Determination of 9 N-Nitrosamines in Milk by Gas Chromatography Tandem Mass Spectrometry with Solid Phase Extraction

A method was established for the simultaneous determination of 9 N-nitrosamines in milk by gas chromatography tandem mass spectrometry (GC-MS/MS) with solid phase extraction. The 9 N-nitrosamines in milk (10.0 g) were extracted with 10 mL acetonitrile, and purified with Captiva EMR-Lipid solid phase extraction cartridge, and then the purified liquid were concentrated with low temperature and microflow nitrogen. The target compounds were detected by GC-MS/MS under multi-reaction monitoring (MRM) mode, and internal standard method was used for quantitative analysis. The results showed that the linearity ranges for 9 N-nitrosamines were all found in the same range of 0.5-37.5 μg·kg^-1, with detection limits (3S/N) between 0.003 to 0.043 μg·kg^-1. Test for recovery was made by standard addition method, giving results in the range of 78.7%-124%, and RSDs (n=6) of the determined values all less than 6.0%.