Which residual chlorine method is most suited for colored samples containing less than 1 mg/L chlorine?

Which residual chlorine method is most suited for colored samples containing less than 1 mg/L chlorine?

• A. DPD colorimetric
• B. Iodometric titration
• C. Orthotolidine comparative
• D. Amperometric titration

Answer: (D)

Amperometric titration is the method most suited for measuring residual chlorine in colored samples containing less than 1 mg/L chlorine due to its high sensitivity and ability to explicitly measure low concentrations of chlorine, even in the presence of color and turbidity. This technique utilizes an electrochemical approach to detect the chlorine level, allowing for accurate readings that are less affected by interference from colored compounds in the sample. The other methods may not be as reliable under these conditions. For instance, DPD colorimetric methods can be influenced by the presence of color in the samples, leading to potential inaccuracies in measuring residual chlorine. Iodometric titration is a classic method but may not be as effective for low chlorine concentrations in colored samples without sophisticated controls. Orthotolidine comparative methods, while useful, can also suffer from inaccuracies due to sample coloration, impacting their effectiveness in detecting low residual chlorine levels. Thus, the choice of amperometric titration is justified based on its specific advantages in analyzing residual chlorine in challenging sample conditions.

Amperometric titration is the method most suited for measuring residual chlorine in colored samples containing less than 1 mg/L chlorine due to its high sensitivity and ability to explicitly measure low concentrations of chlorine, even in the presence of color and turbidity. This technique utilizes an electrochemical approach to detect the chlorine level, allowing for accurate readings that are less affected by interference from colored compounds in the sample.

The other methods may not be as reliable under these conditions. For instance, DPD colorimetric methods can be influenced by the presence of color in the samples, leading to potential inaccuracies in measuring residual chlorine. Iodometric titration is a classic method but may not be as effective for low chlorine concentrations in colored samples without sophisticated controls. Orthotolidine comparative methods, while useful, can also suffer from inaccuracies due to sample coloration, impacting their effectiveness in detecting low residual chlorine levels.

Thus, the choice of amperometric titration is justified based on its specific advantages in analyzing residual chlorine in challenging sample conditions.