Impex Produkter NANOCOLOR COD 40 Instruction Manual
- June 3, 2024
- Impex Produkter
Table of Contents
Impex Produkter NANOCOLOR COD 40
Overview
The test is suitable for the photometric determination of the chemical oxygen demand (COD). The test is in accordance with DIN ISO 38409H41, DIN ISO 15705H45 and is equivalent to the methods EPA 410.4, APHA 5220D and DIN 38409H41-1. This test is suitable for water, wastewater and sludge.
- Measuring range: 240 mg/L O2 (method 0271)
- Number of tests: 20
- Wavelength for photometric determination: 345365 nm
- Shelf life: 12 months
- Reaction time: 120 minutes
- Storage temperature: 28 °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-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. 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
- Digital piston pipette 15 mL (REF 916909) with pipette tips (REF 916916)
- Safety bottle for shaking COD tubes (REF 91637)
Standards
- NANOCONTROL COD 60 (REF 92522)
- NANOCONTROL Multistandard Sewage outflow 2 (REF 925010)
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: 20
- Standard deviation of the method: ± 0.41 mg/L O2
- Coefficient of variation of the process: ± 2.03 %
- Confidence interval: ± 0.94 mg/L O2
Specified data for procedure
- Sensitivity (absorbance of 0.010 A corresponds to): 0.37 mg/L O2
- Accuracy of a measurement value: ± 2.25 mg/L O2 LOT-specific certificates are available at www.mn-net.com.
Procedure
- Open round cell and hold slightly tilted
- Pipette 2 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 or for 30 min at 160 °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
Notes
Test a sample of COD-free water (REF 918993) to generate a blank value for the
reagent. The solution remains cloudy until heated. 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. 10/2019 www.mn-net.com
MACHEREY-NAGEL GmbH & Co. KG · Neumann-Neander-Str. 68 · 52355 Düren · Germany International:
Tel.: +49 24 21 969-0 Fax: +49 24 21 969-199 E-mail: info@mn- net.com
Tel.: +41 62 388 55 00 Fax: +41 62 388 55 05 E-mail: sales-ch@mn- net.com
Tel.: +33 388 68 22 68 Fax: +33 388 51 76 88 E-mail: sales-fr@mn- net.com