Which chemical is combined with a pH buffer (pH 4) in an amperometric chlorine analyzer?

In an amperometric chlorine analyzer, combining a pH buffer with potassium iodide reagent is crucial for accurate chlorine measurement. The potassium iodide reacts with the chlorine present in the sample, resulting in the formation of iodine. This process is essential for the amperometric detection method, as the presence of iodine is directly related to the concentration of chlorine in the water being tested.

The purpose of the pH buffer is to maintain a stable pH level during the analysis, which is vital for ensuring consistent results. A pH buffer at 4 is commonly used because it provides an optimal environment for the reaction between chlorine and potassium iodide, enhancing the sensitivity and reliability of the measurement. A stable pH helps prevent fluctuations that can lead to variations in the readings.

In contrast, while other chemicals like ammonium hydroxide, sodium hydroxide, and sodium thiosulfate are important in various chemical processes, they do not serve the same function in the context of an amperometric chlorine analyzer equipped with a pH buffer. Ammonium hydroxide and sodium hydroxide are typically used to adjust pH levels or as titrants, but they do not facilitate the same reaction or enhance the chlorine detection process like potassium iodide does. Sodium thios