ASTM D-1946 and ASTM D-1945 Permanent Gases and Hydrocarbons

ASTM D-1946 and ASTM D-1945 are methods for measuring permanent gases in refinery samples using gas chromatography (GC) and a thermal conductivity detector (TCD). The TCD is used for measuring percentage levels of compounds so the method can be use to measure nitrogen, oxygen, methane, carbon dioxide, and carbon monoxide in ambient air and gas samples in the range of 0.05 to 100%. The EPA source test method is called EPA 3C. The method also covers measuring light hydrocarbons. The method also can be used with a combination of TCD and flame ionization detection (FID).