MACHEREY-NAGEL NANOCOLOR Advance Mode D'emploi Simplifié page 11

NANOCOLOR COD 160
®
Overview
The test is suitable for the photometric determination of the
chemical oxygen demand (COD). The test is in accordance with
DIN ISO 15705‑H45 and is equivalent to EPA Standard Method 5220
D.
This test is suitable for water, wastewater and sludge.
• Measuring range: 15 – 160 mg/L O (method 0261)
2
• Number of tests: 20
• Wavelength for photometric determination: 436 / 450 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 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 following contaminants do not interfere with the test up to the
indicated concentrations. The cumulative effect of different interfering
ions has not been tested.
Data in mg/L:
• Cl ‑ : 1500
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 1500 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 suppressed COD values.
Fig. 6: Test kit instruction
The use of precipitated mercury sulphate will allow the turbidity to settle.
This method is not suitable for analyzing seawater.
Turbidity leads to lower measured values.
Reagents and accessories
Contents of reagents set:
• 20 test tubes R0
Required devices:
• MACHEREY‑NAGEL photometer
• MACHEREY‑NAGEL heating block
Clean all cuvettes with a lint‑free cloth before insertion to remove any impurities or • Digital piston pipette 1 – 5 mL (REF 916909) with pipette tips
(REF 916916)
• Safety bottle for shaking COD tubes (REF 91637)
Standards
moisture from the cuvette and to prevent soiling of the cuvette slot.
• NANOCONTROL COD 160 (REF 92526)
• NANOCONTROL Multistandard Sewage outflow 1 (REF 925011)
Sampling and preparation
See DIN EN ISO 5667‑3‑A21 and DIN 38409‑H41‑1.
Quality control
Step 5: Run a measurement
The measurement of a blank value and a standard is recommended
before every measuring series as quality control measure.
MACHEREY-NAGEL GmbH & Co. KG · Valencienner Str. 11 · 52355 Düren · Germany
Tel.: +49 24 21 969-0 · info@mn-net.com · www.mn-net.com
Hot cuvettes T> 80 °C can damage the cuvette recognition and lead to incorrect
measurement results. Make sure that the cuvettes have cooled down to the
temperature specified in the instructions before measuring.
Contaminated cuvettes can contaminate the cuvette slot and lead to incorrect measure‑
ment results.
Fig. 7: Measurement of tube tests
Alternatively, the desired method can be called up by selecting from the lists in the MN-Tests
menu or by entering the test number in the corresponding menu.
The first time a method is called up, it is automatically started in sub‑method 1. The
sub‑method (chemical form) can be changed by clicking on the entry "sub‑method" in
the result screen.
Spectrophotometer NANOCOLOR
REF: 985026
en
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: ± 1 mg/L O
2
• Coefficient of variation of the process: ± 1 %
• Confidence interval: ± 2 mg/L O
2
Specified data for procedure:
• Sensitivity (absorbance of 0.010 A corresponds to): 2 mg/L O
2
• Accuracy of a measurement value: ± 5 mg/L O
2
LOT‑specific certificates are available at www.mn-net.com.
Procedure
1. Put the sediment in the reaction cuvette into suspension by swirling
2. Open round cell and hold slightly tilted. Pipette 2 mL of sample into
test tube
3. Seal test tube and shake vigorously (use safety bottle, cuvette will
become hot!).
4. Heat for 2 h at 148 °C or for 30 min at 160 °C
5. Take the tube from the heating block
6. Shake again after 10 min. while still warm
7. Cool to room temperature
8. Clean outside of test tube
9. Measure
Notes
In contrast to the conditions described in the ISO 15705, the short time
COD is characterized by a higher digestion temperature and reduced
reaction time. Therefore we recommend to compare the results of the
short time COD from time to time with measurements made under the
conditions of ISO 15705 (150 ± 5 °C / 2 h ± 10 min).
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.
Correction value e. g. for colored or turbid samples possible (see
photometer manual).
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.
10/2023
Perform the test according to the instruc‑
tions of the respective test kit (Fig. 6). Read
them carefully to obtain accurate and reliable
results. Prepare the sample according to the
instructions.
NOTICE
NOTICE
Test tubes: Insert the barcoded tube into the
cuvette slot. The barcode is recognized and
the barcode is read automatically (Fig. 7).
For test kits without zero measurement the
result is displayed automatically after a few
seconds.
When using a test kit with zero measurement
the device first prompts you to measure
the zero solution. The zero measurement is
triggered by pressing
is inserted and the sample is measured by
pressing .
NOTICE
Advance 1.2, 04.2024
®
. Then the sample
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