Kinetics of Dimethylamine Nitrosation in Relation to Nitrosamine Carcinogenesis<xref ref-type="fn" rid="FN2">2</xref>

The nitrosation of dimethylamine in buffered aqueous solutions was studied with the aid of the tritium-labeled amine. At pH 3.4, the rate of dimethylnitrosamine (DMN) formation was proportional to the dimethylamine concentration and to the square of nitrite concentration. The rate of reaction was maximal at about pH 3.4. The relative constancy of the appropriate rate constants under various conditions confirmed the third-order kinetics of the reaction, though discrepancies were apparent at pH 1–2. The rate constants were used to estimate the amount of DMN expected to be formed in the gastric contents after ingestion of food containing various concentrations of dimethylamine and nitrite and during storage of such food. For example, it was estimated that, if a man ate a 300-g meal containing 12 mg dimethylamine hydrochloride and 60 mg sodium nitrite, not more than about 3 μg DMN might be expected to be formed intragastrically.