ASTM D 1988:2006 Standard Test Method for Mercaptans in Natural Gas Using Length-Of-Stain Detector Tubes ASTM D 2725:1987 Test Method for Hydrogen Sulfide in Natural Gas (Methylene Blue Method) ASTM D 4888:2006 Standard Test Method for Water Vapor in Natural Gas Using Length-of-Stain Detector Tubes ASTM D 4984:2006 Standard Test Method for Carbon Dioxide in Natural Gas Using Length-of-Stain Detector Tubes ASTM D 6273:1998 Standard Test Methods for Natural Gas Odor Intensity ASTM D 6968:2003 Standard Test Method for Simultaneous Measurement of Sulfur Compounds and Minor Hydrocarbons in Natural Gas and Gaseous Fuels by Gas Chromatography and Atomic Emission Detection ASTM D 4891:2006 Standard Test Method for Heating Value of Gases in Natural Gas Range by Stoichiometric Combustion