Flow injection analysis of environmental samples for nitrate using an ion-selective electrode

Abstract

Based on the flow injection principle and employing a nitrate electrode situated in a flow-through cell, a simple, reliable and sensitive method for the automated determination of nitrate and its use for analysing soil extracts, waste waters, fertiliser solutions and air samples are described. At a sampling rate of 90 samples per hour a standard deviation of only 1–2% is typical. A new approach to identifying and correcting for the presence of interfering species in potentiometric measurements is discussed.