【国外标准】 Standard Test Methods for Analysis of Cyclohexane by Gas Chromatography (Withdrawn 2007)

1.1 These test methods cover the determination of the hydrocarbon impurities typically found in cyclohexane and the purity of cyclohexane by difference by gas chromatography. The absolute purity of cyclohexane cannot be determined, since trace quantities of unknowns may be present. Typical impurities in high purity cyclohexane are listed in Table 1. 1.2 These test methods are applicable to impurity concentrations in the range of 0.0001 to 0.1000 wt% and for cyclohexane purities of 98% or higher when using the internal standard procedure. 1.3 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 last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E29. 1.4 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 Note 2 and Section 7.