Simultaneous determination of ethyl carbamate and urea in Korean rice wine by ultra-performance liquid chromatography coupled with mass spectrometric detection

In this study, a rapid method for simultaneous detection of ethyl carbamate (EC) and urea in Korean rice wine was developed. To achieve quantitative analysis of EC and urea, the conditions for Ultra-performance liquid chromatography (UPLC) separation and atmospheric-pressure chemical ionization tandem mass spectrometry (APCI-MS/MS) detection were first optimized. Under the established conditions, the detection limit, relative standard deviation and linear range were 2.83 μg/L, 3.75-5.96%, and 0.01-10.0 mg/L, respectively, for urea; the corresponding values were 0.17 μg/L, 1.06-4.01%, and 1.0-50.0 μg/L, respectively, for EC. The correlation between the contents of EC and its precursor urea was determined under specific pH (3.5 and 4.5) and temperature (4, 25, and 50 °C) conditions using the developed method. As a result, EC content was increased with greater temperature and lower pH. In Korean rice wine, urea was detected 0.19-1.37 mg/L and EC was detected 2.0-7.7 μg/L. The method developed in this study, which has the advantages of simplified sample preparation, low detection limits, and good selectivity, was successfully applied for the rapid analysis of EC and urea.