Determination of Ethyl Carbamate (Urethane) in Alcoholic Beverages Using Capillary Gas Chromatography with Thermal Energy Analyzer Detection: Collaborative Study

Abstract

A gas chromatographic (GC) procedure for the determination of ethyl carbamate (urethane) in distilled spirits and wines using a thermal energy analyzer (TEA) system was collaboratively studied by 5 laboratories. Distilled spirits such as whiskey, brandy, gin, rum, and vodka containing low solids can be injected directly into the GC system without extraction. Liqueurs require extraction. Wine, beer, sake, and similar samples containing significant solids or other interferences are extracted prior to injection. The sample is analyzed by GC/TEA operating in the nitrogen mode with capillary column capability (30 m × 0.53 mm) and automatic injection. Helium is the carrier gas. The GC system is calibrated with a 100 ppb standard, followed by the samples. The concentration of ethyl carbamate is determined by multiplying peak area ratios by the concentration of the standard. For the distilled spirits, the recovery averaged 92%. The within-labora-tory repeatability (RSDr) ranged from 4.3 to 12.5%, with overall average of 8.0%, and reproducibility (RSDR) varied from 4.8 to 22.0%, with an overall average of 17.4%. For the wines, the recovery averaged 85%, and the RSDr ranged from 8.9 to 42.8%, with an overall average of 34.4%. The method has been adopted first action by AOAC INTERNATIONAL.