The method for the determination of the content of toluene and m-xylene in lycopene sauce by gas chromatography mass spectrometry (GC­MS) was established. The effects of three different sample pretreatment methods were tested. It was found that lycopene could undergo rearrangement and degradation to toluene and m-xylene at high temperature so that their test values were significantly higher than their authentic values. Extraction with ethanol followed by headspace-blowing-condensation proved to be an effective sample pretreatment method that could avoid the adverse high temperature effect and thus enable accurate determination of the content of toluene and m-xylene in lycopene sauce. Following this method, good linear relationships in the range of 1～100 µg/mL for toluene and in the range of 3～300 µg/mL for m-xylene were obtained, accompanied by recovery of 92.2%～98.0% for toluene and 90.3%～97.4% for m-xylene, of which the relative standard deviations were both less than 10.0% and the limits of determination were both 0.03 µg/g.

Key words: lycopene sauce, toluene, m-xylene, GC-MS