In COD analysis, which reagent fixes interference from volatile organics?

In COD analysis, which reagent fixes interference from volatile organics?

• A. Mercuric sulfate
• B. Sodium sulfate
• C. Silver sulfate
• D. Sodium chloride

Answer: (C)

In COD testing, substances that affect how much dichromate is consumed during digestion can skew results. Some volatile organic compounds can escape as vapors or react in unexpected ways, making the measured oxidation appear higher or lower than it truly is. A reagent that acts as a masking or stabilizing agent helps keep those volatile organics from interfering with the digestion, so the amount of dichromate used more accurately reflects the sample’s oxidizable content. Silver sulfate serves this role by suppressing the impact of volatile organics on the digestion. The other options address different issues or simply alter solution properties (such as ionic strength or chloride content) without specifically preventing interference from volatile organics.

In COD testing, substances that affect how much dichromate is consumed during digestion can skew results. Some volatile organic compounds can escape as vapors or react in unexpected ways, making the measured oxidation appear higher or lower than it truly is. A reagent that acts as a masking or stabilizing agent helps keep those volatile organics from interfering with the digestion, so the amount of dichromate used more accurately reflects the sample’s oxidizable content. Silver sulfate serves this role by suppressing the impact of volatile organics on the digestion. The other options address different issues or simply alter solution properties (such as ionic strength or chloride content) without specifically preventing interference from volatile organics.