Determination of N-nitrosodimethylamine in environmental aqueous samples by isotope-dilution GC/MS-SIM

An analytical method for the determination of N-nitrosodimethylamine (N-NDMA) in environmental aqueous samples has been developed using isotope dilution gas chromatography/mass spectrometry in the selected ion monitoring mode (GC/MS-SIM). After deuterated N-nitrosodimethylamine (d6-N-NDMA) as surrogate standard was added to the samples, the analytes were extracted with methylene chloride, dried with anhydrous sodium sulfate, and concentrated in a rotary evaporator. The concentrated extracts were analyzed by GC/MS-SIM after adding N-nitrosodiethylamine as an internal standard. The method detection limit for N-NDMA was 0.003 pg/microL and was validated by an analysis of a fortified water sample. The method was applied to real samples.