosphate directly in the field.
	visocolor® Powder Pillows Nitrite - Reagent for Photometric Water Analysis SEO optimized description for visocolor® Powder Pillows Nitrite reagent, detailing its use in photometric determination of nitrite in surface, ground, and drinking water, including measuring ranges, method, procedure, and safety information.
	visocolor HE Phosphate Test Kit - High Sensitivity Water Analysis Detailed guide for the visocolor HE Phosphate test kit, covering its method, procedure, specifications, and handling for determining phosphate levels in water from 0.05 to 1.0 mg/L P.
	Visocolor HE Carbonate Hardness C 20: Test Kit Instructions Detailed instructions for using the MACHEREY-NAGEL Visocolor HE Carbonate Hardness C 20 test kit to determine p and m values and carbonate hardness in water samples.