On‐column trace‐level formation of N‐nitrosamine in a liquid chromatography–mass spectrometry analytical system.

A model reaction between di‐n‐butylamine and sodium nitrite was studied to investigate trace‐level N‐nitrosamine formation. Liquid chromatography–mass spectrometry (LC–MS) analysis of kinetic time points from an in‐progress reaction showed a systematic offset in nitrosamine concentration between quenched and unquenched samples. By combining samples of amine and nitrite in the needle of the autosampler it was demonstrated that N‐nitrosamine was formed in the LC–MS system. Further experimentation indicated that nitrosation was occurring on‐column. [ABSTRACT FROM AUTHOR]