HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Nelson, D. W. Articles by Sommers, L. E. Search for Related Content PubMed Articles by Nelson, D. W. Articles by Sommers, L. E. Agricola Articles by Nelson, D. W. Articles by Sommers, L. E.

Determination of Total Nitrogen in Natural Waters¹

ABSTRACT

A simple, precise, and rapid method for estimating total N (to include nitrate and nitrite) in natural water is given. The proposed method involves evaporation of the water sample, pretreatment of the evaporated sample with reduced iron and H₂SO₄ to reduce nitrate to ammonium, and subsequent Kjeldahl digestion of the sample to recover organic N. Evaporation, pretreatment, and digestion of samples are accomplished in Folin-Wu nonprotein tubes. Ammonium in the digest is estimated by steam distillation and subsequent titration. Evaluation of the proposed method revealed that the recovery of nitrate N and organic N in samples was affected by the amount of reduced iron added (200 mg was satisfactory), by the brand of reduced iron used (several preparations were satisfactory), and by gently boiling the sample with reduced iron and H₂SO₄ prior to digestion. The proposed method was effective in recovering nitrate N and organic N from water solution over a wide range in concentration and the method was successful in recovering nitrate N and organic N added to filtered and unfiltered river and pond water samples. The precision of the proposed method was satisfactory for total N analysis of water samples, and the method appears adequate for estimation of total N in most water and waste water samples.

Key Words: Kjeldahl • steam distillation • nitrate • organic N • waste water

¹ Contribution of the Agricultural Experiment Station, Purdue University, West Lafayette, IN 47907. Purdue Journal Paper No. 5768.

² Associate Professor and Assistant Professor of Agronomy, respectively, Department of Agronomy.

Received for publication January 17, 1975.