Determination of Nitrate, Nitrite, and Phosphate at 214 NM by Reverse PhaseHPLC

Abstract

Nitrate and nitrite can be determined by reverse phase HPLC, using 1:1 methanol-water at pH 3.0 as the mobile phase and UV detection at 214 nm. Phosphate can be determined using 1:1:1 methanol-water-isopropyl alcohol at pH 3.0. At a flow rate of 1.0 mL/min, these anions elute within 5 min. A comparison of the mobile phases 1:1 methanol-water and Low UV PIC A reagent, indicates that 1:1 methanol-water yields 10 fold greater sensitivity to nitrate and 2 fold less to nitrite. The use of 1:1 methanol-water for the extraction of nitrate and nitrite from soil results in 19% higher recovery than in the case of water alone.