Determination of N-nitrosodimethylamine in artificial gastric juice by gas chromatography-mass spectrometry and by gas chromatography-thermal energy analysis.

The thermal energy analyser (TEA) is considered to be the gold standard for the determination of nitrosamines. However, since many laboratories cannot justify the use of such a very specific detection system, alternative detection methods are useful. While standard gas chromatography (GC) detectors lack the selectivity of the TEA detector, mass spectrometry (MS) seems to be the method of choice to combine GC separation with mass selective detection. Moreover, the detection limits of the GC-MS assay in general use are about 4 times lower than those of the GC-TEA assay. A comparison of GC-MS and GC-TEA data on N-nitrosodimethylamine determinations showed a strong correlation between the two assays (R2 = 0.86), demonstrating the exchangeability of these methods.