Section 2: Principle

A sample of the stack gas is extracted from a single point near the centre of the stack over a sampling duration of about 20 minutes. After the removal of particulate matter from the sample gas, hydrogen chloride is collected by impingement in a series of midget impingers containing measured amounts of distilled or deionized water. The resulting solutions are analyzed for chlorides by ion chromatography (2).

The accuracy of the method may be limited by the presence of water soluble chloride ions from compounds other than hydrogen chloride.