Nitrogen-phosphorus detection and nitrogen chemiluminescence detection of volatile nitrosamines in water matrices: optimization and performance comparison

Two nitrogen-specific detection methods, nitrogen-phosphorus detection (NPD) and nitrogen chemiluminescence detection (NCD), were investigated as low cost alternatives to mass spectrometry (MS) with chemical ionization (CI) for analysis of nitrosamines in aqueous samples. NCD showed greater sensitivity to N-nitrosodimethylamine (NDMA) and seven other volatile nitrosamines than did NPD. Instrument detection levels for NDMA were established at 2.6 microg/L and 4.0 microg/L in solvent with 3 microL splitless gas chromatograph (GC) injection for NCD and NPD, respectively. Using a dual-column confirmation method, both NCD and NPD compared favorably with CI-MS results for NDMA analysis in a variety of water sample types. For seven other nitrosamines, both detectors showed excellent accuracy in analyzing high concentrations (greater than 300 ng/L) in complex wastewater matrices, while the accuracy of spike recoveries of very low levels (less than 15 ng/L) in clean matrices varied for each nitrosamine and detection method.