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Flow Injection Analysis of Urea Nitrogen in Soil Extracts
Author(s) -
Sullivan D. M.,
Havlin J. L.
Publication year - 1991
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/sssaj1991.03615995005500010019x
Subject(s) - reagent , flow injection analysis , chromatography , chemistry , urea , detection limit , absorbance , nitrogen , volumetric flow rate , soil test , sample (material) , analytical chemistry (journal) , soil water , environmental science , soil science , organic chemistry , physics , quantum mechanics
Flow injection analysis (FIA) is a relatively new technique with advantages over traditional automated analysis methods in precision and sample throughput. A new procedure has been developed to measure urea in soil extracts using automated FIA. This procedure utilizes the diacetyl monoxime thiosemicarbazide colorimetric method, with a modified acid reagent that increases the rate of color formation and improves the mixing of sample with reagent in narrow‐diameter (0.8‐mm) tubing. Sixty samples can be analyzed per hour, with a detection limit of 0.01 mg urea‐N L −1 . Residence time between sample injection and maximum absorbance is 130 s.