Nitrite interferes with which chlorine residual measurement method?

Nitrite interferes with which chlorine residual measurement method?

• A. Aerometric method
• B. Colorimetric method
• C. Titrimetric method
• D. Membrane method

Answer: (A)

Nitrite is a reducing agent, so it reacts with and consumes free chlorine in water. The aerometric chlorine residual test relies on the oxidizing power of chlorine to drive a reaction in the test setup, and the amount of chlorine available to produce the measurable signal determines the result. When nitrite is present, it consumes part of the chlorine before that signal can form, causing the aerometric method to read lower than the actual chlorine residual. This specific susceptibility to nitrite interference is why the aerometric method is the one most affected. The other methods use different detection principles. Colorimetric tests (like DPD) rely on forming a color proportional to chlorine and are less sensitive to nitrite in typical testing conditions, while titrimetric and membrane methods involve different redox or electrochemical processes that aren’t as prone to the same nitrite-induced bias in routine use.

Nitrite is a reducing agent, so it reacts with and consumes free chlorine in water. The aerometric chlorine residual test relies on the oxidizing power of chlorine to drive a reaction in the test setup, and the amount of chlorine available to produce the measurable signal determines the result. When nitrite is present, it consumes part of the chlorine before that signal can form, causing the aerometric method to read lower than the actual chlorine residual. This specific susceptibility to nitrite interference is why the aerometric method is the one most affected.

The other methods use different detection principles. Colorimetric tests (like DPD) rely on forming a color proportional to chlorine and are less sensitive to nitrite in typical testing conditions, while titrimetric and membrane methods involve different redox or electrochemical processes that aren’t as prone to the same nitrite-induced bias in routine use.