Determination of purity and impurities of ethylene glycol for industrial use by gas chromatography

: A new test method was established for the determination of purity and impurities of ethylene glycol (EG) by gas chromatography (GC) using a Rtx-624 column (30 m×0.32 mm×1.8 μm). The method determined not only the impurities in EG from the ethylene oxidation process, such as diethylene glycol, triethylene glycol and (1,3-dioxolan-2-yl)methanol, but also the impurities from the oxalate hydrogenation process, such as 1,2-butanediol, 1,4-butanediol, 1,2-hexanediol, and ethylene carbonate, etc. The method showed good repeatability and high detection sensitivity. The lowest LOD of the impurities reached to 0.0002% (mass fraction), and the recoveries of the impurities were in the range of 91.2%-105.4%. The proposed method can be applied in production control, product testing and market trade of ethylene glycol.