title: Analysis of nitrosamines in aqueous and biological fluids based on measurement of photochemically liberated nitrite.
abstract: A method is described for the analysis of nitrosamines in aqueous solution and in biological fluids (blood, plasma, and rat liver microsomal suspensions). The method is based on photochemical degradation of the nitrosamine in a controlled environment to yield the corresponding amine and nitrite ion, and the latter is subsequently used to form a chromophoric or fluorescent product. The analysis scheme is a modular three-component system consisting of a column to remove contaminating nitrite prior to photolysis, a photochemical reactor, and a chemical reactor. Additional modules are used to accommodate biological samples or large-volume (5--50 ml) aqueous samples. In this study, N-nitrosopyrrolidine, N-nitrosodimethylamine, and N,N-diethanolnitrosamine were utilized as substrates. Because of intersubstrate variability in the photochemical decomposition rate and overall nitrite yield, the structure (i.e., photochemical behavior) of the particular nitrosamine in the sample must be known prior to analysis. With a colorimetric readout, the sensitivity for analysis of N-nitrosopyrrolidine was 800 ng/ml for a 5-ml sample and the measurement precision was +/- 6% in the biological fluids. Fluorometric analysis improved sensitivity to 4 ng/ml with a precision of +/- 10% in biological media.
mesh_terms: D000818:Animals; D001826:Body Fluids / Q000032:analysis; D006801:Humans; D007700:Kinetics; D008722:Methods; D009573:Nitrites / Q000032:analysis*; D009602:Nitrosamines / Q000032:analysis*; D010777:Photochemistry; D051381:Rats
chemical_list: D009573:Nitrites; D009602:Nitrosamines