Nitrate and organic N analyses with second-derivative spectroscopy

Abstract

Simple and reliable procedures have been developed for analyses of NO3−, total N, and organic N in freshwaters. NO3− is determined by second-derivative UV spectroscopy. Total N and organic N are determined based on second-derivative analyses of NO3− following persulfate digestion. Resolution of organic N determinations was increased by using ion-exchange resins to remove NO3− from samples with high concentrations of NO3− prior to persulfate oxidation of the organic N.