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Freezing Low Volume Aqueous Solutions to Preserve Ammonia and Nitrate plus Nitrite
Author(s) -
Menchyk Nicholas,
Park Dara,
Moon Phillip H.,
Unruh J. Bryan,
Trenholm Laurie E.
Publication year - 2014
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2013.12.0807
Subject(s) - leachate , nitrate , nitrite , volume (thermodynamics) , ammonia , environmental chemistry , nitrogen , nitrous acid , chemistry , environmental science , biology , ecology , inorganic chemistry , biochemistry , physics , organic chemistry , quantum mechanics
Analysis of N and P in leachate is important in studying the fate of fertilizers after they are applied to turfgrass and landscape plants. Depending on environmental factors, in situ leachate samples collected from the field are often less than 20 mL. Due to the time and resource commitment of N and P analysis, it is desirable for many samples to be collected before analysis is conducted. In addition, past research has documented that acid preservation of low volume samples for N analysis can lead to inaccurate P measurements. Two experiments conducted in June 2007 and August 2008 compared ammonia‐nitrogen (NH 3 –N) and nitrite‐nitrogen plus nitrate‐nitrogen (NO 2 –N + NO 3 –N) concentrations within low volume samples preserved by freezing to other commonly used preservation techniques, including the accepted USEPA method. All preservation methods, including storage at less than −20°C, resulted in NH 3 and NO 2 + NO 3 concentrations similar to concentrations measured in immediately analyzed aliquots. Freezing low volume leachate water samples for later N analysis is an adequate method of preservation.