An isotope dilution headspace method with gas chromatography-mass spectrometry for determination of propylene oxide
Xu-Liang Cao1, Jeannette Corriveau
1Food Research Division, Bureau of Chemical Safety, Food Directorate, Health Canada, 251 Sir Frederick Banting Driveway, AL: 2203D, Ottawa, Ontario K1A 0K9, Canada. xu-liang_cao@hc-sc.gc.ca
Abstract:
A method based on isotope dilution headspace and gas chromatography-mass spectrometry was developed for the determination of propylene oxide in foods. Optimum method sensitivity was achieved by the addition of NaCl in water at saturation and with the sample solution incubated at 90 degrees C. The method had good repeatability with relative standard deviations of 6.0, 7.6 and 2.2% at 5, 20 and 40 microg l(-1), respectively. The method was used to determine propylene oxide in 36 selected food composite samples from the 2007 Canadian total diet study. Propylene oxide was not detected in any samples analyzed with an average method detection limit of 0.5 ng g(-1). Hydrolysis of propylene oxide in water was observed as a first-order reaction with a half-life of 15 h at room temperature and less than 10 min at 90 degrees C. This confirms that it is very unlikely to find propylene oxide in foods as consumed due to its volatility and reaction with water.
