Ethylene glycol and diethylene glycol are considered toxic to human health and both are commonly present as impurities in propylene glycol. In response to these toxic considerations and adhering to the recommendations from US Food and Drug Administration (USFDA), United States Pharmacopoeia (USP) revised its monograph for propylene glycol in 2010. This monograph addresses the toxicity concerns by specifying the limit for ethylene glycol and diethylene glycol while using propylene glycol as an inactive ingredient to meet quality standards in pharmaceutical products. This updated monograph identifies propylene glycol and defines a limit test for ethylene glycol and diethylene glycol through Gas Chromatography/Flame Ionization Detection (GC-FID).

This application note shows the performance of the PerkinElmer GC 2400^™ System with FID for the analysis of propylene glycol quality according to the updated USP monograph, while demonstrating superior performance and a 40% improvement to the required resolution.