Development of Analytical Methods for the Identification of Organic NitrogenChlorination By-Products in North Carolina Surface Waters

摘要

The goal of the research was to develop an analytical method for selectively andsensitively detecting N-chloramines in dilute aqueous systems. The organic N-chloramines comprise a class of chlorination by-products which is justifiably of concern since they interfere in measurements of free chlorine and monochloramine and because of their potentially deleterious environmental and human health effects. The method developed exploited the mild conditions of high-performance liquid chromatography (HPLC) and reductive amperometry for selective and sensitive detection of these relatively unstable oxidant compounds. Because large overpotentials were required for their direct amperometric detection, post-column reaction with iodide to produce iodine was employed. Using this technique, organic N-chloramines were measurable by direct injections. In addition, detector response was highly reproducible and could be calibrated over concentration ranges greater than three orders of magnitude with minimum error. This allowed quantitative measurement of oxidants separated by HPLC.