COD standard solution, 300 mg/L O2 (NIST)

Description

The use of standard solutions can provide control of the laboratory process, increase confidence, and help provide a clear demonstration of performance to various inspectors, regulatory agencies and clients. One-parameter analysis can be performed on different analyzed samples and concentrations to confirm accuracy.

COD standard solution (1218649) from Hach for one-parameter water analysis. For accuracy checks in Chemical Oxygen Demand (COD) determinations. 500 mL bottle.

Application: For water and wastewater. Digestion is required. 

Parameter: COD.

Platform: Solution.

Summary of method: The results in mg/L COD are defined as the milligrams of O2 consumed per liter of sample under the conditions of this procedure. The sample is heated for 2 hours with sulfuric acid and a strong oxidizing agent, potassium dichromate. Oxidizable organic compounds react, reducing the dichromate ion (Cr2O7 2–) to green chromic ion (Cr3+). When the 0.7–40.0 or the 3–150 mg/L colorimetric method is used, the amount of Cr6+ that remains is measured. When the 20–1500 mg/L or 200–15,000 mg/L colorimetric method is used, the amount of Cr3+ that is produced is measured. The COD reagent also contains silver and mercury ions. Silver is a catalyst, and mercury is used to complex chloride interferences