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DETERMINATION OF ETHYL CARBAMATE IN COMMERCIAL PROTEIN BASED CONDIMENT SAUCES BY GAS CHROMATOGRAPHY‐MASS SPECTROMETRY
Author(s) -
HARTMAN THOMAS G.,
ROSEN ROBERT T.
Publication year - 1988
Publication title -
journal of food safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 43
eISSN - 1745-4565
pISSN - 0149-6085
DOI - 10.1111/j.1745-4565.1988.tb00518.x
Subject(s) - ethyl carbamate , chemistry , chromatography , mass spectrometry , gas chromatography , carbamate , detection limit , chemical ionization , gas chromatography–mass spectrometry , selected ion monitoring , electron ionization , ionization , ion , organic chemistry , food science , wine
Commercially obtained protein based condiments, including soy sauces, were analyzed for the presence of ethyl carbamate (urethane) using combined gas chromatography‐mass spectrometry (GC‐MS). Samples were spiked with 100 parts‐per‐billion (ppb) of t ‐butyl carbamate internal standard, extracted with methylene chloride and concentrated prior to GC‐MS analysis. For quantitation, the ratio of the pseudomolecular ions produced during isobutane chemical ionization (CI) at m/z 90 (ethyl carbamate) and m/z 118 ( t ‐butyl carbamate) were monitored by mass chromatography. Response factors for ethyl carbamate versus the internal standard were determined in both the electron ionization (EI) and chemical ionization modes. The CI mode was used for quantitation as it was more sensitive and interference free. Samples testing positive by CI‐MS were subsequently scanned by EI‐MS for confirmation of identity as the CI spectra did not contain fragment ions necessary for adequate specificity. This method proved simple and reliable with detection limits less than 1 ppb. Limits of confirmation were 10 ppb. The recovery of internal standard was 86.7%± 5.6%. Only fermented products were found to contain ethyl carbamate.