A method for the determination of methyl carbamate and ethyl carbamate in wines.
A method is described for the simultaneous determination of methyl carbamate (MC) and ethyl carbamate (EC) in wines that is based on: (a) extraction of the sample with dichloromethane using an extraction tube or an alumina-Celite column, (b) concentration of the extract to a small volume, and (c) determination by gas-liquid chromatography-thermal energy analyser (N-mode). The method is highly sensitive (1-2 ng/ml), accurate (recoveries greater than 80%), and precise (CV, 5-10%). Nineteen of 27 samples of wines analysed contained traces (up to 2.7 ng/ml) of MC, and most contained EC (up to 70 ng/ml). Wines treated in the laboratory with 200 ppm dimethyl pyrocarbonate (DMPC)-a cold sterilant recently approved for use in wines-indicated that such a treatment may increase the MC contents of the wines to 10 ng/ml. Additional studies suggested that formation of MC in DMPC-treated wines is dependent on both pH and ammonia content of the wines. The identity of MC in a few selected samples was confirmed by gas-liquid chromatography-high resolution (10 K) mass spectrometry. The natural low levels of MC found in these wines are not considered to pose a risk to human health.
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Food Research Division, Health and Welfare Canada, Ottawa, Ontario.
Seaman
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Weber
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D
D000641:Ammonia / Q000032:analysis; D002219:Carbamates / Q000032:analysis*; D002849:Chromatography, Gas / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D006863:Hydrogen-Ion Concentration; D008752:Methylene Chloride; D014520:Urethane / Q000032:analysis*; D014920:Wine / Q000032:analysis*
D002219:Carbamates; D014520:Urethane; D008752:Methylene Chloride; D000641:Ammonia; C036868:methyl carbamate