Pollution Control of Nitrate-selective Membrane by the Inner Solution and On-site Monitoring of Nitrate Concentration in Soil.

A liquid-membrane type nitrate-selective electrode was improved to lower the influence of contaminants by modifying its inner electrode system from Ag | AgCl | Cl to Ag | Ag. The NO-selective electrode displayed a linear response to the concentration of NO with a Nernstian slope of -53 ± 1 mV decade, in the concentration region between 10 and 2 mol dm (M). The NO detection limit was about 10 M. The electrochemical response of this electrode was stable for more than 30 days. The deterioration in responding characteristics due to the coexistence of Cl was suppressed by use of the Ag | Ag redox couple in the absence of Cl inside the NO-selective electrode.