Non-volatile nitrosamines exemplified by nitroso amino acids, -dipeptides, -oxazolidines and -thiazolidines have been analysed by moving belt liquid chromatography/mass spectrometry (LC/MS) and spectra obtained by ammonia chemical ionization. Optimal conditions such as source temperature, source pressure and belt vaporizer temperature have been established. Interface degradation involving decarboxylation and denitrosation was experienced but could be alleviated to some extent by deactivation of the polyimide belt by silylation.