Analytical Sciences

Abstract − Analytical Sciences, 37(6), 887 (2021).

Pollution Control of Nitrate-selective Membrane by the Inner Solution and On-site Monitoring of Nitrate Concentration in Soil
Eisaku NAKAO, Yuki KITAZUMI, Kenji KANO, and Osamu SHIRAI
Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake, Sakyo, Kyoto 606-8502, Japan
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 NO3-selective electrode displayed a linear response to the concentration of NO3 with a Nernstian slope of –53 ± 1 mV decade−1, in the concentration region between 10−5 and 2 mol dm−3 (M). The NO3 detection limit was about 10−5 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 NO3-selective electrode.