Direct quantification of ethyl carbamate in distilled alcoholic beverages using a cold capillary injection system and optimised selected ion monitoring

A simple and sensitive method for the determination of ethyl carbamate (urethane) in various fermented foods has been developed. Twenty g of sample was homogenized and extracted with 150 ml of acetone. Twenty ml of water was added to the extract which was then evaporated to remove organic solvent. The residual aqueous solution was extracted three times with 100 ml of dichloromethane. The organic layer was concentrated by rotary evaporator and was charged on an acid-celite column. After washing the column with 100 ml of pentane and 100 ml of pentane-dichloromethane mixture (80:20), ethyl carbamate was eluted with 60 ml of dichloromethane. The eluant was concentrated to 1 ml using a rotary evaporator, and ethyl carbamate was determined by gas chromatography-mass spectrometry in the selected ion monitoring mode. For liquid samples, extraction with acetone was not necessary. The column purification step was also unnecessary for alcoholic beverages. The detection limit for this procedure was 0.5 ppb/sample, and the recovery was 70 to 105% for miso, moromi, natto, soy sauce, sake, yogurt, and bread when they were fortified with 5 to 50 ppb of ethyl carbamate. Ethyl carbamate levels in various fermented foods including yogurt, bread, mirin, or sakekasu were determined by this method. Relatively high levels of ethyl carbamate were detected in sake and soy sauce.

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Determination of Ethyl Carbamate in Distilled Alcoholic Beverages by Gas Chromatography with Flame Ionization or Mass Spectrometric Detection

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/71.4.781 ◽

1988 ◽

Vol 71 (4) ◽

pp. 781-784 ◽

Cited By ~ 2

Author(s):

William M Pierce ◽

Adora O Clark ◽

Harrell E Hurst

Keyword(s):

Gas Chromatography ◽

Quantitative Methods ◽

Limit Of Detection ◽

Ethyl Carbamate ◽

Alcoholic Beverages ◽

Gas Chromatography Mass Spectrometry ◽

Selected Ion Monitoring ◽

Flame Ionization ◽

Coefficients Of Variation

Abstract Quantitative methods are detailed for determination of ethyl carbamate in distilled alcoholic beverages by capillary gas chromatography with flame ionization detection (GC/FID) and by packedcolumn gas chromatography/mass spectrometry (GC/MS) using selected ion monitoring. Five g samples of distillate of known ethanol concentration are diluted with water to 25% ethanol (v/v), washed with petroleum ether, and extracted with dichloromethane prior to GC/FID or GC/MS analysis. As necessary, sample extracts that exhibit GC/FID interference are passed through alumina for additional cleanup. When internal standards (ferf-butyl carbamate and n-butyl carbamate for GC/FID, or ethyl ,3C-,sN-carbamate for GC/ MS) were used for quantitation, the limit of detection for ethyl carbamate was in the range of 5-25 ppb. Coefficients of variation ranged from 3.5 to 6.0% for GC/FID determinations, and from 1.4 to 3.2% for GC/MS. Correlation between methods for 22 random distillate samples ranging in concentration from approximately 40 to 800 ppb gave a correlation coefficient (r) of 0.996.

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