Abstract:

A new method was established for direct determination of ethyl carbamate (EC) in alcoholic beverages by stable
isotope dilution liquid chromatography-tandem mass spectrometry. After being spiked with EC-d5 and filtered with micropore
filters, the samples were directly injected. The chromatographic separation was carried out on a Waters XSELECT
HSS T3 column (2.1 mm × 150 mm, 3.5 μm) with a mobile phase of 80% water containing 0.1% (V/V) acetic acid and 20%
acetonitrile in an isocratic elution mode at a flow rate of 0.2 mL/min. The mass spectrometry detection was performed by
positive electrospray ionization (ESI+) and monitored in a multiple reaction monitoring (MRM) mode (m/z 94.9/63 and
94.9/44 for EC-d5; m/z 89.9/62 and 89.9/44 for EC). The limit of detection (LOD) was lower than 2 ng/mL and the limit of
quantification (LOQ) was lower than 5 ng/mL. The calibration curve showed good linearity in the range of 5–500 ng/mL
with a correlation coefficient of 0.999 8. The spiked recoveries of EC ranged from 92.4% to 108.5%, and the relative
standard deviations (RSDs) were 3.12%–8.65% (n = 6). EC content increased significantly when wine was stored at room
temperatures (21–28 ℃) than at 4 ℃ as determined by the proposed method. Heating (at 95 ℃) before drinking resulted in
significantly increased levels of EC content in distilled spirits and mixed alcoholic drinks.

Key words: ethyl carbamate, liquid chromatography-tandem mass spectrometry, alcoholic drink, isotope dilution