【国外标准】 Standard Test Method for Analysis of o-Xylene by Gas Chromatography (Withdrawn 2014)

This test method is suitable for setting specifications on o-xylene and for use as an internal quality control tool where o-xylene is used in a manufacturing process. It may be used in development or research work involving o-xylene. Purity is commonly reported by subtracting the determined expected impurities from 100 %. Absolute purity cannot be determined if unknown impurities are present.1.1 This test method covers the analysis of normally occurring impurities in, and the purity of, o-xylene by gas chromatography. Impurities determined include nonaromatic hydrocarbons, benzene, toluene, p- and m-xylenes, cumene, styrene, and ethylbenzene.1.2 This test method is applicable for impurities at concentrations from 0.001 to 2.000 % and for o-xylene purities of 98 % or higher.1.3 The following applies to all specified limits in this standard: for purposes of determining conformance with this standard, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E 29.1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.5 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 8.