Integrated Automatic Determination of Nitrate, Ammonium and Organic Carbon in Soil Samples

Abstract

An automated photometric method for the sequential determination of nitrate, ammonium and organic carbon in soils by use of a single-line flow injection assembly is reported, but differently programmed for the assay of the individual analytes. These analytes, which are determined by using suitable photometric reagents, are directly related to the nutritional properties of soil. A filtration probe was used for the continuous filtration of soil extract. The precision, expressed as RSD, was 2.0, 2.6 and 2.1% for nitrate, ammonium and organic carbon, respectively. The proposed method features a high throughput and low reagent consumption, and requires minimal sample handling. Its performance was tested in routine analyses of soil samples, all with satisfactory results.