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Devarda's Alloy Method for Total Nitrogen Determination
Author(s) -
Liao Christina F. H.
Publication year - 1981
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1981.03615995004500050005x
Subject(s) - kjeldahl method , nitrogen , chemistry , digestion (alchemy) , soil water , alloy , chromatography , analytical chemistry (journal) , mathematics , environmental science , organic chemistry , soil science
A modified semimicro‐Kjeldahl procedure for total nitrogen (N) determination to include No 3 ‐ ‐N, NO 2 ‐ ‐N, or both is described. The method involves use of Devarda's alloy as a reducing agent in the pretreatment procedure to convert NO 3 ‐ ‐N, or NO 2 ‐ ‐N, into NH 4 + ‐N in 6 N H 2 SO 4 with subsequent Kjeldahl digestion of the sample using a mixture of K 2 SO 4 − Se and concentrated H 2 SO 4 . The proposed method was effective in recovering NO 3 ‐ ‐N or low‐level NO 2 ‐ ‐N from water, soil, plant, and organic N compounds in total N determinations. The method gives essentially the same or slightly higher values for total N in a variety of soils when compared with other commonly used methods. The advantage of the proposed method is that it includes both NO 3 ‐ ‐N and low‐level NO 2 ‐ ‐N in one single pretreatment procedure and gives a smooth digestion during the subsequent Kjeldahl analysis.