Electron spin resonance studies of the reactions of sorbate with nitrite in the presence of a spin trap

An esr spectrum was generated when a spin trap, t-nitroso butane (tNB), was added to potassium sorbate solution at pH of 6.4. This spectrum can be explained by the abstraction of allylic hydrogen by NO 2 , generated by the decomposition of tNB, followed by spin trapping of the radical product. With increasing concentration of NO 2 , which was accomplished by either the addition of sodium nitrite or by lowering the pH to cause rapid decomposition of tNB, a different esr spectrum was observed. This spectrum can be accounted for by a radical formed by addition of NO 2 to the 4,5 double bond of the sorbate and subsequent trapping by tNB.