N-Nitroso Compounds in Tobacco Smoke II/Zur Frage der N-Nitroso-Verbindungen im Tabakrauch ll

The cold pentane traps of the precipitation procedure described in the preceding paper (cotton wool trap, water trap, pentane traps) favour the formation of N-nitroso components and, as a result, the emergence of artefacts. If, however, the smoke sojourns in the aerosol state for a period of 40 seconds (compared to 5 seconds) also that part of condensate of smoke from cigarette tobaccos rich in nitrates and bases which is trapped on cotton wool at normal temperature, contains N-nitroso-dimethylamine and N-nitroso-pyrrolidine in quantities corresponding to 0.004 µg N-NO per cigarette. The formation of N-nitroso components in the smoke of tobaccos of high nitrate and base contents accordingly occurs during a gas phase reaction which is dependent on time.

In conformity with the previously reported findings N-nitrosomethyl-n-butylamine was identified in the condensate gathered in pentane traps. Presumably, it has however to be regarded as an artefact produced by the precipitation system employed. Condensates collected in cold and acetone traps were found to contain more N-nitroso components than condensates precipitated simply by the gas phase reaction of the smoke. The quantity of N-nitroso components contained in condensates gathered in cold traps was found to increase during aging.

Model experiments with pure substances showed that the formation of N-nitroso components in the gas phase requires the presence of a mixture of NO and NO₂.

The competitive reaction of dimethylamine and methanol with the gaseous mixture of nitrogen oxides displays the prevailing formation of N-nitroso-dimethylamine. The yield of N-nitroso-dimethylamine in NO-air-mixtures is probably only dependent on the rate of the oxidation NO undergoes to NO₂.

Nitramines cannot occur in smoke.