Determination of a non-volatile nitrosamine by using denitrosation and a chemiluminescence analyser

Abstract

A method has been devised for the determination of N-nitrososarcosine, representative of the group of non-volatile nitrosamines of physiological origin, whereby the nitrosamine is denitrosated with hydrogen bromide to form the volatile nitrosyl bromide. After dehalogenation in a heated converter, the nitrosamine can be determined as nitric oxide by using a chemiluminescence analyser, the response being linear up to at least 200 µg. The limit of detection is below 6 ng, and is therefore much lower than that for the determination of N-nitrososarcosine as inorganic nitrite in solution after denitrosation. A response is also obtained from inorganic nitrite but this can be differentiated from that of N-nitrososarcosine by the use of acetic acid alone, prior to denitrosation with hydrogen bromide in the same solvent.