GB/T 7489-1987 (English Version) PDF

Standard No.: GB/T 7489-1987
Language: Chinese, Available in English version
Release Date: 1987
Published By: General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China
Latest: GB/T 7489-1987

Scope: The iodometric method is the benchmark method for the determination of dissolved oxygen in water. In the absence of interference, this method is suitable for various water samples with dissolved oxygen concentrations greater than 0.2mg/L and less than twice the saturation concentration of oxygen (about 20mg/L). Easily oxidized organic substances, such as tannin, humic acid and lignin, will interfere with the determination. Oxidizable sulfur compounds, such as the sulfide thiourea, also interfere with the respiratory system, which tends to consume oxygen. When such substances are contained, the electrochemical probe method should be used. Nitrite concentrations up to 15 mg/L do not interfere because they are destroyed by the added sodium azide. If there are oxidizing substances or reducing substances, the determination method needs to be improved, see Chapter 8. If there are suspended substances that can fix or consume iodine, this method can only be used after being modified according to the method described in Appendix A.

GB/T 7489-1987 history

1987 GB/T 7489-1987 Water quality--Determination of dissolved oxygen--Iodometric method