Continuous Monitoring of Soil Nitrate Using a Miniature Sensor with Poly(3-octyl-thiophene) and Molybdenum Disulfide Nanocomposite

• DOI: 10.1021/acsami.9b07120
• Publication Date: 2019-07-18T16:17:32Z
• Authors: Md. Azahar Ali; Xinran Wang; Yuncong Chen; Yueyi Jiao; Navreet K. Mahal; Satyanarayana Moru; Michael J. Castel...; James C. Schnable; Patrick S. Schnable; Liang Dong
• Keywords: Electrochemical gas sensor; Potentiometric sensor

There is an unmet need for improved fertilizer management in agriculture. Continuous monitoring of soil nitrate would address this need. This paper reports all-solid-state miniature potentiometric sensor that works direct contact with soils to monitor nitrate-nitrogen (NO3--N) solution parts-per-million (ppm) resolution. A working electrode formed from a novel nanocomposite poly(3-octyl-thiophene) and molybdenum disulfide (POT-MoS2) coated on patterned Au covered nitrate-selective membrane using robotic dispenser. The POT-MoS2 layer acts as ion-to-electron transducing high hydrophobicity redox properties. modification the POT chain MoS2 increases both conductivity anion exchange, while minimizing formation thin water at interface between ion-selective membrane, which notorious solid-state ion sensors. Therefore, use results sensitivity selectivity electrode. reference comprises screen-printed silver/silver chloride (Ag/AgCl) by protonated Nafion prevent (Cl-) leaching long-term measurements. was calibrated standard extracted solutions, exhibiting dynamic range includes all concentrations relevant agricultural applications (1-1500 ppm NO3--N). With nanocomposite, offers 64 mV/decade detection, compared 48 38 MoS2. embedded into slurries where it accurately monitored duration 27 days.