In-field determination of soil ion content using a handheld device and screen-printed solid-state ion-selective electrodes
Name
journal.pone.0203862.pdf
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16.68 MB
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Checksum (MD5)
7e7c80c8b709105848678a4c4de84384
Author(s)
Rosenberg, Ron
Bono Jr, Michael S
Braganza, Soumya
Vaishnav, Chintan H.
Karnik, Rohit
Hart, Anastasios John
Date Issued
September 2018
Journal
PLOS ONE
Publisher
Public Library of Science
Citation
Rosenberg, Ron, Michael S. Bono, Soumya Braganza, Chintan Vaishnav, Rohit Karnik, and A. John Hart. “In-Field Determination of Soil Ion Content Using a Handheld Device and Screen-Printed Solid-State Ion-Selective Electrodes.” Edited by Virgilio Mattoli. PLOS ONE 13, no. 9 (September 25, 2018): e0203862.
Version
Final published version
Abstract
Small-holding farmers in the developing world suffer from sub-optimal crop yields because they lack a soil diagnostic system that is affordable, usable, and actionable. This paper details the fabrication and characterization of an integrated point-of-use soil-testing system, comprised of disposable ion-selective electrode strips and a handheld electrochemical reader. Together, the strips and reader transduce soil ion concentrations into to an alphanumeric output that can be communicated via text message to a central service provider offering immediate, customized fertilizer advisory. The solid-state ion-selective electrode (SSISE) strips employ a two-electrode design with screen-printable carbon nanotube ink serving as the electrical contacts for the working and reference electrodes. The working electrode comprises a plasticizer-free butyl acrylate ion-selective membrane (ISM), doped with an ion-selective ionophore and lipophilic salt. Meanwhile, the reference electrode includes a screen-printed silver-silver chloride ink and a polyvinyl-butyral membrane, which is doped with sodium chloride for stable reference potentials. As a proof of concept, potassium-selective electrodes are studied, given potassium's essential role in plant growth and reproduction. The ISE-based system is reproducibly manufactured to yield a Nernstian response with a sub-micromolar detection limit (pK+ of 5.18 ± 0.08) and near-Nernstian sensitivity (61 mV/decade) in the presence of a 0.02 M strontium chloride extraction solution. Analysis of soil samples using the printed electrodes and reader yielded a correlation coefficient of R2 = 0.89 with respect to values measured via inductively coupled plasma atomic emission spectroscopy (ICP-AES). The reliable performance of this system is encouraging toward its deployment for soil nutrient management in resource-limited environments.
MIT Department
Massachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Massachusetts Institute of Technology. Department of Mechanical Engineering
Massachusetts Institute of Technology. Department of Political Science
Massachusetts Institute of Technology. Institute for Data, Systems, and Society
Sloan School of Management
Terms of Use
Creative Commons Attribution 4.0 International License
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1371/journal.pone.0203862
