【国外标准】 Standard Test Methods for Aromatics in Mineral Spirits by Gas Chromatography

4.1 These test methods were developed to measure the types and amounts of aromatics in mineral spirits to determine compliance with air pollution regulations that restrict the aromatic content of solvents. They have been demonstrated to be workable and to produce accurate results. However, due to the sensitivity of the tests to operating variables, some laboratories having limited experience with gas chromatographic analyses of hydrocarbons may experience difficulty in performing the tests.1.1 These test methods cover the determination of ethylbenzene and total eight-carbon (C8) and heavier aromatics in the concentration range from 0.1 to 30 % in mineral spirits having a distillation range from 149 to 210 °C (300 to 410 °F) as determined by Test Method D86. The procedures permit the identification and calculation of concentrations of aromatic components to 0.1 volume %.1.2 It is recognized by analytical chemists that a single column gas chromatography analysis of an unknown sample is risky. In such cases, multiple and different analytical techniques must be used for absolutely positive identification, for example, several different gas chromatography columns, gas chromatography/mass spectrometer, or gas chromatography/infrared, etc. In these test methods the material is known and is clearly defined.1.3 Oxygenated compounds, if present, may interfere and cause erroneous results. Such oxygenated compounds are not normally present in mineral spirits.1.4 Three test methods are covered as follows:1.4.1 Test Method A, measurement of ethylbenzene content, C8 plus higher aromatics (except ethylbenzene), and total aromatics by means of a single packed column gas chromatographic analysis.1.4.2 Test Method B, measurement of ethylbenzene content by means of a rapid packed column gas chromatographic analysis.1.4.3 Test Method C, measurement of ethylbenzene content, C8 plus higher aromatics (except ethylbenzene) and total aromatics by means of a capillary column gas chromatographic analysis.1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.6 For purposes of determining conformance of an observed or a calculated value using this test method to relevant specifications, test result(s) 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 E29.1.7 For hazard information and guidance, see the supplier’s Material Safety Data Sheet.1.8 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.