5.1 This test method is suitable for setting specifications on the materials referenced in Table 1 and for use as an internal quality control tool where cyclohexane is produced or is used in a manufacturing process. It may also be used in development or research work involving cyclohexane.

5.2 This test method is useful in determining the purity of cyclohexane with normal impurities present. If extremely high boiling or unusual impurities are present in the cyclohexane, this test method would not necessarily detect them and the purity calculation would be erroneous.

1.1 This test method covers the determination of the purity of cyclohexane by gas chromatography. Calibration of the gas chromatography system is done by the external standard calibration technique.

1.2 This test method has been found applicable to the measurement of impurities such as those found in Table 1, which are impurities that may be found in cyclohexane. The impurities can be analyzed over a range of 3 to 200 mg/kg by this method, but may be applicable to a wider range.

 C₄

(1) n-butane

(2) isobutene

 C₅

(3) n-pentane

(4) isopentane

(5) cyclopentane

 C₆

(6) n-hexane

(7) 2-methylpentane

(8) 3-methylpentane

(9) methylcyclopentane

(10) benzene

(11) cyclohexene

(12) 2,2-dimethylbutane

(13) 2,3-dimethylbutane

 C₇

(14) 3,3-dimethylpentane

(15) 2,2-dimethylpentane

(16) 2,3-dimethylpentane

(17) 2,4-dimethylpentane

(18) 1,1-dimethylcyclopentane

(19) trans-1,3-dimethylcyclopentane

(20) trans-1,2-dimethylcyclopentane

(21) cis-1,2-dimethylcyclopentane

(22) 2,2-dimethylcyclopentane

(23) 2,4-dimethylcyclopentane

(24) cis-1,3-dimethylcyclopentane

(25) ethylcyclopentane

(26) methylcyclohexane

(27) 3-ethylpentane

(28) 3-methylhexane

(29) 2-methylhexane

(30) n-heptane

(31) toluene

 C₈

(32) iso-octane

(33) p-xylene

 C₉

(34) isopropylcylohexane

1.3 The limit of detection is 1 mg/kg.

1.4 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.

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6 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 7.