【国外标准】 Standard Test Method for Benzene, Toluene, Xylene (BTX) Concentrates Analysis by Gas Chromatography (Withdrawn 2018)

5.1 This test method was primarily developed to determine benzene, toluene, and xylenes in chemical intermediate and solvent streams such as reformate, BTX extracts, pyrolysis gasoline, hydrogenated pyrolysis gasoline, crude benzene, crude ethylbenzene, commercial toluene, and light blending aromatic feedstocks. This test method may not detect all components and there may be unknown components that would be assigned inappropriate response factors and thus, the results may not be absolute.5.2 The relative distribution of C8 aromatics is useful for determining conformance to p-xylene feedstock specifications.1.1 This test method covers the determination of the total nonaromatic hydrocarbons, benzene, toluene, ethylbenzene, xylenes, and total C9 + aromatic hydrocarbons in BTX concentrates by capillary column gas chromatography. This test method is applicable to materials with a final boiling point below 215°C.1.2 This test method may also be used to determine the relative distribution of the individual C8 aromatic hydrocarbon isomers in mixed xylenes.1.3 Individual components can be determined from 0.01 to 90 %.1.4 In determining the conformance of the test results using this method to applicable specifications, results shall be rounded off in accordance with the rounding-off method of Practice E29.1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific precautionary statement, see Section 9.