ASTM D4492-07

This test method is suitable for determining the concentrations of known impurities in finished benzene and for use as an integral quality control tool where 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.

Absolute purity cannot be determined if unknown impurities are present. Test Method D 852 is generally used as a criteria for determining the absolute purity.

1.1 This test method covers the determination of normally occurring trace impurities in, and the purity of, finished benzene by gas chromatography.

1.2 This test method is applicable for benzene purities of 99.80 weight % or higher.

1.3 The lower limit of detection for total non-aromatic impurities is 0.005 weight %. The lower limit of detection for individual aromatic hydrocarbon impurities in 0.001 weight %. The lower limit of detection for 1,4-dioxane is 0.0005 weight %.

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 E 29.

1.5 &solely-SI-units;

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.