1. Scope
1.1 This test method covers the determination of normally occurring trace impurities in, and the purity of, finished benzene by gas chromatography with external calibration. A similar test method, using the internal standard technique of calibration is D4492. 1.2 This test method is applicable for nonaromatic hydrocarbon impurities at levels from 5 to 2000 mg/kg and for benzene purities of 99.80 weight % or higher. 1.3 This test method is applicable for aromatic impurities from 5 to 2000 mg/kg in benzene. 1.4 This test method has been found applicable to heteroatomic species such as 1,4-dioxane, from 10 to 2000 mg/kg in benzene. 1.5 The limit of detection for aromatic impurities is 1.4 mg/kg and 2.9 mg/kg for 1,4 dioxane. Lower impurity levels can be quantified, but the precision stated in this test method may not be applicable. 1.6 In determining the conformance of the test results using this test method to applicable specifications, results shall be rounded off in accordance with the rounding-off method of Practice E29. 1.7 Units--The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. 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 and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 8.
This test method is suitable for determining the concentrations of known impurities in finished benzene and use as an integral quality control tool in which benzene is either produced or used in a manufacturing procedure. It is generally applied to impurities such as nonaromatics containing nine carbons or less, toluene, C8 aromatics, and 1, 4-dioxane. In accordance with Committee D16 policies, the external standard test method is being prepared because of the ease of use of the test method and the repeatablity available with autoinjectors.
Keywords
benzene; gas chromatography; purity
The title and scope are in draft form and are under development within this ASTM Committee.
Citing ASTM Standards
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