Nitrogen oxide derivatives nitrosamine formation

The massive contamination of NDE1A in alkaline synthetic fluids (3%) found by Fan et al Q) cannot be explained by known nitrosation kinetics of di- or triethanolamine. Instead, more powerful nitrosation routes, possibly involving nitrogen oxide (N0X) derivatives (e.g., N02> N O t) may be responsible for the amounts of NDE1A in these products (34). In fact, a nitrite-free commercial concentrate was shown to accumulate NDE1A up to about 10 0 days at which time the levels dropped dramatically (19). Inhibition of N0X contaminants may be an effective route to the inhibition of nitrosamine formation in metalworking fluids. 

Methods of formation of IV-nitrosamines from secondary amines have been reviewed. The most widely used reagent is sodium nitrite in an aqueous acidic medium others include nitrosyl chloride, nitrogen oxides and nitrite esters. Fremy s stdt (S03")2N0-] reacts with hydroxylamine in the presence of secondary amines to give A -nitrosamines, or, in the presence of an excess of hydroxylamine, tetrazenes RaNN sNNR . The nitrosating agent derived from hydroxylamine and Fremy s salt is suggested to be the anion (S03")2N0N0. ... 

Nitrosamines are produced in foodstuffs from reactions of nitrites (added as preservatives to bacon and other processed meat products) with amines in (or derived from) the foodstuff, particularly during cooking, e.g., frying anti-oxidants such as ascorbic acid (vitamin C) are added to such foodstuffs to inhibit formation of nitrosamines. A source of nitrosamines that may be of interest to some analytical chemists is beer, in this case attributed (Sen 1983) to reaction of nitrogen oxides with alkaloids (usually present in germinated malt) during the drying process. NMDA can also be formed inadvertently in a number of industrial processes. 

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