Rapid Determination of Very Low Nitrogen Levels in Water

Abstract

THE importance of nitrogen in the various life cycles of interacting ecosystems has been well described^1–4. The pertinent concentration levels may be as low as 5 × 10⁻⁹ g kg⁻¹ in water³. Quick, accurate and nondestructive tests for the presence of these levels of nitrogen are of practical importance. We report here a new approach to ¹⁴N assay, associated with the evaporated detritus of less than 4 ml. of water. The present overall accuracy is about ±25% at concentrations greater than 200 × 10⁻⁹ g kg⁻¹; the test is sensitive down to levels of about 20 × 10⁻⁹ g kg⁻¹. These figures can be improved by relatively simple procedures. The testing time per sample is about 3 min and the sample is not destroyed by the test.