Acceleration of nitrosamine formation by contaminant(s) in sodium chondroitin sulfate preparations

Abstract

Formation of nitrosamines from secondary amines and nitrite was markedly accelerated by sodium chondroitin sulfate (SCS) preparations. The nitrosation of dimethylamine in the presence of the SCS preparation was proportional neither to the nitrite concentration nor to the square of the nitrite concentration. Among dimethylamine, dibutylamine, pyrrolidine, piperidine, and morpholine, nitrosation of dimethylamine was most strongly accelerated. The nitrosation-accelerating activity was inhibited by cupric and silver ions. The nitrosation-accelerating substance in the SCS preparation was dialyzable and not chondroitin sulfate itself. The potency of the accelerating effect was about 18 times of that of a similar weight of sodium thiocyanate or potassium iodide. The importance of the substance in human exposure to carcinogens was suggested.Secondary amines and other nitrosatable compounds easily react with nitrite in acidic medium and form nitroso National Institute of Hygienic Sciences, Setagaya-ku, Tokyo 158, Japan.compounds. The secondary amine that was most frequently found in foods was dimethylamine (DMA) (Neurath et al., 1977). Although the nitrosation rate of DMA by nitrite is rather slow (Mirvish, 1975), the rate is affected by many coexisting substances in the reaction mixture. Anions such as thiocyanate and iodide were reported to