Identification and quantitation of N-nitrosamines in human postmortem organs.

Abstract

A gas-liquid chromatographic method for quantitative determination of six volatile N-nitrosamines in human postmortem organs (brain, liver, kidneys, and pancreas) is described. This method, which is highly sensitive and selective, makes use of two different detectors, i.e., the electron capture detector (ECD) and the thermal energy analyzer (TEA). The mean absolute percentage recoveries of N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosodipropylamine (NDPA), N-nitrosodibutylamine (NDBA), N-nitrosodipropylamine (NDPA, N-nitrosodibutylamine (NDBA), N-nitrosopiperidine (NPIP), and N-nitrosopyrrolidine (NPY) were 54.7, 80.0, 79.6, 72.5, 75.5, and 79.6, respectively. N-Nitrosamines in the organ extracts were converted to their corresponding N-nitramine analogs by pertrifluoroacetic acid oxidation. These derivatives were purified by adsorption chromatography on basic alumina and then analyzed by ECD. N-Nitrosamines were analyzed without derivatization in the organ extracts with the TEA detector. The described method did not cause artifactual formation of N-nitrosomethyl-N-butylamine (NMBA) when methyl-N-butylamine was used as an internal marker of nitrosation. NDMA was found in all the organs examined, whereas NDPA was only detected in the liver of one in four subjects. NDMA was found in all brain samples, indicating that it crosses the blood-brain barrier.