Abstract:
For quantifying trace levels of ethyl carbamate (EC) in daily foods and cigarette smoke, a reverse-phase solid phase extraction cleanup method coupled with solid phase reverse extraction and gas chromatography/tandem mass spectrometry was developed by adopting pulse splitless injection mode. After extracting EC from samples by using water as a solvent, the extract was cleaned up by C
18 reverse-phase solid phase extraction column, then was reversely extracted by diatomite solid phase extraction column with dichloromethane. The eluent was detected with gas chromatography-tandem mass spectrometry after concentration with deuterium-labeled EC as internal standard for quantitation. The results showed that:1) Under optimal condition, the calibration curve was linear (
R2=0.999 9) when the concentration of EC was in the range of 0.75-48.00 μg/L, the limits of detection and quantitation were 0.025 9 and 0.086 3 μg/kg, respectively. The recoveries of different sample matrix ranged from 91.56% to 112.22% with relative standard deviations of 4.24%-7.97%. 2) The results from surveyed samples indicated that the contents of EC in several daily foods, including alcoholic beverage (yellow rice wine, white spirit, beer and red wine), cooking wine, soy sauce, yoghourt and fermented bean curd ranged from 5.17-523.66 μg/kg, and the release of EC in cigarette smoke ranged from 0.33 to 1.20 ng/cig. With higher sensitivity and better applicability, this method could be used to detect trace EC in other daily foods and cigarette smoke.