Confirmation of low microgram/kg amounts of volatile N-nitrosamines in foods by low resolution mass spectrometry.

Volatile N-nitrosamines were confirmed in foods at concentrations of less than 10 micrograms/kg by full scan low resolution mass spectrometry. Ground samples were vacuum-distilled from mineral oil and condensed in liquid nitrogen-cooled vapor traps. The thawed distillate was extracted, the extract was cleaned up and concentrated, and the N-nitrosamine content was determined by combined gas chromatograph-thermal energy analysis. Positive samples were further cleaned up, trapped from a gas chromatographic column, and purged into a gas chromatograph-mass spectrometer for qualitative confirmation by full scan low resolution mass spectrometry. This procedure was applied to foods spiked at 1 microgram/kg and to fried commercial bacons with volatile N-nitrosamine contents of 2 to 5 micrograms/kg.