Abstract: An analytical method was developed to determine 4 kinds of chloropropanols in foods using gas chromatography mass spectrometer coupled with the multi-isotopic internal standard technique. The derivative performance was between the compared HFBI of different Brands and the internal standard selection for quantifying was discussed. Under the optimized condition, the detection limits (LOD) were 2.5~10 μg/kg for 4 kinds of chloropropanols. According to the internal standard calibration, an excellent linearity between 100 and 2000ng of chloropropanols (R2>0.9990) was obtained. When chloropropanols was spiked at levels of 100-400 mg/kg to soy sauce and seasoning powder of instant noodles, the average recoveries were 90.1~107%, and relative standard deviation (RSD) were 3.86～10.4% (n=6). It was proved that the use of only 2 kinds of the internal standards (chloropropane-1, 2-diol-d5 or 2-chloropropane-1, 3-diol-d5 and 1, 3-dichloro-2-propanol-d5) can be sure the accuracy and precision of determination of 4 kinds of chloropropanols. When 3-chloropropane-1,2-diol(3-MCPD) was used to calibrate 2-MCPD in foods, the level of 2-chloropropane-1,3-diol(2-MCPD) was only 52.1～77.8% of the real content.

Key words: Food, Chloropropanol, Dispersion matrix solid-phase extraction, Isotopic internal standard technique, Gas chromatography-mass spectrometer（GC-MS）