【国外标准】 Standard Test Method for Analysis of p-Xylene by Gas Chromatography (Withdrawn 2009)

This test method is suitable for setting specifications on p-xylene and for use as an internal quality control tool where p-xylene is produced or is used in a manufacturing process. It may also be used in development or research work involving p-xylene. It is generally applied to determining those commonly occurring impurities such as nonaromatic hydrocarbons, benzene, toluene, ethylbenzene, m-xylene, o-xylene, and cumene (isopropylbenzene). Purity is commonly reported by subtracting the determined expected impurities from 100.00. However, a gas chromatographic analysis cannot determine absolute purity if unknown components are contained within the material being examined. Refer to Specification D 5136 for determining other chemical and physical properties of p-xylene.1.1 This test method covers the determination of known hydrocarbon impurities in, and the purity of p-xylene by gas chromatography (GC). It is generally meant for the analysis of p-xylene of 99 % or greater purity. Impurity concentrations that can be measured range from 0.001 to 1.000 weight %.1.2 The following applies to all specified limits in this test method: for purposes of determining conformance with this test method, an observed value or a calculated value shall be rounded off 'to the nearest unit' in the right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E 29.1.3 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 hazard statement, see Section 9.