New Methods of Nitrite and Nitrate Analysis for Natural Waters.

摘要

Several aromatic orth-diamines were found to react with nitrite. After optimizing the conditions for these reactions two reagents were selected for method development,namely, 2,3-DAF (2,3-diaminofluorene) and DABSe, (the monopiazselenol of 3,3'-diaminobenzidine). The DABSe reagent was found to have high sensitivity when used with a DCE (1,2-dichlorethane) extraction but could not be used without extraction. A DCE extraction using 2,3-DAF was found to have the highest sensitivity of all the reagents evaluated and had the versatility of use without extraction. The Cd-Hg reduction column was used for nitrates reduction,with analysis with 2,3-DAF or DABSe. The DABSe and 2,3-DAF methods are adequate for nitrite and nitrate analysis. They are highly sensitive and the DAF-aqueous procedure is somewhat simpler than the sulfanilic acid method because of the need for only one reagent addition. The 2,3-DAF-aqueous procedure should not be used for water containing high levels of organic material. The potential for using these reagents in nitrate analysis is great if adequate reducing agents can be found.