Dual column chromatographic method for determination of N-nitrosothiazolidine in fried bacon

A dual column chromatographic procedure is described that permits the determination of N-nitrosothiazolidine (NTHZ), a newly identified nitrosamine, and N-nitrosopyrrolidine (NPYR), the principal volatile nitrosamine, in the same fried bacon sample. The procedure used an acid-Celite, Celite, sodium sulfate column followed by a partially deactivated basic alumina column to isolate NTHZ from bacon for subsequent quantitation by gas chromatography with a thermal energy analyzer (GC-TEA). A limited intralaboratory study gave standard deviations for repeatability and reproducibility of 1.20 and 1.55 ppb, respectively. The recovery of N-nitrosothiomorpholine, the internal standard added at the 10 ppb level, was 93.3 +/- 6.03%. The method is also free from artifactual nitrosamine formation.