Nitrosation of water-soluble (diethanolamine) and oil-soluble (dodecylmethylamine and dicyclohexylamine) amines in the absence and presence of inhibitors in model anionic and non-ionic emulsions was studied. Nitrosation of diethanolamine occurred at similar rates in non-ionic and anionic emulsions. Surprisingly, dodecylmethylamine and dicyclohexylamine were readily nitrosated in non-ionic emulsions, but not in anionic emulsions. Sodium bisulfite and ascorbyl palmitate were effective inhibitors, but the activity of ascorbic acid was lower. Considerably less effective were potassium sorbate, alpha-tocopherol and butylated hydroxyanisole. The results of this study will help formulators of emulsion products to minimize N-nitrosamine contamination.
