MACHEREY-NAGEL 985023 NANOCOLOR COD 10000 Tube Test User Manual
- June 3, 2024
- MACHEREY-NAGEL
Table of Contents
MACHEREY-NAGEL 985023 NANOCOLOR COD 10000 Tube Test
Overview
The test is suitable for the photometric determination of the chemi-cal oxygen
demand (COD).
This test is suitable for water, wastewater and sludge.
Measuring range
- 1.00–10.00 g/L O2 (method 0231)
- 1000–10000 mg/L O2 (method 0232)
- Number of tests: 20
- Wavelength for photometric determination: 595 / 605 / 620 nm
- Shelf life: 12 months
- Reaction time: 120 minutes
- 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 con-centration 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 following contaminants do not interfere with the test up to the indicated
concentrations. The cumulative effect of different interfe-ring ions has not
been tested.
Data in mg/L
- Cl-: 3000
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 3000 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.
The use of precipitated mercury sulphate will allow the turbidity to settle.
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 1–5 mL (REF 916909) with pipette tips (REF 916916)
- Safety bottle for shaking COD tubes (REF 91637)
Standards
- NANOCONTROL COD 15000 (REF 92528)
- NANOCONTROL Multi standard Sewage (REF 925013)
Sampling and preparation
See DIN EN ISO 5667-3-A 21.
Quality control
The measurement of a blank value and a standard is recommended before every
measuring series as quality control measure.
Quality data
The following data were determined during production according to ISO 8466-1
and DIN 38402-A51:
- Number of LOTs: 75
- Standard deviation of the method: ± 0.10 g/L O2
- Coefficient of variation of the process: ± 1.89 %
- Confidence interval: ± 0.24 g/L O2
Specified data for procedure
- Sensitivity (absorbance of 0.010 A corresponds to): 0.06 g/L O2
- Accuracy of a measurement value: ± 0.16 g/L O2
LOT-specific certificates are available at www.mn-net.com.
Procedure
- Put the sediment in the reaction cuvette into suspension by swirling
- Open round cell and hold slightly tilted
- Pipette 1 mL of sample into test tube
- Seal test tube and shake vigorously (use safety bottle, cuvette will become hot!).
- Heat for 2 h at 148°C
- Take the tube from the heating block
- Shake again after 10 min. while still warm
- Cool to room temperature
- Clean outside of test tube
- Measure
Disposal
Information regarding disposal can be found in the safety data sheet. You can download the SDS from www.mn-net.com/SDS.
Notes
- Test a sample of COD-free water (REF 918993) to generate a blank value for the reagent.
- When using a standard, the measured value is constant over a period of min. 30 min.
- The mixture may heat up significantly.
- When using other photometers, make sure measurements are possible in test tubes (16 mm OD) and calibrate the method.
- Information regarding safety can be found on the box’ label and in the safety data sheet. You can download the SDS from www.mn-net.com/SDS.
03/2021
MACHEREY-NAGEL GmbH & Co. KG
Neumann-Neander-Str. 6–8
52355 Düren Germany
US Tel.: +1 484 821 0984
sales-us@mn-net.com
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