Isotope dilution gas chromatography - mass spectrometry for the development of certified reference material of ethyl carbamate in hydroalcoholic matrix

Ethyl carbamate (EC) is a toxic organic contaminant naturally present in some foods and alcoholic beverages. In order to improve the reliability of EC analysis, certified reference materials (CRM) can be used by the laboratories for quality control and for validation and standardization of analytical methods. This paper presents the development of a CRM of EC in hydroalcoholic matrix. This matrix is comprised by a 43% (v/v) aqueous ethanol solution that simulates distilled alcoholic beverages, which generally have alcoholic degree between 35% and 50%. An isotope dilution gas chromatography–mass spectrometry (ID GC–MS) method was developed, validated and employed to attribute the property value and to carry out the appropriate CRM studies, according to ISO Guide 35. Hydroalcoholic matrix was preferred instead of some distilled beverage because in the natural matrix there are EC precursors, which reacting with ethanol enable EC formation, even along storage under appropriate conditions. The applicability of the developed ID GC–MS method was evaluated by testing 26 samples of whisky, vodka, tequila, pisco, rum and the Brazilian cachaça. No interference was observed showing that it can be employed for EC quality control in distilled beverages. According to the analysis of variance, the CRM was considered homogeneous and stable at (4 ± 2) °C for at least three years. The EC concentration is (149.2 ± 5.7) ng/g.