Interferences in the determination of total nitrogen in natural waters by photo-oxidation to nitrate-nitrite mixture

Investigation of the Ultraviolet Photolysis Method for the Determination of Organic Nitrogen in Aerosol Samples

“…Evidence supporting the decomposition to NH 4 ϩ of amino acids and amines can be found elsewhere. 6,23,42,44,45 Methylamine is the simplest amine of the aliphatic family, therefore, the authors decided to test mixtures of other amines commonly found in atmospheric samples. A mixture of 75.4 M-N of dimethylamine, 26.6 M-N of diethanolamine, and 97.8 M-N methylamine generated after UV photolysis Ͼ95% of NH 4 ϩ , following the same tendency as pure methylamine solutions.…”

“…23,25 To measure the extent of this conversion, the conversion efficiency () was defined as the molar ratio of the DON measured to the initial organic nitrogen concentration of the standards (DON standard ), as shown in eq 1:…”

“…The amount of organic nitrogen present in an aqueous sample was assumed to be the difference in the total concentration of the inorganic forms before and after sample irradiance. The UV photolysis method offers the advantages of minimal reagent use and sample handling, with potentially low blanks 9,[21][22][23] for analysis of preconversion and postconversion inorganic nitrogen by ion chromatography (IC). The purported disadvantages of this method are low recovery of organic nitrogen compounds from standard samples, losses in nitrogen that appear as negative DON concentrations, 22,24 and inconsistencies in the method performance as compared with other methods.…”