DIN ISO 15705:2003-01

This International Standard specifies a method for the determination of chemical oxygen demand (ST-COD) using the sealed tube method. The test is empirical and is applicable to any aqueous sample, which includes all sewage and waste waters. The method is applicable for undiluted samples having ST-COD values up to 1000 mg/l and a chloride concentration not exceeding 1000 mg/l. Samples with higher ST-COD values require predilution. For samples with a low COD, this will degrade the precision of the measurement. It will also degrade the detection limit. Samples with a high chloride concentration should be pre-diluted to give a chloride concentration of approximately 1000 mg/l or less before analysis.