A COMPARISON OF HPLC ANALYSIS OF NITRATE IN SOILS WITH THE PHENOLDISULFONIC ACID AND HYDRAZINE SULFATE METHODS

Abstract

Six Manitoba soils of varying physical and chemical compositions were used to determine the efficiency of nitrate analysis by high-performance liquid chromatography (HPLC). The nitrate was extracted with distilled water and the extract was analyzed with a reverse phase column using a mobile phase of 1:1 methanol-water, pH 3.0. In five soils, the HPLC method of nitrate analysis resulted in near 100% recovery of added nitrate. An average 90.2% recovery was obtained with the hydrazine sulfate method using sodium bicarbonate, pH 8.5, as the soil extractant. Variable recoveries were obtained with the phenoldisulfonic acid method using a silver sulfate-copper sulfate extractant. Key words: HPLC, nitrate analysis, soil