Simultaneous Quantification of Ethanol and Propylene Glycol in Nonbeverage Alcohol Products Using Gas Chromatography Flame Ionization Detection

Abstract

Liquid nonbeverage alcohol products including flavors/flavorings, dietary supplements, medicines, etc. can be complex mixtures of flavor chemicals, adjuvants, and solvents. Ethanol and propylene glycol (PG) are common solvents used in the manufacture of nonbeverage alcohol products and the quantification of these analytes is important for both regulatory and quality control purposes. Presented here is a simple and robust gas chromatography-flame ionization detector (GC-FID) method which simultaneously quantifies ethanol and PG in liquid nonbeverage alcohol samples. The linear range is 0.4–95% v/v for ethanol and 1–99% v/v for PG with r2 of > 0.999. The limit of detection for ethanol was 0.025% v/v and for PG was 0.05% v/v. The limit of quantification was calculated to be 0.075% v/v for ethanol and 0.15% v/v for PG. The method reproducibility was < 2.9%-RSD and < 3.2%-RSD for ethanol and PG, respectively. Spike recoveries for various matrices tested were between 98 and 107% at three different spike concentrations.