Identification of Nitrogenous Organic Compounds in Aquatic Sources by Stopped-Flow Spectral Scanning Technique

Abstract

The presence of nitrogenous organic compounds in raw water sources for municipal supplies is of environmental concern because many of them exert significant chlorine demand (1), while some produce complex stable mutagenic products upon chlorination (2, 3) or are precursors in haloform formation (1). To assist in assessing the importance of this problem high performance liquid chromatography (HPLC) was utilized to identify trace quantities of N-organic contaminants in concentrated samples of municipal water supplies of northeastern Massachusetts. Chromatographic resolution of complex mixtures was achieved on a reversed phase column (Zorbax C-8, DuPont Co.) using a 0.05 M phosphate buffer (pH = 6.9) or a 0.05 M borate buffer (pH = 8.9) to 50% methanol gradient. Constituents of concentrated samples were identified by the amount of time required for elution from the analytical column (retention position), and the positions of maximum and minimum U.V. absorbances, which were measured by stoppedflow spectral scanning of resolved chromatographic peaks. A fluorometric monitor utilizing fluorescamine and borate buffer revealed groups of primary amine compounds not detectable by U.V. spectroscopy.