Effect of organic solvents and unsaturated fatty acids on nitrosamine formation.

Formation of N-nitrosodimethylamine in chloroform or in mixtures of chloroform/citrate buffer or methyl stearate-chloroform (1:9)/citrate buffer was faster than that in citrate buffer alone. The chemically inert non-aqueous solvent may increase the level of the non-ionized active species of the nitrosating agent. The presence of unsaturated fatty acid methyl esters in chloroform suppressed formation of N-nitrosodimethylamine compared to that in chloroform alone but, because of the non-aqueous solvent effect, nitrosamine formation was slightly higher than that in citrate buffer. Fats containing unsaturated fatty acids also inhibited nitrosamine formation in chloroform indicating that the unsaturated fatty acid residues were effective scavengers of the nitrosating agent. Methyl linoleate was converted into peroxide(s) with carbonyl or carbonyl-liberating functions by reaction with nitrous acid, although it is not clear whether the reaction was relevant to the loss of nitrous acid.