Determination of Hydrogen Halide and Halogen Emissions From Stationary Sources (Non-Isokinetic Method)
An integrated sample is extracted from the source and passed through a prepurged heated
probe and filter into dilute sulfuric acid and dilute sodium hydroxide solutions which collect the
gaseous hydrogen halides and halogens, respectively. The filter collects particulate matter
including halide salts but is not routinely recovered and analyzed. The hydrogen halides are
solubilized in the acidic solution and form chloride (Cl−), bromide (Br−), and fluoride (F−) ions.
The halogens have a very low solubility in the acidic solution and pass through to the alkaline
solution where they are hydrolyzed to form a proton (H +), the halide ion, and the hypohalous
acid (HClO or HBrO). Sodium thiosulfate is added in excess to the alkaline solution to assure
reaction with the hypohalous acid to form a second halide ion such that 2 halide ions are formed
for each molecule of halogen gas. The halide ions in the separate solutions are measured by ion
chromatography (IC).
For the isokinetic version of this method, please refer to Method 26A.
For more information and documents about Method 26, please consult the EPA's Method 26 webpage.
Apex Instruments offers a Method 26 Extension Kit. If interested in Method 26 sampling, Apex Instruments works with our customers to make sure we are providing the correct products for your project and will provide you with a price quote. For any questions about our extension kit, please contact sales@apexinst.com.