High-performance liquid chromatographic detection of trace N-nitrosoamines by pre-column derivatization with 4-(2-phthalimidyl)benzoyl chloride

Abstract

A simple and sensitive method for the detection of N-nitrosoamines is described. N-Nitrosoamines in dichloromethane solution can be denitrosated to secondary amines with a hydrogen bromide–acetic acid mixture, the amines formed then react rapidly with 4-(2-phthalimidyl)benzoyl chloride to give fluorescent amides, which can be separated on an octadecylsilane column with aqueous acetonitrile as eluent. N-Nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosodipropylamine, N-nitrosodibutylamine, N-nitrosopyrrolidine and N-nitrosopiperidine were used as model compounds to optimize the derivatization and chromatographic conditions. The realtive standard deviations (n= 7) at an analyte concentration of 8 × 10^–6 mol l^–1 were less than 5%. The detection limits were in the range 0.4–1.6 pmol per injection.