LCK314 COD Cuvette Test, 15-150 mg/L O₂

13 mm LCK Cuvette test measures COD in the range of 15-150 mg/L O₂ in wastewater. The product uses dichromate method (ISO 6060-1989, DIN 38409-H41-H44). Article LCK314 can be used to perform 25 tests. Water sample can be assessed on DR3900, DR6000, DR1900, DR2800, DR3800 and DR5000.

Before you start take into account the following:

• Water samples (including diluted samples) with maximum chloride concentrations of 1500 mg/L may be used for this method.
• Large surplus of chemical oxygen demand may display results within the measuring range. It is recommended to conduct plausibility check by making dilutions.

Procedure for O₂ determination

Cuvette must be inverted a few times to bring the sediment to suspended state, mixed with 2.0 mL of wastewater sample and afterwards heated in the classic thermostat for 2 hours at 148 °C (298.4 °F). HT-COD Test should be heated in high temperature thermostat as it requires higher digestion temperature and shorter digestion time (15 minutes).

Summary of method

Oxidizable substances react with sulphuric acid and potassium dichromate solution in the presence of silver sulphate that serves as reaction catalyst. Chloride is masked by mercury sulphate. Yellow coloration reduction of Cr6+ should be analyzed photometrically.

Sample preparation

The required conservation temperature of the water sample for up to 24 hours is between +2 °C and +5 °C. For conservation for up to 14 days the sample should be stored at the temperature of around -18 °C. The sample must be carried in glass or polyethylene container. The storage conditions of the Article LCK314 are between 15 °C and 25 °C protected from light rays.