GAS CHROMATOGRAPHIC DETERMINATION OF VOLATILE NITROSAMINES IN FOODS

Abstract

Methods are presented for determination of certain volatile nitrosamines which have been reported to occur in foods. Nitrosamines were removed from foods using a Likens‐Nickerson extractor; 60% of added dimethylnitrosamine and 70% of added diethyl‐nitrosamine were recovered from 10 rig/g aqueous solutions. Potential gas chromatographic (GC) interferences were removed from the extract by a simple acid extraction step and, when needed, by liquid column chromatography. Dilute solutions containing nitrosamines were analyzed directly with a GC solvent stripping technique. Nitrosamines were detected with a Coulson electrolytic conductivity detector operated in the pyrolytic mode and with a flame ionization detector. Sensitivities of these detectors are compared for selected volatile alkyl and heterocyclic nitrosamines of potential significance in foods. The specificity of the Coulson detector is demonstrated for analysis of extracts of smoked fish and a number of processed meats. Additional clean‐up of concentrates from foods is required to insure unambiguous identification of nitrosamines by combined GC‐mass spectrometry.