Agricultural and Biosystems Engineering Publications

Document Type

Article

Publication Date

2000

Journal or Book Title

Transactions of the ASAE

Volume

43

Issue

2

First Page

197

Last Page

206

Research Focus Area(s)

Advanced Machinery Engineering and Manufacturing Systems

DOI

10.13031/2013.2694

Abstract

Successful implementation of site-specific crop management relies on accurate quantification of spatial variation of important factors. Data collection on a finer spatial resolution than is feasible with manual and/or laboratory methods is often required but cost prohibitive. Therefore, there is a need for the development of sensors to more accurately characterize within-field variability. The objective of this research was to investigate matrix membranes produced from different combinations of ligand and plasticizer materials using ion-selective electrode (ISE) technology, and to use selected membranes to develop a nitrate ion-selective field effect transistor (ISFET) which might be integrated with a flow injection analysis (FIA) system for real-time soil analysis. Several ion-selective membranes were tested, and all of the evaluated membranes proved to be viable candidates for the development of a nitrate ISFET. Membranes using methyltridodecylammonium chloride (MTDA) as the ligand showed a better response to nitrates at low concentrations while those using tetradodecylammonium nitrate (TDDA) ligand showed superior selectivity for the nitrate ion. A multi- ISFET nitrate sensor was successfully developed. The electrical responses of the ISFETs were consistent and predictable. While significant difficulty was found in preparing a multi-ISFET chip with all four sensors operational, once prepared, the multi-ISFET chips were reliable and performed through extensive tests without failure. The sensitivities of the nitrate ISFETs (38-46 mV/decade) were lower than the theoretical Nernst sensitivity. The nitrate ISFETs proved to be viable sensors for the development of a real-time soil nitrate analysis system, under the conditions of our tests.

Comments

This article is from Transactions of the ASAE 43 (2000):197–206, doi:10.13031/2013.2694.

Rights

Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.

Language

en

File Format

application/pdf

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