ASTM D8681-26

1.1 This test method covers the determination of organic impurities in commercial methanol and uses those values to determine the purity of methanol (methanol in dry basis) by gas chromatography.

1.2 This test method is applicable to the measurement of methyl formate, ethanol, acetone, isopropanol, methyl acetate, n-propanol, butanone, 2-butanol, isobutanol(2-methyl-1-propanol), n-butanol, 2-pentanone, 3-pentanone, MTBE, benzene, toluene, ethylbenzene, and xylenes in methanol. The limit of detection (LOD) is 1.1 mg/kg, 1.4 mg/kg, 2.0 mg/kg, 0.6 mg/kg for ethanol, acetone, methyl acetate and benzene in methanol, respectively.

1.3 In determining the conformance of the test results using this method to applicable specification, results shall be rounded off in accordance with the rounding-off method of Practice E29.

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

1.5 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.

1.6 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.

5.1 Determination of impurity contents in methanol product is often required. This test method is suitable for setting specifications and for use as an internal quality control tool where these products are produced or are used in a manufacturing process. Typical impurities derived from manufacture of methanol could include methyl formate, ethanol, acetone, isopropanol, methyl acetate, n-propanol, butanone, 2-butanol, isobutanol(2-methyl-1-propanol), n-butanol, 2-pentanone, and 3-pentanone. Typical transport or storage contamination including MTBE, benzene, toluene, ethylbenzene, or xylenes, or combinations thereof.

5.2 Purity of methanol on dry basis is commonly reported by subtracting the determined expected impurities from 100.00. However, this method may not detect all components and there may be unknown components that would be assigned inappropriate correction factors. The results may not be absolute.