in a study of rubber nipples from one manufacturer , n-nitrosodimethylamine , n-nitrosodiethylamine and n-nitrosopiperidine were determined by gas chromatography , using a thermal energy analyser , and their presence was confirmed by mass spectrometry with average levels of individual nitrosamines ranging from 22 to 281 ppb .
C0012431
n-nitrosodimethylamine
C0028197
nitrosamines